MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Developmental Biology' source. Thu, 09 Feb 2012 14:32:06 +0100 http://www.medworm.com/index.php?rid=5620803&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22261149%26dopt%3DAbstract Authors: Bentaya S, Ghogomu SM, Vanhomwegen J, Van Campenhout C, Thelie A, Dhainaut M, Bellefroid E, Souopgui J Abstract The maternal-zygotic transition (MZT) is an embryonic event that overlaps with and plays key roles in primary germ layer specification in vertebrates. During MZT, maternally supplied mRNAs are degraded while zygotic transcripts are synthesized to either reinforce the already specified cell fate or to trigger new cell identity. Here, we show that forced expression of the RNA-binding protein, XSeb4R, in animal pole blastomeres of Xenopus embryos, inappropriately stabilizes transcripts there, including maternal Sox3. This leads to the impaired ability of the ectodermal progenitors to respond to factors regulating brain patterning and their eventual loss by apoptosis... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5620803 Wed, 11 Jan 2012 05:00:00 +0100 5620803 http://www.medworm.com/index.php?rid=5620804&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22248825%26dopt%3DAbstract Authors: Andersen RO, Turnbull DW, Johnson EA, Doe CQ Abstract Drosophila neuroblasts are a model system for studying stem cell self-renewal and the establishment of cortical polarity. Larval neuroblasts generate a large apical self-renewing neuroblast, and a small basal cell that differentiates. We performed a genetic screen to identify regulators of neuroblast self-renewal, and identified a mutation in sgt1 (suppressor-of-G2-allele-of-skp1) that had fewer neuroblasts. We found that sgt1 neuroblasts have two polarity phenotypes: failure to establish apical cortical polarity at prophase, and lack of cortical Scribble localization throughout the cell cycle. Apical cortical polarity was partially restored at metaphase by a microtubule-induced cortical polarity pathway. Double mutants... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5620804 Tue, 10 Jan 2012 05:00:00 +0100 5620804 http://www.medworm.com/index.php?rid=5620802&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22261150%26dopt%3DAbstract Authors: Theveneau E, Mayor R Abstract After induction and specification in the ectoderm, at the border of the neural plate, the neural crest (NC) population leaves its original territory through a delamination process. Soon afterwards, the NC cells migrate throughout the embryo and colonize a myriad of tissues and organs where they settle and differentiate. The delamination involves a partial or complete epithelium-to-mesenchyme transition (EMT) regulated by a complex network of transcription factors including several proto-oncogenes. Studying the relationship between these genes at the time of emigration, and their individual or collective impact on cell behavior, provides valuable information about their role in EMT in other contexts such as cancer metastasis. During migration, ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5620802 Mon, 09 Jan 2012 05:00:00 +0100 5620802 http://www.medworm.com/index.php?rid=5599023&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245052%26dopt%3DAbstract Authors: Evans TA, Bashaw GJ Abstract As the complexity of animal nervous systems has increased during evolution, developmental control of neuronal connectivity has become increasingly refined. How has functional diversification within related axon guidance molecules contributed to the evolution of nervous systems? To address this question, we explore the evolution of functional diversity within the Roundabout (Robo) family of axon guidance receptors. In Drosophila, Robo and Robo2 promote midline repulsion, while Robo2 and Robo3 specify the position of longitudinal axon pathways. The Robo family has expanded by gene duplication in insects; robo2 and robo3 exist as distinct genes only within dipterans, while other insects, like the flour beetle Tribolium castaneum, retain an ancestr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599023 Sun, 08 Jan 2012 05:00:00 +0100 5599023 http://www.medworm.com/index.php?rid=5599026&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22236962%26dopt%3DAbstract In this study we provide in vivo and in vitro evidence that Robo-Slit signaling guides trigeminal nerves during cornea innervation. Transient, localized inhibition of Robo-Slit signaling, by means of beads loaded with inhibitory Robo-Fc protein implanted into the developing eyefield in vivo, led to disorganized nerve ring formation and premature cornea innervation. Additionally, when trigeminal explants (source of neurons) were oriented adjacent to lens vesicles or corneas (source of repellant molecules) in organotypic tissue culture both lens and cornea tissues strongly repelled E7 trigeminal neurites, except in the presence of inhibitory Robo-Fc protein. In contrast, E10 trigeminal neurites were not as strongly repelled by cornea, and presence of Robo-Slit inhibitory protein had no effec... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599026 Tue, 03 Jan 2012 05:00:00 +0100 5599026 http://www.medworm.com/index.php?rid=5599025&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22240097%26dopt%3DAbstract In this study, we generated two genomic truncations to delete three elements that were previously shown to bind to the Meis/Prep family homeoproteins. One 3.1kb deletion (Pax6(∆DP/∆DP)) removed two putative pancreatic enhancers and a previously identified ectodermal enhancer, while a 450bp sub-deletion (Pax6(∆PE/∆PE)) eliminated only the promoter-proximal pancreatic enhancer. Immunohistochemistry and quantitative RT-PCR showed that the Pax6(∆PE/∆PE) pancreata had a significant decrease in Pax6, glucagon, and insulin expression, while no further reductions were observed in the Pax6(∆DP/∆DP) mice, indicating that only the 450bp region is required for pancreatic development. In contrast, Pax6(∆DP/∆DP), but not Pax6(∆PE/∆PE) mice, developed stunted lacrimal gland and le... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599025 Tue, 03 Jan 2012 05:00:00 +0100 5599025 http://www.medworm.com/index.php?rid=5599024&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22240098%26dopt%3DAbstract Authors: Wong YL, Behringer RR, Kwan KM Abstract Bone morphogenetic proteins (BMPs) are secreted signals that regulate apical ectodermal ridge (AER) functions and interdigital programmed cell death (PCD) of developing limb. However the identities of the intracellular mediators of these signals are unknown. To investigate the role of Smad proteins in BMP-regulated AER functions in limb development, we inactivated Smad1 and Smad5 selectively in AER and ventral ectoderm of developing limb, using Smad1 or/and Smad5 floxed alleles and an En1(Cre/+) knock-in allele. Single inactivation of either Smad1 or Smad5 did not result in limb abnormalities. However, the Smad1/Smad5 double mutants exhibited syndactyly due to a reduction in interdigital PCD and an increase in interdigital cell proli... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599024 Tue, 03 Jan 2012 05:00:00 +0100 5599024 http://www.medworm.com/index.php?rid=5599029&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22230616%26dopt%3DAbstract Authors: White PM, Stone JS, Groves AK, Segil N Abstract Proliferation and transdifferentiaton of supporting cells in the damaged auditory organ of birds lead to robust regeneration of sensory hair cells. In contrast, regeneration of lost auditory hair cells does not occur in deafened mammals, resulting in permanent hearing loss. In spite of this failure of regeneration in mammals, we have previously shown that the perinatal mouse supporting cells harbor a latent potential for cell division. Here we show that in a subset of supporting cells marked by p75, EGFR signaling is required for proliferation, and this requirement is conserved between birds and mammals. Purified p75+ mouse supporting cells express receptors and ligands for the EGF signaling pathway, and their proliferation i... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599029 Mon, 02 Jan 2012 05:00:00 +0100 5599029 http://www.medworm.com/index.php?rid=5599028&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22230617%26dopt%3DAbstract Authors: Bronner ME, Ledouarin NM PMID: 22230617 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599028 Mon, 02 Jan 2012 05:00:00 +0100 5599028 http://www.medworm.com/index.php?rid=5599031&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22230614%26dopt%3DAbstract This study shows that the LECs play a more active role in morphogenesis than previously thought, with their migrations contributing to abdominal closure. It furthermore provides insights into how the migratory behaviour of cells is regulated during morphogenesis. PMID: 22230614 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599031 Thu, 29 Dec 2011 05:00:00 +0100 5599031 http://www.medworm.com/index.php?rid=5599030&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22230615%26dopt%3DAbstract Authors: François M, Short K, Secker GA, Combes A, Schwarz Q, Davidson TL, Smyth I, Hong YK, Harvey NL, Koopman P Abstract During lymphangiogenesis in the mammalian embryo, a subset of vascular endothelial cells in the cardinal veins is reprogrammed to adopt a lymphatic endothelial fate. The prevailing model of lymphangiogenesis contends that these lymphatic precursor cells migrate away from the cardinal veins and reassemble peripherally as lymph sacs from which a lymphatic vasculature is generated. However, this model fails to account for a number of observations that, as a result, have remained anecdotal. Here, we use optical projection tomography, confocal microscopy and in vivo live imaging to uncover three key stages of lymphatic vascular morphogenesis in the mouse embryo at ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599030 Thu, 29 Dec 2011 05:00:00 +0100 5599030 http://www.medworm.com/index.php?rid=5599027&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22233545%26dopt%3DAbstract In this study we find that the winged helix transcription factor Rfx2 is expressed in motile cilia in mouse and zebrafish embryos. Morpholino knockdown of Rfx2 function in the whole embryo or specifically in cells of the zebrafish COA (Kupffer's Vesicle, KV) leads to reduced KV cilia length and perturbations in LR asymmetry. LR patterning defects include randomization of the early asymmetric Nodal signaling pathway genes southpaw, lefty1 and lefty2 and subsequent reversals in the organ primordia of the heart and gut. Rfx2 is also required for ciliogenesis in zebrafish pronephric duct. We further show that by restoring Left-Right dynein (LRD) expression and motility specifically in a subset of ciliated cells of the mouse COA (posterior notochord, PNC), we can restore fluid flow, asymmetric ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5599027 Thu, 29 Dec 2011 05:00:00 +0100 5599027 http://www.medworm.com/index.php?rid=5577975&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22226977%26dopt%3DAbstract Authors: Chakraborty S, Yutzey KE Abstract TBX20 gain-of-function mutations in humans are associated with congenital heart malformations and myocardial defects. However the effects of increased Tbx20 function during cardiac chamber development and maturation have not been reported previously. CAG-CAT-Tbx20 transgenic mice were generated for Cre-dependent induction of Tbx20 in myocardial lineages in the developing heart. βMHCCre-mediated overexpression of Tbx20 in fetal ventricular cardiomyocytes results in increased thickness of compact myocardium, induction of cardiomyocyte proliferation, and increased expression of Bmp10 and pSmad1/5/8 at embryonic day (E) 14.5. βMHCCre-mediated Tbx20 overexpression also leads to increased expression of cardiac conduction system (CCS) genes Tbx... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577975 Thu, 29 Dec 2011 05:00:00 +0100 5577975 http://www.medworm.com/index.php?rid=5577971&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22227339%26dopt%3DAbstract Authors: Chung MI, Peyrot SM, Leboeuf S, Park TJ, McGary KL, Marcotte EM, Wallingford JB Abstract In Caenorhabditis elegans, the RFX (Daf19) transcription factor is a major regulator of ciliogenesis, controlling the expression of the many essential genes required for making cilia. In vertebrates, however, seven RFX genes have been identified. Bioinformatic analysis suggests that Rfx2 is the closest homologue of the Daf19. We therefore hypothesize that Rfx2 broadly controls ciliogenesis during vertebrate development. Indeed, here we show that Rfx2 in Xenopus is expressed preferentially in ciliated tissues, including neural tube, gastrocoel roof plate, epidermal multi-ciliated cells, otic vesicles, and kidneys. Knockdown of Rfx2 results in cilia-defective embryonic phenotypes and few... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577971 Thu, 29 Dec 2011 05:00:00 +0100 5577971 http://www.medworm.com/index.php?rid=5577970&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22227340%26dopt%3DAbstract Authors: Wei S, Xu G, Bridges LC, Williams P, Nakayama T, Shah A, Grainger RM, White JM, Desimone DW Abstract Pericellular proteolysis by ADAM family metalloproteinases has been widely implicated in cell signaling and development. We recently found that Xenopus ADAM13, an ADAM metalloproteinase, is required for activation of canonical Wnt signaling during cranial neural crest (CNC) induction by regulating a novel crosstalk between Wnt and ephrin B (EfnB) signaling pathways (Wei et al., 2010b). In the present study we show that the metalloproteinase activity of ADAM13 also plays important roles in eye development in Xenopus tropicalis. Knockdown of ADAM13 results in reduced expression of eye field markers pax6 and rx1, as well as that of the pan-neural marker sox2. Activation of can... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577970 Wed, 28 Dec 2011 05:00:00 +0100 5577970 http://www.medworm.com/index.php?rid=5577972&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22227295%26dopt%3DAbstract Authors: Frances D, Niemann C Abstract The hair follicle (HF) and the sebaceous gland (SG) constitute the two integral parts of the pilosebaceous unit and significantly contribute to the barrier function of mammalian skin. Considerable progress has been made in our understanding how HF formation is regulated. However, the development of the SG is poorly understood, both at the molecular and cellular level. Here, we investigate the process of SG morphogenesis and the dynamics of its cellular organisation in more detail. The spatial and temporal organisation of distinct stem and progenitor compartments was analysed during morphogenesis of the pilosebaceous unit in mouse tail epidermis. Our experiments reveal a dynamic expression pattern for diverse HF stem cell marker molecules inclu... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577972 Tue, 27 Dec 2011 05:00:00 +0100 5577972 http://www.medworm.com/index.php?rid=5577973&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22226979%26dopt%3DAbstract This study demonstrates that hypoxia-inducible factor 1 alpha subunit (HIF-1α), a key transcription factor involved in cellular responses to hypoxia, is most abundantly expressed in the neuroretina, especially retinal progenitor cells (RPCs). A neuroretina-specific knockout of HIF-1α (αCre(+)Hif1α(flox/flox)) showed impaired vascular development characterized by decreased tip cell filopodia and reduced vessel branching. The astrocyte network was hypoplastic in αCre(+)Hif1α(flox/flox) mice. Mechanistically, platelet-derived growth factor A (PDGF-A), a mitogen for astrocytes, was downregulated in the neuroretina of αCre(+)Hif1α(flox/flox) mice. Supplementing PDGF-A restored reduced astrocytic and vascular density in αCre(+)Hif1α(flox/flox) mice. Our data demonstrates that the neuro... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577973 Sat, 24 Dec 2011 05:00:00 +0100 5577973 http://www.medworm.com/index.php?rid=5577976&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222761%26dopt%3DAbstract Authors: Schaub M, Nussbaum J, Verkade H, Ober EA, Stainier DY, Sakaguchi TF Abstract Biliary epithelial cells line the intrahepatic biliary network, a complex three-dimensional network of conduits. The loss of differentiated biliary epithelial cells is the primary cause of many congenital liver diseases. We identified a zebrafish snapc4 (small nuclear RNA-activating complex polypeptide 4) mutant in which biliary epithelial cells initially differentiate but subsequently disappear. In these snapc4 mutant larvae, the biliary epithelial cells undergo apoptosis, leading to the degeneration of the intrahepatic biliary network. Consequently, in snapc4 mutant larvae, biliary transport of ingested fluorescent lipids to the gallbladder is blocked. Snapc4 is the largest subunit of the protei... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577976 Fri, 23 Dec 2011 05:00:00 +0100 5577976 http://www.medworm.com/index.php?rid=5577981&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206757%26dopt%3DAbstract Authors: Liu J, Zeng L, Kennedy RM, Gruenig NM, Childs SJ Abstract The growth of new blood vessels by angiogenesis and their stabilization by the recruitment of perivascular mural cells are thought to be two sequential, yet independent events. Here we identify molecular links between both processes through the βPix and integrin α(v)β(8) proteins. Bubblehead (bbh) mutants with a genetic mutation in βPix show defective vascular stabilization. βPix is a guanine nucleotide exchange factor and scaffold protein that binds many proteins including Git1, which bridges βPix to integrins at focal adhesions. Here we show that the ability of βPix to stabilize vessels requires Git1 binding residues. Knockdown of Git1 leads to a hemorrhage phenotype similar to loss of integrin α(v), integ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577981 Thu, 22 Dec 2011 05:00:00 +0100 5577981 http://www.medworm.com/index.php?rid=5577978&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22210002%26dopt%3DAbstract Authors: Yaguchi J, Angerer LM, Inaba K, Yaguchi S Abstract Serotonergic neurons differentiate in the neurogenic animal plate ectoderm of the sea urchin embryo. The regulatory mechanisms that control the specification or differentiation of these neurons in the sea urchin embryo are not yet understood, although, after the genome was sequenced, many genes encoding transcription factors expressed in this region were identified. Here, we report that zinc finger homeobox (zfhx1/z81) is expressed in serotonergic neural precursor cells, using double in situ hybridization screening with a serotonergic neural marker, tryptophan 5-hydroxylase (tph) encoding a serotonin synthase that is required for the differentiation of serotonergic neurons. zfhx1/z81 begins to be expressed at gastrula stag... