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. Sat, 20 Mar 2010 16:04:27 +0100 http://www.medworm.com/index.php?rid=3328037&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%3D20188234%26dopt%3DAbstract Authors: Krumlauf R, Levine M PMID: 20188234 [PubMed - in process] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3328037 Thu, 04 Mar 2010 07:56:19 +0100 3328037 http://www.medworm.com/index.php?rid=3328033&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%3D20193674%26dopt%3DAbstract Authors: Williams C, Kim SH, Ni TT, Mitchell L, Ro H, Penn JS, Baldwin SH, Solnica-Krezel L, Zhong TP In vertebrate embryos, the dorsal aorta and the posterior cardinal vein form in the trunk to comprise the original circulatory loop. Previous studies implicate Hedgehog (Hh) signaling in the development of the dorsal aorta. However, the mechanism controlling specification of artery versus vein remains unclear. Here, we investigated the cell-autonomous mechanism of Hh signaling in angioblasts (endothelial progenitor cells) during arterial-venous specification utilizing zebrafish mutations in Smoothened (Smo), a G protein-coupled receptor essential for Hh signalling. smo mutants exhibit an absence of the dorsal aorta accompanied by a reciprocal expansion of the posterior cardinal vein. T... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3328033 Fri, 26 Feb 2010 00:00:00 +0100 3328033 http://www.medworm.com/index.php?rid=3328032&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%3D20193675%26dopt%3DAbstract Authors: Hosokawa R, Oka K, Yamaza T, Iwata J, Urata M, Xu X, Bringas P, Nonaka K, Chai Y Skeletal muscles are formed from two cell lineages, myogenic and fibroblastic. Mesoderm-derived myogenic progenitors form muscle cells whereas fibroblastic cells give rise to the supportive connective tissue of skeletal muscles, such as the tendons and perimysium. It remains unknown how myogenic and fibroblastic cell-cell interactions affect cell fate determination and the organization of skeletal muscle. In the present study, we investigated the functional significance of cell-cell interactions in regulating skeletal muscle development. Our study shows that cranial neural crest (CNC) cells give rise to the fibroblastic cells of the tongue skeletal muscle in mice. Loss of Tgfbr2 in CNC cells (Wnt1... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3328032 Fri, 26 Feb 2010 00:00:00 +0100 3328032 http://www.medworm.com/index.php?rid=3328036&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%3D20188721%26dopt%3DAbstract Authors: Tannoury H, Rodriguez V, Kovacevic I, Ibourk M, Lee M, Cram EJ The two specialized C. elegans distal tip cells (DTCs) provide an in vivo model system for the study of developmentally regulated cell migration. We identified cacn-1/cactin, a well-conserved, novel regulator of cell migration in a genome-wide RNAi screen for regulators of DTC migration. RNAi depletion experiments and analysis of the hypomorphic allele cacn-1(tm3126) indicate that CACN-1 is required during DTC migration for proper pathfinding and for cessation of DTC migration at the end of larval morphogenesis. Strong expression of CACN-1 in the DTCs, and data from cell-specific RNAi depletion experiments, suggest that CACN-1 is required cell-autonomously to control DTC migration. Importantly, genetic interaction ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3328036 Wed, 24 Feb 2010 00:00:00 +0100 3328036 http://www.medworm.com/index.php?rid=3328035&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%3D20188722%26dopt%3DAbstract Authors: van Eekelen M, Runtuwene V, Overvoorde J, den Hertog J Convergence and extension (C&E) cell movements are essential to shape the body axis during vertebrate gastrulation. We have used the zebrafish to assess the role of the receptor protein-tyrosine phosphatases, RPTPalpha and PTPepsilon, in gastrulation cell movements. Both RPTPalpha and PTPepsilon knockdown and ptpra(-/-) embryos show defects in C&E movements. A method was developed to track gastrulation cell movements using confocal microscopy in a quantitative manner and ptpra(-/-) embryos displayed reduced convergence as well as extension speeds. RPTPalpha and PTPepsilon knockdowns cooperated with knockdown of a well known factor in C&E cell movement, non-canonical Wnt11. RPTPalpha and PTPepsilon dephosphoryla... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3328035 Wed, 24 Feb 2010 00:00:00 +0100 3328035 http://www.medworm.com/index.php?rid=3328034&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%3D20188723%26dopt%3DAbstract Authors: Fisher K, Southall SM, Wilson JR, Poulin GB The conserved Mixed Lineage Leukaemia (MLL) complex deposits activating methyl marks on histone tails through a methyltransferase (MT) activity. Here we provide in vivo evidence that in addition to methylation, the C. elegans MLL-like complex can remove specific methyl marks linked to repression of transcription. This supports the proposed model in which the MLL complex orchestrates both the deposition and the removal of methyl marks to activate transcription. We have uncovered the MLL-like complex in a large-scale RNAi screen designed to identify attenuators of RAS signalling during vulval development. We have also found that the histone acetyltransferase complex, NuA4/TIP60, cooperates with the C. elegans MLL-like complex in the at... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3328034 Wed, 24 Feb 2010 00:00:00 +0100 3328034 http://www.medworm.com/index.php?rid=3315479&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%3D20184871%26dopt%3DAbstract Authors: Thomas PS, Kim J, Nunez S, Glogauer M, Kaartinen V The small GTP-binding protein Rac1, a member of the Rho family of small GTPases, has been implicated in regulation of many cellular processes including adhesion, migration and cytokinesis. These functions have largely been attributed to its ability to reorganize cytoskeleton. While the function of Rac1 is relatively well known in vitro, its role in vivo has been poorly understood. It has previously been shown that in neural crest cells (NCCs) Rac1 is required in a stage-specific manner to acquire responsiveness to mitogenic EGF signals. Here we demonstrate that mouse embryos lacking Rac1 in neural crest cells (Rac1/Wnt1-Cre) showed abnormal craniofacial development including regional ectodermal detachment associated with mesen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3315479 Mon, 22 Feb 2010 00:00:00 +0100 3315479 http://www.medworm.com/index.php?rid=3311205&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%3D20178780%26dopt%3DAbstract We report the presence of a single point mutation in Tmed2/p24beta(1) in a mutant mouse line, 99J, identified in an ENU mutagenesis screen for recessive developmental abnormalities. This mutation does not affect Tmed2/ p24beta(1) mRNA levels but results in loss of TMED2/p24beta(1) protein. Prior to death at mid-gestation, 99J homozygous mutant embryos exhibit developmental delay, abnormal rostral-caudal elongation, randomized heart looping, and absence of the labyrinth layer of the placenta. We find that Tmed2/ p24beta(1) is normally expressed in tissues showing morphological defects in 99J mutant embryos and that these affected tissues lack the TMED2/p24beta(1) oligomerization partners, TMED7/p24gamma(3) and TMED10/p24delta(1). Our data reveal a requirement for TMED2/p24beta(1) protein in... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3311205 Sat, 20 Feb 2010 00:00:00 +0100 3311205 http://www.medworm.com/index.php?rid=3311204&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%3D20178781%26dopt%3DAbstract Authors: Dumas KJ, Guo C, Wang X, Burkhart KB, Adams EJ, Alam H, Hu PJ Steroid hormone and insulin/insulin-like growth factor signaling (IIS) pathways control development and lifespan in the nematode Caenorhabditis elegans by regulating the activity of the nuclear receptor DAF-12 and the FoxO transcription factor DAF-16, respectively. The DAF-12 ligands Delta(4)- and Delta(7)-dafachronic acid (DA) promote bypass of the dauer diapause and proper gonadal migration during larval development; in adults, DAs influence lifespan. Whether Delta(4)- and Delta(7)-DA have unique biological functions is not known. We identified the 3-beta-hydroxysteroid dehydrogenase (3betaHSD) family member HSD-1, which participates in Delta(4)-DA biosynthesis, as an inhibitor of DAF-16/FoxO activity. Whereas IIS... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3311204 Sat, 20 Feb 2010 00:00:00 +0100 3311204 http://www.medworm.com/index.php?rid=3311203&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%3D20178782%26dopt%3DAbstract Authors: Nguyen CT, Langenbacher A, Hsieh M, Chen JN Leo1 is a component of the Polymerase-Associated Factor 1 (PAF1) complex, an evolutionarily conserved protein complex involved in gene transcription regulation and chromatin remodeling. The role of leo1 in vertebrate embryogenesis has not previously been examined. Here, we report that zebrafish leo1 encodes a nuclear protein that has a similar molecular structure to Leo1 proteins from other species. From a genetic screen, we identified a zebrafish mutant defective in the leo1 gene. The truncated Leo1(LA1186) protein lacks a nuclear localization signal and is distributed mostly in the cytoplasm. Phenotypic analysis showed that while the initial patterning of the primitive heart tube is not affected in leo1(LA1186) mutant embryos, the ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3311203 Sat, 20 Feb 2010 00:00:00 +0100 3311203 http://www.medworm.com/index.php?rid=3302839&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%3D20171962%26dopt%3DAbstract Authors: Hrycaj S, Chesebro J, Popadić A The cockroach, Periplaneta americana represents a basal insect lineage that undergoes the ancestral hemimetabolous mode of development. Here, we examine the embryonic and post-embryonic functions of the hox gene Scr in Periplaneta as a way of better understanding the roles of this gene in the evolution of insect body plans. During embryogenesis, Scr function is strictly limited to the head with no role in the prothorax. This indicates that the ancestral embryonic function of Scr was likely restricted to the head, and that the posterior expansion of expression in the T1 legs may have preceded any apparent gain of function during evolution. In addition, Scr plays a pivotal role in the formation of the dorsal ridge, a structure that separates... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302839 Thu, 18 Feb 2010 00:00:00 +0100 3302839 http://www.medworm.com/index.php?rid=3302846&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%3D20171200%26dopt%3DAbstract Authors: Wada H, Ghysen A, Satou C, Higashijima SI, Kawakami K, Hamaguchi S, Sakaizumi M The lateral line system displays highly divergent patterns in adult teleost fish. The mechanisms underlying this variability are poorly understood. Here, we demonstrate that the lateral line mechanoreceptor, the neuromast, gives rise to a series of accessory neuromasts by a serial budding process during postembryonic development in zebrafish. We also show that accessory neuromast formation is highly correlated to the development of underlying dermal structures such as bones and scales. Abnormalities in opercular bone morphogenesis, in endothelin 1-knockdown embryos, is accompanied by stereotypic errors in neuromast budding and positioning, further demonstrating the tight correlation between the pat... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302846 Wed, 17 Feb 2010 00:00:00 +0100 3302846 http://www.medworm.com/index.php?rid=3302845&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%3D20171201%26dopt%3DAbstract Authors: Sotillos S, Espinosa-Vázquez JM, Foglia F, Hu N, Hombría JC The ventral veinless (vvl) and trachealess (trh) genes are determinants of the Drosophila trachea. Early in development both genes are independently activated in the tracheal primordia by signals that are ill defined. Mutants blocking JAK/STAT signalling at any level do not form a tracheal tree suggesting that STAT92E may be an upstream transcriptional activator of the early trachea determinants. To test this hypothesis we have searched for STAT92E responsive enhancers activating the expression of vvl and trh in the tracheal primordia. We show that STAT92E regulated enhancers can be rapidly and efficiently isolated by focusing the analysis on genomic regions with clusters of putative STAT binding sites where... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302845 Wed, 17 Feb 2010 00:00:00 +0100 3302845 http://www.medworm.com/index.php?rid=3302844&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%3D20171202%26dopt%3DAbstract Authors: Koenig SF, Brentle S, Hamdi K, Fichtner D, Wedlich D, Gradl D Among Xenopus Lef/Tcfs, XTcf-4 has an outstanding role. In early development it is located exclusively in the midbrain where it is essential for midbrain and isthmus development. In order to identify transcription factors responsible for the restriction of XTcf-4 expression we isolated a 3.8 kb fragment of the XTcf-4 promoter. We found that this promoter fragment is sufficient to mimic endogenous XTcf-4 expression in the midbrain. Characterization of putative binding sites for en2 and pax2/5 revealed that en2, but not pax2/5 directly represses XTcf-4 promoter activity. Gain-of-function experiments in Xenopus embryos confirmed this en2-mediated repression. Loss-of-function experiments demonstrate that both en2 and pa... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302844 Wed, 17 Feb 2010 00:00:00 +0100 3302844 http://www.medworm.com/index.php?rid=3302843&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%3D20171203%26dopt%3DAbstract In conclusion, Hoxa1 lineage-tracing uncovered new domains of Hoxa1 expression in rhombomere 3, the otic epithelium and cardiac precursors, suggesting a more direct role for Hoxa1 in development of these tissues than previously believed. PMID: 20171203 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302843 Wed, 17 Feb 2010 00:00:00 +0100 3302843 http://www.medworm.com/index.php?rid=3302842&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%3D20171204%26dopt%3DAbstract Authors: Kuraku S, Takio Y, Sugahara F, Takechi M, Kuratani S In jawed vertebrates, the Dlx code, or nested expression patterns of Dlx genes, specify the dorsoventral polarity of pharyngeal arches, downstream of endothelin-1 (Edn-1) and its effectors, Bapx1 (Nkx3.2) and dHand (Hand2). To elucidate the evolution of the specification mechanism of the oropharyngeal skeletal system, lamprey homologs of Dlx, Edn, endothelin receptor (Ednr), Bapx1, and dHand were identified. Our analysis suggested that the Edn gene family emerged at the advent of vertebrates, and that gene duplications leading to the different Edn gnathostome subtypes (Edn1-3) occurred before the cyclostome-gnathostome split. This timing of gene duplications, giving rise to multiple subtypes, was also implied for Dlx, Ednr, ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302842 Wed, 17 Feb 2010 00:00:00 +0100 3302842 http://www.medworm.com/index.php?rid=3302841&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%3D20171205%26dopt%3DAbstract Authors: Quiñones HI, Savage TK, Battiste J, Johnson JE The bHLH transcription factor Neurog1 (Ngn1, Neurod3, neurogenin 1) is involved in neuronal differentiation and cell-type specification in distinct regions of the developing nervous system. Here, transgenic mouse models were developed that use a Bacterial Artificial Chromosome (BAC) containing 208kb flanking the Neurog1 gene to efficiently drive expression of GFP and Cre in all Neurog1 domains. Two characteristics of Neurog1 gene regulation were uncovered. First, a 4kb region previously shown to be sufficient for driving expression of a reporter gene to a subset of the Neurog1 pattern in the developing midbrain, hindbrain, and spinal cord is required uniformly for high levels of expression in all Neurog1 domains, even those n... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302841 Wed, 17 Feb 2010 00:00:00 +0100 3302841 http://www.medworm.com/index.php?rid=3302840&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%3D20171206%26dopt%3DAbstract Authors: Urness LD, Paxton CN, Wang X, Schoenwolf GC, Mansour SL The inner ear epithelium, with its complex array of sensory, non-sensory, and neuronal cell types necessary for hearing and balance, is derived from a thickened patch of head ectoderm called the otic placode. Mouse embryos lacking both Fgf3 and Fgf10 fail to initiate inner ear development because appropriate patterns of gene expression fail to be specified within the pre-otic field. To understand the transcriptional "blueprint" initiating inner ear development, we used microarray analysis to identify prospective placode genes that were differentially expressed in control and Fgf3(-/-);Fgf10(-/-) embryos. Several genes in the down-regulated class, including Hmx3, Hmx2, Foxg1, Sox9, Has2, and Slc26a9 were validated by in si... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302840 Wed, 17 Feb 2010 00:00:00 +0100 3302840 http://www.medworm.com/index.php?rid=3302847&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%3D20170648%26dopt%3DAbstract Authors: Liu F, Smith J, Zhang Z, Cole R, Herron BJ Angiogenesis, the formation of new blood vessels from existing vasculature, is a complex process that is essential for normal embryonic development. Current models for experimental evaluation of angiogenesis often use tissue from large vessels like the aorta and umbilical vein, which are phenotypically distinct from microvasculature. We demonstrate that the utilization of skin to measure microvascular angiogenesis in embryonic and adult tissues is an efficient way to quantify microvasculature angiogenesis. We validate this approach and demonstrate its added value by showing significant differences in angiogenesis in monogenic and polygenic mouse models. We discovered that the pattern of angiogenic response among inbred mouse strains i... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3302847 Tue, 16 Feb 2010 00:00:00 +0100 3302847 http://www.medworm.com/index.php?rid=3276611&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%3D20153744%26dopt%3DAbstract Authors: Barske LA, Capel B Production of male offspring in viviparous eutherian mammals requires a sex-determining mechanism resistant to maternal hormones. This constraint is relaxed in egg-laying species, which are sensitive to hormones during sex determination and often use an increase in aromatase, the estrogen-synthesizing enzyme, as a key feminizing signal. In the turtle Trachemys scripta, sex is normally determined by temperature, but estrogen treatment overrides this cue and leads exclusively to female development. We assessed whether the expression of SOX9, a central male sex-determining gene in mammals, or three other conserved transcription factors (WT1, GATA4, and LHX9) were regulated by estrogen signaling in the turtle. As in mice, all somatic cell types in the immature t... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276611 Thu, 11 Feb 2010 00:00:00 +0100 3276611 http://www.medworm.com/index.php?rid=3276612&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%3D20153311%26dopt%3DAbstract Authors: Aze A, Fayet C, Lapasset L, Genevière AM Fertilization relieves the oocyte from a cell cycle arrest, inducing progression towards mitotic cycles. While the signalling pathways involved in oocyte to embryo transition have been widely investigated, how they specifically trigger DNA replication is still unclear. We used sea urchin eggs whose oocytes are arrested in G1 to investigate in vivo the molecular mechanisms regulating initiation of replication after fertilization. Unexpectedly, we found that CDC6, Cdt1 and MCM3, components of the pre-replication complexes (pre-RC) which license origins for replication, were already loaded on female chromatin before fertilization. This is the first demonstration of a cell cycle arrest in metazoan in which chromatin is already licensed... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276612 Wed, 10 Feb 2010 00:00:00 +0100 3276612 http://www.medworm.com/index.php?rid=3276617&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%3D20152825%26dopt%3DAbstract We describe the gene structure of a newly described ECM molecule, tenectin, and demonstrate that it is a hormonally regulated ECM protein required for proper morphogenesis of the adult wing and male genitalia. Tenectin's function as a new ligand of the PS2 integrins is demonstrated by both genetic interactions in the fly and by cell spreading and cell adhesion assays in cultured cells. Its interaction with the PS2 integrins is dependent on RGD and RGD-like motifs. Tenectin's function in looping morphogenesis in the development of the male genitalia led to experiments that demonstrate a role for PS integrins in the execution of left-right asymmetry. PMID: 20152825 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276617 Tue, 09 Feb 2010 00:00:00 +0100 3276617 http://www.medworm.com/index.php?rid=3276616&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%3D20152826%26dopt%3DAbstract In this study, we identify a novel allele of baz, the Drosophila homolog of Par-3, that has allowed the analysis of baz function throughout oogenesis. We demonstrate that baz is required for spatial restriction of the germ plasm and axis patterning and we uncover multiple requirements for baz in regulating the organization of the oocyte microtubule cytoskeleton. Our results suggest that distinct cortical domains established by Par proteins polarize the oocyte through differential effects on microtubule organization. We further show that microtubule plus-end enrichment is sufficient to drive germ plasm assembly even at a distance from the oocyte cortex, suggesting that control of microtubule organization is critical not only for the localization of germ plasm components to the posterior of ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276616 Tue, 09 Feb 2010 00:00:00 +0100 3276616 http://www.medworm.com/index.php?rid=3276615&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%3D20152827%26dopt%3DAbstract Authors: Holley M, Rhodes C, Kneebone A, Herde MK, Fleming M, Steel KP Emx2 is a homeodomain protein that plays a critical role in inner ear development. Homozygous null mice die at birth with a range of defects in the CNS, renal system and skeleton. The cochlea is shorter than normal with about 60% fewer auditory hair cells. It appears to lack outer hair cells and some supporting cells are either absent or fail to differentiate. Many of the hair cells differentiate in pairs and although their hair bundles develop normally their planar cell polarity is compromised. Measurements of cell polarity suggest that classic planar cell polarity molecules are not directly influenced by Emx2 and that polarity is compromised by developmental defects in the sensory precursor population or by defect... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276615 Tue, 09 Feb 2010 00:00:00 +0100 3276615 http://www.medworm.com/index.php?rid=3276614&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%3D20152828%26dopt%3DAbstract Authors: Liakhovitskaia A, Lana-Elola E, Stamateris E, Rice DP, van 't Hof RJ, Medvinsky A Runx1 is highly expressed in chondro- and osteo-progenitor cells and in vitro experiments suggest that Runx1 is important in early stages of osteoblast and chondrocyte differentiation. However, as Runx1 knockout mice are early embryonic lethal due to failure of haematopoiesis, the role of Runx1 in skeletogenesis remains unclear. We studied the role of Runx1 in skeletal development using a Runx1 reversible knockout mouse model. By crossing with Tie2-Cre deletor mice, Runx1 expression was selectively rescued in the endothelial and haematopoietic systems but not in the skeleton. Although Runx1(Re/Re) embryos survived until birth and had a generally normal skeleton, the development of mineralisation ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276614 Tue, 09 Feb 2010 00:00:00 +0100 3276614 http://www.medworm.com/index.php?rid=3276613&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%3D20152829%26dopt%3DAbstract Authors: Tripathi P, Guo Q, Wang Y, Coussens M, Liapis H, Jain S, Kuehn MR, Capecchi MR, Chen F The role of axial structures, especially the notochord, in metanephric kidney development has not been directly examined. Here, we showed that disruption of the notochord and floor plate by diphtheria toxin (DTA)-mediated cell ablation did not disrupt nephrogenesis, but resulted in kidney fusions, resembling horseshoe kidneys in humans. Axial disruptions led to more medially positioned metanephric mesenchyme (MM) in midgestation. However, neither axial disruption nor the ensuing positional shift of the MM affected the formation of nephrons and other structures within the kidney. Response to Shh signaling was greatly reduced in midline cell populations in the mutants. To further ascertain the... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3276613 Tue, 09 Feb 2010 00:00:00 +0100 3276613 http://www.medworm.com/index.php?rid=3268219&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%3D20149789%26dopt%3DAbstract Authors: Cohen MA, Itsykson P, Reubinoff BE The mechanisms that govern human neural specification are not completely characterized. Here we used human embryonic stem cells (hESCs) to study the role of fibroblast growth factor (FGF)-signaling in early human neural specification. Differentiation was obtained by culturing clusters of hESCs in chemically-defined medium. We show that FGF-signaling, which is endogenously active during early differentiation of hESCs, induces early neural specification, while its blockage inhibits neuralization. The early neuralization effect of FGF-signaling is not mediated by promoting the proliferation of existing neural precursors (NPs) or prevention of their apoptosis. The neural instructive effect of FGF-signaling occurs after an initial FGF-independent ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3268219 Mon, 08 Feb 2010 00:00:00 +0100 3268219 http://www.medworm.com/index.php?rid=3262961&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%3D20144602%26dopt%3DAbstract Authors: Ishida T, Nakajima T, Kudo A, Kawakami A Tissue regeneration is fundamental for multi-cellular organisms to maintain their integrity, but the competence of tissue restoration is different depending on tissues, species, and ages. In spite of the recent progresses of the molecular basis of regeneration, little is known about its regulative processes. We previously identified the junb and junb-like (junbl) as transcripts induced in response to tissue injury in zebrafish. It has been demonstrated that the mammalian JunB is not phosphorylated by the Jun N-terminal kinase (JNK) due to the absence of target site. Here, we show that the zebrafish Junb proteins retain the target site and are phosphorylated by the JNK. Significantly, we found that the phosphorylated Junb proteins (pJunb... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262961 Fri, 05 Feb 2010 00:00:00 +0100 3262961 http://www.medworm.com/index.php?rid=3262960&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%3D20144603%26dopt%3DAbstract Authors: Cossais F, Sock E, Hornig J, Schreiner S, Kellerer S, Bösl MR, Russell S, Wegner M Neural crest cells and oligodendrocytes as the myelinating glia of the central nervous system exist only in vertebrates. Their development is regulated by complex regulatory networks, of which the SoxE-type high-mobility-group domain transcription factors Sox8, Sox9 and Sox10 are essential components. Here we analyzed by in ovo electroporation in chicken and by gene replacement in the mouse whether the Drosophila ortholog Sox100B can functionally substitute for vertebrate SoxE proteins. Sox100B overexpression in the chicken neural tube led to the induction of neural crest cells as previously observed for vertebrate SoxE proteins. Furthermore, many aspects of neural crest and oligodendrocyte... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262960 Fri, 05 Feb 2010 00:00:00 +0100 3262960 http://www.medworm.com/index.php?rid=3262959&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%3D20144604%26dopt%3DAbstract Authors: Rafiqi AM, Lemke S, Schmidt-Ott U The amnioserosa is an extraembryonic epithelium that evolved in higher cyclorrhaphan flies from distinct serosal and amniotic epithelia. The underlying genetic mechanism of this evolutionary transition is unknown. Amnioserosa development of Drosophila correlates with novel expression characteristics of the homeobox gene zerknüllt (zen), including a broad zen expression domain in the syncytial blastoderm and the complete absence of postgastrular zen expression. Here we examine the functional significance of these features by altering the activity profile of zen in Megaselia (a lower cyclorrhaphan fly with distinct serosal and amniotic epithelia) and Drosophila, and by examining in Megaselia the function of u-shaped group (ush-group) genes,... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262959 Fri, 05 Feb 2010 00:00:00 +0100 3262959 http://www.medworm.com/index.php?rid=3262958&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%3D20144605%26dopt%3DAbstract Authors: Zehir A, Hua L, Maska E, Morikawa Y, Cserjesi P The neural crest (NC) lineage gives rise to a wide array of cell types ranging from neurons and glia of the peripheral nervous system to skeletal elements of the head. The mechanisms regulating NC differentiation into such a large number of cell types remains largely unknown. MicroRNAs (miRNAs) play key roles in regulating developmental events suggesting they may also play a role during NC differentiation. To determine what roles miRNAs play in differentiation of NC-derived tissues, we deleted the miRNA processing gene Dicer in NC cells using the Wnt1-Cre deleter line. We show that deletion of Dicer soon after NC cells have formed does not affect their migration and colonization of their targets in the embryo. However, the post-m... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262958 Fri, 05 Feb 2010 00:00:00 +0100 3262958 http://www.medworm.com/index.php?rid=3262957&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%3D20144606%26dopt%3DAbstract In this study, we evaluate the expression and function of proneural bHLH transcription factors during the onset of mouse retinal neurogenesis. Dorso-central retinal progenitor cells that give rise to the first postmitotic neurons express Neurog2/Ngn2 and Atoh7/Math5. In the absence of Neurog2, the spread of neurogenesis stalls, along with Atoh7 expression and RGC differentiation. However, neurogenesis is eventually restored, and at birth Neurog2 mutant retinas are reduced in size, with only a slight increase in the retinal ganglion cell population. We find that the re-establishment of neurogenesis coincides with the onset of Ascl1 expression, and that Ascl1 can rescue the early arrest of neural development in the absence of Neurog2. Together, this study supports the hypothesis that the int... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262957 Fri, 05 Feb 2010 00:00:00 +0100 3262957 http://www.medworm.com/index.php?rid=3262956&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%3D20144607%26dopt%3DAbstract Authors: Lieven O, Knobloch J, Rüther U During embryogenesis, the Dkk1 mediated Wnt inhibition controls the spatiotemporal dynamics of cell fate determination, cell differentiation and cell death. Furthermore, the Dkk1 dose is critical for the normal Wnt homeostasis, as alteration of the Dkk1 activity is associated with various diseases. We investigated the regulation of Dkk1 expression during embryonic development. We identified nine conserved non-coding elements (CNEs), located 3' to the Dkk1 locus. Analyses of the regulatory potential revealed that four of these CNEs in combination drive reporter expression very similar to Dkk1 expression in several organs of transgenic embryos. We extended the knowledge Dkk1 expression during hypophysis, external genitalia and kidney developme... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262956 Fri, 05 Feb 2010 00:00:00 +0100 3262956 http://www.medworm.com/index.php?rid=3262955&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%3D20144608%26dopt%3DAbstract Authors: Holler KL, Hendershot TJ, Troy SE, Vincentz JW, Firulli AB, Howard MJ The basic helix-loop-helix DNA binding protein Hand2 has critical functions in cardiac development both in neural crest-derived and mesoderm-derived structures. Targeted deletion of Hand2 in the neural crest has allowed us to genetically dissect Hand2-dependent defects specifically in outflow tract and cardiac cushion independent of Hand2 functions in mesoderm-derived structures. Targeted deletion of Hand2 in the neural crest results in misalignment of the aortic arch arteries and outflow tract, contributing to development of double outlet right ventricle (DORV) and ventricular septal defects (VSD). These neural crest-derived developmental anomalies are associated with altered expression of Hand2-target gene... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262955 Fri, 05 Feb 2010 00:00:00 +0100 3262955 http://www.medworm.com/index.php?rid=3262954&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%3D20144609%26dopt%3DAbstract Authors: Punnamoottil B, Herrmann C, Pascual Anaya J, D'Aniello S, Garcia-Fernàndez J, Akalin A, Becker TS, Rinkwitz S Hox genes are key regulators of anterior-posterior axis patterning and have a major role in hindbrain development. The zebrafish Hox4 paralogs have strong overlapping activities in hindbrain rhombomeres 7 and 8, in the spinal cord and in the pharyngeal arches. With the aim to predict enhancers that act on the hoxa4a, hoxb4a, hoxc4a and hoxd4a genes, we used sequence conservation around the Hox4 genes to analyze all fish:human conserved non-coding sequences by reporter assays in stable zebrafish transgenesis. Thirty-four elements were functionally tested in GFP reporter gene constructs and more than 100 F1 lines were analyzed to establish a correlation between sequ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3262954 Fri, 05 Feb 2010 00:00:00 +0100 3262954 http://www.medworm.com/index.php?rid=3254968&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%3D20138861%26dopt%3DAbstract Authors: Hong E, Jayachandran P, Brewster R Microtubules are essential regulators of cell polarity, architecture and motility. The organization of the microtubule network is context-specific. In non-polarized cells, microtubules are anchored to the centrosome and form radial arrays. In most epithelial cells, microtubules are noncentrosomal, align along the apico-basal axis and the centrosome templates a cilium. It follows that cells undergoing mesenchyme-to-epithelium transitions must reorganize their microtubule network extensively, yet little is understood about how this process is orchestrated. In particular, the pathways regulating the apical positioning of the centrosome are unknown, a central question given the role of cilia in fluid propulsion, sensation and signaling. In zebraf... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3254968 Thu, 04 Feb 2010 00:00:00 +0100 3254968 http://www.medworm.com/index.php?rid=3244622&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%3D20123092%26dopt%3DAbstract Authors: Nakatomi M, Wang XP, Key D, Lund JJ, Turbe-Doan A, Kist R, Aw A, Chen Y, Maas RL, Peters H Developmental abnormalities of craniofacial structures and teeth often occur sporadically and the underlying genetic defects are not well understood, in part due to unknown gene-gene interactions. Pax9 and Msx1 are co-expressed during craniofacial development, and mice that are single homozygous mutant for either gene exhibit cleft palate and an early arrest of tooth formation. Whereas in vitro assays have demonstrated that protein-protein interactions between Pax9 and Msx1 can occur, it is unclear if Pax9 and Msx1 interact genetically in vivo during development. To address this question, we compounded the Pax9 and Msx1 mutations and observed that double homozygous mutants exhibit an inc... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244622 Sat, 30 Jan 2010 00:00:00 +0100 3244622 http://www.medworm.com/index.php?rid=3244621&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%3D20123093%26dopt%3DAbstract Authors: Pillay LM, Forrester AM, Erickson T, Berman JN, Waskiewicz AJ During vertebrate development, the initial wave of hematopoiesis produces cells that help to shape the developing circulatory system and oxygenate the early embryo. The differentiation of primitive erythroid and myeloid cells occurs within a short transitory period, and is subject to precise molecular regulation by a hierarchical cascade of transcription factors. The TALE-class homeodomain transcription factors Meis and Pbx function to regulate embryonic hematopoiesis, but it is not known where Meis and Pbx proteins participate in the hematopoietic transcription factor cascade. To address these questions, we have ablated Meis1 and Pbx proteins in zebrafish, and characterized their molecular effects on known markers ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244621 Sat, 30 Jan 2010 00:00:00 +0100 3244621 http://www.medworm.com/index.php?rid=3244620&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%3D20123094%26dopt%3DAbstract Authors: Nielsen CM, Dymecki SM Critical to the exchange and metabolic functions served by tissues like brain choroid plexi and lung is the coherent development of an epithelial sheet of large surface area in tight apposition to an extensive vascular bed. Here, we present functional experiments in the mouse demonstrating that Sonic hedgehog (Shh) produced by hindbrain choroid plexus epithelium induces the extensive vascular outgrowths and vascular surface area fundamental to choroid plexus functions, but does not induce the more specialized endothelial cell features of fenestrations and bore size. Our findings indicate that these Shh-dependent vascular elaborations occur even in the presence of Vegf and other established angiogenic factors, suggesting either that the levels of these fa... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244620 Sat, 30 Jan 2010 00:00:00 +0100 3244620 http://www.medworm.com/index.php?rid=3244630&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%3D20122912%26dopt%3DAbstract Authors: Binot AC, Manfroid I, Flasse L, Winandy M, Motte P, Martial JA, Peers B, Voz ML In mice, the Nkx6 genes are crucial to alpha- and beta-cell differentiation, but the molecular mechanisms by which they regulate pancreatic subtype specification remain elusive. Here it is shown that in zebrafish, nkx6.1 and nkx6.2 are co-expressed at early stages in the first pancreatic endocrine progenitors, but that their expression domains gradually segregate into different layers, nkx6.1 being expressed ventrally with respect to the forming islet while nkx6.2 is expressed mainly in beta-cells. Knockdown of nkx6.2 or nkx6.1 expression leads to nearly complete loss of alpha-cells but has no effect on beta-, delta-, or epsilon-cells. In contrast, nkx6.1/nkx6.2 double knockdown leads additionally ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244630 Fri, 29 Jan 2010 00:00:00 +0100 3244630 http://www.medworm.com/index.php?rid=3244629&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%3D20122913%26dopt%3DAbstract Authors: Kumar S, Duester G Morphogenesis during eye development requires retinoic acid (RA) receptors plus RA-synthesizing enzymes, and loss of RA signaling leads to ocular disorders associated with loss of Pitx2 expression in perioptic mesenchyme. Several Wnt signaling components are expressed in ocular tissues during eye development including Dkk2, encoding an inhibitor of Wnt/beta-catenin signaling, which was previously shown to be induced by Pitx2 in the perioptic mesenchyme. Here, we investigated potential cross-talk between RA and Wnt signaling during ocular development. Genetic studies using Raldh1/Raldh3 double null mice deficient for ocular RA synthesis demonstrated that Pitx2 and Dkk2 were both down-regulated in perioptic mesenchyme. Chromatin immunoprecipitation and gel mob... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244629 Fri, 29 Jan 2010 00:00:00 +0100 3244629 http://www.medworm.com/index.php?rid=3244628&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%3D20122914%26dopt%3DAbstract Authors: van Bueren KL, Papangeli I, Rochais F, Pearce K, Roberts C, Calmont A, Szumska D, Kelly RG, Bhattacharya S, Scambler PJ 22q11 deletion syndrome (22q11DS) is characterised by aberrant development of the pharyngeal apparatus and heart with haploinsufficiency of the transcription factor TBX1 considered to be the major underlying cause of the disease. Tbx1 mutations in mouse phenocopy the disorder. In order to identify transcriptional dysregulation in Tbx1-expressing lineages we optimised fluorescent-activated cell sorting of beta-galactosidase expressing cells (FACS-Gal) to compare the expression profile of Df1/Tbx1(lacZ) (effectively Tbx1 null) and Tbx1 heterozygous cells isolated from mouse embryos. Hes1, a major effector of Notch signalling, was identified as downregulated in ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244628 Fri, 29 Jan 2010 00:00:00 +0100 3244628 http://www.medworm.com/index.php?rid=3244627&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%3D20122915%26dopt%3DAbstract Authors: Monzo K, Dowd SR, Minden JS, Sisson JC Fragile X mental retardation protein (FMRP) is an RNA-binding protein that is required for the translational regulation of specific target mRNAs. Loss of FMRP causes Fragile X Syndrome (FXS), the most common form of inherited mental retardation in humans. Understanding the basis for FXS has been limited because few in vivo targets of FMRP have been identified and mechanisms for how FMRP regulates physiological targets is unclear. We have previously demonstrated that Drosophila FMRP (dFMRP) is required in early embryos for cleavage furrow formation. In an effort to identify new targets of dFMRP-dependent regulation and new effectors of cleavage furrow formation, we used two-dimensional difference gel electrophoresis and mass spectrometry t... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244627 Fri, 29 Jan 2010 00:00:00 +0100 3244627 http://www.medworm.com/index.php?rid=3244626&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%3D20122916%26dopt%3DAbstract Authors: Li J, Kim H, Aceto DG, Hung J, Aono S, Kemphues KJ PAR-6 is a conserved protein important for establishment and maintenance of cell polarity in a variety of metazoans. PAR-6 proteins function together with PAR-3, aPKC and CDC-42. Mechanistic details of their interactions, however, are not fully understood. We studied the biochemical interactions between C. elegans PAR-6 and its binding partners and tested the requirements of these interactions in living worms. We show that PB1 domain-mediated binding of PAR-6 to PKC-3 is necessary for polarity establishment and PAR-6 cortical localization in C. elegans embryos. We also show that binding of PAR-6 and PAR-3 is mediated in vitro by a novel type of PDZ-PDZ interaction; the betaC strand of PAR-6 PDZ binds the betaD strand of PAR-3 ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244626 Fri, 29 Jan 2010 00:00:00 +0100 3244626 http://www.medworm.com/index.php?rid=3244625&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%3D20122917%26dopt%3DAbstract Authors: Patel AV, Krimm RF In mice lacking functional brain-derived neurotrophic factor (BDNF), the number of geniculate ganglion neurons, which innervate taste buds, is reduced by one-half. Here, we determined how and when BDNF regulates the number of neurons in the developing geniculate ganglion. The loss of geniculate neurons begins at embryonic day 13.5 (E13.5) and continues until E18.5 in BDNF-null mice. Neuronal loss in BDNF-null mice was prevented by removal of the pro-apoptotic gene Bax. Thus, BDNF regulates embryonic geniculate neuronal number by preventing cell death rather than promoting cell proliferation. The number of neurofilament-positive neurons expressing activated caspase-3 increased on E13.5 in bdnf(-/-) mice, compared to wild-type mice, demonstrating that differen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244625 Fri, 29 Jan 2010 00:00:00 +0100 3244625 http://www.medworm.com/index.php?rid=3244624&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%3D20122918%26dopt%3DAbstract Authors: Calestani C, Rogers DJ The Strongylocentrotus purpuratus polyketide synthase gene (SpPks) encodes an enzyme required for the biosynthesis of the larval pigment echinochrome. SpPks is expressed exclusively in pigment cells and their precursors starting at blastula stage. The 7th-9th cleavage Delta-Notch signaling, required for pigment cell development, positively regulates SpPks. In previous studies, the transcription factors glial cells missing (SpGcm), SpGatae and kruppel-like (SpKrl/z13) have been shown to positively regulate SpPks. To uncover the structure of the Gene Regulatory Network (GRN) regulating the specification and differentiation processes of pigment cells, we experimentally analyzed the putative SpPks cis-regulatory region. We established that the -1.5Kb region ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244624 Fri, 29 Jan 2010 00:00:00 +0100 3244624 http://www.medworm.com/index.php?rid=3244623&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%3D20122919%26dopt%3DAbstract Authors: Gates KP, Mentzer L, Karlstrom RO, Sirotkin HI The spatial and temporal control of gene expression is key to generation of specific cellular fates during development. Studies of the transcriptional repressor REST/NRSF (RE1 Silencing Transcription Factor or Neural Restrictive Silencing Factor) have provided important insight into the role that epigenetic modifications play in differential gene expression. However, the precise function of REST during embryonic development is not well understood. We have discovered a novel interaction between zebrafish Rest and the Hedgehog (Hh) signaling pathway. We observed that Rest knockdown enhances or represses Hh signaling in a context-dependant manner. In wild-type embryos and embryos with elevated Hh signaling, Rest knockdown augments tr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3244623 Fri, 29 Jan 2010 00:00:00 +0100 3244623 http://www.medworm.com/index.php?rid=3236633&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%3D20116373%26dopt%3DAbstract Authors: Maczkowiak F, Matéos S, Wang E, Roche D, Harland R, Monsoro-Burq AH Pax3 and Pax7 paralogous genes have functionally diverged in vertebrate evolution, creating opportunity for a new distribution of roles between the two genes and the evolution of novel functions. Here we focus on the regulation and function of Pax7 in the brain and neural crest of amphibian embryos, which display a different pax7 expression pattern, compared to the other vertebrates already described. Pax7 expression is restricted to the midbrain, hindbrain and anterior spinal cord, and Pax7 activity is important for maintaining the fates of these regions, by restricting otx2 expression anteriorly. In contrast, pax3 displays broader expression along the entire neuraxis and Pax3 function is important for p... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3236633 Wed, 27 Jan 2010 00:00:00 +0100 3236633 http://www.medworm.com/index.php?rid=3218910&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%3D20102707%26dopt%3DAbstract Authors: Michon F, Tummers M, Kyyrönen M, Frilander MJ, Thesleff I Teeth form as appendages of the ectoderm and their morphogenesis is regulated by tissue interactions mediated by networks of conserved signal pathways. Micro-RNAs (miRNAs) have emerged as important regulators of various aspects of embryonic development but their function in odontogenesis has not been elucidated. We show that the expression of RNAi pathway effectors is dynamic during tooth morphogenesis and differentiation of dental cells. Based on microarray profiling we selected 8 miRNAs expressed during morphogenesis and 7 miRNAs in the incisor cervical loop containing the stem cell niche. These miRNAs were mainly expressed in the dental epithelium. Conditional deletion of Dicer-1 in the epithelium (Dcr(K14-/-)) ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3218910 Sat, 23 Jan 2010 00:00:00 +0100 3218910 http://www.medworm.com/index.php?rid=3218909&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%3D20102708%26dopt%3DAbstract Authors: Zimmerman SG, Thorpe LM, Medrano VR, Mallozzi CA, McCartney BM The tumor suppressor Adenomatous polyposis coli (APC) is a negative regulator of Wnt signaling and functions in cytoskeletal organization. Disruption of human APC in colonic epithelia initiates benign polyps that progress to carcinoma following additional mutations. The early events of polyposis are poorly understood, as is the role of canonical Wnt signaling in normal epithelial architecture and morphogenesis. To determine the consequences of complete loss of APC in a model epithelium, we generated APC2 APC1 double null clones in the Drosophila wing imaginal disc. APC loss leads to segregation, apical constriction, and invagination that result from transcriptional activation of canonical Wnt signaling. Further, we... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3218909 Sat, 23 Jan 2010 00:00:00 +0100 3218909 http://www.medworm.com/index.php?rid=3212755&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%3D20100474%26dopt%3DAbstract Authors: Martín-Durán JM, Amaya E, Romero R Although patterning during regeneration in adult planarians has been studied extensively, very little is known about how the initial planarian body plan arises during embryogenesis. Herein, we analyze the process of embryo patterning in the species Schmidtea polychroa by comparing the expression of genes involved in the establishment of the metazoan body plan. Planarians present a derived ectolecithic spiralian development characterized by dispersed cleavage within a yolk syncytium and an early transient embryo capable of feeding on the maternally supplied yolk cells. During this stage of development, we only found evidence of canonical Wnt pathway, mostly associated with the development of its transient pharynx. At these stages, ge... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3212755 Fri, 22 Jan 2010 00:00:00 +0100 3212755 http://www.medworm.com/index.php?rid=3212758&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%3D20096681%26dopt%3DAbstract Authors: Christie TL, Carter A, Rollins EL, Childs SJ Spleen tyrosine kinase (Syk) plays critical roles in B-cell and T-cell development, the maintenance of vascular integrity, and proper partitioning of the blood vascular and lymphatic vascular system. Here, we utilize the zebrafish as an in vivo system to demonstrate novel roles for Syk and the related kinase Zeta associated protein (Zap-70) in promoting angioblast migration. Partial knockdown of either gene results in early angiogenic delay of the intersegmental vessels, dorsal intersegmental vessel patterning defects, and partial loss of the thoracic duct. Higher dose knockdown of both genes results in little to no angiogenic sprouting of the intersegmental vessels, a phenotype which resembles knockdown of vegfa. Di-phosphorylated ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3212758 Wed, 20 Jan 2010 00:00:00 +0100 3212758 http://www.medworm.com/index.php?rid=3212757&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%3D20096682%26dopt%3DAbstract Authors: Kourakis MJ, Newman-Smith E, Smith WC Tunicates and vertebrates share a common ancestor that possessed cranial neurogenic placodes, thickenings in embryonic head epidermis giving rise to sensory structures. Though orthology assignments between vertebrate and tunicate placodes are not entirely resolved, vertebrate otic placodes and tunicate atrial siphon primordia are thought to be homologous based on morphology and position, gene expression, and a common signaling requirement during induction. Here, we probe key points in the morphogenesis of the tunicate atrial siphon. We show that the siphon primordium arises within a non-dividing field of lateral-dorsal epidermis. The initial steps of atrial primordium invagination are similar to otic placode invagination, but a placode-der... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3212757 Wed, 20 Jan 2010 00:00:00 +0100 3212757 http://www.medworm.com/index.php?rid=3212756&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%3D20096683%26dopt%3DAbstract Authors: Endoh-Yamagami S, Karkar KM, May SR, Cobos I, Thwin MT, Long JE, Ashique AM, Rubenstein JL, Peterson AS Precise control of neuronal migration is essential for proper function of the brain. Taking a forward genetic screen, we isolated a mutant mouse with defects in interneuron migration. By genetic mapping, we identified a frame shift mutation in the pericentrin (Pcnt) gene. The Pcnt gene encodes a large centrosomal coiled-coil protein that has been implicated in schizophrenia. Recently, frame shift and premature termination mutations in the pericentrin (PCNT) gene were identified in individuals with Seckel syndrome and microcephalic osteodysplastic primordial dwarfism (MOPD II), both of which are characterized by greatly reduced body and brain sizes. The mouse Pcnt mutant shar... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3212756 Wed, 20 Jan 2010 00:00:00 +0100 3212756 http://www.medworm.com/index.php?rid=3212760&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%3D20096279%26dopt%3DAbstract Authors: Taneda Y, Konno S, Makino S, Morioka M, Fukuda K, Imai Y, Kudo A, Kawakami A The size and morphology of organs are largely determined by a genetic program. However in some cases, an epigenetic mechanism influences the process of organ development. Particularly, epigenetic factors such as hemodynamic stress and blood pressure affect the morphogenesis of cardiac chambers and valves. Here, we report that the epigenetic influences affect the cardiomyocyte production. Taking advantage of longer developmental period of medaka fish, we could examine the later emerging tissue responses to the defect of ventricular beating, which occurred in the hozuki (hoz) mutant that harbors the mutated ventricular myosin heavy chain (vmhc) gene. The mutant showed a remarkable ventricular enlargemen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3212760 Tue, 19 Jan 2010 00:00:00 +0100 3212760 http://www.medworm.com/index.php?rid=3212759&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%3D20096280%26dopt%3DAbstract Authors: Shimeld SM, Boyle MJ, Brunet T, Luke GN, Seaver EC FoxC, FoxF, FoxL1 and FoxQ1 genes have been shown to be clustered in some animal genomes, with mesendodermal expression hypothesised as a selective force maintaining cluster integrity. Hypotheses are, however, constrained by a lack of data from the Lophotrochozoa. Here we characterise members of the FoxC, FoxF, FoxL1 and FoxQ1 families from the annelid Capitella teleta and the molluscs Lottia gigantea and Patella vulgata. We cloned FoxC, FoxF, FoxL1 and FoxQ1 genes from C. teleta, and FoxC, FoxF and FoxL1 genes from P. vulgata, and established their expression during development. We also examined their genomic organisation in C. teleta and L. gigantea, and investigated local syntenic relationships. Our results show mesodermal ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3212759 Tue, 19 Jan 2010 00:00:00 +0100 3212759 http://www.medworm.com/index.php?rid=3194535&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%3D20083100%26dopt%3DAbstract Authors: Callery EM, Thomsen GH, Smith JC T-box family transcription factors play many roles in Metazoan development. Here we characterise Tbx6r, a unique Tbx6 paralogue isolated from the amphibian Xenopus. The evolution and developmental integration of this divergent T-box gene within the vertebrates reveals an unexpected level of plasticity within this conserved family of developmental regulators. We show that despite their co-expression, Tbx6 and Tbx6r have dissimilar transcriptional responses to ligand treatment, and their ability to activate ligand expression is also very different. The two paralogues have distinct inductive properties: Tbx6 induces mesoderm whereas Tbx6r induces anterior neural markers. We use hybrid proteins in an effort to understand this difference, and implic... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3194535 Fri, 15 Jan 2010 00:00:00 +0100 3194535 http://www.medworm.com/index.php?rid=3194534&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%3D20083101%26dopt%3DAbstract Authors: Zhang D, Brinas IM, Binder BJ, Landman KA, Newgreen DF Midbrain, hindbrain and vagal neural crest (NC) produced abundant enteric nervous system (ENS) in co-grafted aneural hindgut and midgut, using chick-quail chorio-allantoic membrane grafts, forming complete myenteric and submucosal plexuses. This ability dropped suddenly in cervical and thoracic NC levels, furnishing an incomplete ENS in one or both plexuses. Typically, one plexus was favored over the other. This deficiency was not caused by lower initial trunk NC number, yet overloading the initial number decreased the deficiency. No qualitative difference in neuronal and glial differentiation between cranial and trunk levels was observed. All levels formed HuC/D+ve, NOS+ve, ChAT+ve, TH-ve enteric neurons with SoxE+ve, GFA... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3194534 Fri, 15 Jan 2010 00:00:00 +0100 3194534 http://www.medworm.com/index.php?rid=3186229&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%3D20080085%26dopt%3DAbstract Authors: Yamada Y, Kay RR, Bloomfield G, Ross S, Ivens A, Williams JG The mature fruiting body of Dictyostelium consists of stalk and spore cells but its construction, and the migration of the preceding slug stage, requires a number of specialized sub-types of prestalk cell whose nature and function are not well understood. The prototypic prestalk-specific gene, ecmA, is inducible by the polyketide DIF-1 in a monolayer assay and requires the DimB and MybE transcription factors for full inducibility. We perform genome-wide micro-array analyses, on parental, mybE- and dimB- cells, and identify many additional genes that depend on MybE and DimB for their DIF-1 inducibility. Surprisingly, an even larger number of genes are only DIF-inducible in mybE- cells, some genes are only inducible in... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186229 Thu, 14 Jan 2010 00:00:00 +0100 3186229 http://www.medworm.com/index.php?rid=3186235&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%3D20079726%26dopt%3DAbstract Authors: Revinski DR, Paganelli AR, Carrasco AE, López SL In Vertebrates, the induction of the three germ layers (ectoderm, mesoderm and endoderm) has been extensively studied, but less is known about how they segregate. Here, we investigated whether Delta-Notch signaling is involved in this process. Activating the pathway in the marginal zone with Notch(ICD) resulted in an expansion of endodermal and neural ectoderm precursors, leaving a thinner mesodermal ring around the blastopore at gastrula stage, when germ layers are segregated. On the other hand, when the pathway was blocked with Delta-1(STU) or with an antisense morpholino oligonucleotide against Notch, the pan-mesodermal brachyury (bra) domain was expanded and the neural border was moved animalwards. Strikingly, the supra... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186235 Wed, 13 Jan 2010 00:00:00 +0100 3186235 http://www.medworm.com/index.php?rid=3186234&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%3D20079727%26dopt%3DAbstract Authors: Hebbar S, Fernandes JJ Motor neurons that innervate the dorsal longitudinal (flight) muscles, DLMs, make multiple points of contact along the length of fibers. The stereotypy of the innervation lies in the number of contact points (CPs) made by each motor neuron and is established as a consequence of pruning that occurs during metamorphosis. Coincident with the onset of pruning is the arrival of glial processes that eventually ensheath persistent branches. To test a possible role for glia during pruning, the development of adult-specific glial ensheathment was disrupted using a targeted expression of dominant negative shibire. Such a manipulation resulted in fewer contact points at the DLM fibers. The development of innervation was examined during metamorphosis, specifically t... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186234 Wed, 13 Jan 2010 00:00:00 +0100 3186234 http://www.medworm.com/index.php?rid=3186233&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%3D20079728%26dopt%3DAbstract Authors: Fotopoulou S, Oikonomou N, Grigrorieva E, Nikitopoulou I, Paparountas T, Thanassopoulou A, Zhao Z, Xu Y, Kontoyiannis DL, Remboutsika E, Aidinis V Autotaxin (ATX) is a secreted glycoprotein widely present in biological fluids, originally isolated from the supernatant of melanoma cells as an autocrine motility stimulation factor. Its enzymatic product, lysophosphatidic acid (LPA), is a phospholipid mediator that evokes growth-factor-like responses in almost all cell types through G protein coupled receptors. To assess the role of ATX and LPA signalling in pathophysiology, a conditional knockout mouse was created. Ubiquitous, obligatory deletion resulted to embryonic lethality most likely due to aberrant vascular branching morphogenesis and chorio-allantoic fusion. Moreover, the... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186233 Wed, 13 Jan 2010 00:00:00 +0100 3186233 http://www.medworm.com/index.php?rid=3186232&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%3D20079729%26dopt%3DAbstract Authors: Day K, Shefer G, Shearer A, Yablonka-Reuveni Z Satellite cells are myogenic progenitors residing on the myofiber surface that support skeletal muscle repair. We used mice in which satellite cells were detected by GFP expression driven by nestin gene regulatory elements to define age-related changes in both numbers of satellite cells that occupy hindlimb myofibers and their individual performance. We demonstrate a reduction in satellite cells per myofiber with age that is more prominent in females compared to males. Satellite cell loss also persists with age in myostatin-null mice regardless of increased muscle mass. Immunofluorescent analysis of isolated myofibers from nestin-GFP/Myf5(nLacZ/+) mice reveals a decline with age in the number of satellite cells that express detect... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186232 Wed, 13 Jan 2010 00:00:00 +0100 3186232 http://www.medworm.com/index.php?rid=3186231&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%3D20079730%26dopt%3DAbstract Authors: Gaur T, Hussain S, Mudhasani R, Parulkar I, Colby JL, Frederick D, Kream BE, van Wijnen AJ, Stein JL, Stein GS, Jones SN, Lian JB MicroRNA attenuation of protein translation has emerged as an important regulator of mesenchymal cell differentiation into the osteoblast lineage. A compelling question is the extent to which miR biogenesis is obligatory for bone formation. Here we show conditional deletion of Dicer in osteoprogenitors by Col1a1-Cre compromised fetal survival after E14.5. A mechanism was associated with the post-commitment stage of osteoblastogenesis, demonstrated by impaired ECM mineralization and expression of mature osteoblast markers in ex vivo deleted Dicer(c/c) during differentiation of mesenchymal cells. In contrast, in vivo excision of Dicer by Osteocalcin-C... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186231 Wed, 13 Jan 2010 00:00:00 +0100 3186231 http://www.medworm.com/index.php?rid=3186230&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%3D20079731%26dopt%3DAbstract This study demonstrates that NEDD1 is an essential component of acentriolar oocyte MTOCs, which functions in the regulation of meiotic spindle stability. Moreover, it underscores that disruption of spindle stability in oocytes can lead to chromosomes segregation errors that are not fully resolved by SAC. PMID: 20079731 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3186230 Wed, 13 Jan 2010 00:00:00 +0100 3186230 http://www.medworm.com/index.php?rid=3172273&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%3D20067783%26dopt%3DAbstract In conclusion, we show that PCP effector gene Intu is an important regulator of cilia formation, Hh signal transduction, and embryonic development in mammals. PMID: 20067783 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3172273 Sat, 09 Jan 2010 00:00:00 +0100 3172273 http://www.medworm.com/index.php?rid=3172272&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%3D20067784%26dopt%3DAbstract We present evidence that BDNF is required for the survival of a significant fraction of peptidergic and non-peptidergic nociceptors in dorsal root ganglia (DRG) postnatally. Bdnf homozygous mutant mice lose approximately half of all nociceptive neurons during the first two weeks of life and adult heterozygotes exhibit hypoalgesia and a loss of 25% of all nociceptive neurons. Our in vitro analyses indicate that BDNF-dependent nociceptive neurons also respond to NGF and GDNF. Expression analyses at perinatal times indicate that BDNF is predominantly produced within sensory ganglia and is more abundant than skin-derived NGF or GDNF. Function-blocking studies with BDNF specific antibodies in vitro or cultures of BDNF-deficient sensory neurons suggest that BDNF acts in an autocrine/paracrine wa... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3172272 Sat, 09 Jan 2010 00:00:00 +0100 3172272 http://www.medworm.com/index.php?rid=3172271&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%3D20067785%26dopt%3DAbstract Authors: Hadjantonakis K, Solnica-Krezel L PMID: 20067785 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3172271 Sat, 09 Jan 2010 00:00:00 +0100 3172271 http://www.medworm.com/index.php?rid=3172270&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%3D20067786%26dopt%3DAbstract Authors: Peyrot SM, Martin BL, Harland RM Lymph hearts are pulsatile organs, present in lower vertebrates, that function to propel lymph into the venous system. Although they are absent in mammals, the initial veno-lymphatic plexus that forms during mammalian jugular lymph sac development has been described as the vestigial homologue of the nascent stage of ancestral anterior lymph hearts. Despite the widespread presence of lymph hearts among vertebrate species and their unique function, extremely little is known about lymph heart development. We show that Xenopus anterior lymph heart muscle expresses skeletal muscle markers such as myoD and 12/101, rather than cardiac markers. The onset of lymph heart myoblast induction can be visualized by engrailed-1 (en1) staining in anterior trunk... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3172270 Sat, 09 Jan 2010 00:00:00 +0100 3172270 http://www.medworm.com/index.php?rid=3164252&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%3D20060823%26dopt%3DAbstract Authors: Zhang M, Liu X, Zhang Y, Zhao J Less is known the connection between the malfunction of betaarrestins and developmental defects as the mice with either of two betaarrestin isoforms knockout appear normal. In order to address the biological function of betaarrestins during developmental process, we generate betaarrestin1/2 double knockout mice. We found that betaarrestin1/2 dual-null mice developed respiratory distress and atelectasis that subsequently caused neonatal death. Morphological examination revealed type II pneumocyte immaturity. Our results indicate that not only betaarrestin1/2 double knockout lung tissue show disturbances in cell proliferation but betaarrestin1 and betaarrestin2 contributes to pulmonary surfactant complex generation during pulmonary maturation. Int... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164252 Thu, 07 Jan 2010 00:00:00 +0100 3164252 http://www.medworm.com/index.php?rid=3164255&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%3D20060391%26dopt%3DAbstract Authors: Jones R, Howes E, Dunne PD, James P, Bruckbauer A, Klenerman D The molecules on mammalian spermatozoa that mediate recognition and binding to the zona pellucida of the egg are still not understood. Current concepts favour their assembly into multimolecular complexes in the plasma membrane in response to cholesterol efflux, an important step during sperm capacitation. Here, we track in real time diffusion of cross-linked clusters containing zona-binding molecules and GM1 gangliosides in the plasma membrane of live boar spermatozoa before and after cholesterol reduction. Both GM1 gangliosides and zona-binding molecules partition into a low density Triton X100 resistant phase suggesting their association with lipid rafts. Initially, GM1 and zona-binding molecules localize to the ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164255 Wed, 06 Jan 2010 00:00:00 +0100 3164255 http://www.medworm.com/index.php?rid=3164254&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%3D20060392%26dopt%3DAbstract Authors: Frische EW, Zwartkruis FJ The small Ras-like GTPase Rap1 is an evolutionary conserved protein that originally gained interest because of its capacity to revert the morphological phenotype of Ras-transformed fibroblasts. Rap1 is regulated by a large number of stimuli that include growth factors and cytokines, but also physical force and osmotic stress. Downstream of Rap1, a plethora of effector molecules has been proposed on the basis of biochemical studies. Here we present an overview of genetic studies on Rap1 in various model organisms and relate the observed phenotypes to in vitro studies. The picture that emerges is one in which Rap1 is a versatile regulator of morphogenesis, by regulating diverse processes that include establishment of cellular polarity, cell-matrix inter... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164254 Wed, 06 Jan 2010 00:00:00 +0100 3164254 http://www.medworm.com/index.php?rid=3164253&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%3D20060393%26dopt%3DAbstract Authors: Pan Y, Martinez-De Luna RI, Lou CH, Nekkalapudi S, Kelly LE, Sater AK, El-Hodiri HM The retinal homeobox (Rx) gene product is essential for eye development. However little is known about its molecular function. It has been demonstrated that Rx binds to photoreceptor conserved element (PCE-1), a highly conserved element found in the promoter region of photoreceptor-specific genes such as rhodopsin and red cone opsin. We verify that Rx is co-expressed with rhodopsin and red cone opsin in maturing photoreceptors and demonstrate that Rx binds to the rhodopsin and red cone opsin promoters in vivo. We also find that Rx can cooperate with the Xenopus analogs of Crx and Nrl, otx5b and XLMaf (respectively), to activate a Xenopus opsin promoter-dependent reporter. Finally, we demonstrat... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164253 Wed, 06 Jan 2010 00:00:00 +0100 3164253 http://www.medworm.com/index.php?rid=3164258&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%3D20059993%26dopt%3DAbstract Authors: Shah MM, Sakurai H, Sweeney DE, Gallegos TF, Bush KT, Esko JD, Nigam SK Heparan sulfate proteoglycans (HSPGs) are central modulators of developmental processes likely through their interaction with growth factors, such as GDNF, members of the FGF and TGFbeta superfamilies, EGF receptor ligands and HGF. Absence of the biosynthetic enzyme, heparan sulfate 2-O-sulfotransferase (Hs2st) leads to kidney agenesis. Using a novel combination of in vivo and in vitro approaches, we have reanalyzed the defect in morphogenesis of the Hs2st(-/-) kidney. We observed that, while the ureteric bud (UB) forms from all Hs2st(-/-) Wolffian ducts, about two-thirds do not branch at all, and the remainder stop after the first branching event. Utilizing assays that separately model distinct stages of ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164258 Tue, 05 Jan 2010 00:00:00 +0100 3164258 http://www.medworm.com/index.php?rid=3164257&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%3D20059994%26dopt%3DAbstract This study reveals previously unknown principles of oral siphon and OPO regeneration that will be important for developing Ciona as a regeneration model in urochordates, which may be the closest living relatives of vertebrates. PMID: 20059994 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164257 Tue, 05 Jan 2010 00:00:00 +0100 3164257 http://www.medworm.com/index.php?rid=3164256&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%3D20059995%26dopt%3DAbstract Authors: Liu J, Maduzia LL, Shirayama M, Mello CC The nonmuscle myosin II NMY-2 is required for cytokinesis as well as for the establishment of zygote asymmetry during embryogenesis in C. elegans. Here we describe two conditional nmy-2 alleles that rapidly and reversibly inactivate the protein. We show that NMY-2 has late-cell-cycle roles in maintaining embryonic asymmetries and is also required for a surprisingly late step in the maintenance of the cytokinesis furrow. Finally, during a signaling-induced asymmetric cell division, NMY-2 is required for SRC-dependent phosphotyrosine signaling and acts in parallel with WNT-signaling to specify endoderm. PMID: 20059995 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3164256 Tue, 05 Jan 2010 00:00:00 +0100 3164256 http://www.medworm.com/index.php?rid=3146728&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%3D20045678%26dopt%3DAbstract This study addresses late extraembryonic morphogenesis in the milkweed bug, Oncopeltus fasciatus. Cell shape changes and apoptosis profiles are used to characterize the membranes as they undergo a large repertoire of final reorganizational events that reposition the embryo (katatrepsis), and eliminate the membranes themselves in an ordered fashion (dorsal closure). A number of key features were identified. First, amnion-serosa "fusion" involves localized apoptosis in the amnion and the formation of a supracellular actin purse string at the amnion-serosa border. During katatrepsis, a 'focus' of serosal cells undergoes precocious columnarization and may serve as an anchor for contraction. Lastly, dorsal closure involves novel modifications of the amnion and embryonic flank that are without c... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146728 Thu, 31 Dec 2009 00:00:00 +0100 3146728 http://www.medworm.com/index.php?rid=3146727&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%3D20045679%26dopt%3DAbstract Authors: Zeitlinger J, Stark A Genetic experiments over the last few decades have identified many developmental control genes critical for pattern formation and cell fate specification during the development of multi-cellular organisms. A large fraction of these genes encode transcription factors and signaling molecules, show highly dynamic expression patterns during development, and are deeply evolutionarily conserved and deregulated in various human diseases such as cancer. Because of their importance in development, evolution and disease, a fundamental question in biology is how these developmental control genes are regulated in such an extensive and precise fashion. Using genomics methods, it has become clear that developmental control genes are a distinct group of genes with speci... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146727 Thu, 31 Dec 2009 00:00:00 +0100 3146727 http://www.medworm.com/index.php?rid=3146726&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%3D20045680%26dopt%3DAbstract Authors: Degenhardt KR, Milewski RC, Padmanabhan A, Miller M, Singh MK, Lang D, Engleka KA, Wu M, Li J, Zhou D, Antonucci N, Li L, Epstein JA Pax3 is a transcription factor expressed in somitic mesoderm, dorsal neural tube and pre-migratory neural crest during embryonic development. We have previously identified cis-acting enhancer elements within the proximal upstream genomic region of Pax3 that are sufficient to direct functional expression of Pax3 in neural crest. These elements direct expression of a reporter gene to pre-migratory neural crest in transgenic mice, and transgenic expression of a Pax3 cDNA using these elements is sufficient to rescue neural crest development in mice otherwise lacking endogenous Pax3. We show here that deletion of these enhancer sequences by homologous... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146726 Thu, 31 Dec 2009 00:00:00 +0100 3146726 http://www.medworm.com/index.php?rid=3146725&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%3D20045681%26dopt%3DAbstract In conclusion, our study shows that early post-ovulation events are particularly sensitive to oxidant insult, which abrogates the developmental competence of HSF1-depleted oocytes. They also reveal that Hsf1 knock-out mice constitute a genetic model that can be used to evaluate the importance of redox homeostasis in oocytes. PMID: 20045681 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146725 Thu, 31 Dec 2009 00:00:00 +0100 3146725 http://www.medworm.com/index.php?rid=3146724&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%3D20045682%26dopt%3DAbstract Authors: Gee L, Hartig J, Law L, Wittlieb J, Khalturin K, Bosch TC, Bode HR In an adult hydra the head organizer, located in the hypostome, is constantly active in maintaining the structure of the animal in the context of its steady state tissue dynamics. Several Wnt genes, TCF, and elevated levels of beta-catenin are expressed in the hypostome as well as during the formation of a new organizer region in developing buds suggesting they play a role in the organizer. Transgenic hydra were generated in which a modified hydra beta-catenin gene driven by an actin promoter is continuously expressed at a high level throughout the animal. These animals formed heads and secondary axes in multiple locations along the body column. Transplantation experiments indicate they have a high and stable l... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146724 Thu, 31 Dec 2009 00:00:00 +0100 3146724 http://www.medworm.com/index.php?rid=3146723&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%3D20045683%26dopt%3DAbstract Authors: Beck SA, Falconer E, Catching A, Hodgson JW, Brock HW Polycomb group (PcG) genes are required for heritable silencing of target genes. Many PcG mutants have chromatin bridges and other mitotic defects in early embryos. These phenotypes can arise from defects in S phase or mitosis, so the phenotype does not show where PcG proteins act in cell cycle regulation. We analyzed the cell cycle role of the proximal subunit of Polyhomeotic (PhP) in Drosophila. Time-lapse imaging reveals that chromatin bridges during mitosis are able to resolve but sometimes result in chromosome breakage. Chromosome bridging is also observed in canonical cell cycles occurring in larval brains and is therefore not unique to the rapid embryonic cycles. PhP colocalizes with chromatin in S phase but not in m... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146723 Thu, 31 Dec 2009 00:00:00 +0100 3146723 http://www.medworm.com/index.php?rid=3146722&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%3D20045684%26dopt%3DAbstract In this study, we found that transgene activation by the IAB5 enhancer can be delayed by inserting a 9.5kb 3' Abd-B regulatory region containing the Frontabdominal-8 (Fab-8) insulator and the PTS element. We found that the delay is caused by the PTS and an insulator, and it is not specific to the enhancer or the promoter tested. Based on these findings, we hypothesize that the delay of remote enhancers is responsible for the Abd-B expression pattern, which is at least in part due to the regulatory activities of the PTS elements and chromatin boundaries. PMID: 20045684 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146722 Thu, 31 Dec 2009 00:00:00 +0100 3146722 http://www.medworm.com/index.php?rid=3146721&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%3D20045685%26dopt%3DAbstract Authors: Hartmann B, Müller M, Hislop NR, Roth B, Tomljenovic L, Miller DJ, Reichert H The ems/Emx genes encode homeodomain transcription factors that have conserved actions in anterior embryonic patterning in bilaterian animals ranging from insects to mammals. Recently, genes of the ems/Emx family have been identified in cnidarians raising the possibility that some of their develomental functions might be conserved throughout the Eumetazoa. To determine to what extent functions of a cnidarian ems/Emx protein have been retained across phyla, we carried out cross-phylum rescue expression experiments in which the coral Acropora emx-Am gene was misexpressed in Drosophila ems mutants. Our findings demonstrate that coral emx-Am can substitute for fly ems in embryonic head development a... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146721 Thu, 31 Dec 2009 00:00:00 +0100 3146721 http://www.medworm.com/index.php?rid=3146720&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%3D20045686%26dopt%3DAbstract Authors: Lewandowski JP, Sheehan KB, Bennett PE, Boswell RE During Drosophila melanogaster oogenesis, a germline stem cell divides forming a cyst of 16 interconnected cells. One cell enters the oogenic pathway and the remaining 15 differentiate as nurse cells. Although directed transport and localization of oocyte differentiation factors within the single cell are indispensible for selection, maintenance, and differentiation of the oocyte, the mechanisms regulating these events are poorly understood. Mago Nashi and Tsunagi/Y14, core components of the exon junction complex (a multiprotein complex assembled on spliced RNAs), are essential for restricting oocyte fate to a single cell and for localization of oskar mRNA. Here we provide evidence that Mago Nashi and Tsunagi/Y14 form an oogen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146720 Thu, 31 Dec 2009 00:00:00 +0100 3146720 http://www.medworm.com/index.php?rid=3146729&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%3D20044986%26dopt%3DAbstract Authors: Maynard JC, Pham T, Zheng T, Jockheck-Clark A, Rankin HB, Newgard CB, Spana EP, Nicchitta CV GRP94, the endoplasmic reticulum Hsp90, is a metazoan-restricted chaperone essential for early development in mammals, yet dispensable for mammalian cell viability. This dichotomy suggests that GRP94 is required for the functional expression of secretory and/or membrane proteins that enable the integration of cells into tissues. To explore this hypothesis, we have identified the Drosophila ortholog of GRP94, Gp93, and report that Gp93 is an essential gene in Drosophila. Loss of zygotic Gp93 expression is late larval lethal and causes prominent defects in the larval midgut, the sole endoderm-derived larval tissue. Gp93 mutant larvae display pronounced defects in the midgut epithelium, w... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3146729 Tue, 29 Dec 2009 00:00:00 +0100 3146729 http://www.medworm.com/index.php?rid=3137089&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%3D20043898%26dopt%3DAbstract Authors: Abelló G, Khatri S, Radosevic M, Scotting PJ, Giráldez F, Alsina B The development of neural tissue starts with the activation of early neural genes such as the SoxB1 transcription factors, which are expressed in response to signaling molecules. Neural progenitors in the inner ear are only generated in the anterior placodal domain, but the mechanisms that determine when and how otic neural fate is acquired are still unknown. Here, we show that Sox3 expression becomes restricted to the anterior territory of the chick otic field and that misexpression of Sox3 induces Sox2 and Delta1 in the non-neurogenic otic territory. This suggests that Sox3 plays a central role in the establishment of an otic neural fate. Furthermore, Sox3 down-regulates the expression of Lmx1b, a m... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3137089 Mon, 28 Dec 2009 00:00:00 +0100 3137089 http://www.medworm.com/index.php?rid=3137088&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%3D20043899%26dopt%3DAbstract Authors: Gordon J, Patel SR, Mishina Y, Manley NR The thymus and parathyroids are pharyngeal endoderm-derived organs that develop from common organ primordia, which undergo a series of morphological events resulting in separate organs in distinct locations in the embryo. Previous gene expression and functional analyses have suggested a role for BMP4 signaling in early thymus organogenesis. We have used conditional deletion of Bmp4 or Alk3 from the pharyngeal endoderm and/or the surrounding mesenchyme using Foxg1-Cre, Wnt1-Cre or Foxn1-Cre. Deleting Bmp4 from both neural crest cells (NCC) and early endoderm-derived epithelial cells in Foxg1-Cre;Bmp4 conditional mutants resulted in defects in thymus-parathyroid morphogenesis. Defects included reduced condensation of mesenchymal cells aro... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3137088 Mon, 28 Dec 2009 00:00:00 +0100 3137088 http://www.medworm.com/index.php?rid=3137087&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%3D20043900%26dopt%3DAbstract Authors: Pennimpede T, Cameron DA, Maclean GA, Petkovich M The role of retinoic acid (RA) in limb development is unclear, although it has been suggested to be a proximalizing factor which plays a morphogenetic role in pattern formation. Exogenous RA produces a teratogenic effect on limb morphology; similarly, changes in the endogenous distribution of RA following genetic ablation of the RA-metabolizing enzyme, CYP26B1, results in phocomelia accompanied by changes in expression of proximo-distal (P-D) patterning genes, increased cell death, and delayed chondrocyte maturation. Here we show that disruption of RA receptor (RAR) gamma in a Cyp26b1(-/-)background is able to partially rescue limb skeletal morphology without restoring normal expression of proximo-distal patterning genes. We fu... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3137087 Mon, 28 Dec 2009 00:00:00 +0100 3137087 http://www.medworm.com/index.php?rid=3137086&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%3D20043901%26dopt%3DAbstract Authors: Feng Y, Xu Q hmx2 (nkx5.2) and hmx3 (nkx5.1) are highly conserved homeobox transcription factors required for mouse inner ear development. We have identified four hmx genes that are expressed in developing mechanosensory organs in zebrafish. Knockdown of both hmx2 and hmx3 disrupts formation of the mechanosensory neuromasts and also leads to impaired vestibular function in which utricular maculae fail to develop and the utricular otolith gradually fuses with the saccular otolith. We demonstrate that pax5, known to be required for development of the utricular maculae, is expressed downstream of hmx2 and hmx3. In addition, we show that FGF signalling regulates expression of hmx2 and hmx3 in the otic vesicle, and conversely, hmx2 and hmx3 maintain the expression of fgf ligands, t... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3137086 Mon, 28 Dec 2009 00:00:00 +0100 3137086 http://www.medworm.com/index.php?rid=3137085&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%3D20043902%26dopt%3DAbstract Authors: Grainger S, Savory JG, Lohnes D Cdx1, Cdx2 and Cdx4 encode homeodomain transcription factors that are involved in vertebral anterior-posterior (AP) patterning. Cdx1 and Cdx2 are also expressed in the intestinal epithelium during development, suggesting a role in this tissue. Intestinal defects have not been reported in Cdx1 null mutants, while Cdx2 null mutants die at embryonic day 3.5 (E3.5), thus precluding assessment of the null phenotype at later stages. To circumvent this latter shortcoming, we have used a conditional Cre-lox strategy to inactivate Cdx2 in the intestinal epithelium. Using this approach, we found that ablation of Cdx2 at E13.5 led to a transformation of the small intestine to a pyloric stomach-like identity, although the molecular nature of the underlying ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3137085 Mon, 28 Dec 2009 00:00:00 +0100 3137085 http://www.medworm.com/index.php?rid=3129962&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%3D20036652%26dopt%3DAbstract Authors: McLennan R, Teddy JM, Kasemeier-Kulesa JC, Romine MH, Kulesa PM The neural crest is an excellent model to study embryonic cell migration, since cell behaviors can be studied in vivo with advanced optical imaging and molecular intervention. What is unclear is how molecular signals direct neural crest cell (NCC) migration through multiple microenvironments and into specific targets. Here, we tested the hypothesis that the invasion of cranial NCCs, specifically the rhombomere 4 (r4) migratory stream into branchial arch 2 (ba2), is due to chemoattraction through neuropilin-1-vascular endothelial growth factor (VEGF) interactions. We found that the spatio-temporal expression pattern of VEGF in the ectoderm correlated with the NCC migratory front. RT-PCR analysis of the r4 migratory... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129962 Thu, 24 Dec 2009 00:00:00 +0100 3129962 http://www.medworm.com/index.php?rid=3129961&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%3D20036653%26dopt%3DAbstract Authors: McNally KL, Martin JL, Ellefson M, McNally FJ During female meiosis, meiotic spindles are positioned at the oocyte cortex to allow expulsion of chromosomes into polar bodies. In C. elegans, kinesin-dependent translocation of the entire spindle to the cortex precedes dynein-dependent rotation of one spindle pole toward the cortex. To elucidate the role of kinesin-1 in spindle translocation, we examined the localization of kinesin subunits in meiotic embryos. Surprisingly, kinesin-1 was not associated with the spindle and instead was restricted to the cytoplasm in the middle of the embryo. Yolk granules moved on linear tracks, in a kinesin-dependent manner, away from the cortex, resulting in their concentration in the middle of the embryo where the kinesin was concentrated. Thes... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129961 Thu, 24 Dec 2009 00:00:00 +0100 3129961 http://www.medworm.com/index.php?rid=3129966&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%3D20036227%26dopt%3DAbstract Authors: Yamada A, Martindale MQ, Fukui A, Tochinai S Brachyury, a member of the T-box transcription family identified in a diverse array of metazoans, was initially recognized for its function in mesoderm formation and notochord differentiation in vertebrates, however its ancestral role has been suggested to be in control of morphogenetic movements. Here, we show that morpholino oligonucleotide knockdown of Brachyury (MlBra) in embryos of a ctenophore, one of the most ancient groups of animals, prevents the invagination of MlBra expressing stomodeal cells and was rescued with corresponding RNA injections. Injection of RNA encoding a dominant-interfering construct of MlBra causes identical phenotypes to that of RNA encoding a dominant-interfering form of Xenopus Brachyury (Xbra) in Xen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129966 Wed, 23 Dec 2009 00:00:00 +0100 3129966 http://www.medworm.com/index.php?rid=3129965&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%3D20036228%26dopt%3DAbstract Authors: Lopes CS, Casares F During Drosophila eye development, recruitment of retinal precursors from a pool of progenitor cells is tightly coupled to proliferation control. However, how this coupling operates is still unclear. Here we show that the transcription factor hth, together with the gene eyeless, is required to stimulate proliferation of progenitor cells. Accordingly, knocking down hth expression results in severely reduced eyes. Our experiments reveal three additional functions for hth: the cell cycle of progenitors is characterized by a relatively long G2 phase, which makes them prone to enter mitosis; hth represses the burst of string/cdc25 expression that precedes G1 arrest, and also the early expression of the proneural gene atonal. Thereby, hth maintains the proliferat... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129965 Wed, 23 Dec 2009 00:00:00 +0100 3129965 http://www.medworm.com/index.php?rid=3129964&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%3D20036229%26dopt%3DAbstract Authors: Huang C, Gu S, Yu P, Yu F, Feng C, Gao N, Du J Mutations in SMARCAL1 cause Schimke Immuno-Osseous Dysplasia (SIOD), an autosomal recessive multisystem developmental disease characterized by growth retardation, T-cell deficiency, bone marrow failure, anemia and renal failure. SMARCAL1 encodes an ATP-driven annealing helicase. However, the biological function of SMARCAL1 and the molecular basis of SIOD remain largely unclear. In this work, we cloned the zebrafish homologue of the human SMARCAL1 gene and found that smarcal1 regulated cell cycle progression. Morpholino knockdown of smarcal1 in zebrafish recapitulated developmental abnormalities in SIOD patients, including growth retardation, craniofacial abnormality, and haematopoietic and vascular defects. Lack of smarcal1 caused... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129964 Wed, 23 Dec 2009 00:00:00 +0100 3129964 http://www.medworm.com/index.php?rid=3129963&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%3D20036230%26dopt%3DAbstract Authors: Wagner N, Weyhersmueller A, Blauth A, Schuhmann T, Heckmann M, Krohne G, Samakovlis C BMP signaling responses are refined by distinct secreted and intracellular antagonists in different cellular and temporal contexts. Here, we show that the nuclear LEM-domain protein MAN1 is a tissue-specific antagonist of BMP signaling in Drosophila. MAN1 contains two potential Mad binding sites. We generated MAN1(DeltaC) mutants, harbouring a MAN1 protein that lacks part of the C-terminus including the RNA recognition motif, a putative Mad-binding domain. MAN1(DeltaC) mutants show wing crossvein (CV) patterning defects but no detectable alterations in nuclear morphology. MAN1(DeltaC) pupal wings display expanded phospho-Mad (pMad) accumulation and ectopic expression of the BMP-responsive gen... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129963 Wed, 23 Dec 2009 00:00:00 +0100 3129963 http://www.medworm.com/index.php?rid=3129968&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%3D20035736%26dopt%3DAbstract Authors: Rallis A, Moore C, Ng J Signaling proteins often control multiple aspects of cell morphogenesis. Yet the mechanisms that govern their pleiotropic behavior are often unclear. Here we show activity levels and timing mechanisms determine distinct aspects of Jun N-terminal kinase (JNK) pathway dependent axonal morphogenesis in Drosophila mushroom body (MB) neurons. In the complete absence of Drosophila JNK (Basket), MB axons fail to stabilize, leading to their subsequent degeneration. However, with a partial loss of Basket (Bsk), or of one of the upstream JNK kinases, Hemipterous or Mkk4, these axons overextend. This suggests that Bsk activity prevents axons from destabilizing, resulting in degeneration and overextension beyond their terminal targets. These distinct phenotypes req... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129968 Tue, 22 Dec 2009 00:00:00 +0100 3129968 http://www.medworm.com/index.php?rid=3129967&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%3D20035737%26dopt%3DAbstract Authors: Nakatani T, Kumai M, Mizuhara E, Minaki Y, Ono Y Mesencephalic dopaminergic (mesDA) neurons control movement and behavior, and their loss causes severe neurological disorders, such as Parkinson's disease. Recent studies have revealed that mesDA neurons originate from mesencephalic floor plate (FP) cells, which had been thought of as non-neurogenic organizer cells regulating regional patterning and axonal projections. Otx2 and its FP-specific downstream factor Lmx1a have been shown to be sufficient to confer neurogenic activity on FP cells and determine a mesDA fate. However, the mechanism underlying how these factors control mesDA development and how FP cells and mesDA neurons are coordinately specified are still largely unknown. In the present study, we obtained evidence that... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3129967 Tue, 22 Dec 2009 00:00:00 +0100 3129967 http://www.medworm.com/index.php?rid=3119423&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%3D20026024%26dopt%3DAbstract We examined the expression and function of four additional hunchback/Ikaros-like (HIL) genes in C. elegans reproductive system development. Two genes, ehn-3 and R08E3.4, are expressed in somatic gonadal precursors (SGPs) and have overlapping functions in their development. In ehn-3; R08E3.4 double mutants, we find defects in the generation of distal tip cells, anchor cells, and spermatheca; three of the five tissues derived from the SGPs. We provide in vivo evidence that C. elegans HIL proteins have functionally distinct zinc finger domains, with specificity residing in the N-terminal set of four zinc fingers and a likely protein-protein interaction domain provided by the C-terminal pair of zinc fingers. In addition, we find that a chimeric human Ikaros protein containing the N-terminal zi... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119423 Wed, 16 Dec 2009 00:00:00 +0100 3119423 http://www.medworm.com/index.php?rid=3119422&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%3D20026025%26dopt%3DAbstract Giant, Krüppel and caudal act as gap genes with extensive roles in patterning the honeybee embryo. Dev Biol. 2009 Dec 16; Authors: Wilson MJ, Havler M, Dearden PK In Drosophila, gap genes translate positional information from gradients of maternal coordinate activity and act to position the periodic patterns of pair-rule gene stripes across broad domains of the embryo. In holometabolous insects maternal coordinate genes are fast evolving, the domains that gap genes specify often differ from their orthologues in Drosophila while the expression of pair-rule genes is more conserved. This implies that gap genes may buffer the fast evolving maternal coordinate genes to give a more conserved pair-rule output. To test this idea we have examined the function and expression of thre... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119422 Wed, 16 Dec 2009 00:00:00 +0100 3119422 http://www.medworm.com/index.php?rid=3119421&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%3D20026026%26dopt%3DAbstract Authors: Oviedo NJ, Morokuma J, Walentek P, Kema IP, Gu MB, Ahn JM, Hwang JS, Gojobori T, Levin M Having the ability to coordinate the behavior of stem cells to induce regeneration of specific large-scale structures would have far reaching consequences in the treatment of degenerative diseases, acute injury, and aging. Thus, identifying and learning to manipulate the sequential steps that determine the fate of new tissue within the overall morphogenetic program of the organism is fundamental. We identified novel early signals, mediated by the central nervous system and 3 innexin proteins, which determine the fate and axial polarity of regenerated tissue in planarians. Modulation of gap junction-dependent and neural signals specifically induces ectopic anterior regeneration blastemas in... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119421 Wed, 16 Dec 2009 00:00:00 +0100 3119421 http://www.medworm.com/index.php?rid=3119429&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%3D20025861%26dopt%3DAbstract Authors: Wang S, Yan J, Anderson DA, Xu Y, Kanal MC, Cao Z, Wright CV, Gu G The basic helix-loop-helix transcription factor Neurog3 (Neurogenin3 or Ngn3) actively drives endodermal progenitor cells towards endocrine islet cell differentiation during embryogenesis. Here, we manipulate Neurog3 expression levels in endocrine progenitor cells without altering its expression pattern using heterozygosity and a hypomorph. Lowered Neurog3 gene dosage in the developing pancreatic epithelium reduces the overall production of endocrine islet cells without significantly affecting the proportions of various islet cell types that do form. A reduced Neurog3 production level in the endocrine-directed pancreatic progenitor population activates the expression of Neurog3 in an increased number of epithel... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119429 Tue, 15 Dec 2009 00:00:00 +0100 3119429 http://www.medworm.com/index.php?rid=3119428&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%3D20025862%26dopt%3DAbstract Authors: Zhao F, Edwards R, Dizon D, Mastroianni JR, Geyfman M, Ouellette AJ, Andersen B, Lipkin SM Anterior Gradient 2 (AGR2) is a protein disulfide isomerase that plays important roles in diverse processes in multiple cell lineages as a developmental regulator, survival factor and susceptibility gene for inflammatory bowel disease. Here, we show using germline and inducible Agr2-/- mice that Agr2 plays important roles in intestinal homeostasis. Agr2-/- intestine has decreased goblet cell Mucin 2, dramatic expansion of the Paneth cell compartment, abnormal Paneth cell localization, elevated endoplasmic reticulum (ER) stress, severe terminal ileitis and colitis. Cell culture experiments show that Agr2 expression is induced by ER stress, and that siRNA knockdown of Agr2 increases ER str... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119428 Tue, 15 Dec 2009 00:00:00 +0100 3119428 http://www.medworm.com/index.php?rid=3119427&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%3D20025863%26dopt%3DAbstract Authors: Bulger M, Groudine M Transcriptional control in mammals and Drosophila is often mediated by regulatory sequences located far from gene promoters. Different classes of such elements - particularly enhancers, but also locus control regions and insulators-have been defined by specific functional assays, although it is not always clear how these assays relate to the function of these elements within their native loci. Recent advances in genomics suggest, however, that such elements are highly abundant within the genome and may represent the primary mechanism by which cell-and developmental-specific gene expression is accomplished. In this review, we discuss the functional parameters of enhancers as defined by specific assays, along with the frequency with which they occur in the g... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119427 Tue, 15 Dec 2009 00:00:00 +0100 3119427 http://www.medworm.com/index.php?rid=3119426&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%3D20025864%26dopt%3DAbstract Authors: Zhou B, von Gise A, Ma Q, Hu YW, Pu WT The annulus fibrosis electrically insulates the atria and ventricles, allowing the timed sequential beating of these structures that is necessary for efficient heart function. Abnormal development of the annulus fibrosis leads to persistence of accessory electrical pathways from atria to ventricles, providing the anatomical substrate for re-entrant cardiac arrhythmias such as Wolff-Parkinson-White syndrome. To better understand the development of the annulus fibrosis and the etiology of these cardiac arrhythmias, we used Cre-LoxP technology to assess the contribution of epicardium derived cells (EPDCs) to the annulus fibrosis. We found that EPDCs migrated into the region of the forming annulus fibrosis, marked by the protein periostin. Th... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119426 Tue, 15 Dec 2009 00:00:00 +0100 3119426 http://www.medworm.com/index.php?rid=3119425&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%3D20025865%26dopt%3DAbstract Authors: Millimaki BB, Sweet EM, Riley BB Sox2 has been variously implicated in maintenance of pluripotent stem cells or, alternatively, early stages of cell differentiation, depending on context. In the developing inner ear, Sox2 initially marks all cells in the nascent sensory epithelium and, in mouse, is required for sensory epithelium formation. Sox2 is eventually downregulated in hair cells but is maintained in support cells, the functional significance of which is unknown. Here we describe regulation and function of sox2 in the zebrafish inner ear. Expression of sox2 begins after the onset of sensory epithelium development and is regulated by Atoh1a/b, Fgf and Notch. Knockdown of sox2 does not prevent hair cell production, but the rate of accumulation is reduced due to sporadic d... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119425 Tue, 15 Dec 2009 00:00:00 +0100 3119425 http://www.medworm.com/index.php?rid=3119424&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%3D20025866%26dopt%3DAbstract Authors: Su H, Marcheva B, Meng S, Liang FA, Kohsaka A, Kobayashi Y, Xu AW, Bass J, Wang X The hypothalamic neuronal circuits that modulate energy homeostasis become mature and functional during early postnatal life. However, the molecular mechanism underlying this developmental process remains largely unknown. Here we use a mouse genetic approach to investigate the role of gamma-protocadherins (Pcdh-gammas) in hypothalamic neuronal circuits. First, we show that rat insulin promoter (RIP)-Cre conditional knockout mice lacking Pcdh-gammas in a broad subset of hypothalamic neurons are obese and hyperphagic. Second, specific deletion of Pcdh-gammas in anorexigenic proopiomelanocortin (POMC) expressing neurons also leads to obesity. Using cell lineage tracing, we show that POMC and RIP-Cre... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3119424 Tue, 15 Dec 2009 00:00:00 +0100 3119424 http://www.medworm.com/index.php?rid=3105446&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%3D20004187%26dopt%3DAbstract Authors: Hoffmann M, Segbert C, Helbig G, Bossinger O Understanding how epithelial organs form during morphogenesis is a major problem in developmental biology. In the present paper, we provide a detailed analysis of vang-1, the only homolog of the planar cell polarity protein Strabismus/Van Gogh in Caenorhabditis elegans. We demonstrate that during organogenesis of the intestine, (i) VANG-1 specifically interacts with PDZ 2 domain of DLG-1 (Discs large) and becomes phosphorylated by the kinase domain of the FGF-like receptor tyrosine kinase EGL-15; (ii) VANG-1 is predominantly restrained to the cell cortex but relocates to the apical junction; and (iii) in vang-1 embryos epithelial cells of the intestine are not correctly arranged along the anterior-posterior axis. To investigate what... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105446 Fri, 11 Dec 2009 00:00:00 +0100 3105446 http://www.medworm.com/index.php?rid=3105445&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%3D20004188%26dopt%3DAbstract Authors: Mizuhara E, Minaki Y, Nakatani T, Kumai M, Inoue T, Muguruma K, Sasai Y, Ono Y GABAergic Purkinje cells (PCs) provide the primary output from the cerebellar cortex, which controls movement and posture. Although the mechanisms of PC differentiation have been well studied, the precise origin and initial specification mechanism of PCs remain to be clarified. Here, we identified a cerebellar and spinal cord GABAergic progenitor-selective cell surface marker, Neph3, which is a direct downstream target gene of Ptf1a, an essential regulator of GABAergic neuron development. Using FACS, Neph3(+) GABAergic progenitors were sorted from the embryonic cerebellum, and the cell fate of this population was mapped by culturing in vitro. We found that most of the Neph3(+) populations sorted fro... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105445 Fri, 11 Dec 2009 00:00:00 +0100 3105445 http://www.medworm.com/index.php?rid=3105442&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%3D20005870%26dopt%3DAbstract Authors: Inoue T, Sternberg PW The control of cell division is critical to organogenesis, but how this control is achieved is not fully understood. We found that mutations in bed-3, encoding a BED Zn-finger domain transcription factor, confer a phenotype where a specific set of cell divisions during vulval organogenesis is lost. Unlike general cell cycle regulators in C. elegans, the function of bed-3 is restricted to specific lineages. Transcriptional reporters suggest that bed-3 is expressed in a limited number of cell types including vulval cells whose divisions are affected in bed-3 mutants. A bed-3 mutation also affects the expression pattern of the cdh-3 cadherin gene in the vulva. The phenotype of bed-3 mutants is similar to the phenotype caused by mutations in cog-1 (Nkx6), a c... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105442 Thu, 10 Dec 2009 00:00:00 +0100 3105442 http://www.medworm.com/index.php?rid=3105441&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%3D20005871%26dopt%3DAbstract Authors: Fridolfsson HN, Ly N, Meyerzon M, Starr DA Nuclei migrate during many events, including fertilization, establishment of polarity, differentiation, and cell division. The C. elegans KASH protein UNC-83 localizes to the outer nuclear membrane where it recruits kinesin-1 to provide the major motor activity required for nuclear migration in embryonic hyp7 cells. Here we show that UNC-83 also recruits two dynein-regulating complexes to the cytoplasmic face of the nucleus that play a regulatory role. One consists of the NudE homolog NUD-2 and the NudF/Lis1/Pac1 homolog LIS-1; the other includes dynein light chain DLC-1, the BicaudalD homolog BICD-1, and the egalitarian homologue EGAL-1. Genetic disruption of any member of these two complexes caused nuclear migration defects that wer... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105441 Thu, 10 Dec 2009 00:00:00 +0100 3105441 http://www.medworm.com/index.php?rid=3105440&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%3D20005872%26dopt%3DAbstract Authors: Price AL, Modrell MS, Hannibal RL, Patel NH In Parhyale hawaiensis, the first three divisions are holoblastic and asymmetric, resulting in an embryo comprised of eight cells - four macromeres and four micromeres. Lineage studies performed at this stage demonstrate that the progeny of each cell contribute to specific portions of different germ layers. However, it is not known if this lineage pattern means a given blastomere is committed to its specific fate, indicative of mosaic development, or if regulation can occur between blastomere progeny so that the loss of a blastomere could be compensated for during development. Furthermore, if compensation occurs, what would be the source of such replacement? To investigate these possibilities, we performed ablation experiments at the... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105440 Thu, 10 Dec 2009 00:00:00 +0100 3105440 http://www.medworm.com/index.php?rid=3105443&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%3D20005219%26dopt%3DAbstract Authors: Brown KE, Keller PJ, Ramialison M, Rembold M, Stelzer EH, Loosli F, Wittbrodt J During development, different cell types must undergo distinct morphogenetic programs so that tissues develop the right dimensions in the appropriate place. In early eye morphogenesis, retinal progenitor cells (RPCs) move first towards the midline, before turning around to migrate out into the evaginating optic vesicles. Neighbouring forebrain cells, however, converge rapidly and then remain at the midline. These differential behaviours are regulated by the transcription factor Rx3. Here, we identify a downstream target of Rx3, the Ig-domain protein Nlcam, and characterise its role in regulating cell migration during the initial phase of optic vesicle morphogenesis. Through sophisticated live imagi... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105443 Wed, 09 Dec 2009 00:00:00 +0100 3105443 http://www.medworm.com/index.php?rid=3105444&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%3D20004656%26dopt%3DAbstract Authors: Salzberg Y, Eldar T, Karminsky O, Itach SB, Pietrokovski S, Don J Meig1 is a mouse gene, abundantly expressed in the testis. It encodes two alternative transcripts that are expressed differentially in the somatic and germinal compartments of the testis. These transcripts share the same coding region but differ in their 5' un-translated regions, due to alternative promoters. Here we show that MEIG1 is a highly conserved short metazoan protein with a conserved core of 81 residues. It is present from chordates to radial symmetry animals, with an intriguing absence in insects and nematodes. It is also present in two earlier diverging protist lineages. To elucidate the role of MEIG1 during gamete production we established a knockout mouse line by eliminating the common coding regio... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105444 Tue, 08 Dec 2009 00:00:00 +0100 3105444 http://www.medworm.com/index.php?rid=3105447&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%3D20004186%26dopt%3DAbstract Authors: Katherine J Fishwick , Li RA, Halley P, Deng P, Kate G Storey Regulated neuron production within the vertebrate nervous system relies on input from multiple signalling pathways. Work in the Drosophila retina has demonstrated that PI3-kinase and downstream TOR signalling regulate the timing of photoreceptor differentiation, however, the function of such signals during vertebrate neurogenesis is not well understood. Here we show that mutant mice lacking PKB activity downstream of PDK1, the master kinase of the PI3-kinase pathway, exhibit deficient neuron production. We further demonstrate expression of PI3-kinase signalling components and active PKB and TOR signalling in the chick spinal cord, an early site of neurogenesis. Neuron production was also attenuated in the chick neu... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3105447 Mon, 07 Dec 2009 00:00:00 +0100 3105447 http://www.medworm.com/index.php?rid=3072364&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%3D19968984%26dopt%3DAbstract Authors: Sugiyama Y, Stump RJ, Nguyen A, Wen L, Chen Y, Wang Y, Murdoch JN, Lovicu FJ, McAvoy JW Planar cell polarity (PCP) signaling polarises cells along tissue axes. Although pathways involved are becoming better understood, outstanding issues include; (i) existence/identity of cues that orchestrate global polarisation in tissues, and (ii) the generality of the link between polarisation of primary cilia and asymmetric localisation of PCP proteins. Mammalian lenses are mainly comprised of epithelial-derived fiber cells. Concentrically arranged fibers are precisely aligned as they elongate along the anterior-posterior axis and orientate towards lens poles where they meet fibers from other segments to form characteristic sutures. We show that lens exhibits PCP, with each fiber cell hav... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3072364 Fri, 04 Dec 2009 00:00:00 +0100 3072364 http://www.medworm.com/index.php?rid=3072363&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%3D19968985%26dopt%3DAbstract Authors: Guo Q, Li K, Sunmonu NA, Li JY The single Fgf8 gene in mice produces eight protein isoforms (Fgf8a-h) with different N-termini by alternative splicing. Gain-of-function studies have demonstrated that Fgf8a and Fgf8b have distinct activities in the developing midbrain and hindbrain (MHB) due to their different binding affinities with FGF receptors. Here we have performed loss-of-function analyses to determine the in vivo requirement for these two Fgf8 spliceforms during MHB development. We showed that deletion of Fgf8b-containing spliceforms (b, d, f and h) leads to loss of multiple key regulatory genes, including Fgf8 itself, in the MHB region. Therefore, specific inactivation of Fgf8b-containing spliceforms, similar to the loss of Fgf8, in MHB progenitors results in deletion ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3072363 Fri, 04 Dec 2009 00:00:00 +0100 3072363 http://www.medworm.com/index.php?rid=3065864&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%3D19962975%26dopt%3DAbstract Authors: Niro C, Demignon J, Vincent S, Liu Y, Giordani J, Sgarioto N, Favier M, Guillet-Deniau I, Blais A, Maire P While the signaling pathways and transcription factors active in adult slow-and fast-type muscles begin to be characterized, genesis of muscle fiber-type diversity during mammalian development remains unexplained. We provide evidence showing that Six homeoproteins are required to activate the fast-type muscle program in the mouse primary myotome. Affymetrix transcriptomal analysis of Six1(-/-)Six4(-/-) E10.5 somites revealed the specific down-regulation of many genes of the fast-type muscle program. This data was confirmed by in situ hybridization performed on Six1(-/-)Six4(-/-) embryos. The first mouse myocytes express both fast-type and slow-type muscle genes. In these ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3065864 Thu, 03 Dec 2009 00:00:00 +0100 3065864 http://www.medworm.com/index.php?rid=3065865&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%3D19962374%26dopt%3DAbstract Authors: Franz A, Riechmann V The function of epithelial tissues is dependent on their polarised architecture, and loss of cell polarity is a hallmark of various diseases. Here we analyse cell polarisation in the follicular epithelium of Drosophila, an epithelium that arises by a mesenchymal-epithelial transition. Although many epithelia are formed by mesenchymal precursors, it is unclear how they polarise. Here we show how lateral, apical and adherens junction proteins act stepwise to establish polarity in the follicular epithelium. Polarisation starts with the formation of adherens junctions, whose positioning is controlled by combined activities of Par-3, Beta-catenin and Discs large. Subsequently, Par-6 and aPKC localise to the apical membrane in a Par-3 dependent manner. Apical me... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3065865 Wed, 02 Dec 2009 00:00:00 +0100 3065865 http://www.medworm.com/index.php?rid=3065867&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%3D19961843%26dopt%3DAbstract Authors: Barton MK The shoot apical meristem of angiosperm plants generates leaf, stem and floral structures throughout the plant's lifetime. To do this, the plant must maintain a population of stem cells within the meristem while at the same time carefully controlling the placement and establishment of new leaf primordia. As there is little cell rearrangement in plants, underlying patterning mechanisms must exert careful control of cell division rates and orientations to achieve the correct final form. It has been twenty years since the first genes controlling meristem development were molecularly cloned. In the intervening decades, our understanding of the inner workings directing meristem development has increased enormously. This review summarizes our current knowledge of how the m... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3065867 Tue, 01 Dec 2009 00:00:00 +0100 3065867 http://www.medworm.com/index.php?rid=3065866&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%3D19961844%26dopt%3DAbstract Authors: Alfieri CM, Cheek J, Chakraborty S, Yutzey KE Wnt signaling mediated by beta-catenin has been implicated in early endocardial cushion development, but its roles in later stages of heart valve maturation and homeostasis have not been identified. Multiple Wnt ligands and pathway genes are differentially expressed during heart valve development. At E12.5, Wnt2 is expressed in cushion mesenchyme, whereas Wnt4 and Wnt9b are predominant in overlying endothelial cells. At E17.5, both Wnt3a and Wnt7b are expressed in the remodeling atrioventricular (AV) and semilunar valves. In addition, the TOPGAL Wnt reporter transgene is active throughout the developing AV and semilunar valves at E16.5, with more localized expression in the stratified valve leaflets after birth. In chicken embryo a... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3065866 Tue, 01 Dec 2009 00:00:00 +0100 3065866 http://www.medworm.com/index.php?rid=3061611&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%3D19958756%26dopt%3DAbstract Authors: Ohgo S, Itoh A, Suzuki M, Satoh A, Yokoyama H, Tamura K During limb regeneration, anuran tadpoles and urodele amphibians generate pattern-organizing, multipotent, mesenchymal blastema cells, which give rise to a replica of the lost limb including patterning in three dimensions. To facilitate the regeneration of nonregenerative limbs in other vertebrates, it is important to elucidate the molecular differences between blastema cells that can regenerate the pattern of limbs and those that cannot. In Xenopus froglet (soon after metamorphosis), an amputated limb generates blastema cells that do not produce proper patterning, resulting in a patternless regenerate, a spike, regardless of the amputation level. We found that re-expression of hoxa11 and hoxa13 in the froglet blastema is... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3061611 Mon, 30 Nov 2009 00:00:00 +0100 3061611 http://www.medworm.com/index.php?rid=3048986&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%3D19944676%26dopt%3DAbstract Authors: Bejarano F, Smibert P, Lai EC Loss of Drosophila mir-9a induces a subtle increase in sensory bristles, but a substantial loss of wing tissue. Here, we establish that the latter phenotype is largely due to ectopic apoptosis in the dorsal wing primordium, and we could rescue wing development in the absence of this microRNA by dorsal-specific inhibition of apoptosis. Such apoptosis was a consequence of de-repressing Drosophila LIM-only (dLMO), which encodes a transcriptional regulator of wing and neural development. We observed cell-autonomous elevation of endogenous dLMO and a GFP-dLMO 3'UTR sensor in mir-9a mutant wing clones, and heterozygosity for dLMO rescued the apoptosis and wing defects of mir-9a mutants. We also provide evidence that dLMO, in addition to senseless, contr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3048986 Wed, 25 Nov 2009 00:00:00 +0100 3048986 http://www.medworm.com/index.php?rid=3048989&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%3D19944088%26dopt%3DAbstract We report on an experimental model for the regeneration of a CSD in the axolotl (the Excisional Regeneration Model) that allows for the identification of signals to induce fibroblast dedifferentiation and skeletal regeneration. This regenerative response is mediated in part by BMP signaling, as is the case in mammals; however, a complete regenerative response requires the induction of a population of undifferentiated, regeneration-competent cells. These cells can be induced by signaling from limb amputation to generate blastema cells that can be grafted to the wound, as well as by signaling from a nerve and a wound epithelium to induce blastema cells from fibroblasts within the wound environment. (195 words). PMID: 19944088 [PubMed - as supplied by publisher] (Source: Developmental Bio... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3048989 Tue, 24 Nov 2009 00:00:00 +0100 3048989 http://www.medworm.com/index.php?rid=3048988&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%3D19944089%26dopt%3DAbstract Authors: Gutkovich Y, Ofir R, Elkouby YM, Dibner C, Gefen A, Elias S, Frank D In Xenopus embryos, XMeis3 protein activity is required for normal hindbrain formation. Our results show that XMeis3 protein knock down also causes a loss of primary neuron and neural crest cell lineages, without altering expression of Zic, Sox or Pax3 genes. Knock down or inhibition of the Pax3, Zic1 or Zic5 protein activities extinguishes embryonic expression of the XMeis3 gene, as well as triggering the loss of hindbrain, neural crest and primary neuron cell fates. Ectopic XMeis3 expression can rescue the Zic knock down phenotype. HoxD1 is an XMeis3 direct-target gene, and ectopic HoxD1 expression rescues cell fate losses in either XMeis3 or Zic protein knock down embryos. FGF3 and FGF8 are direct target g... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3048988 Tue, 24 Nov 2009 00:00:00 +0100 3048988 http://www.medworm.com/index.php?rid=3048987&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%3D19944090%26dopt%3DAbstract Authors: Klein Y, Halachmi N, Egoz-Matia N, Toder M, Salzberg A Coordinated locomotion of Drosophila larvae depends on accurate patterning and stable attachment to the cuticle of both muscles and proprioceptors (chordotonal organs). Unlike muscle spindles in mammals, the fly chordotonal organs are not embedded in the body-wall muscles. Yet, the contractile system (muscles and tendons) and the chordotonal organs constitute two parts of a single functional unit that controls locomotion, and thus must be patterned in full coordination. It is not known how such coordination is achieved. Here we show that the positioning and differentiation of the migrating chordotonal organs are instructed by Stripe, the same transcription factor that promotes tendon cell specification and differentiation ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3048987 Tue, 24 Nov 2009 00:00:00 +0100 3048987 http://www.medworm.com/index.php?rid=3036431&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%3D19941846%26dopt%3DAbstract Authors: Szabo-Rogers HL, Smithers LE, Yakob W, Liu KJ The vertebrate head is an extremely complicated structure. Development of the head requires tissue-tissue interactions between all the germ layers and coordinated morphogenetic movements in three dimensions. Small changes in these interactions can lead to diverse species-specific phenotypic outcomes. In humans, genetic or environmental influences during embryogenesis can result in craniofacial diseases and disorders. This review summarizes a number of recent embryological studies, using chicken, frog, zebrafish and mouse, which have identified crucial signaling centers in the embryonic face. These studies demonstrate how small variations in growth factor signaling can lead to a diversity of phenotypic outcomes. We also highlight ne... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3036431 Mon, 23 Nov 2009 00:00:00 +0100 3036431 http://www.medworm.com/index.php?rid=3036430&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%3D19941847%26dopt%3DAbstract Authors: McCauley BS, Weideman EP, Hinman VF Comparisons of orthologous developmental gene regulatory networks (GRNs) from different organisms explain how transcriptional regulation can, or cannot, change over time to cause morphological evolution and stasis. Here, we examine a subset of the GRN connections in the central vegetal pole mesoderm of the late sea star blastula and compare them to the GRN for the same embryonic territory of sea urchins. In modern sea urchins, this territory gives rise to skeletogenic mesoderm; in sea stars, it develops into other mesodermal derivatives. Orthologs of many transcription factors that function in the sea urchin skeletogenic mesoderm are co-expressed in the sea star vegetal pole, although this territory does not form a larval skeleton. Systemati... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3036430 Mon, 23 Nov 2009 00:00:00 +0100 3036430 http://www.medworm.com/index.php?rid=3031370&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%3D19932206%26dopt%3DAbstract Authors: Rochlin K, Yu S, Roy S, Baylies MK Cell-cell fusion is a crucial and highly regulated event in the genesis of both form and function of many tissues. One particular type of cell fusion, myoblast fusion, is a key cellular process that shapes the formation and repair of muscle. Despite its importance for human health, the mechanisms underlying this process are still not well understood. The purpose of this review is to highlight the recent literature pertaining to myoblast fusion and to focus on a comparison of these studies across several model systems, particularly the fly, zebrafish and mouse. Advances in technical analysis and imaging have allowed identification of new fusion genes and propelled further characterization of previously identified genes in each of these systems... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3031370 Fri, 20 Nov 2009 00:00:00 +0100 3031370 http://www.medworm.com/index.php?rid=3031371&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%3D19931525%26dopt%3DAbstract In this study, morpholino antisense oligonucleotides were used to create an in-frame deletion of the active site of the obscurin A RhoGEF domain in order to examine its functions in zebrafish development. Cardiac myocytes in the morphant embryos lacked the intercalated disks that were present in controls by 72 hpf and, in the more severely affected embryos, the contractile filaments were not organized into mature sarcomeres. Neural abnormalities included delay or loss of retinal lamination. Rescue of the phenotype with co-injection of mini-obscurin A expression constructs demonstrated that the observed effects were due to the loss of small GTPase activation by obscurin A. The immature phenotype of the cardiac myocytes and the retinal neuroblasts observed in the morphant embryos suggests th... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3031371 Wed, 18 Nov 2009 00:00:00 +0100 3031371 http://www.medworm.com/index.php?rid=3031372&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%3D19931238%26dopt%3DAbstract In this study, we developed a melanocyte differentiation assay, used together with drugs that ablate the MSC, to investigate whether MSC-derived melanocytes contribute to the ontogenetic pattern. We found that essentially all melanocytes that develop before 3 dpf arise from the ErbB-independent, direct-developing population. Similarly, late-developing (after 3 dpf) melanocytes of the head are also ErbB independent. In contrast, the melanocytes that develop after three days postfertilization in the lateral and dorsal stripe are sensitive to ErbB inhibitor, indicating that they are derived from the MSC. We show that melanocyte regeneration mutants kit(j1e99) and skiv2l2(j24e1), that are grossly normal for the overall ontogenetic pattern, also lack the MSC-derived contribution to the lateral ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3031372 Tue, 17 Nov 2009 00:00:00 +0100 3031372 http://www.medworm.com/index.php?rid=3000572&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%3D19914231%26dopt%3DAbstract Authors: Ballard SL, Jarolimova J, Wharton KA The coordination of animal growth and development requires adequate nutrients. During times of insufficient food, developmental progression is slowed and stored energy is utilized to ensure that cell and tissue survival are maintained. Here, we report our finding that the Gbb/BMP signaling pathway known to play an important role in many developmental processes in both vertebrates and invertebrates, is critical in the Drosophila larval fat body for regulating energy homeostasis. Animals with mutations in the Drosophila BMP-5,7 orthologue, glass bottom boat (gbb), or in its signaling components, display phenotypes similar to nutrient-deprived and Tor mutant larvae. These phenotypes include a developmental delay with reduced overall growth, a ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000572 Thu, 12 Nov 2009 00:00:00 +0100 3000572 http://www.medworm.com/index.php?rid=3000571&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%3D19914232%26dopt%3DAbstract Authors: Alexander MS, Shi X, Voelker KA, Grange RW, Garcia JA, Hammer RE, Garry DJ The mechanisms that regulate skeletal muscle differentiation, fiber type diversity and muscle regeneration are incompletely defined. Forkhead transcription factors are critical regulators of cellular fate determination, proliferation, and differentiation. We identified a forkhead/winged helix transcription factor, Foxj3, which was expressed in embryonic and adult skeletal muscle. To define the functional role of Foxj3, we examined Foxj3 mutant mice. Foxj3 mutant mice are viable, but have significantly fewer Type I slow-twitch myofibers and have impaired skeletal muscle contractile function compared to their wild type controls. In response to a severe injury, Foxj3 mutant mice have impaired muscle regene... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000571 Thu, 12 Nov 2009 00:00:00 +0100 3000571 http://www.medworm.com/index.php?rid=3000570&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%3D19914233%26dopt%3DAbstract In this report, we show that the augmentation of BMP signaling by a BMP-binding secreted factor, Crossveinless2 (Cv2), is essential for the early embryonic development of mammalian nephrons. In the Cv2-null mouse, the number of cap condensates (clusters of nephron progenitors, which normally express Cv2) was decreased, and the condensate cells exhibited a reduced level of aggregation. In these Cv2(-/-) condensates, the level of phosphorylated Smad1 (pSmad1) was substantially lowered. The loss of a Bmp7 allele in the Cv2(-/-) mouse enhanced the cap condensate defects and further decreased the level of pSmad1 in this tissue. These observations indicated that Cv2 has a pro-BMP function in early nephrogenesis. Interestingly, the renal defects of the Cv2(-/-) mutant were totally suppressed by a... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000570 Thu, 12 Nov 2009 00:00:00 +0100 3000570 http://www.medworm.com/index.php?rid=3000569&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%3D19914234%26dopt%3DAbstract Authors: Berger C, Kannan R, Myneni S, Renner S, Shashidhara LS, Technau GM During development, neural progenitor cells or neuroblasts generate a great intra-and inter-segmental diversity of neuronal and glial cell types in the nervous system. In thoracic segments of the embryonic central nervous system of Drosophila, the neuroblast NB6-4t undergoes an asymmetric first division to generate a neuronal and a glial sublineage, while abdominal NB6-4a divides once symmetrically to generate only 2 glial cells. We had earlier reported a critical function for the G1 cyclin, CyclinE (CycE) in regulating asymmetric cell division in NB6-4t. Here we show that (i) this function of CycE is independent of its role in cell cycle regulation and (ii) the two functions are mediated by distinct domains at... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000569 Thu, 12 Nov 2009 00:00:00 +0100 3000569 http://www.medworm.com/index.php?rid=3000568&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%3D19914235%26dopt%3DAbstract Authors: Surendran K, Boyle S, Barak H, Kim M, Stromberski C, McCright B, Kopan R We previously determined that Notch2, and not Notch1 was required for forming proximal nephron segments. The dominance of Notch2 may be conserved in humans, since Notch2 mutations occur in Alagille syndrome (ALGS) 2 patients, which includes renal complications. To test whether mutations in Notch1 could increase the severity of renal complications in ALGS, we inactivated conditional Notch1 and Notch2 alleles in mice using a Six2-GFP::Cre. This BAC transgene is expressed mosaically in renal epithelial progenitors but uniformly in cells exiting the progenitor pool to undergo mesenchymal to epithelial transition. Although delaying Notch2 inactivation had a marginal effect on nephron numbers, it created a sens... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000568 Thu, 12 Nov 2009 00:00:00 +0100 3000568 http://www.medworm.com/index.php?rid=3000567&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%3D19914236%26dopt%3DAbstract Authors: Aman A, Piotrowski T PMID: 19914236 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000567 Thu, 12 Nov 2009 00:00:00 +0100 3000567 http://www.medworm.com/index.php?rid=3000566&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%3D19914237%26dopt%3DAbstract Authors: Koop D, Holland ND, Sémon M, Alvarez S, Rodriguez de Lera A, Laudet V, Holland LZ, Schubert M Previous developmental studies of vertebrate development have shown that retinoic acid (RA) signaling at the gastrula stage strongly influences anterior-posterior (A-P) patterning of the neurula and later stages. However, much less is known about the more immediate effects of RA signaling on gene transcription and developmental patterning at the gastrula stage. To investigate the targets of RA signaling during the gastrula stage, we used the basal chordate amphioxus, in which gastrulation involves very minimal tissue movements. First, we determined the effect of altered RA signaling on expression of 42 genes (encoding transcription factors and components of major signaling cascad... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000566 Thu, 12 Nov 2009 00:00:00 +0100 3000566 http://www.medworm.com/index.php?rid=3000574&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%3D19913529%26dopt%3DAbstract Authors: Ho LL, Wei X, Shimizu T, Lai ZC Growth-inhibition mediated by Hippo (Hpo) signaling is essential for tissue growth and organ size control in Drosophila. However, the cellular mechanism by which the core components like Mob as tumor suppressor (Mats) and Warts (Wts) protein kinase are activated is poorly understood. In this work, we found that the endogenous Mats is located at the plasma membrane in developing tissues. Membrane-targeting constitutively activates Mats to promote apoptosis and reduce cell proliferation, which leads to reduced tissue growth and organ size. Moreover, the ability of membrane-targeted Mats to inhibit tissue growth required the wts gene activity and Wts kinase activity was increased by the activated Mats in developing tissues. Consistent with the idea... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000574 Wed, 11 Nov 2009 00:00:00 +0100 3000574 http://www.medworm.com/index.php?rid=3000573&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%3D19913530%26dopt%3DAbstract Authors: Posnien N, Bucher G The insect head is composed of several segments. During embryonic development the segments fuse to form a rigid head capsule where obvious segmental boundaries are lacking. Hence, the assignment of regions of the insect head to specific segments is hampered, especially with respect to dorsal (vertex) and lateral (gena) parts. We show that upon Tribolium labial (Tc-lab) knock down the intercalary segment is deleted but not transformed. Further, we find that the intercalary segment contributes to lateral parts of the head cuticle in Tribolium. Based on several additional mutant and RNAi phenotypes that interfere with gnathal segment development, we show that these segments do not contribute to the dorsal head capsule apart from the dorsal ridge. Opposing the ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000573 Wed, 11 Nov 2009 00:00:00 +0100 3000573 http://www.medworm.com/index.php?rid=3000581&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%3D19913004%26dopt%3DAbstract Authors: Deng M, Pan L, Xie X, Gan L During development, compartmentalization of an early embryonic structure produces blocks of cells with distinct properties and developmental potentials. The auditory and vestibular components of vertebrate inner ears are derived from defined compartments within the otocyst during embryogenesis. The vestibular apparatus, including three semicircular canals, saccule, utricle, and their associated sensory organs, detects angular and linear acceleration of the head and relays the information through vestibular neurons to vestibular nuclei in the brainstem. How the early developmental events manifest vestibular structures at the molecular level is largely unknown. Here, we show that LMO4, a LIM-domain-only transcriptional regulator, is required for the f... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000581 Tue, 10 Nov 2009 00:00:00 +0100 3000581 http://www.medworm.com/index.php?rid=3000580&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%3D19913005%26dopt%3DAbstract Authors: Barembaum M, Bronner-Fraser M The transcription factor spalt4 is a key early-response gene in otic placode induction. Here, we characterize the cis-regulatory regions of spalt4 responsible for activation of its expression in the developing otic placode and report the isolation of a novel core enhancer. Identification and mutational analysis of putative transcription factor binding sites reveal that Pea3, a downstream effector of FGF signaling, and Pax2 directly activate spalt4 during ear development. Morpholino-mediated knock-down of each factor reduces or eliminates reporter expression. In contrast, combined over-expression of Pea3 and Pax2 drives ectopic reporter expression, suggesting that they function synergistically. These studies expand the gene regulatory network under... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000580 Tue, 10 Nov 2009 00:00:00 +0100 3000580 http://www.medworm.com/index.php?rid=3000579&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%3D19913006%26dopt%3DAbstract Authors: Talamillo A, Delgado I, Nakamura T, de-Vega S, Yoshitomi Y, Unda F, Birchmeier W, Yamada Y, Ros MA The formation and maintenance of the apical ectodermal ridge (AER) is critical for the outgrowth and patterning of the vertebrate limb. In the present work, we have investigated the role of Epiprofin (Epfn/Sp6), a member of the SP/KLF transcription factor family that is expressed in the limb ectoderm and the AER, during limb development. Epfn mutant mice have a defective autopod that shows mesoaxial syndactyly in the forelimb and synostosis (bony fusion) in the hindlimb and partial bidorsal digital tips. Epfn mutants also show a defect in the maturation of the AER that appears flat and broad, with a double ridge phenotype. By genetic analysis, we also show that Epfn is controlled... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000579 Tue, 10 Nov 2009 00:00:00 +0100 3000579 http://www.medworm.com/index.php?rid=3000578&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%3D19913007%26dopt%3DAbstract Authors: Ioannides AS, Massa V, Ferraro E, Cecconi F, Spitz L, Henderson DJ, Copp AJ Foregut division - the separation of dorsal (oesophageal) from ventral (tracheal) foregut components - is a crucial event in gastro-respiratory development, and frequently disturbed in clinical birth defects. Here, we examined three outstanding questions of foregut morphogenesis. The origin of the trachea is suggested to result either from respiratory outgrowth or progressive septation of the foregut tube. We found normal foregut lengthening despite failure of tracheo-oesophageal separation in Adriamycin-treated embryos, whereas active septation was observed only in normal foregut morphogenesis, indicating a primary role for septation. Dorso-ventral patterning of Nkx2.1 (ventral) and Sox2 (dorsal) expr... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000578 Tue, 10 Nov 2009 00:00:00 +0100 3000578 http://www.medworm.com/index.php?rid=3000577&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%3D19913008%26dopt%3DAbstract Authors: Christiaen L, Stolfi A, Levine M Gene regulatory networks control the progressive specification of cell types and govern morphogenetic events during development. However, how morphogenetic events reciprocally affect gene expression remains poorly understood. Here, we analyzed the function of BMP signaling and expression of downstream target genes during cell migration of the precardiac mesoderm (trunk ventral cells, TVCs) in ascidian embryos. Our results indicate that migrating TVCs experience increasing BMP signaling as they migrate towards the ventral trunk epidermis, which expresses sustained levels of Bmp2/4. This increasing signaling intensity allows the successive activation of GATAa, Tolloid, Bmp2/4 and NK4. Initial activation of GATAa, Tolloid and Bmp2/4 contribute to ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000577 Tue, 10 Nov 2009 00:00:00 +0100 3000577 http://www.medworm.com/index.php?rid=3000576&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%3D19913009%26dopt%3DAbstract Authors: Wills AE, Choi VM, Bennett MJ, Khokha MK, Harland RM In ectodermal explants from Xenopus embryos, inhibition of BMP signaling is sufficient for neural induction, leading to the idea that neural fate is the default state in the ectoderm. Many of these experiments assayed the action of BMP antagonists on animal caps, which are relatively naïve explants of prospective ectoderm, and different results have led to debate regarding both the mechanism of neural induction and the appropriateness of animal caps as an assay system. Here we address whether BMP antagonists are only able to induce neural fates in pre-patterned explants, and the extent to which neural induction requires FGF signaling. We suggest that some discrepancies in conclusion depend on the interpretations of sox ... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000576 Tue, 10 Nov 2009 00:00:00 +0100 3000576 http://www.medworm.com/index.php?rid=3000575&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%3D19913010%26dopt%3DAbstract Authors: Smith AN, Radice G, Lang RA PMID: 19913010 [PubMed - as supplied by publisher] (Source: Developmental Biology) Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3000575 Tue, 10 Nov 2009 00:00:00 +0100 3000575 http://www.medworm.com/index.php?rid=2985166&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%3D19900437%26dopt%3DAbstract Authors: Colombo M, Brambilla V, Marcheselli R, Caporali E, Kater MM, Colombo L Gynoecium development is a complex process which is regulated by key factors that control the spatial formation of the apical, medial and basal parts. SHATTERPROOF1 (SHP1) and SHP2, two closely related MADS-box genes, redundantly control the differentiation of the dehiscence zone and promote the lignification of adjacent cells. Furthermore, SHP1 and SHP2 have shown to play an important role in ovule identity determination. The present work identifies a new function for these two genes in promoting stigma, style and medial tissue development. This new role was discovered by combining the shp1 shp2 double mutant with the aintegumenta (ant) and crabs claw (crc) mutants. In quadruple mutant flowers, the inner w... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2985166 Fri, 06 Nov 2009 00:00:00 +0100 2985166 http://www.medworm.com/index.php?rid=2985165&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%3D19900438%26dopt%3DAbstract In this study, we show that the LIM-homeobox gene Lhx2 is extensively expressed in the developing ventral diencephalon, including the infundibulum and the posterior lobe of the pituitary. Deletion of Lhx2 gene results in persistent cell proliferation, a complete failure of evagination of the neuroectoderm in the ventral diencephalon, and defects in the formation of the distinct morphological features of the infundibulum and the posterior pituitary lobe. Rathke's pouch is formed and endocrine cell lineages are generated in the anterior/intermediate pituitary lobes of the Lhx2 mutant. However, the shape and organization of the pouch and the anterior/intermediate pituitary lobes are severely altered due to the defects in development of the infundibulum and the posterior lobe. Our study thus r... Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2985165 Fri, 06 Nov 2009 00:00:00 +0100 2985165