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577978 Thu, 22 Dec 2011 05:00:00 +0100 5577978 http://www.medworm.com/index.php?rid=5577977&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22210003%26dopt%3DAbstract Authors: Shen YC, Thompson DL, Kuah MK, Wong KL, Wu KL, Linn SA, Jewett EM, Shu-Chien AC, Barald KF Abstract Macrophage migration inhibitory factor (MIF) plays versatile roles in the immune system. MIF is also widely expressed during embryonic development, particularly in the nervous system, although its roles in neural development are only beginning to be understood. Evidence from frogs, mice and zebrafish suggests that MIF has a major role as a neurotrophin in the early development of sensory systems, including the auditory system. Here we show that the zebrafish mif pathway is required for both sensory hair cell (HC) and sensory neuronal cell survival in the ear, for HC differentiation, semicircular canal formation, statoacoustic ganglion (SAG) development, and lateral line HC d... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577977 Thu, 22 Dec 2011 05:00:00 +0100 5577977 http://www.medworm.com/index.php?rid=5577982&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22202776%26dopt%3DAbstract Authors: Katsu K, Tokumori D, Tatsumi N, Suzuki A, Yokouchi Y Abstract During left-right (L-R) axis formation, Nodal is expressed in the node and has a central role in the transfer of L-R information in the vertebrate embryo. Bone morphogenetic protein (BMP) signaling also has an important role for maintenance of gene expression around the node. Several members of the Cerberus/Dan family act on L-R patterning by regulating activity of the transforming growth factor-β (TGF-β) family. We demonstrate here that chicken Dan plays a critical role in L-R axis formation. Chicken Dan is expressed in the left side of the node shortly after left-handed Shh expression and before the appearance of asymmetrically expressed genes in the lateral plate mesoderm (LPM). In vitro experiments reveale... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577982 Tue, 20 Dec 2011 05:00:00 +0100 5577982 http://www.medworm.com/index.php?rid=5577980&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206758%26dopt%3DAbstract This study investigates the specific requirement for Sin3a in the early mouse embryo, and shows that embryos lacking Sin3a suffer unresolved DNA damage and acute p53-independent apoptosis specifically in the E3.5-4.5 epiblast. Surprisingly, Myc and E2F targets in Sin3a-null ICMs are downregulated, suggesting a central but non-canonical role for Sin3a in the regulation of the pluripotent embryonic cell cycle. ES cells deleted for Sin3a mount a DNA damage response indicative of unresolved double-strand breaks, profoundly arrest at G2, and undergo apoptosis. These results indicate that Sin3a protects the genomic integrity of pluripotent embryonic cells, and governs their unusual cell cycle. PMID: 22206758 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577980 Tue, 20 Dec 2011 05:00:00 +0100 5577980 http://www.medworm.com/index.php?rid=5577979&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206759%26dopt%3DAbstract Authors: Sachdev M, Mandal A, Mulders S, Digilio LC, Panneerdoss S, Suryavathi V, Pires E, Klotz KL, Hermens L, Herrero MB, Flickinger CJ, van Duin M, Herr JC Abstract Molecular mechanisms by which fertilization competent acrosome-reacted sperm bind to the oolemma remain uncharacterized. To identify oolemmal binding partner(s) for sperm acrosomal ligands, affinity panning was performed with mouse oocyte lysates using sperm acrosomal protein, SLLP1 as a target. An oocyte specific membrane metalloproteinase, SAS1B (Sperm Acrosomal SLLP1 Binding), was identified as a SLLP1 binding partner. cDNA cloning revealed six SAS1B splice variants, each containing a zinc binding active site and a putative transmembrane domain, with signal peptides in three variants. SAS1B transcripts were ovary ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577979 Tue, 20 Dec 2011 05:00:00 +0100 5577979 http://www.medworm.com/index.php?rid=5577974&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22226978%26dopt%3DAbstract This study aims to clarify the functional significance of class I GLUT during murine tooth development using immunohistochemistry and an in vitro organ culture experiment with an inhibitor of GLUTs1/2, phloretin, and Glut1 and Glut2 short interfering RNA (siRNA). An intense GLUT1-immunoreaction was localized in the enamel organ of bud-stage molar tooth germs, where the active cell proliferation occurred. By the bell stage, the expression of GLUT1 in the dental epithelium was dramatically decreased in intensity, and subsequently began to appear in the stratum intermedium at the late bell stage. On the other hand, GLUT2-immunoreactivity was weakly observed in the whole tooth germs throughout all stages. The inhibition of GLUTs1/2 by phloretin in the bud-stage tooth germs induced the disturba... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5577974 Tue, 20 Dec 2011 05:00:00 +0100 5577974 http://www.medworm.com/index.php?rid=5548878&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200594%26dopt%3DAbstract Authors: Enriquez J, de Taffin M, Crozatier M, Vincent A, Dubois L Abstract The diversity of Drosophila muscles correlates with the expression of combinations of identity transcription factors (iTFs) in muscle progenitors. Here, we address the question of when and how a combinatorial code is translated into muscle specific properties, by studying the roles of the Collier and Nautilus iTFs that are expressed in partly overlapping subsets of muscle progenitors. We show that the three dorso-lateral (DL) progenitors which express Nautilus and Collier are specified in a fixed temporal sequence and that each expresses additionally other, distinct iTFs. Removal of Collier leads to changes in expression of some of these iTFs and mis-orientation of several DL muscles, including the dorsal a... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5548878 Tue, 20 Dec 2011 05:00:00 +0100 5548878 http://www.medworm.com/index.php?rid=5548880&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200592%26dopt%3DAbstract Authors: Sarikaya DP, Belay AA, Ahuja A, Dorta A, Green DA, Extavour CG Abstract All insect ovaries are composed of functional units called ovarioles, which contain sequentially developing egg chambers. The number of ovarioles varies between and within species. Ovariole number is an important determinant of fecundity and thus affects individual fitness. Although Drosophila oogenesis has been intensively studied, the genetic and cellular basis for determination of ovariole number remains unknown. Ovariole formation begins during larval development with the morphogenesis of terminal filament cells (TFCs) into stacks called terminal filaments (TFs). We induced changes in ovariole number in Drosophila melanogaster by genetically altering cell size and cell number in the TFC population,... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5548880 Mon, 19 Dec 2011 05:00:00 +0100 5548880 http://www.medworm.com/index.php?rid=5548879&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200593%26dopt%3DAbstract Authors: Sabado V, Barraud P, Baker CV, Streit A Abstract A small population of neuroendocrine cells in the rostral hypothalamus and basal forebrain is the key regulator of vertebrate reproduction. They secrete gonadotropin-releasing hormone (GnRH-1), communicate with many areas of the brain and integrate multiple inputs to control gonad maturation, puberty and sexual behavior. In humans, disruption of the GnRH-1 system leads to hypogonadotropic gonadism and Kallmann syndrome. Unlike other neurons in the central nervous system, GnRH-1 neurons arise in the periphery, however their embryonic origin is controversial, and the molecular mechanisms that control their initial specification are not clear. Here, we provide evidence that in chick GnRH-1 neurons originate in the olfactory pla... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5548879 Mon, 19 Dec 2011 05:00:00 +0100 5548879 http://www.medworm.com/index.php?rid=5548881&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197835%26dopt%3DAbstract Authors: Lucas ME PMID: 22197835 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5548881 Wed, 14 Dec 2011 05:00:00 +0100 5548881 http://www.medworm.com/index.php?rid=5548882&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22192888%26dopt%3DAbstract Authors: Lin YF, Swinburne I, Yelon D Abstract Cardiomyocyte hypertrophy is a complex cellular behavior involving coordination of cell size expansion and myofibril content increase. Here, we investigate the contribution of cardiomyocyte hypertrophy to cardiac chamber emergence, the process during which the primitive heart tube transforms into morphologically distinct chambers and increases its contractile strength. Focusing on the emergence of the zebrafish ventricle, we observed trends toward increased cell surface area and myofibril content. To examine the extent to which these trends reflect coordinated hypertrophy of individual ventricular cardiomyocytes, we developed a method for tracking cell surface area changes and myofibril dynamics in live embryos. Our data reveal a previ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5548882 Tue, 13 Dec 2011 05:00:00 +0100 5548882 http://www.medworm.com/index.php?rid=5533496&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182522%26dopt%3DAbstract Authors: Langenbacher AD, Huang J, Chen Y, Chen JN Abstract Na(+),K(+) ATPase pumps Na(+) out of and K(+) into the cytosol, maintaining a resting potential that is essential for the function of excitable tissues like cardiac muscle. In addition to its well-characterized physiological role in the heart, Na(+),K(+) ATPase also regulates the morphogenesis of the embryonic zebrafish heart via an as yet unknown mechanism. Here, we describe a novel non-cell autonomous function of Na(+),K(+) ATPase/Atp1a1 in the elongation of the zebrafish heart tube. Embryos lacking Atp1a1 function exhibit abnormal migration behavior of cardiac precursors, defects in the elongation of the heart tube, and a severe reduction in ECM/Fibronectin deposition around the myocardium, despite the presence of norma... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533496 Tue, 13 Dec 2011 05:00:00 +0100 5533496 http://www.medworm.com/index.php?rid=5533493&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185794%26dopt%3DAbstract We report that brush cell numbers increase dramatically following conditional Atoh1-deletion, demonstrating that brush cell production, determination, differentiation and survival are Atoh1-independent. We also report that brush cells are derived from Gfi1b-expressing progenitors. These and related results suggest a model in which initially equivalent DOM progenitors have three metastable states defined by the transcription factors Hes1, Atoh1, and Gfi1b. Lateral inhibitory Notch signaling normally ensures that Hes1 dominates in one of the two DOMs, invoking a columnar lineage program, while either Atoh1 or Gfi1b dominates in the other DOM, invoking a granulocytic or brush cell lineage program, respectively, and thus implementing a cell fate-determining ternary switch. PMID: 22185794 [... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533493 Tue, 13 Dec 2011 05:00:00 +0100 5533493 http://www.medworm.com/index.php?rid=5533492&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185795%26dopt%3DAbstract Authors: Rebeiz M, Castro B, Liu F, Yue F, Posakony JW Abstract Among developmental control genes, transcription factor-target gene "linkages" - the direct connections between target genes and the factors that control their patterns of expression - can show remarkable evolutionary stability. However, the specific binding sites that mediate and define these regulatory connections are themselves often subject to rapid turnover. Here we describe several instances in which particular transcription factor binding motif combinations have evidently been conserved upstream of orthologous target genes for extraordinarily long evolutionary periods. This occurs against a backdrop in which other binding sites for the same factors are coming and going rapidly. Our examples include a particular ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533492 Tue, 13 Dec 2011 05:00:00 +0100 5533492 http://www.medworm.com/index.php?rid=5533499&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182519%26dopt%3DAbstract Authors: Liu J, Heydeck W, Zeng H, Liu A Abstract The morphogen Sonic hedgehog, one of the Hedgehog (Hh) family of secreted proteins, plays a key role in patterning the mammalian spinal cord along its dorsoventral (D/V) axis through the activation of Glioma-associated oncogene (Gli) family of transcription factors. Suppressor of Fused (Sufu), a Gli-interacting protein, modulates the D/V patterning of the spinal cord by antagonizing Hh signaling. The molecular mechanisms underlying the function of Sufu in Hh pathway activation and spinal cord D/V patterning remain controversial, particularly in light of recent findings that Sufu protects Gli2 and Gli3 proteins from proteasomal degradation. In the current study, we show that Hh pathway activation and dorsal expansion of ventral spina... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533499 Sun, 11 Dec 2011 05:00:00 +0100 5533499 http://www.medworm.com/index.php?rid=5533498&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182520%26dopt%3DAbstract Authors: Stepanik VA, Harte PJ Abstract Drosophila Polycomb Repressive Complex 2 (PRC2) is a lysine methyltransferase that trimethylates histone H3 lysine 27 (H3K27me3), a modification essential for Polycomb silencing. Mutations in its catalytic subunit, E(Z), that abolish its methyltransferase activity disrupt Polycomb silencing, causing derepression of Polycomb target genes in cells where they are normally silenced. In contrast, the unusual E(z) mutant allele Trithorax mimic (E(z)(Trm)) causes dominant homeotic phenotypes similar to those caused by mutations in trithorax (trx), an antagonist of Polycomb silencing. This suggests that E(z)(Trm) causes inappropriate silencing of Polycomb target genes in cells where they are normally active. Here we show that E(z)(Trm) mutants have a... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533498 Sun, 11 Dec 2011 05:00:00 +0100 5533498 http://www.medworm.com/index.php?rid=5533497&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182521%26dopt%3DAbstract In this study, we sought to use the zebrafish model system to examine for the first time the role of ccm3 in cranial vessel development. We report that inhibition of zebrafish ccm3a/b causes heart and circulation defects distinct from those seen in ccm1 (santa) and ccm2 (valentine) mutants, and leads to a striking dilation and mispatterning of cranial vessels reminiscent of the human disease pathology. ccm3, but not ccm2, defects can be rescued upon overexpression of stk25b, a GCKIII kinase previously shown to interact with CCM3. Morpholino knockdown of the GCKIII gene stk25b results in heart and vasculature defects similar to those seen in ccm3 morphants. Finally, additional loss of ccm3 in ccm2 mutants leads to a synergistic increase in cranial vessel dilation. These results support a mo... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533497 Sun, 11 Dec 2011 05:00:00 +0100 5533497 http://www.medworm.com/index.php?rid=5533495&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182523%26dopt%3DAbstract Authors: Grimsley-Myers CM, Sipe CW, Wu DK, Lu X Abstract Development of the mammalian inner ear requires coordination of cell proliferation, cell fate determination and morphogenetic movements. While significant progress has been made in identifying developmental signals required for inner ear formation, less is known about how distinct signals are coordinated by their downstream mediators. Members of the Rac family of small GTPases are known regulators of cytoskeletal remodeling and numerous other cellular processes. However, the function of Rac GTPases in otic development is largely unexplored. Here, we show that Rac1 and Rac3 redundantly regulate many aspects of inner ear morphogenesis. While no morphological defects were observed in Rac3(-/-) mice, Rac1(CKO); Rac3(-/-) double ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533495 Sun, 11 Dec 2011 05:00:00 +0100 5533495 http://www.medworm.com/index.php?rid=5533494&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22185793%26dopt%3DAbstract Authors: Balczerski B, Matsutani M, Castillo P, Osborne N, Stainier DY, Crump JG Abstract Development of the head skeleton involves reciprocal interactions between cranial neural crest cells (CNCCs) and the surrounding pharyngeal endoderm and ectoderm. Whereas elegant experiments in avians have shown a prominent role for the endoderm in facial skeleton development, the relative functions of the endoderm in growth versus regional identity of skeletal precursors have remained unclear. Here we describe novel craniofacial defects in zebrafish harboring mutations in the Sphingosine-1-phospate (S1P) type 2 receptor (s1pr2) or the S1P transporter Spinster 2 (spns2), and we show that S1P signaling functions in the endoderm for the proper growth and positioning of the jaw skeleton. Surprisi... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533494 Sun, 11 Dec 2011 05:00:00 +0100 5533494 http://www.medworm.com/index.php?rid=5533500&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178246%26dopt%3DAbstract Authors: Fujioka M, Jaynes JB Abstract In order to investigate regulation and redundancy within the sloppy paired (slp) locus, we analyzed 30 kilobases of DNA encompassing the tandem, coordinately regulated slp1 and slp2 transcription units. We found a remarkable array of stripe enhancers with overlapping activities surrounding the slp1 transcription unit, and, unexpectedly, glial cell enhancers surrounding slp2. The slp stripe regulatory region generates 7 stripes at blastoderm, and later 14 stripes that persist throughout embryogenesis. Phylogenetic analysis among drosophilids suggests that the multiplicity of stripe enhancers did not evolve through recent duplication. Most of the direct integration among cis-regulatory modules appears to be simply additive, with one notable exce... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533500 Fri, 09 Dec 2011 05:00:00 +0100 5533500 http://www.medworm.com/index.php?rid=5533503&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178152%26dopt%3DAbstract Authors: Eckalbar WL, Lasku E, Infante CR, Elsey RM, Markov GJ, Allen AN, Corneveaux JJ, Losos JB, Denardo DF, Huentelman MJ, Wilson-Rawls J, Rawls A, Kusumi K Abstract The axial skeleton is a defining feature of vertebrates and is patterned during somitogenesis. Cyclically expressed members of the notch and other signaling pathways, described as the 'segmentation clock', regulate the formation of somite boundaries. Comparisons among vertebrate model systems have revealed fundamental shifts in the regulation of expression among critical genes in the notch pathway. However, insights into the evolution of these expression differences have been limited by the lack of information from non-avian reptiles. We analyzed the segmentation clock of the first Lepidosaurian reptile sequenced, t... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533503 Thu, 08 Dec 2011 05:00:00 +0100 5533503 http://www.medworm.com/index.php?rid=5533502&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178153%26dopt%3DAbstract Authors: Loebel DA, Hor AC, Bildsoe H, Jones V, Chen YT, Behringer RR, Tam PP Abstract Development of the mouse forelimb bud depends on normal Twist1 activity. Global loss of Twist1 function before limb bud formation stops limb development and loss of Twist1 throughout the mesenchyme after limb bud initiation leads to polydactyly, the ulnarization or loss of the radius and malformations and reductions of the shoulder girdle. Here we show that conditional deletion of Twist1 by Mesp1-Cre in the mesoderm that migrates into the anterior-proximal part of the forelimb bud results in the development of supernumerary digits and carpals, the acquisition of ulna-like characteristics by the radius and malformations of the humerus and scapula. The mirror-like duplications and posteriorization ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533502 Thu, 08 Dec 2011 05:00:00 +0100 5533502 http://www.medworm.com/index.php?rid=5533501&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178154%26dopt%3DAbstract In conclusion, our results demonstrate that PLD-dependent actin polymerization is a critical step needed for the development of HAM during mouse and human sperm capacitation. PMID: 22178154 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5533501 Thu, 08 Dec 2011 05:00:00 +0100 5533501 http://www.medworm.com/index.php?rid=5512684&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22166339%26dopt%3DAbstract Authors: Noda T, Oki S, Kitajima K, Harada T, Komune S, Meno C Abstract The mouse inner ear develops from a simple epithelial pouch, the otocyst, with the dorsal and ventral portions giving rise to the vestibule and cochlea, respectively. The otocyst undergoes a morphological change to generate flattened saclike structures, known as outpocketings, in the dorsal and lateral regions. The semicircular canals of the vestibule form from the periphery of the outpocketings, with the central region (the fusion plate) undergoing de-epithelialization and disappearing. However, little is known of the mechanism that orchestrates formation of the semicircular canals. We now show that the area of canonical Wnt signaling changes dynamically in the dorsal otocyst during its morphogenesis. The gene... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512684 Wed, 07 Dec 2011 05:00:00 +0100 5512684 http://www.medworm.com/index.php?rid=5512687&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155525%26dopt%3DAbstract We examined the loss of function phenotypes of the major components of the miRNA biogenesis pathway. Inhibition of de novo synthesis of Drosha and Dicer in the embryo led to consistent developmental defects, a failure to gastrulate, and embryonic lethality, including changes in the steady state levels of transcription factors and signaling molecules involved in germ layer specification. We annotated and profiled small RNA expression from the ovary and several early embryonic stages by deep sequencing followed by computational analysis. All miRNAs have dynamic accumulation profiles through early development as do a large population of putative piRNAs (piwi-interacting RNAs). Defects in morphogenesis caused by loss of Drosha can be rescued with four miRNAs which permits a strong miRNA functi... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512687 Sat, 03 Dec 2011 05:00:00 +0100 5512687 http://www.medworm.com/index.php?rid=5512686&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155526%26dopt%3DAbstract Authors: Duffy DJ, Millane RC, Frank U Abstract Both Wnt signaling and heat shock proteins play important roles in development and disease. As such, they have been widely, though separately, studied. Here we show a link between a heat shock protein and Wnt signaling in a member of the basal phylum, Cnidaria. A heat shock at late gastrulation in the clonal marine hydrozoan, Hydractinia, interferes with axis development, specifically inhibiting head development, while aboral structures remain unaffected. The heat treatment upregulated Hsc71, a constitutive Hsp70 related gene, followed by a transient upregulation, and long-term downregulation, of Wnt signaling components. Downregulating Hsc71 by RNAi in heat-shocked animals rescued these defects, resulting in normal head development. ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512686 Fri, 02 Dec 2011 05:00:00 +0100 5512686 http://www.medworm.com/index.php?rid=5512685&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155527%26dopt%3DAbstract Authors: Tu X, Joeng KS, Long F Abstract Indian hedgehog (Ihh) is indispensable for osteoblast differentiation during embryonic development of the endochondral skeleton. In the absence of Ihh, cells of the osteoblast lineage fail to activate the expression of Runx2, a transcription factor integral to osteoblast differentiation. However, it is hitherto unclear whether the lack of Runx2 expression is solely responsible for the failure of osteoblast formation in Ihh-null embryos. Here, by creating a mouse allele that expresses Runx2 in a Cre-dependent manner, we show that force-expression of Runx2 in the skeletogenic cells restores bone formation in the Runx2-null, but not in the Ihh-null embryo. Thus, the mechanism through which Ihh induces osteoblast differentiation requires other e... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512685 Fri, 02 Dec 2011 05:00:00 +0100 5512685 http://www.medworm.com/index.php?rid=5512682&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22173066%26dopt%3DAbstract Authors: Park BY, Hong CS, Weaver JR, Rosocha EM, Saint-Jeannet JP Abstract Lower vertebrates develop a unique set of primary sensory neurons located in the dorsal spinal cord. These cells, known as Rohon-Beard (RB) sensory neurons, innervate the skin and mediate the response to touch during larval stages. Here we report the expression and function of the transcription factor Xaml1/Runx1 during RB sensory neurons formation. In Xenopus embryos Runx1 is specifically expressed in RB progenitors at the end of gastrulation. Runx1 expression is positively regulated by Fgf and canonical Wnt signaling and negatively regulated by Notch signaling, the same set of factors that control the development of other neural plate border cell types, i.e. the neural crest and cranial placodes. Embryos ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512682 Fri, 02 Dec 2011 05:00:00 +0100 5512682 http://www.medworm.com/index.php?rid=5512688&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155407%26dopt%3DAbstract Authors: Marlow H, Roettinger E, Boekhout M, Martindale MQ Abstract Notch signaling is among the oldest of known Metazoan signaling pathways and is used in a multitude of developmental contexts to effect cellular differentiation, specification and the maintenance of stem cell state. Here we report the isolation and expression of the canonical Notch signaling pathway in the early branching metazoan Nematostella vectensis (Anthozoa, Cnidaria) during embryonic and larval development. We have used pharmacological treatment, morpholino knockdown, and dominant negative misexpression experiments to demonstrate that Notch signaling acts to mediate cnidogenesis, the development of cnidarian-specific neural effecter cells. Notch signaling often results in the transcriptional activation of Nv... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512688 Thu, 01 Dec 2011 05:00:00 +0100 5512688 http://www.medworm.com/index.php?rid=5512689&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22146645%26dopt%3DAbstract Authors: Kopinke D, Brailsford M, Pan FC, Magnuson MA, Wright CV, Murtaugh LC Abstract The Notch signaling pathway regulates embryonic development of the pancreas, inhibiting progenitor differentiation into exocrine acinar and endocrine islet cells. The adult pancreas appears to lack progenitor cells, and its mature cell types are maintained by the proliferation of pre-existing differentiated cells. Nonetheless, Notch remains active in adult duct and terminal duct/centroacinar cells (CACs), in which its function is unknown. We previously developed mice in which cells expressing the Notch target gene Hes1 can be labeled and manipulated, by expression of Cre recombinase, and demonstrated that Hes1(+) CACs do not behave as acinar or islet progenitors in the uninjured pancreas, or as i... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512689 Tue, 29 Nov 2011 05:00:00 +0100 5512689 http://www.medworm.com/index.php?rid=5512683&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22173065%26dopt%3DAbstract Authors: Saravanamuthu SS, Le TT, Gao CY, Cojocaru RI, Pandiyan P, Liu C, Zhang J, Zelenka PS, Brown NL Abstract Notch signaling is essential for proper lens development, however the specific requirements of individual Notch receptors have not been investigated. Here we report the lens phenotypes of Notch2 conditionally mutant mice, which exhibited severe microphthalmia, reduced pupillary openings, disrupted fiber cell morphology, eventual loss of the anterior epithelium, fiber cell dysgenesis, denucleation defects, and cataracts. Notch2 mutants also had persistent lens stalks as early as E11.5, and aberrant DNA synthesis in the fiber cell compartment by E14.5. Gene expression analyses showed that upon loss of Notch2, there were elevated levels of the cell cycle regulators Cdkn1a (... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512683 Tue, 29 Nov 2011 05:00:00 +0100 5512683 http://www.medworm.com/index.php?rid=5512693&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138055%26dopt%3DAbstract Authors: Oikonomou G, Perens EA, Lu Y, Shaham S Abstract The endings of sensory receptor cells often lie within specialized compartments formed by glial cells. The main sensory organ of Caenorhabditis elegans, the amphid, provides a powerful setting for studying glial compartment morphogenesis. Our previous studies showed that amphid compartment size is controlled by opposing activities of the Nemo-like kinase LIT-1, which promotes compartment expansion, and the Patched-related protein DAF-6, which restricts compartment growth. From a genetic screen for mutations able to suppress the bloated sensory compartments of daf-6 mutants, we identified an allele of the sorting nexin gene snx-1. SNX-1 protein is a component of the retromer, a protein complex that facilitates recycling of tra... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512693 Wed, 23 Nov 2011 05:00:00 +0100 5512693 http://www.medworm.com/index.php?rid=5512692&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138056%26dopt%3DAbstract Authors: Chapnik E, Sasson V, Blelloch R, Hornstein E Abstract DiGeorge syndrome (DGS), characterized genetically by a deletion within chromosome 22q11.2, is associated with a constellation of congenital heart defects. DiGeorge critical region 8 (Dgcr8), a gene that maps to the common deletion region for DGS, encodes a double stranded RNA-binding protein that is essential for miRNA biogenesis. To address the potential contribution of Dgcr8 insufficiency to cardiovascular development, we have inactivated Dgcr8 in cardiac neural crest cells (cNCCs). Dgcr8 mutants displayed a wide spectrum of malformations, including persistent truncus arteriosus (PTA) and ventricular septal defect (VSD). Interestingly, Dgcr8-null cNCCs that properly migrated into the cardiac outflow tract (OFT) proli... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512692 Wed, 23 Nov 2011 05:00:00 +0100 5512692 http://www.medworm.com/index.php?rid=5512694&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133918%26dopt%3DAbstract Authors: Yang Y, Primrose DA, Leung AC, Fitzsimmons RB, McDermand MC, Missellbrook A, Haskins J, Smylie AS, Hughes SC Abstract The signalling activities of Merlin and Moesin, two closely related members of the protein 4.1 Ezrin/Radixin/Moesin family, are regulated by conformational changes. These changes are regulated in turn by phosphorylation. The same sterile 20 kinase-Slik co-regulates Merlin or Moesin activity whereby phosphorylation inactivates Merlin, but activates Moesin. Thus, the corresponding coordinate activation of Merlin and inactivation of Moesin would require coordinated phosphatase activity. We find that Drosophila melanogaster protein phosphatase type 1 β (flapwing) fulfils this role, co-regulating dephosphorylation and altered activity of both Merlin and Moesin.... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512694 Sat, 19 Nov 2011 05:00:00 +0100 5512694 http://www.medworm.com/index.php?rid=5512691&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138381%26dopt%3DAbstract We describe a timeline for embryonic development, with a detailed staging system based on photographs of live eggs and fixed embryos. We show that the early, cleavage and nuclear migration, stages of development are remarkably prolonged, accounting for nearly half of the total developmental period (approx 22 of 48days at 13°C). Towards the end of this period, cleavage cells migrate to the egg periphery to generate a uniform blastoderm. Asymmetry quickly becomes apparent as cells in the anterior half of the egg condense ventrally to form the presumptive head. Five anterior segments, the mandibular to the first leg bearing segment (1st LBS) become clearly visible through the chorion almost simultaneously. Then, after a short pause, the next 35 leg bearing segments appear at a uniform rate o... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512691 Sat, 19 Nov 2011 05:00:00 +0100 5512691 http://www.medworm.com/index.php?rid=5512699&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119053%26dopt%3DAbstract Authors: Shibata Y, Uchida M, Takeshita H, Nishiwaki K, Sawa H Abstract The SWI/SNF-like chromatin remodeling complexes consist of two evolutionarily conserved subclasses, which are characterized by specific accessory components, the OSA/BAF250 and Polybromo proteins. These complexes regulate the expressions of distinct sets of target genes, with some overlap, and the regulatory components are thought to determine the target specificity for each complex. Here we isolated C. elegans mutants of the genes for the OSA/BAF250 homolog, LET-526, and the Polybromo homolog, PBRM-1, in a screen for the abnormal asymmetric cell division phenotype. In the asymmetric division of the T cell, both LET-526 and PBRM-1 regulated the asymmetric expression of psa-3/Meis between the T cell daughters, s... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512699 Fri, 18 Nov 2011 05:00:00 +0100 5512699 http://www.medworm.com/index.php?rid=5512697&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119055%26dopt%3DAbstract Authors: Ochoa SD, Salvador S, Labonne C Abstract The neural crest (NC) is a population of multipotent stem cell-like progenitors that arise at the neural plate border in vertebrates and migrate extensively before giving rise to diverse derivatives. A number of components of the neural crest gene regulatory network (NC-GRN) are used reiteratively to control multiple steps in the development of these cells. It is therefore important to understand the mechanisms that control the distinct function of reiteratively used factors in different cellular contexts, and an important strategy for doing so is to identify and characterize the regulatory factors they interact with. Here we report that the LIM adaptor protein, LMO4, is a Slug/Snail interacting protein that is essential for NC deve... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512697 Fri, 18 Nov 2011 05:00:00 +0100 5512697 http://www.medworm.com/index.php?rid=5512690&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22142964%26dopt%3DAbstract Authors: Du S, Draper BW, Mione M, Moens CB, Bruce A Abstract The T-box transcription factor Eomesodermin (Eomes) has been implicated in patterning and morphogenesis in frog, fish and mouse. In zebrafish, one of the two Eomes homologs, Eomesa, has been implicated in dorsal-ventral patterning, epiboly and endoderm specification in experiments employing over-expression, dominant-negative constructs and antisense morpholino oligonucleotides. Here we report for the first time the identification and characterization of an Eomesa mutant generated by TILLING. We find that Eomesa has a strictly maternal role in the initiation of epiboly, which involves doming of the yolk cell up into the overlying blastoderm. By contrast, epiboly progression is normal, demonstrating for the first time that... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512690 Fri, 18 Nov 2011 05:00:00 +0100 5512690 http://www.medworm.com/index.php?rid=5512696&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119056%26dopt%3DAbstract Authors: Guseva N, Mondal T, Kanduri C Abstract Epigenetic marks at cis acting imprinting control regions (ICRs) regulate parent of origin-specific expression of multiple genes in imprinted gene clusters. Epigenetic marks are acquired during gametogenesis and maintained faithfully thereafter. However, the mechanism by which differential epigenetic marks are established and maintained at ICRs is currently unclear. By using Kcnq1 ICR as a model system, we have investigated the functional role of genetic signatures in the acquisition and maintenance of epigenetic marks. Kcnq1 ICR is methylated on the maternal chromosome but remains unmethylated on the paternal chromosome. Here, we show that a paternal allele of Kcnq1 ICR lacking the Kcnq1ot1 promoter remains unmethylated during sperma... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512696 Tue, 15 Nov 2011 05:00:00 +0100 5512696 http://www.medworm.com/index.php?rid=5512698&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119054%26dopt%3DAbstract Authors: Wong KS, Rehn K, Palencia-Desai S, Kohli V, Hunter W, Uhl JD, Rost MS, Sumanas S Abstract Endocardial cells form the inner endothelial layer of the heart tube, surrounded by the myocardium. Signaling pathways that regulate endocardial cell specification and differentiation are largely unknown and the origin of endocardial progenitors is still being debated. To study pathways that regulate endocardial differentiation in a zebrafish model system, we isolated zebrafish NFATc1 homolog which is expressed in endocardial but not vascular endothelial cells. We further demonstrate that Hedgehog (Hh) but not VegfA or Notch signaling is required for early endocardial morphogenesis. Pharmacological inhibition of Hh signaling with cyclopamine treatment resulted in nearly complete loss ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512698 Sat, 12 Nov 2011 05:00:00 +0100 5512698 http://www.medworm.com/index.php?rid=5512695&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22123032%26dopt%3DAbstract Authors: Weymouth N, Shi Z, Rockey DC Abstract Smooth muscle α-actin (Acta2) is one of six highly conserved mammalian actin isoforms that appear to exhibit functional redundancy. Nonetheless, we have postulated a specific functional role for the smooth muscle specific isoform. Here, we show that Acta2 deficient mice have a remarkable mammary phenotype such that dams lacking Acta2 are unable to nurse their offspring effectively. The phenotype was rescued in cross fostering experiments with wild type mice, excluding a developmental defect in Acta2 null pups. The mechanism for the underlying phenotype is due to myoepithelial dysfunction postpartum resulting in precocious involution. Further, we demonstrate a specific defect in myoepithelial cell contractility in Acta2 null mammary gl... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512695 Sat, 12 Nov 2011 05:00:00 +0100 5512695 http://www.medworm.com/index.php?rid=5512700&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22108505%26dopt%3DAbstract Authors: Herr P, Basler K Abstract Wnt proteins are members of a conserved family of secreted signaling ligands and play crucial roles during development and in tissue homeostasis. There is increasing evidence that aberrant Wnt production is an underlying cause of dysregulated Wnt signaling, however little is known about this process. One protein known to play a role in secretion is the transmembrane protein Wntless (Wls). However, the mechanism by which Wls promotes Wnt secretion is a riddle. It is not known which Wnt family members require Wls and what the structural requirements are that make some of them reliant on Wls for secretion. Here we present a systematic analysis of all known Drosophila Wnt family members with respect to their dependence on Wls function for secretion. W... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512700 Fri, 11 Nov 2011 05:00:00 +0100 5512700 http://www.medworm.com/index.php?rid=5512702&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22094018%26dopt%3DAbstract Authors: McKeown KA, Moreno R, Hall VL, Ribera AB, Downes GB Abstract Analysis of zebrafish mutants that have defects in motor behavior can allow entrée into the hindbrain and spinal cord networks that control locomotion. Here, we report that zebrafish techno trousers (tnt) locomotor mutants harbor a mutation in slc1a2b, which encodes Eaat2b, a plasma membrane glutamate transporter. We used tnt mutants to explore the effects of impaired glutamate transporter activity on locomotor network function. Wild-type larvae perform robust swimming behavior in response to touch stimuli at two and four days after fertilization. In contrast, tnt mutant larvae demonstrate aberrant, exaggerated body bends beginning two days after fertilization and they are almost fully paralyzed four days after ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512702 Sun, 06 Nov 2011 04:00:00 +0100 5512702 http://www.medworm.com/index.php?rid=5512701&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22094019%26dopt%3DAbstract Authors: Bridges JP, Lin S, Ikegami M, Shannon JM Abstract Hypoxia inducible factor (HIF) 1a, EPAS1 and NEPAS are expressed in the embryonic mouse lung and each isoform exhibits distinct spatiotemporal expression patterns throughout morphogenesis. To further assess the role of the HIF1a isoform in lung epithelial cell differentiation and homeostasis, we created transgenic mice that express a constitutively active isoform of human HIF-1a (HIF-1a three point mutant (TPM)), in a doxycycline-dependent manner. Expression of HIF1a TPM in the developing pulmonary epithelium resulted in lung hypoplasia characterized by defective branching morphogenesis, altered cellular energetics and impaired epithelial maturation, culminating in neonatal lethality at birth from severe respiratory distres... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512701 Sun, 06 Nov 2011 04:00:00 +0100 5512701 http://www.medworm.com/index.php?rid=5512703&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22094017%26dopt%3DAbstract Authors: Dohn TE, Waxman JS Abstract Normal heart formation requires reiterative phases of canonical Wnt/β-catenin (Wnt) signaling. Understanding the mechanisms by which Wnt signaling directs cardiomyocyte (CM) formation in vivo is critical to being able to precisely direct differentiated CMs from stem cells in vitro. Here, we investigate the roles of Wnt signaling in zebrafish CM formation using heat-shock inducible transgenes that increase and decrease Wnt signaling. We find that there are three phases during which CM formation is sensitive to modulation of Wnt signaling through the first 24h of development. In addition to the previously recognized roles for Wnt signaling during mesoderm specification and in the pre-cardiac mesoderm, we find a previously unrecognized role during... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5512703 Fri, 04 Nov 2011 04:00:00 +0100 5512703 http://www.medworm.com/index.php?rid=5419083&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22079694%26dopt%3DAbstract In this study, to examine further the basis of progressive tarsal patterning, the precise expression pattern and function of several transcription factor genes were investigated in relation to the temporal regulation of Bar expression. The results indicate that nubbin is expressed over a broad region at early stages but gradually disappears from the middle of the tarsal region. This causes the progressive expansion of rotund expression, which in turn progressively represses Bar expression, leading to the formation of the tarsal segment 3. The region corresponding to the tarsal segment 4 is formed when apterous expression is initiated, which renders Bar expression refractory to rotund. In addition, the tarsal segment 2 appears to be derived from the region that expresses Bar at a very early... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419083 Mon, 31 Oct 2011 04:00:00 +0100 5419083 http://www.medworm.com/index.php?rid=5419082&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22079695%26dopt%3DAbstract Authors: Roode M, Blair K, Snell P, Blair KE, Marchant S, Smith A, Nichols J Abstract Mouse embryos segregate three different lineages during preimplantation development: trophoblast, epiblast and hypoblast. These differentiation processes are associated with restricted expression of key transcription factors (Cdx2, Oct4, Nanog and Gata6). The mechanisms of segregation have been extensively studied in the mouse, but are not as well characterised in other species. In the human embryo, hypoblast differentiation has not previously been characterised. Here we demonstrate co-exclusive immunolocalisation of Nanog and Gata4 in human blastocysts, implying segregation of epiblast and hypoblast, as in rodent embryos. However, the formation of hypoblast in the human is apparently not dependen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419082 Mon, 31 Oct 2011 04:00:00 +0100 5419082 http://www.medworm.com/index.php?rid=5419085&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22063212%26dopt%3DAbstract Authors: Fuerst PG, Bruce F, Rounds RP, Erskine L, Burgess RW Abstract Cell adhesion molecules (CAMs) provide identifying cues by which neural architecture is sculpted. The Down Syndrome Cell Adhesion Molecule (DSCAM) is required for many neurodevelopmental processes in different species and also has several potential mechanisms of activity, including homophilic adhesion, homophilic repulsion and heterophilic interactions. In the mouse retina, Dscam is expressed in many, but not all neuronal subtypes. Mutations in Dscam cause the fasciculation of dendrites of neighboring homotypic neurons, indicating a role in self-avoidance among cells of a given type, a disruption of the non-random patterning of their cell bodies, and a decrease in developmental cell death in affected cell popula... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419085 Sat, 29 Oct 2011 04:00:00 +0100 5419085 http://www.medworm.com/index.php?rid=5419084&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22074987%26dopt%3DAbstract Authors: Middelkoop TC, Williams L, Yang PT, Luchtenberg J, Betist MC, Ji N, van Oudenaarden A, Kenyon C, Korswagen HC Abstract Wnt proteins are secreted signaling molecules that play a central role in development and adult tissue homeostasis. Although several Wnt signal transduction mechanisms have been described in detail, it is still largely unknown how cells are specified to adopt such different Wnt signaling responses. Here, we have used the stereotypic migration of the C. elegans Q neuroblasts as a model to study how two initially equivalent cells are instructed to activate either β-catenin dependent or independent Wnt signaling pathways to control the migration of their descendants along the anteroposterior axis. We find that the specification of this difference in Wnt sign... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419084 Sat, 29 Oct 2011 04:00:00 +0100 5419084 http://www.medworm.com/index.php?rid=5419092&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22056783%26dopt%3DAbstract Authors: González IM, Martin PM, Burdsal C, Sloan JL, Mager S, Harris T, Sutherland AE Abstract Uterine implantation is a critical element of mammalian reproduction and is a tightly and highly coordinated event. An intricate and reciprocal uterine-embryo dialog exists to synchronize uterine receptivity with the concomitant activation of the blastocyst, maximizing implantation success. While a number of pathways involved in regulating uterine receptivity have been identified in the mouse, less is understood about blastocyst activation, the process by which the trophectoderm (TE) receives extrinsic cues that initiate new characteristics essential for implantation. Amino acids (AA) have been found to regulate blastocyst activation and TE motility in vitro. In particular, we find that... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419092 Fri, 28 Oct 2011 04:00:00 +0100 5419092 http://www.medworm.com/index.php?rid=5419088&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22057081%26dopt%3DAbstract Authors: Neves H, Dupin E, Parreira L, Le Douarin NM Abstract Epithelial-mesenchymal interactions are crucial for the development of the endoderm of the pharyngeal pouches into the epithelia of thymus and parathyroid glands. Here we investigated the dynamics of epithelial-mesenchymal interactions that take place at the earliest stages of thymic and parathyroid organogenesis using the quail-chick model together with a co-culture system capable of reproducing these early events in vitro. The presumptive territories of thymus and parathyroid epithelia were identified in three-dimensionally preserved pharyngeal endoderm of embryonic day 4.5 chick embryos on the basis of the expression of Foxn1 and Gcm2, respectively: the thymic rudiment is located in the dorsal domain of the third and ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419088 Fri, 28 Oct 2011 04:00:00 +0100 5419088 http://www.medworm.com/index.php?rid=5419093&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22056782%26dopt%3DAbstract Authors: Fujimi TJ, Hatayama M, Aruga J Abstract Zic3 controls neuroectodermal differentiation and left-right patterning in Xenopus laevis embryos. Here we demonstrate that Zic3 can suppress Wnt/β-catenin signaling and control development of the notochord and Spemann's organizer. When we overexpressed Zic3 by injecting its RNA into the dorsal marginal zone of 2-cell-stage embryos, the embryos lost mesodermal dorsal midline structures and showed reduced expression of organizer markers (Siamois and Goosecoid) and a notochord marker (Xnot). Co-injection of Siamois RNA partially rescued the reduction of Xnot expression caused by Zic3 overexpression. Because the expression of Siamois in the organizer region is controlled by Wnt/β-catenin signaling, we subsequently examined the functio... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419093 Wed, 26 Oct 2011 04:00:00 +0100 5419093 http://www.medworm.com/index.php?rid=5419091&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22056784%26dopt%3DAbstract Authors: Suzuki H, Ahn HW, Chu T, Bowden W, Gassei K, Orwig K, Rajkovic A Abstract Spermatogonial self-renewal and differentiation are essential for male fertility and reproduction. We discovered that germ cell specific genes Sohlh1 and Sohlh2, encode basic helix-loop-helix (bHLH) transcriptional regulators that are essential in spermatogonial differentiation. Sohlh1 and Sohlh2 individual mouse knockouts show remarkably similar phenotypes. Here we show that SOHLH1 and SOHLH2 proteins are co-expressed in the entire spermatogonial population except in the GFRA1(+) spermatogonia, which includes spermatogonial stem cells (SSCs). SOHLH1 and SOHLH2 are expressed in both KIT negative and KIT positive spermatogonia, and overlap Ngn3/EGFP and SOX3 expression. SOHLH1 and SOHLH2 heterodimeriz... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419091 Wed, 26 Oct 2011 04:00:00 +0100 5419091 http://www.medworm.com/index.php?rid=5419090&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22056785%26dopt%3DAbstract Authors: Beucher A, Martín M, Spenle C, Poulet M, Collin C, Gradwohl G Abstract During mouse pancreas development, the transient expression of Neurogenin3 (Neurog3) in uncommitted pancreas progenitors is required to determine endocrine destiny. However it has been reported that Neurog3-expressing cells can eventually adopt acinar or ductal fates and that Neurog3 levels were important to secure the islet destiny. It is not known whether the competence of Neurog3-induced cells to give rise to non-endocrine lineages is an intrinsic property of these progenitors or depends on pancreas developmental stage. Using temporal genetic labeling approaches we examined the dynamic of endocrine progenitor differentiation and explored the plasticity of Neurog3-induced cells throughout development... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419090 Wed, 26 Oct 2011 04:00:00 +0100 5419090 http://www.medworm.com/index.php?rid=5419089&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22056786%26dopt%3DAbstract Authors: Schachterle W, Rojas A, Xu SM, Black BL Abstract The developing heart contains an inner tube of specialized endothelium known as endocardium, which performs multiple essential functions. In spite of the essential role of the endocardium in heart development and function, the transcriptional pathways that regulate its development remain largely undefined. GATA4 is a zinc finger transcription factor that is expressed in multiple cardiovascular lineages and is required for endocardial cushion development and embryonic viability, but the transcriptional pathways upstream of Gata4 in the endocardium and its derivatives in the endocardial cushions are unknown. Here, we describe a distal enhancer from the mouse Gata4 gene that is briefly active in multiple cardiac lineages early ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419089 Wed, 26 Oct 2011 04:00:00 +0100 5419089 http://www.medworm.com/index.php?rid=5419086&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22061481%26dopt%3DAbstract Authors: Wheeler SR, Pearson JC, Crews ST Abstract The Drosophila CNS midline glia (MG) are multifunctional cells that ensheath and provide trophic support to commissural axons, and direct embryonic development by employing a variety of signaling molecules. These glia consist of two functionally distinct populations: the anterior MG (AMG) and posterior MG (PMG). Only the AMG ensheath axon commissures, whereas the function of the non-ensheathing PMG is unknown. The Drosophila MG have proven to be an excellent system for studying glial proliferation, cell fate, apoptosis, and axon-glial interactions. However, insight into how AMG migrate and acquire their specific positions within the axon-glial scaffold has been lacking. In this paper, we use time-lapse imaging, single-cell analysis... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419086 Wed, 26 Oct 2011 04:00:00 +0100 5419086 http://www.medworm.com/index.php?rid=5419087&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22061480%26dopt%3DAbstract Authors: Carney TD, Miller MR, Robinson KJ, Bayraktar OA, Osterhout JA, Doe CQ Abstract The Drosophila larval central brain contains about 10,000 differentiated neurons and 200 scattered neural progenitors (neuroblasts), which can be further subdivided into ~95 type I neuroblasts and eight type II neuroblasts per brain lobe. Only type II neuroblasts generate self-renewing intermediate neural progenitors (INPs), and consequently each contributes more neurons to the brain, including much of the central complex. We characterized six different mutant genotypes that lead to expansion of neuroblast numbers; some preferentially expand type II or type I neuroblasts. Transcriptional profiling of larval brains from these mutant genotypes versus wild-type allowed us to identify small clusters... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5419087 Tue, 25 Oct 2011 04:00:00 +0100 5419087 http://www.medworm.com/index.php?rid=5379364&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22040871%26dopt%3DAbstract In this study, we examined arch artery morphogenesis during mouse development, and the role of RA in this process. We show in normal embryos that the arch arteries form by vasculogenic differentiation of pharyngeal mesoderm. Using various genetic backgrounds and tissue-specific mutation approaches, we segregate pharyngeal arch artery and pharyngeal pouch defects in RA receptor mutants, and show that RA signal transduction only in pharyngeal mesoderm is required for arch artery formation. RA does not control pharyngeal mesodermal differentiation to endothelium, but instead promotes the aggregation of endothelial cells into nascent vessels. Expression of VE-cadherin was substantially reduced in RAR mutants, and this deficiency may underlie the arch artery defects. The consequences of disrupt... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379364 Thu, 20 Oct 2011 04:00:00 +0100 5379364 http://www.medworm.com/index.php?rid=5379363&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22040872%26dopt%3DAbstract Authors: Chen Y, Moon AM, Gaufo GO Abstract The interaction between the cranial neural crest (NC) and the epibranchial placode is critical for the formation of parasympathetic and visceral sensory ganglia, respectively. However, the molecular mechanism that controls this intercellular interaction is unknown. Here we show that the spatiotemporal expression of Fibroblast growth factor 8 (Fgf8) is strategically poised to control this cellular relationship. A global reduction of Fgf8 in hypomorph embryos leads to an early loss of placode-derived sensory ganglia and reduced number of NC-derived postganglionic (PG) neurons. The latter finding is associated with the early loss of NC cells by apoptosis. This loss occurs concurrent with the interaction between the NC and placode-derived gan... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379363 Thu, 20 Oct 2011 04:00:00 +0100 5379363 http://www.medworm.com/index.php?rid=5379367&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22036477%26dopt%3DAbstract Authors: Wells BS, Johnston LA Abstract Following irradiation (IR), the DNA damage response (DDR) activates p53, which triggers death of cells in which repair cannot be completed. Lost tissue is then replaced and re-patterned through regeneration. We have examined the role of p53 in co-regulation of the DDR and tissue regeneration following IR damage in Drosophila. We find that after IR, p53 is required for imaginal disk cells to repair DNA, and in its absence the damage marker, γ-H2AX is persistently expressed. p53 is also required for the compensatory proliferation and re-patterning of the damaged disks, and our results indicate that cell death is not required to trigger these processes. We identify an IR-induced delay in developmental patterning in wing disks that accompanies a... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379367 Wed, 19 Oct 2011 04:00:00 +0100 5379367 http://www.medworm.com/index.php?rid=5379366&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22037235%26dopt%3DAbstract Authors: Zhang H, Deo M, Thompson RC, Uhler MD, Turner DL Abstract Regulated proliferation and cell cycle exit are essential aspects of neurogenesis. The Yap transcriptional coactivator controls proliferation in a variety of tissues during development, and this activity is negatively regulated by kinases in the Hippo signaling pathway. We find that Yap is expressed in mitotic mouse retinal progenitors and it is downregulated during neuronal differentiation. Forced expression of Yap prolongs proliferation in the postnatal mouse retina, whereas inhibition of Yap by RNA interference (RNAi) decreases proliferation and increases differentiation. We show Yap is subject to post-translational inhibition in the retina, and also downregulated at the level of mRNA expression. Using a cell cul... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379366 Tue, 18 Oct 2011 04:00:00 +0100 5379366 http://www.medworm.com/index.php?rid=5379371&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22024319%26dopt%3DAbstract Authors: Liu HX, Grosse AS, Iwatsuki K, Mishina Y, Gumucio DL, Mistretta CM Abstract Although canonical Wnt signaling is known to regulate taste papilla induction and numbers, roles for noncanonical Wnt pathways in tongue and taste papilla development have not been explored. With mutant mice and whole tongue organ cultures we demonstrate that Wnt5a protein and message are within anterior tongue mesenchyme across embryo stages from the initiation of tongue formation, through papilla placode appearance and taste papilla development. The Wnt5a mutant tongue is severely shortened, with an ankyloglossia, and lingual mesenchyme is disorganized. However, fungiform papilla morphology, number and innervation are preserved, as is expression of the papilla marker, Shh. These data demonstrate ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379371 Sat, 15 Oct 2011 04:00:00 +0100 5379371 http://www.medworm.com/index.php?rid=5379370&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22024320%26dopt%3DAbstract Authors: Yuan H, Chiang CY, Cheng J, Salzmann V, Yamashita YM Abstract Male germline stem cells (GSCs) in Drosophila melanogaster divide asymmetrically by orienting the mitotic spindle with respect to the niche, a microenvironment that specifies stem cell identity. The spindle orientation is prepared during interphase through stereotypical positioning of the centrosomes. We recently demonstrated that GSCs possess a checkpoint ("the centrosome orientation checkpoint") that monitors correct centrosome orientation prior to mitosis to ensure an oriented spindle and thus asymmetric outcome of the division. Here, we show that Par-1, a serine/threonine kinase that regulates polarity in many systems, is involved in this checkpoint. Par-1 shows a cell cycle-dependent localization to the spe... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379370 Sat, 15 Oct 2011 04:00:00 +0100 5379370 http://www.medworm.com/index.php?rid=5379369&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22024321%26dopt%3DAbstract Authors: Nakagawa H, Ishizu H, Hasegawa R, Kobayashi K, Matsumoto M Abstract A piwi homolog is required for the regulation of stem cells, formation and maintenance of germline stem cells, and gametogenesis in many metazoans. Planarians can change their reproductive mode seasonally, both asexually and sexually, and develop and maintain germ cells and sexual organs. They have many pluripotent stem cells (neoblasts) that can differentiate into both somatic and germline stem cells. Thus, we searched for a piwi subfamily in the planarian Dugesia ryukyuensis. Four piwi homologs, identified as Drpiwi-1, -2, -3, and -4, were expressed in sexually reproductive worms. We then selectively destroyed the neoblasts by irradiating the worms with X-rays. In such worms, Drpiwi-1, -2, and -3 were no... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379369 Sat, 15 Oct 2011 04:00:00 +0100 5379369 http://www.medworm.com/index.php?rid=5379368&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22027434%26dopt%3DAbstract In this study, we investigated huckebein (hkb), which has a gap expression domain at the anterior tip of the embryo. Using genetic methods we were able to detect deviations from the wild-type patterns of the anterior-most pair-rule stripes in different genetic backgrounds, which were consistent with Hkb-mediated repression. Moreover, we developed an image processing tool that, for the most part, confirmed our assumptions. Using an hkb misexpression system, we further detected specific repression on anterior stripes. Furthermore, bioinformatics analysis predicted an increased significance of binding site clusters in the CRMs of h 1, eve 1, run 1 and ftz 1when Hkb was incorporated in the analysis, indicating that Hkb plays a direct role in these CRMs. We further discuss that Hkb and Slp1, wh... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379368 Sat, 15 Oct 2011 04:00:00 +0100 5379368 http://www.medworm.com/index.php?rid=5379365&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22037676%26dopt%3DAbstract We report here that compared to the fast EDL muscles, slow SOL muscles are more enriched with adipogenic progenitors and have higher propensity to form adipose. Using Cre/LoxP mediated lineage tracing in mice, we show that intramuscular adipose in both EDL and SOL muscles is exclusively derived from a Pax3(-) non-myogenic lineage. In contrast, inter-scapular brown adipose is derived from the Pax3(+) lineage. To dissect the interaction between adipose and skeletal muscle tissues, we used Myf5-Cre and aP2-Cre mice in combination with ROSA26-iDTR mice to genetically ablate myogenic and adipogenic cell lineages, respectively. Whereas ablation of the myogenic cell lineage facilitated adipogenic differentiation, ablation of the adipogenic cell lineage surprisingly impaired the regeneration of ac... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379365 Sat, 15 Oct 2011 04:00:00 +0100 5379365 http://www.medworm.com/index.php?rid=5379362&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22051107%26dopt%3DAbstract In this study, we demonstrated that BMP4 signaling induces the formation of a polarized epithelium in XEN cells. This morphological transition was reversible, and was associated with the acquisition of a molecular signature comparable to extraembryonic (ex) VE. Resembling exVE which will form the endoderm of the visceral yolk sac, BMP4-treated XEN cells regulated hematopoiesis by stimulating the expansion of primitive erythroid progenitors. We also observed that LIF exerted an antagonistic effect on BMP4-induced XEN cell differentiation, thereby impacting the extrinsic conditions used for the isolation and maintenance of XEN cells in an undifferentiated state. Taken together, our data suggest that XEN cells can be differentiated towards an exVE identity upon BMP4 stimulation, and therefore... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5379362 Sat, 15 Oct 2011 04:00:00 +0100 5379362 http://www.medworm.com/index.php?rid=5277451&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839069%26dopt%3DAbstract We describe Ptf1a as a strong, negative regulator of Atoh7 expression. Furthermore, the Rbpj-interacting domains of Ptf1a protein were required for its effects on cell fate specification. Together, these data provide a novel insight into the molecular basis of Ptf1a activity on early cell specification in the chick retina. PMID: 21839069 [PubMed - in process] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277451 Mon, 03 Oct 2011 20:02:59 +0100 5277451 http://www.medworm.com/index.php?rid=5277446&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839733%26dopt%3DAbstract Authors: Laforest B, Nemer M Abstract Members of the GATA family of transcription factors are critical regulators of heart development and mutations in 2 of them, GATA4 and GATA6 are associated with outflow tract and septal defects in human. The heart expresses 3 GATA factors, GATA4, 5 and 6 in a partially overlapping pattern. Here, we report that compound Gata4/Gata5 and Gata5/Gata6 mutants die embryonically or perinatally due to severe congenital heart defects. Almost all Gata4(+/-)Gata5(+/-) mutant embryos have double outlet right ventricles (DORV), large ventricular septal defects (VSD) as well as hypertrophied mitral and tricuspid valves. Only 25% of double compound Gata4/Gata5 heterozygotes survive to adulthood and these mice have aortic stenosis. Compound loss of a Gata5 and... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277446 Mon, 03 Oct 2011 20:02:46 +0100 5277446 http://www.medworm.com/index.php?rid=5277419&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21958744%26dopt%3DAbstract Authors: Zhou B, Wu Y, Lin X Abstract Epithelial cells are characterized by an "apical-basal" polarization. The transmembrane protein Crumbs (Crb) is an essential apical determinant which confers apical membrane identity. Previous studies indicated that Crb did not constantly reside on the apical membrane, but was actively recycled. However, the cellular mechanism(s) underlying this process was unclear. Here we showed that in Drosophila, retromer, which was a retrograde complex recycling certain transmembrane proteins from endosomes to trans-Golgi network (TGN), regulated Crb in epithelial cells. In the absence of retromer, Crb was mis-targeted into lysosomes and degraded, causing a disruption of the apical-basal polarity. We further showed that Crb co-localized and interacted with... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277419 Mon, 19 Sep 2011 04:00:00 +0100 5277419 http://www.medworm.com/index.php?rid=5277426&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945073%26dopt%3DAbstract Authors: Doll CA, Burkart JT, Hope KD, Halpern ME, Gamse JT Abstract The dorsal habenular nuclei (Dh) of the zebrafish are characterized by significant left-right differences in gene expression, anatomy, and connectivity. Notably, the lateral subnucleus of the Dh (LsDh) is larger on the left side of the brain than on the right, while the medial subnucleus (MsDh) is larger on the right compared to the left. A screen for mutations that affect habenular laterality led to the identification of the sec61a-like 1(sec61al1) gene. In sec61al1(c163) mutants, more neurons in the LsDh and fewer in the MsDh develop on both sides of the brain. Generation of neurons in the LsDh occurs more rapidly and continues for a longer time period in mutants than in WT. Expression of Nodal pathway genes on ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277426 Fri, 16 Sep 2011 04:00:00 +0100 5277426 http://www.medworm.com/index.php?rid=5277425&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945074%26dopt%3DAbstract Authors: Gradus B, Alon I, Hornstein E Abstract The specific program that enables the stereotypic differentiation of specialized cartilages, including the trachea, must be intrinsically distinct from the program that gives rise to growth plate hypertrophic chondrocytes. For example, Snail1 is an effector of FGF signaling in growth plate pre-hypertrophic chondrocytes, but it derails the normal program of permanent chondrocytes, repressing the transcription of Aggrecan and Collagen type 2a1 (Col2a1). Here we show that miRNA activity is essential for normal trachea development and that miR-125b and miR-30a/c keep Snail1 at low levels, thus enabling full functional differentiation of Col2a1 tracheal chondrocytes. Specific inhibition of miR-125b and miR-30a/c in chondrocytes or Dicer1 k... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277425 Fri, 16 Sep 2011 04:00:00 +0100 5277425 http://www.medworm.com/index.php?rid=5277424&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945075%26dopt%3DAbstract Authors: Maddala R, Chauhan BK, Walker C, Zheng Y, Robinson ML, Lang RA, Rao PV Abstract Morphogenesis and shape of the ocular lens depend on epithelial cell elongation and differentiation into fiber cells, followed by the symmetric and compact organization of fiber cells within an enclosed extracellular matrix-enriched elastic capsule. The cellular mechanisms orchestrating these different events however, remain obscure. We investigated the role of the Rac1 GTPase in these processes by targeted deletion of expression using the conditional gene knockout (cKO) approach. Rac1 cKO mice were derived from two different Cre (Le-Cre and MLR-10) transgenic mice in which lens-specific Cre expression starts at embryonic day 8.75 and 10.5, respectively, in both the lens epithelium and fiber ce... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277424 Fri, 16 Sep 2011 04:00:00 +0100 5277424 http://www.medworm.com/index.php?rid=5277423&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945076%26dopt%3DAbstract Authors: Berbari NF, Kin NW, Sharma N, Michaud EJ, Kesterson RA, Yoder BK Abstract Tumor necrosis factor alpha receptor 3 interacting protein 1 (Traf3ip1), also known as MIPT3, was initially characterized through its interactions with tubulin, actin, TNFR-associated factor-3 (Traf3), IL-13R1, and DISC1. It functions as an inhibitor of IL-13-mediated phosphorylation of Stat6 and in sequestration of Traf3 and DISC1 to the cytoskeleton. Studies of the Traf3ip1 homologs in C. elegans (DYF-11), Zebrafish (elipsa), and Chlamydomonas (IFT54) revealed that the protein localizes to the cilium and is required for ciliogenesis. Similar localization data has now been reported for mammalian Traf3ip1. This raises the possibility that Traf3ip1 has an evolutionarily conserved role in mammalian cil... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277423 Fri, 16 Sep 2011 04:00:00 +0100 5277423 http://www.medworm.com/index.php?rid=5277422&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945077%26dopt%3DAbstract Authors: Heckman-Stoddard BM, Vargo-Gogola T, Herrick MP, Visbal AP, Lewis MT, Settleman J, Rosen JM Abstract P190A and p190B Rho GTPase activating proteins (GAPs) are essential genes that have distinct, but overlapping roles in the developing nervous system. Previous studies from our laboratory demonstrated that p190B is required for mammary gland morphogenesis, and we hypothesized that p190A might have a distinct role in the developing mammary gland. To test this hypothesis, we examined mammary gland development in p190A-deficient mice. P190A expression was detected by in situ hybridization in the developing E14.5day embryonic mammary bud and within the ducts, terminal end buds (TEBs), and surrounding stroma of the developing virgin mammary gland. In contrast to previous results ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277422 Fri, 16 Sep 2011 04:00:00 +0100 5277422 http://www.medworm.com/index.php?rid=5277421&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945862%26dopt%3DAbstract Authors: Adamo L, García-Cardeña G Abstract More than a century ago, several embryologists described sites of hematopoietic activity in the vascular wall of mid-gestation vertebrate embryos, and postulated the transient existence of a blood generating endothelium during ontogeny. This hypothesis gained significant attention in the 1970s when orthotopic transplantation experiments between quail and chick embryos revealed specific vascular areas as the site of the origin of definitive hematopoiesis. However, the vascular origin of hematopoietic precursors remained elusive and controversial for decades. Only recently, multiple experimental approaches have clearly documented that during vertebrate development definitive hematopoietic precursors arise from a subset of vascular endothe... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277421 Fri, 16 Sep 2011 04:00:00 +0100 5277421 http://www.medworm.com/index.php?rid=5277420&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945863%26dopt%3DAbstract Authors: Bachy I, Franck MC, Li L, Abdo H, Pattyn A, Ernfors P Abstract The developmental process and unique molecular identity between the many different types of dorsal root ganglion (DRG) sensory neurons generated during embryogenesis provide the cellular basis for the distinct perceptual modalities of somatosensation. The mechanisms leading to the generation of different types of nociceptive sensory neurons remain only partly understood. Here, we show that the transcription factor Cux2 is a novel marker of sensory neurons subpopulations of three main sublineages as defined by the expression of neurotrophic factor receptors TrkA, TrkB and TrkC. In particular, it is expressed in a subpopulation of early TrkA(+) neurons that arise during the early, Ngn1-independent initiated neuro... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277420 Fri, 16 Sep 2011 04:00:00 +0100 5277420 http://www.medworm.com/index.php?rid=5277418&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21958745%26dopt%3DAbstract Authors: Takebayashi-Suzuki K, Kitayama A, Terasaka-Iioka C, Ueno N, Suzuki A Abstract The formation of the dorsal-ventral (DV) and anterior-posterior (AP) axes, fundamental to the body plan of animals, is regulated by several groups of polypeptide growth factors including the TGF-β, FGF, and Wnt families. In order to ensure the establishment of the body plan, the processes of DV and AP axis formation must be linked and coordinately regulated. However, the molecular mechanisms responsible for these interactions remain unclear. Here, we demonstrate that the forkhead box transcription factor FoxB1, which is upregulated by the neuralizing factor Oct-25, plays an important role in the formation of the DV and AP axes. Overexpression of FoxB1 promoted neural induction and inhibited BMP-... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5277418 Fri, 16 Sep 2011 04:00:00 +0100 5277418 http://www.medworm.com/index.php?rid=5246284&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925489%26dopt%3DAbstract Authors: Noda T Abstract I isolated a Ciona intestinalis homolog of p53, Ci-p53/p73-a, in a microarray screen of rapidly degraded maternal mRNA by comparing the transcriptomes of unfertilized eggs and 32-cell stage embryos. Higher expression of the gene in eggs and lower expression in later embryonic stages were confirmed by whole-mount in situ hybridization (WISH) and quantitative reverse transcription-PCR (qRT-PCR); expression was ubiquitous in eggs and early embryos. Knockdown of Ci-p53/p73-a by injection of antisense morpholino oligonucleotides (MOs) severely perturbed gastrulation cell movements and expression of notochord marker genes. A key regulator of notochord differentiation in Ciona embryos is Brachyury (Ci-Bra), which is directly activated by a zic-like gene (Ci-ZicL).... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246284 Fri, 09 Sep 2011 04:00:00 +0100 5246284 http://www.medworm.com/index.php?rid=5246282&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925491%26dopt%3DAbstract Authors: Trowe MO, Maier H, Petry M, Schweizer M, Schuster-Gossler K, Kispert A Abstract In the cochlea, sensory transduction depends on the endocochlear potential (EP) and the unique composition of the endolymph, both of which are maintained by a highly specialized epithelium at the cochlear lateral wall, the stria vascularis. The generation of the EP by the stria vascularis, in turn, relies on the insulation of an intrastrial extracellular compartment by epithelial basal cells. Despite the physiological importance of basal cells, their cellular origin and the molecular pathways that lead to their differentiation are unclear. Here, we show by genetic lineage tracing in the mouse that basal cells exclusively derive from the otic mesenchyme. Conditional deletion of E-cadherin in the... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246282 Fri, 09 Sep 2011 04:00:00 +0100 5246282 http://www.medworm.com/index.php?rid=5246281&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925492%26dopt%3DAbstract Authors: Liu ZC, Geisbrecht ER Abstract It is the precise connectivity between skeletal muscles and their corresponding tendon cells to form a functional myotendinous junction (MTJ) that allows for the force generation required for muscle contraction and organismal movement. The Drosophila MTJ is composed of secreted extracellular matrix (ECM) proteins deposited between integrin-mediated hemi-adherens junctions on the surface of muscle and tendon cells. In this paper, we have identified a novel, cytoplasmic role for the canonical nuclear import protein Moleskin (Msk) in Drosophila embryonic somatic muscle attachment. Msk protein is enriched at muscle attachment sites in late embryogenesis and msk mutant embryos exhibit a failure in muscle-tendon cell attachment. Although the muscle... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246281 Fri, 09 Sep 2011 04:00:00 +0100 5246281 http://www.medworm.com/index.php?rid=5246291&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21924254%26dopt%3DAbstract In this study, we identified and characterized rice mutants that specifically disrupted the development of palea, one of the outer whorl floral organs. The depressed palea1 (dp1) mutants show a primary defect in the main structure of palea, implying that palea is a fusion between the main structure and marginal tissues on both sides. The sterile lemma at the palea side is occasionally elongated in dp1 mutants. In addition, we found a floral organ number increase in dp1 mutants at low penetration. Both the sterile lemma elongation and the floral organ number increase phenotype are enhanced by the mutation of an independent gene SMALL DEGENERATIVE PALEA1 (SDP1), whose single mutation causes reduced palea size. E function and presumable A function floral homeotic genes were found suppressed i... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246291 Wed, 07 Sep 2011 04:00:00 +0100 5246291 http://www.medworm.com/index.php?rid=5246287&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925157%26dopt%3DAbstract Authors: Gallagher TL, Arribere JA, Geurts PA, Exner CR, McDonald KL, Dill KK, Marr HL, Adkar SS, Garnett AT, Amacher SL, Conboy JG Abstract Rbfox RNA binding proteins are implicated as regulators of phylogenetically-conserved alternative splicing events important for muscle function. To investigate the function of rbfox genes, we used morpholino-mediated knockdown of muscle-expressed rbfox1l and rbfox2 in zebrafish embryos. Single and double morphant embryos exhibited changes in splicing of overlapping sets of bioinformatically-predicted rbfox target exons, many of which exhibit a muscle-enriched splicing pattern that is conserved in vertebrates. Thus, conservation of intronic Rbfox binding motifs is a good predictor of Rbfox-regulated alternative splicing. Morphology and developm... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246287 Wed, 07 Sep 2011 04:00:00 +0100 5246287 http://www.medworm.com/index.php?rid=5246286&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925158%26dopt%3DAbstract Authors: Rash BG, Grove EA Abstract In human holoprosencephaly (HPE), the forebrain does not separate fully into two hemispheres. Further, the border between the telencephalon and diencephalon, the telencephalic/diencephalic junction (TDJ), is often indistinct, and the ventricular system can be blocked at the third ventricle, creating a forebrain 'holosphere'. Mice deficient in Sonic Hedgehog (Shh) have previously been described to show HPE and associated cyclopia. Here we report that the third ventricle is blocked in Shh null mutants, similar to human HPE, and that characteristic telencephalic and diencephalic signaling centers, the cortical hem and zona limitans intrathalamica (ZLI), are merged, obliterating the TDJ. The resulting forebrain holosphere comprises Foxg1-positive tel... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246286 Wed, 07 Sep 2011 04:00:00 +0100 5246286 http://www.medworm.com/index.php?rid=5246285&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925159%26dopt%3DAbstract In conclusion, MSTN in medaka regulates the number and size of muscle fiber in a temporally-controlled manner during posthatch growth. PMID: 21925159 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246285 Wed, 07 Sep 2011 04:00:00 +0100 5246285 http://www.medworm.com/index.php?rid=5246283&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925490%26dopt%3DAbstract Authors: Korzh S, Winata CL, Zheng W, Yang S, Yin A, Ingham P, Korzh V, Gong Z Abstract Developmental patterning and growth of the vertebrate digestive and respiratory tracts requires interactions between the epithelial endoderm and adjacent mesoderm. The esophagus is a specialized structure that connects the digestive and respiratory systems and its normal development is critical for both. Shh signaling from the epithelium regulates related aspects of mammalian and zebrafish digestive organ development and has a prominent effect on esophageal morphogenesis. The mechanisms underlying esophageal malformations, however, are poorly understood. Here, we show that zebrafish Ihha signaling from the epithelium acting in parallel, but independently of Shh, controls epithelial and mesenchym... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246283 Wed, 07 Sep 2011 04:00:00 +0100 5246283 http://www.medworm.com/index.php?rid=5246290&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21924255%26dopt%3DAbstract Authors: Miyagaki Y, Kanemori Y, Baba T Abstract Ovulated oocytes are arrested at the metaphase of second meiotic division. The metaphase-II arrest in Xenopus oocytes is regulated by RSKs located downstream of the Mos-MAPK pathway. In mice, other kinase(s) besides RSKs may be responsible for the metaphase-II arrest, because RSK1/RSK2/RSK3-triple knockout mice exhibit no obvious phenotype. Here, we show the subcellular localization and possible role of mitogen- and stress-activated kinase 1, MSK1 known as another downstream kinase of the Mos-MAPK pathway, in the mouse oocytes. Immunostaining analysis indicated that MSK1 is present in the germinal vesicle (GV) and cytoplasm of oocytes at the GV and metaphase-II stages, respectively. An active, phosphorylated form of MSK1 was predomin... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246290 Mon, 05 Sep 2011 04:00:00 +0100 5246290 http://www.medworm.com/index.php?rid=5246289&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21924256%26dopt%3DAbstract Authors: Joeng KS, Schumacher C, Zylstra-Diegel CR, Long F, Williams BO Abstract The role of Wnt signaling in osteoblastogenesis in the embryo remains to be fully established. Although β-catenin, a multifunctional protein also mediating canonical Wnt signaling, is indispensable for embryonic osteoblast differentiation, the roles of the key Wnt co-receptors Lrp5 and Lrp6 are unclear. Indeed, global deletion of either Lrp5 or Lrp6 did not overtly affect osteoblast differentiation in the mouse embryo. Here, we generated mice lacking both receptors specifically in the embryonic mesenchyme and observed an absence of osteoblasts in the embryo. In addition, the double-deficient embryos developed supernumerary cartilage elements in the zeugopod, revealing an important role for mesenchymal... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246289 Mon, 05 Sep 2011 04:00:00 +0100 5246289 http://www.medworm.com/index.php?rid=5246288&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925156%26dopt%3DAbstract Authors: Huettl RE, Huber AB Abstract Interaction of the axon guidance receptor Neuropilin-1 (Npn-1) with its repulsive ligand Semaphorin 3A (Sema3A) is crucial for guidance decisions, fasciculation, timing of growth and axon-axon interactions of sensory and motor projections in the embryonic limb. At cranial levels, Npn-1 is expressed in motor neurons and sensory ganglia and loss of Sema3A-Npn-1 signaling leads to defasciculation of the superficial projections to the head and neck. The molecular mechanisms that govern the initial fasciculation and growth of the purely motor projections of the hypoglossal and abducens nerves in general, and the role of Npn-1 during these events in particular are, however, not well understood. We show here that selective removal of Npn-1 from somati... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5246288 Mon, 05 Sep 2011 04:00:00 +0100 5246288 http://www.medworm.com/index.php?rid=5229263&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920357%26dopt%3DAbstract In this study we show that Snai1 is highly expressed in endothelial, and newly transformed mesenchyme cells during EC development. Mice with targeted snai1 knockdown display hypocellular ECs at E10.5 associated with decreased expression of mesenchyme cell markers and downregulation of the matrix metalloproteinase (mmp) family member, mmp15. Snai1 overexpression studies in atrioventricular canal collagen I gel explants indicate that Snai1 is sufficient to promote mmp15 expression, cell transformation, and mesenchymal cell migration and invasion. However, treatment with the catalytically active form of MMP15 promotes cell motility, and not transformation. Further, we show that Snai1-mediated cell migration requires MMP activity, and caMMP15 treatment rescues attenuated migration defects obse... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5229263 Mon, 05 Sep 2011 04:00:00 +0100 5229263 http://www.medworm.com/index.php?rid=5229264&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920356%26dopt%3DAbstract In this study, we examine the possible contribution of one such source of prepattern, namely gene length. We developed quantitative imaging tools to measure gene expression levels for several loci at a time on a single-cell basis and applied these quantitative imaging tools to dissect the establishment of a gene expression border separating the mesoderm and neuroectoderm in the early Drosophila embryo. We first characterized the formation of a transient ventral-to-dorsal gradient of the Snail (Sna) repressor and then examined the relationship between this gradient and repression of neural target genes in the mesoderm. We found that neural genes are repressed in a nested pattern within a zone of the mesoderm abutting the neuroectoderm, where Sna levels are graded. While several factors may ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5229264 Sat, 03 Sep 2011 04:00:00 +0100 5229264 http://www.medworm.com/index.php?rid=5229266&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920354%26dopt%3DAbstract Authors: Singh A, Tare M, Kango-Singh M, Son WS, Cho KO, Choi KW Abstract Patterning in multi-cellular organisms involves progressive restriction of cell fates by generation of boundaries to divide an organ primordium into smaller fields. We have employed the Drosophila eye model to understand the genetic circuitry responsible for defining the boundary between the eye and the head cuticle on the ventral margin. The default state of the early eye is ventral and depends on the function of Lobe (L) and the Notch ligand Serrate (Ser). We identified homothorax (hth) as a strong enhancer of the L mutant phenotype of loss of ventral eye. Hth is a MEIS class gene with a highly conserved Meis-Hth (MH) domain and a homeodomain (HD). Hth is known to bind Extradenticle (Exd) via its MH domain ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5229266 Fri, 02 Sep 2011 04:00:00 +0100 5229266 http://www.medworm.com/index.php?rid=5229265&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920355%26dopt%3DAbstract This report shows that mutation of rbf and rhinoceros (rno), which encodes a PHD domain protein, leads to a synergistic delay in photoreceptor cell differentiation in the developing eye disc. We show that this differentiation delay phenotype is caused by decreased levels of different components of the Epidermal Growth Factor Receptor (EGFR) signaling pathway in the absence of rbf and rno. We show that rbf is required for normal expression of Rhomboid proteins and activation of MAP kinase in the morphogenetic furrow (MF), while rno is required for the expression of Pointed (Pnt) and Ebi proteins, which are key factors that mediate EGFR signaling output in the nucleus. Interestingly, while removing the transcription activation function of dE2F1 is sufficient to suppress the synergistic diffe... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5229265 Fri, 02 Sep 2011 04:00:00 +0100 5229265 http://www.medworm.com/index.php?rid=5218568&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889936%26dopt%3DAbstract Authors: Mattingly BC, Buechner M Abstract Maintenance of the shape of biological tubules is critical for development and physiology of metazoan organisms. Loss of function of the Caenorhabditis elegans FGD protein EXC-5 allows large fluid-filled cysts to form in the lumen of the single-cell excretory canal tubules, while overexpression of exc-5 causes defects at the tubule's basolateral surface. We have examined the effects of altering expression levels of exc-5 on the distribution of fluorescently-marked subcellular organelles. In exc-5 mutants, early endosomes build up in the cell, especially in areas close to cysts, while recycling endosomes are depleted. Endosome morphology changes prior to cyst formation. Conversely, when exc-5 is overexpressed, recycling endosomes are enrich... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218568 Fri, 26 Aug 2011 04:00:00 +0100 5218568 http://www.medworm.com/index.php?rid=5218569&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889935%26dopt%3DAbstract Authors: Edmonds JW, McKinney SL, Prasain JK, Miller MA Abstract Innexins are the subunits of invertebrate gap junctions. Here we show that the innexin INX-14 promotes sperm guidance to the fertilization site in the Caenorhabditis elegans hermaphrodite reproductive tract. inx-14 loss causes cell nonautonomous defects in sperm migration velocity and directional velocity. Results from genetic and immunocytochemical analyses provide strong evidence that INX-14 acts in transcriptionally active oocyte precursors in the distal gonad, not in transcriptionally inactive oocytes that synthesize prostaglandin sperm-attracting cues. Somatic gonadal sheath cell interaction is necessary for INX-14 function, likely via INX-8 and INX-9 expressed in sheath cells. However, electron microscopy has no... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218569 Thu, 25 Aug 2011 04:00:00 +0100 5218569 http://www.medworm.com/index.php?rid=5218567&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889937%26dopt%3DAbstract Authors: Lakiza O, Miller S, Bunce A, Lee EM, McCauley DW Abstract SoxE genes are multifunctional transcriptional regulators that play key roles in specification and differentiation of neural crest. Three members (Sox8, Sox9, Sox10) are expressed in the neural crest and are thought to modulate the expression and activity of each other. In addition to regulating the expression of other early neural crest marker genes, SoxE genes are required for development of cartilage. Here we investigated the role of SoxE genes in development of the neural crest-derived branchial skeleton in the sea lamprey. Using a morpholino knockdown approach, we show that all three SoxE genes described in lamprey are required for branchial basket development. Our results suggest that SoxE1 and SoxE2 are requi... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218567 Thu, 25 Aug 2011 04:00:00 +0100 5218567 http://www.medworm.com/index.php?rid=5218566&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889938%26dopt%3DAbstract Authors: Fabritius AS, Flynn JR, McNally FJ Abstract Polar body formation is an essential step in forming haploid eggs from diploid oocytes. This process involves completion of a highly asymmetric cytokinesis that results in a large egg and two small polar bodies. Unlike mitotic contractile rings, polar body contractile rings assemble over one spindle pole so that the spindle must move through the contractile ring before cytokinesis. During time-lapse imaging of C. elegans meiosis, the contractile ring moved downward along the length of the spindle and completed scission at the midpoint of the spindle, even when spindle length or rate of ring movement was increased. Patches of myosin heavy chain and dynamic furrowing of the plasma membrane over the entire embryo suggested that glob... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218566 Thu, 25 Aug 2011 04:00:00 +0100 5218566 http://www.medworm.com/index.php?rid=5218572&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21884692%26dopt%3DAbstract Authors: Richard AF, Demignon J, Sakakibara I, Pujol J, Favier M, Strochlic L, Le Grand F, Sgarioto N, Guernec A, Schmitt A, Cagnard N, Huang R, Legay C, Guillet-Deniau I, Maire P Abstract Adult skeletal muscles in vertebrates are composed of different types of myofibers endowed with distinct metabolic and contraction speed properties. Genesis of this fiber-type heterogeneity during development remains poorly known, at least in mammals. Six1 and Six4 homeoproteins of the Six/sine oculis family are expressed throughout muscle development in mice, and Six1 protein is enriched in the nuclei of adult fast-twitch myofibers. Furthermore, Six1/Six4 proteins are known to control the early activation of fast-type muscle genes in myocytes present in the mouse somitic myotome. Using double Si... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218572 Mon, 22 Aug 2011 04:00:00 +0100 5218572 http://www.medworm.com/index.php?rid=5218570&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21884694%26dopt%3DAbstract Authors: Galy A, Schenck A, Sahin HB, Qurashi A, Sahel JA, Diebold C, Giangrande A Abstract Cell rearrangements shape organs and organisms using molecular pathways and cellular processes that are still poorly understood. Here we investigate the role of the Actin cytoskeleton in the formation of the Drosophila compound eye, which requires extensive remodeling and coordination between different cell types. We show that CYFIP/Sra-1, a member of the WAVE/SCAR complex and regulator of Actin remodeling, controls specific aspects of eye architecture: rhabdomere extension, rhabdomere terminal web organization, adherens junctions, retina depth and basement membrane integrity. We demonstrate that some phenotypes manifest independently, due to defects in different cell types. Mutations in WAV... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218570 Mon, 22 Aug 2011 04:00:00 +0100 5218570 http://www.medworm.com/index.php?rid=5218571&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21884693%26dopt%3DAbstract This study demonstrates that Myo/Nog cells are essential regulators of BMP signaling in the early epiblast and are indispensable for normal morphogenesis and striated muscle lineage specification. PMID: 21884693 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5218571 Thu, 18 Aug 2011 04:00:00 +0100 5218571 http://www.medworm.com/index.php?rid=5175037&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21871877%26dopt%3DAbstract Authors: Sánchez NS, Hill CR, Love JD, Soslow JH, Craig E, Austin AF, Brown CB, Czirok A, Camenisch TD, Barnett JV Abstract The epicardium is a major contributor of the cells that are required for the formation of coronary vessels. Mice lacking both copies of the gene encoding the Type III Transforming Growth Factor β Receptor (TGFβR3) fail to form the coronary vasculature, but the molecular mechanism by which TGFβR3 signals coronary vessel formation is unknown. We used intact embryos and epicardial cells from E11.5 mouse embryos to reveal the mechanisms by which TGFβR3 signals and regulates epicardial cell behavior. Analysis of E13.5 embryos reveals a lower rate of epicardial cell proliferation and decreased epicardially derived cell invasion in Tgfbr3(-/-) hearts. Tgfbr3(-/-... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5175037 Wed, 17 Aug 2011 23:00:00 +0100 5175037 http://www.medworm.com/index.php?rid=5175039&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21864525%26dopt%3DAbstract Authors: McKinney MC, Kulesa PM Abstract Examining calcium dynamics within the neural crest (NC) has the potential to shed light on mechanisms that regulate complex cell migration and patterning events during embryogenesis. Unfortunately, typical calcium indicators are added to culture media or have low signal to noise after microinjection into tissue that severely limits analyses to cultured cells or superficial events. Here, we studied in vivo calcium dynamics during NC cell migration and patterning, using a genetically encoded calcium sensor, GCaMP3. We discovered that trunk NC cells displayed significantly more spontaneous calcium transients than cranial NC cells, and during cell aggregation versus cell migration events. Spontaneous calcium transients were more prevalent during... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5175039 Mon, 15 Aug 2011 23:00:00 +0100 5175039 http://www.medworm.com/index.php?rid=5175038&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21871448%26dopt%3DAbstract Authors: O'Brien LL, Grimaldi M, Kostun Z, Wingert RA, Selleck R, Davidson AJ Abstract Podocytes help form the glomerular blood filtration barrier in the kidney and their injury or loss leads to renal disease. The Wilms' tumor suppressor-1 (Wt1) and the FoxC1/2 transcription factors, as well as Notch signaling, have been implicated as important regulators of podocyte fate. It is not known whether these factors work in parallel or sequentially on different gene targets, or as higher-order transcriptional complexes on common genes. Here, we use the zebrafish to demonstrate that embryos treated with morpholinos against wt1a, foxc1a, or the Notch transcriptional mediator rbpj develop fewer podocytes, as determined by wt1b, hey1 and nephrin expression, while embryos deficient in any two... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5175038 Mon, 15 Aug 2011 23:00:00 +0100 5175038 http://www.medworm.com/index.php?rid=5175040&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21864524%26dopt%3DAbstract Authors: Onimaru K, Shoguchi E, Kuratani S, Tanaka M Abstract Possession of paired appendages is regarded as a novelty that defines crown gnathostomes and allows sophisticated behavioral and locomotive patterns. During embryonic development, initiation of limb buds in the lateral plate mesoderm involves several steps. First, the lateral plate mesoderm is regionalized into the cardiac mesoderm (CM) and the posterior lateral plate mesoderm (PLPM). Second, in the PLPM, Hox genes are expressed in a collinear manner to establish positional values along the anterior-posterior axis. The developing PLPM splits into somatic and splanchnic layers. In the presumptive limb field of the somatic layer, expression of limb initiation genes appears. To gain insight into the evolutionary sequence le... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5175040 Thu, 11 Aug 2011 23:00:00 +0100 5175040 http://www.medworm.com/index.php?rid=5175041&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21856296%26dopt%3DAbstract Authors: Mastracci TL, Wilcox C, Panea C, Golden JA, May CL, Sussel L Abstract Nkx2.2 and Arx are essential pancreatic transcription factors. Nkx2.2 is necessary for the appropriate specification of the islet alpha, beta, PP and epsilon cell lineages, whereas Arx is required to form the correct ratio of alpha, beta, delta and PP cells. To begin to understand the cooperative functions of Nkx2.2 and Arx in the development of endocrine cell lineages, we generated progenitor cell-specific deletions of Arx on the Nkx2.2 null background. The analysis of these mutants demonstrates that expansion of the ghrelin cell population in the Nkx2.2 null pancreas is not dependent on Arx; however, Arx is necessary for the upregulation of ghrelin mRNA levels in Nkx2.2 mutant epsilon cells. Alternativ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5175041 Wed, 10 Aug 2011 23:00:00 +0100 5175041 http://www.medworm.com/index.php?rid=5175042&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21854766%26dopt%3DAbstract Authors: Boeck ME, Boyle T, Bao Z, Murray J, Mericle B, Waterston R Abstract end-1 and end-3 are GATA transcription factors important for specifying endoderm cell fate in Caenorhabditis elegans. Deletion of both factors together results in larval arrest, 0% survival and a fate change in the endoderm-specifying E lineage. Individual deletions of either factor, however, result in the development of viable, fertile adults, with 100% of worms developing to adults for end-1(-) and 95% for end-3(-). We sought to quantify the variable phenotypes seen in both deletions using automated cell lineaging. We quantified defects in cell lifetime, cell movement and division axis in end-3(-) embryos, while quantifying perturbations in downstream reporter gene expression in strains with homozygous d... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5175042 Tue, 09 Aug 2011 23:00:00 +0100 5175042 http://www.medworm.com/index.php?rid=5097702&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21803034%26dopt%3DAbstract Authors: Darland DC, Cain JT, Berosik MA, Saint-Geniez M, Odens PW, Schaubhut GJ, Frisch S, Stemmer-Rachamimov A, Darland T, D'Amore PA This work was designed to determine the role of the vascular endothelial growth factor A (VEGF) isoforms during early neuroepithelial development in the mammalian central nervous system (CNS), specifically in the forebrain. An emerging model of interdependence between neural and vascular systems includes VEGF, with its dual roles as a potent angiogenesis factor and neural regulator. Although a number of studies have implicated VEGF in CNS development, little is known about the role that the different VEGF isoforms play in early neurogenesis. We used a mouse model of disrupted VEGF isoform expression that eliminates the predominant brain isoform, VEGF16... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097702 Wed, 27 Jul 2011 23:00:00 +0100 5097702 http://www.medworm.com/index.php?rid=5097707&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798254%26dopt%3DAbstract Authors: Kameda Y, Saitoh T, Fujimura T The lack of the Hes1 gene leads to the failure of cranial neurulation due to the premature onset of neural differentiation. Hes1 homozygous null mutant mice displayed a neural tube closure defect, and exencephaly was induced at the mid/hindbrain boundary. In the mutant mesencephalon, the roof plate was not formed and therefore the ventricular zone showing cell proliferation was displaced to the brain surface. Furthermore, the telencephalon and ventral diencephalon were defective. Despite the severe defects of neurogenesis in null mutants, the mesencephalic dopaminergic (mesDA) neurons were specified at the midline of the ventral mesencephalon in close proximity to two important signal centers - floor plate and mid/hindbrain boundary (i.e., the is... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097707 Fri, 22 Jul 2011 23:00:00 +0100 5097707 http://www.medworm.com/index.php?rid=5097706&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798255%26dopt%3DAbstract Authors: Hinits Y, Williams VC, Sweetman D, Donn TM, Ma TP, Moens CB, Hughes SM Myogenic regulatory factors of the myod family (MRFs) are transcription factors essential for mammalian skeletal myogenesis. Here we show that a mutation in the zebrafish myod gene delays and reduces early somitic and pectoral fin myogenesis, reduces miR-206 expression, and leads to a persistent reduction in somite size until at least the independent feeding stage. A mutation in myog, encoding a second MRF, has little obvious phenotype at early stages, but exacerbates the loss of somitic muscle caused by lack of Myod. Mutation of both myod and myf5 ablates all skeletal muscle. Haploinsufficiency of myod leads to reduced embryonic somite muscle bulk. Lack of Myod causes a severe reduction in cranial musculat... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097706 Fri, 22 Jul 2011 23:00:00 +0100 5097706 http://www.medworm.com/index.php?rid=5097705&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21801717%26dopt%3DAbstract Authors: Ando M, Totani Y, Walldorf U, Furukubo-Tokunaga K Precise neuronal connectivity in the nervous system depends on specific axonal and dendritic targeting of individual neurons. In the Drosophila brain, olfactory projection neurons convey odor information from the antennal lobe to higher order brain centers such as the mushroom body and the lateral horn. Here, we show that Homothorax (Hth), a TALE-class homeodomain transcription factor, is expressed in many of the antennal lobe neurons including projection neurons and local interneurons. In addition, HTH is expressed in the progenitors of the olfactory projection neurons, and the activity of hth is required for the generation of the lateral but not for the anterodorsal and ventral lineages. MARCM analyses show that the hth is es... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097705 Fri, 22 Jul 2011 23:00:00 +0100 5097705 http://www.medworm.com/index.php?rid=5097704&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21801718%26dopt%3DAbstract Authors: Sweet EM, Vemaraju S, Riley BB Atoh1 is required for differentiation of sensory hair cells in the vertebrate inner ear. Moreover, misexpression of Atoh1 is sufficient to establish ectopic sensory epithelia, making Atoh1 a good candidate for gene therapy to restore hearing. However, competence to form sensory epithelia appears to be limited to discrete regions of the inner ear. To better understand the developmental factors influencing sensory-competence, we examined the effects of misexpressing atoh1a in zebrafish embryos under various developmental conditions. Activation of a heat shock-inducible transgene, hs:atoh1a, resulted in ectopic expression of early markers of sensory development within 2h, and mature hair cells marked by brn3c:GFP began to accumulate 9h after heat sh... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097704 Fri, 22 Jul 2011 23:00:00 +0100 5097704 http://www.medworm.com/index.php?rid=5097699&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806977%26dopt%3DAbstract We present here data showing that interaction between FGF signaling and the canonical (β-catenin dependent) and non-canonical branches of Wnt signaling coordinates these two processes. Using the Axin2(lacZ) reporter mice, we find Wnt/β-catenin signaling activity first in the mesenchyme and later, at the time of lumen formation, in the ductal epithelium. Gain and loss of function experiments reveal that this pathway exerts an inhibitory effect on salivary gland branching morphogenesis. We have found that endbuds remain devoid of Wnt/β-catenin signaling activity, a hallmark of ductal structures, through FGF-mediated inhibition of this pathway. Our data also show that FGF signaling has a major role in the control of lumen formation by preventing premature hollowing of epithelial endbuds an... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097699 Fri, 22 Jul 2011 23:00:00 +0100 5097699 http://www.medworm.com/index.php?rid=5097697&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806979%26dopt%3DAbstract Authors: Simrick S, Lickert H, Basson MA Fibroblast growth factor (FGF) signalling has important roles in the development of the embryonic pharyngeal (branchial) arches, but its effects on innervation of the arches and associated structures have not been studied extensively. We investigated the consequences of deleting two receptor tyrosine kinase (RTK) antagonists of the Sprouty (Spry) gene family on the early development of the branchial nerves. The morphology of the facial, glossopharyngeal and vagus nerves are abnormal in Spry1-/-;Spry2-/- embryos. We identify specific defects in the epibranchial placodes and neural crest, which contribute sensory neurons and glia to these nerves. A dissection of the tissue-specific roles of these genes in branchial nerve development shows that Spr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097697 Fri, 22 Jul 2011 23:00:00 +0100 5097697 http://www.medworm.com/index.php?rid=5097696&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806980%26dopt%3DAbstract In this study, we report that DSulfatase-1 (DSulf1), the unique Drosophila Sulf protein, is a regulator of Hedgehog (Hh) signalling during wing development. DSulf1 activity is required in both Hh source and Hh receiving cells for proper positioning of Hh target gene expression boundaries. As assessed by loss- and gain-of-function experiments in specific compartments, DSulf1 displays dual functions with respect to Hh signalling, acting as a positive regulator in Hh producing cells and a negative regulator in Hh receiving cells. In either domain, DSulf1 modulates Hh distribution by locally lowering the concentration of the morphogen at the apical pole of wing disc cells. Thus, we propose that DSulf1, by its desulfation catalytic activity, lowers Hh/HSPG interaction in both Hh source and targ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097696 Fri, 22 Jul 2011 23:00:00 +0100 5097696 http://www.medworm.com/index.php?rid=5097695&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21810415%26dopt%3DAbstract Authors: Huang E, Talukder S, Hughes TR, Curk T, Zupan B, Shaulsky G, Katoh-Kurasawa M The cAMP response element-binding protein (CREB) is a highly conserved transcription factor that integrates signaling through the cAMP-dependent protein kinase A (PKA) in many eukaryotes. PKA plays a critical role in Dictyostelium development but no CREB homologue has been identified in this system. Here we show that Dictyostelium utilizes a CREB-like protein, BzpF, to integrate PKA signaling during late development. bzpF(-) mutants produce compromised spores, which are extremely unstable and germination defective. Previously, we have found that BzpF binds the canonical CRE motif in vitro. In this paper, we determined the DNA binding specificity of BzpF using protein binding microarray (PBM) and show... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097695 Fri, 22 Jul 2011 23:00:00 +0100 5097695 http://www.medworm.com/index.php?rid=5097711&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21787765%26dopt%3DAbstract Authors: Choe SK, Zhang X, Hirsch N, Straubhaar J, Sagerström CG Segmentation of the vertebrate hindbrain into multiple rhombomeres is essential for proper formation of the cerebellum, cranial nerves and cranial neural crest. Paralog group 1 (PG1) hox genes are expressed early in the caudal hindbrain and are required for rhombomere formation. Accordingly, loss of PG1 hox function disrupts development of caudal rhombomeres in model organisms and causes brainstem defects, associated with cognitive impairment, in humans. In spite of this important role for PG1 hox genes, transcriptional targets of PG1 proteins are not well characterized. Here we use ectopic expression together with embryonic dissection to identify novel targets of the zebrafish PG1 gene hoxb1b. Of 100 genes up-regulated ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097711 Thu, 21 Jul 2011 23:00:00 +0100 5097711 http://www.medworm.com/index.php?rid=5097703&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21802414%26dopt%3DAbstract In this study, we demonstrate that deficiency for MMP9 in combination with ablation of either uPA- or tissue-type plasminogen activator (tPA)-catalyzed plasminogen activation is critical to accomplish normal gestation in mice. Gestation was also affected by simultaneous lack of MMP9 and the uPA receptor (uPAR). Interestingly, uPA-deficiency additionally exacerbated the effect of MMP9-deficiency on bone growth and an additive effect caused by combined lack in MMP9 and uPA was observed during healing of cutaneous wounds. By comparison, MMP9-deficiency combined with absence of either tPA or uPAR resulted in no significant effect on wound healing, indicating that the role of uPA during wound healing is independent of uPAR, when MMP9 is absent. Notably, compensatory upregulation of uPA activity... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097703 Thu, 21 Jul 2011 23:00:00 +0100 5097703 http://www.medworm.com/index.php?rid=5097701&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21803035%26dopt%3DAbstract Authors: Bell SM, Zhang L, Mendell A, Xu Y, Haitchi HM, Lessard JL, Whitsett JA Kruppel-like transcription factor 5 (Klf5) was detected in the developing and mature murine bladder urothelium. Herein we report a critical role of KLF5 in the formation and terminal differentiation of the urothelium. The Shh(GfpCre) transgene was used to delete the Klf5(floxed) alleles from bladder epithelial cells causing prenatal hydronephrosis, hydroureter, and vesicoureteric reflux. The bladder urothelium failed to stratify and did not express terminal differentiation markers characteristic of basal, intermediate, and umbrella cells including keratins 20, 14, and 5, and the uroplakins. The effects of Klf5 deletion were unique to the developing bladder epithelium since maturation of the epithelium compr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097701 Thu, 21 Jul 2011 23:00:00 +0100 5097701 http://www.medworm.com/index.php?rid=5097700&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21803036%26dopt%3DAbstract Authors: Sorrell MR, Waxman JS Cardiomelic or heart-hand syndromes include congenital defects affecting both the forelimb and heart, suggesting a hypothesis where similar signals may coordinate their development. In support of this hypothesis, we have recently defined a mechanism by which retinoic acid (RA) signaling acts on the forelimb progenitors to indirectly restrict cardiac cell number. However, we still do not have a complete understanding of the mechanisms downstream of RA signaling that allow for the coordinated development of these structures. Here, we test the hypothesis that appropriate Fgf signaling in the cardiac progenitor field downstream of RA signaling is required for the coordinated development of the heart and forelimb. Consistent with this hypothesis, we find that ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097700 Thu, 21 Jul 2011 23:00:00 +0100 5097700 http://www.medworm.com/index.php?rid=5097709&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21791202%26dopt%3DAbstract Authors: Wang S, Yang J, Tsai A, Kuca T, Sanny J, Lee J, Dong K, Harden N, Krieger C Adducin is a cytoskeletal protein having regulatory roles that involve actin filaments, functions that are inhibited by phosphorylation of adducin by protein kinase C. Adducin is hyperphosphorylated in nervous system tissue in patients with the neurodegenerative disease amyotrophic lateral sclerosis, and mice lacking β-adducin have impaired synaptic plasticity and learning. We have found that Drosophila adducin, encoded by hu-li tai shao (hts), is localized to the post-synaptic larval neuromuscular junction (NMJ) in a complex with the scaffolding protein Discs large (Dlg), a regulator of synaptic plasticity during growth of the NMJ. hts mutant NMJs are underdeveloped, whereas over-expression of Hts pr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097709 Wed, 20 Jul 2011 23:00:00 +0100 5097709 http://www.medworm.com/index.php?rid=5097710&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21787766%26dopt%3DAbstract Authors: He X, Yan YL, Eberhart JK, Herpin A, Wagner TU, Schartl M, Postlethwait JH Vertebrate Hox clusters contain protein-coding genes that regulate body axis development and microRNA (miRNA) genes whose functions are not yet well understood. We overexpressed the Hox cluster microRNA miR-196 in zebrafish embryos and found four specific, viable phenotypes: failure of pectoral fin bud initiation, deletion of the 6th pharyngeal arch, homeotic aberration and loss of rostral vertebrae, and reduced number of ribs and somites. Reciprocally, miR-196 knockdown evoked an extra pharyngeal arch, extra ribs, and extra somites, confirming endogenous roles of miR-196. miR-196 injection altered expression of hox genes and the signaling of retinoic acid through the retinoic acid receptor gene rarab. ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097710 Tue, 19 Jul 2011 23:00:00 +0100 5097710 http://www.medworm.com/index.php?rid=5097698&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21806978%26dopt%3DAbstract Authors: Iglesias M, Almuedo-Castillo M, Aboobaker AA, Saló E Analysis of anteroposterior (AP) axis specification in regenerating planarian flatworms has shown that Wnt/β-catenin signaling is required for posterior specification and that the FGF-like receptor molecule nou-darake (ndk) may be involved in restricting brain regeneration to anterior regions. The relationship between re-establishment of AP identity and correct morphogenesis of the brain is, however, still poorly understood. Here we report the characterization of two axin paralogs in the planarian Schmidtea mediterranea. Although Axins are well known negative regulators of Wnt/β-catenin signaling, no role in AP specification has previously been reported for axin genes in planarians. We show that silencing of Smed-axin gen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097698 Tue, 19 Jul 2011 23:00:00 +0100 5097698 http://www.medworm.com/index.php?rid=5097714&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784065%26dopt%3DAbstract Authors: Makki N, Capecchi MR Hox genes play a crucial role during embryonic patterning and organogenesis. Of the 39 Hox genes, Hoxa1 is the first to be expressed during embryogenesis and the only anterior Hox gene linked to a human syndrome. Hoxa1 is necessary for the proper development of the brainstem, inner ear and heart in humans and mice; however, almost nothing is known about the molecular downstream targets through which it exerts its function. To gain insight into the transcriptional network regulated by this protein, we performed microarray analysis on tissue microdissected from the prospective rhombomere 3-5 region of Hoxa1 null and wild type embryos. Due to the very early and transient expression of this gene, dissections were performed on early somite stage embryos during ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097714 Sun, 17 Jul 2011 23:00:00 +0100 5097714 http://www.medworm.com/index.php?rid=5097713&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784066%26dopt%3DAbstract Authors: Saha S, Kashina A Posttranslational modifications constitute a major field of emerging biological significance as mounting evidence demonstrates their key role in multiple physiological processes. Following in the footsteps of protein phosphorylation studies, new modifications are being shown to regulate protein properties and functions in vivo. Among such modifications, an important role belongs to protein arginylation - posttranslational tRNA-mediated addition of arginine, mediated by arginyltransferase, Ate1. Recent studies show that arginylation is essential for embryogenesis in many organisms and that it regulates such important processes as heart development, angiogenesis, and tissue morphogenesis in mammals. This review summarizes the key data in the protein arginylatio... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097713 Sun, 17 Jul 2011 23:00:00 +0100 5097713 http://www.medworm.com/index.php?rid=5097712&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784067%26dopt%3DAbstract Authors: Schindler AJ, Sherwood DR Cell invasion through basement membrane is a specialized cellular behavior critical for many developmental processes and leukocyte trafficking. Invasive cellular behavior is also inappropriately co-opted during cancer progression. Acquisition of an invasive phenotype is accompanied by changes in gene expression that are thought to coordinate the steps of invasion. The transcription factors responsible for these changes in gene expression, however, are largely unknown. C. elegans anchor cell (AC) invasion is a genetically tractable in vivo model of invasion through basement membrane. AC invasion requires the conserved transcription factor FOS-1A, but other transcription factors are thought to act in parallel to FOS-1A to control invasion. Here we ident... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097712 Sun, 17 Jul 2011 23:00:00 +0100 5097712 http://www.medworm.com/index.php?rid=5097708&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798253%26dopt%3DAbstract Authors: Xiong H, Mohler WA, Soto MC Regulated movements of the nucleus are essential during zygote formation, cell migrations, and differentiation of neurons. The nucleus moves along microtubules (MTs) and is repositioned on F-actin at the cellular cortex. Two families of nuclear envelope proteins, SUN and KASH, link the nucleus to the actin and MT cytoskeletons during nuclear movements. However, the role of actin nucleators in nuclear migration and positioning is poorly understood. We show that the branched actin nucleator, Arp2/3, affects nuclear movements throughout embryonic and larval development in C. elegans, including nuclear migrations in epidermal cells and neuronal precursors. In one-cell embryos the migration of the male pronucleus to meet the female pronucleus after ferti... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097708 Sun, 17 Jul 2011 23:00:00 +0100 5097708 http://www.medworm.com/index.php?rid=5097716&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21782810%26dopt%3DAbstract Authors: Vazquez-Pianzola P, Urlaub H, Suter B RNA localization is tightly coordinated with RNA stability and translation control. Bicaudal-D (Bic-D), Egalitarian (Egl), microtubules and their motors are part of a Drosophila transport machinery that localizes mRNAs to specific cellular regions during oogenesis and embryogenesis. We identified the Poly(A)-binding protein (Pabp) as a protein that forms an RNA-dependent complex with Bic-D in embyros and ovaries. pabp also interacts genetically with Bic-D and, similar to Bic-D, pabp is essential in the germline for oocyte growth and accumulation of osk mRNA in the oocyte. In the absence of pabp, reduced stability of osk mRNA and possibly also defects in osk mRNA transport prevent normal oocyte localization of osk mRNA. pabp also interacts ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097716 Wed, 13 Jul 2011 23:00:00 +0100 5097716 http://www.medworm.com/index.php?rid=5097715&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21782811%26dopt%3DAbstract Authors: Farjo KM, Moiseyev G, Nikolaeva O, Sandell LL, Trainor PA, Ma JX Retinoic acid (atRA) signaling is essential for regulating embryonic development, and atRA levels must be tightly controlled in order to prevent congenital abnormalities and fetal death which can result from both excessive and insufficient atRA signaling. Cellular enzymes synthesize atRA from Vitamin A, which is obtained from dietary sources. Embryos express multiple enzymes that are biochemically capable of catalyzing the initial step of Vitamin A oxidation, but the precise contribution of these enzymes to embryonic atRA synthesis remains unknown. Using Rdh10(trex)-mutant embryos, dietary supplementation of retinaldehyde, and retinol dehydrogenase (RDH) activity assays, we demonstrate that RDH10 is the primary R... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097715 Wed, 13 Jul 2011 23:00:00 +0100 5097715 http://www.medworm.com/index.php?rid=5097717&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21777575%26dopt%3DAbstract Authors: Cox JA, Lamora A, Johnson SL, Voigt MM The formation of branchiomeric nerves (cranial nerves V, VII, IX and X) from their sensory, motor and glial components is poorly understood. The current model for cranial nerve formation is based on the Vth nerve, in which sensory afferents are formed first and must enter the hindbrain in order for the motor efferents to exit. Using transgenic zebrafish lines to discriminate between motor neurons, sensory neurons and peripheral glia, we show that this model does not apply to the remaining three branchiomeric nerves. For these nerves, the motor efferents form prior to the sensory afferents, and their pathfinding show no dependence on sensory axons, as ablation of cranial sensory neurons by ngn1 knockdown had no effect. In contrast, the sen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5097717 Tue, 12 Jul 2011 23:00:00 +0100 5097717 http://www.medworm.com/index.php?rid=5051681&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21771589%26dopt%3DAbstract Authors: Cappello S, Monzo P, Vallee RB NudC is a highly conserved protein necessary for cytoplasmic dynein-mediated nuclear migration in Aspergillus nidulans. NudC interacts genetically with Aspergillus NudF and physically with its mammalian orthologue Lis1, which is crucial for nuclear and neuronal migration during brain development. To test for related roles for NudC, we performed in utero electroporation into embryonic rat brain of cDNAs encoding shRNAs as well as wild-type and mutant forms of NudC. We show here that NudC, like Lis1, is required for neuronal migration during neocorticogenesis and we identify a specific role in apical nuclear migration in radial glial progenitor cells. These results identify a novel neuronal migration gene with a specific role in interkinetic nuclea... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5051681 Tue, 12 Jul 2011 23:00:00 +0100 5051681 http://www.medworm.com/index.php?rid=5051688&cid=s_35510_62_f&fid=35510&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21745462%26dopt%3DAbstract Authors: Maddala R, Skiba NP, Lalane R, Sherman DL, Brophy PJ, Rao PV Transparency of the ocular lens depends on symmetric packing and membrane organization of highly elongated hexagonal fiber cells. These cells possess an extensive, well-ordered cortical cytoskeleton to maintain cell shape and to anchor membrane components. Periaxin (Prx), a PDZ domain protein involved in myelin sheath stabilization, is also a component of adhaerens plaques in lens fiber cells. Here we show that Prx is expressed in lens fibers and exhibits maturation dependent redistribution, clustering discretely at the tricellular junctions in mature fiber cells. Prx exists in a macromolecular complex with proteins involved in membrane organization including ankyrin-B, spectrin, NrCAM, filensin, ezrin and desmoyokin... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5051688 Fri, 01 Jul 2011 23:00:00 +0100 5051688