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Generation of mouse conditional and null alleles of the type III sodium-dependent phosphate cotransporter PiT-1Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Accelerated vascular calcification occurs in several human diseases including diabetes and chronic kidney disease (CKD). In patients with CKD, vascular calcification is highly correlated with elevated serum phosphate levels. In vitro, elevated concentrations of phosphate induced vascular smooth muscle cell matrix mineralization, and the inorganic phosphate transporter-1 (PiT-1), was shown to be required. To determine the in vivo role of PiT-1, mouse conditional and null alleles were generated. Here we show that the conditional allele, PiT-1flox, which has loxP sites flanking exons 3 and 4, is homozygous viable. Cre-mediate...
Source: genesis - October 31, 2009 Category: Genetics & Stem Cells Authors: Maria H. Festing, Mei Y. Speer, Hsueh-Ying Yang, Cecilia M. Giachelli Source Type: journals

Characterization of a dorsal-eye Gal4 Line in DrosophilaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In Drosophila, the Gal4-UAS system is used to drive ectopic gene expression in a tissue-specific manner. In this system, transgenic flies expressing tissue specific Gal4 are crossed to a line in which the gene to be expressed is under the control of a Gal4-responsive UAS sequence. The resulting progeny express the gene of interest in the pattern of the particular Gal4 line. Since a given UAS-transgene can be driven by any Gal4 line, this system is predominantly limited by available Gal4 lines. Here we report the characterization of a novel line, DE-Gal4, which in the eye is expressed in the dorsal compartment for the major...
Source: genesis - October 30, 2009 Category: Genetics & Stem Cells Authors: Clayton M. Morrison, Georg Halder Source Type: journals

The evolution of gnathostome development: Insight from chondrichthyan embryologyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chondrichthyans (cartilaginous fishes) represent one of the two lineages of gnathostomes, the other being the osteicthyans (bony fishes). Classical studies on chondrichthyan embryology have strongly impacted our views of vertebrate body plan evolution, while recent studies highlight oviparous chondrichthyans as emerging vertebrate model systems that are amenable to experimental embryological manipulation. Here, we review three particular areas of interest in the field of chondrichthyan developmental biology - gastrulation, neural development, and appendage patterning - and we discuss recentfindings within a broader chondri...
Source: genesis - October 30, 2009 Category: Genetics & Stem Cells Authors: J. Andrew Gillis, Neil H. Shubin Source Type: journals

An estrogen receptor alpha activity indicator model in miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This reporter transgene consisting of a humanized renilla Green Fluorescent Protein (hrGFP) sequence controlled by the Upstream Activating Sequences for the Gal4 gene (UASG) was inserted into the modified ER[alpha] BAC clone. Expression of Gal4-ER[alpha] and hrGFP reliably recapitulates endogenous ER[alpha] expression and activity in the estrogen target tissues in response to estrogen stimulation. Therefore, the ERAAI mouse represents a novel animal model to investigate dynamic ER[alpha] activity in vivo. genesis 00:1-10, 2009. © 2009 Wiley-Liss, Inc. (Source: genesis)
Source: genesis - October 30, 2009 Category: Genetics & Stem Cells Authors: Sang Jun Han, Bert W. O'Malley, Francesco J. DeMayo Source Type: journals

Intragraft gene expression profile associated with the induction of tolerance by allochimeric MHC I in the rat heart transplantation modelEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The MHC class I allochimeric protein containing donor-type epitopes on recipient-type heavy chains induces indefinite survival of heterotopic cardiac allografts in rats. We analyzed gene expression profile of heart allograft tissue. Mutated peptide [[alpha]1h1/u]-RT1.Aa that contains donor-type (Wistar Furth, WF; RT1u) immunogenic epitopes displayed on recipient-type (ACI, RT1a) was delivered into ACI recipients of WF hearts at the time of transplantation in addition to a 3 days course of oral cyclosporine. Microarray analysis was performed using Affymetrix Rat 230 2.0 Microarray. Allochimeric molecule treatment caused upr...
Source: genesis - October 30, 2009 Category: Genetics & Stem Cells Authors: Wojciech Lisik, Yongquan Gong, Neelam Tejpal, Thomas S. Skelton, Eric G. Bremer, Malgorzata Kloc, Rafik M. Ghobrial Source Type: journals

Textpresso site-specific recombinases: A text-mining server for the recombinase literature including Cre mice and conditional allelesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Textpresso Site Specific Recombinases () is a text-mining web server for searching a database of more than 9,000 full-text publications. The papers and abstracts in this database represent a wide range of topics related to site-specific recombinase (SSR) research tools. Included in the database are most of the papers that report the characterization or use of mouse strains that express Cre recombinase as well as papers that describe or analyze mouse lines that carry conditional (floxed) alleles or SSR-activated transgenes/knockins. The database also includes reports describing SSR-based cloning methods such as the Gateway ...
Source: genesis - October 30, 2009 Category: Genetics & Stem Cells Authors: William M. Urbanski, Brian G. Condie Source Type: journals

BhSGAMP-1, a gene that encodes an antimicrobial peptide, is developmentally regulated by the direct action of 20-OH ecdysone in the salivary gland of Bradysia hygida (Diptera, Sciaridae)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recently we have shown that BhSGAMP-1 is a developmentally regulated reiterated gene that encodes an antimicrobial peptide (AMP) and is expressed exclusively in the salivary glands, at the end of the larval stage. We show, for the first time, that a gene for an AMP is directly activated by 20-OH ecdysone. This control probably involves the participation of short-lived repressor(s). We also found that the promoter of BhSGAMP-1 is not equipped with elements that respond to infection, provoked by the injection of microorganisms, in the salivary glands or in the fat body. We produced polyclonal antibodies against the synthetic...
Source: genesis - October 30, 2009 Category: Genetics & Stem Cells Authors: Gabriela Morilha Zanarotti, Juliana A. Cândido-Silva, Jorge Cury de Almeida Source Type: journals

Developmental regulation of the composite CAG promoter activity in the murine T lymphocyte cell lineageEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Promoter selection is of utmost importance for the study of in vivo gene function using transgenic models. In the present study, we have analyzed the expression of the GFP marker under the control of the composite CAG promoter in the lymphoid compartment of several transgenic mouse strains. Despite the ability of the CAG promoter to drive gene expression in almost all tissues examined to date, its activity appears to be developmentally regulated within the T lymphocyte cell lineage. In particular, CD4 and CD8-expressing, thymic immature T cells displayed lower levels of the GFP marker when compared with both bone marrow pr...
Source: genesis - October 14, 2009 Category: Genetics & Stem Cells Authors: Delphine Baup, Muriel Moser, Stéphane Schurmans, Oberdan Leo Source Type: journals

Dual fluorescent protein reporters for studying cell behaviors in vivoEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
HeLa cells transfected with plasmids expressing dual fluorescent protein reporters with cherry, green, and cyan fluorscent proteins. Histone 2B fusions localize fluorescent proteins to the nucleus, while fluorescent proteins fused to glycosylphosphatidylinositol anchor signal sequence localizes to plasma membranes. These dual fluorescent reporters label nuclear and plasma membranes of live cells to follow their behaviors in developing embryos. See the paper by Stewart et al. in this issue. (Source: genesis)
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: M. David Stewart, Chuan-Wei Jang, Nicholas W. Hong, Anthony P. Austin, Richard R. Behringer Source Type: journals

A Probasin-MerCreMer BAC allows inducible recombination in the mouse prostateEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present mouse lines expressing an inducible Cre protein (MerCreMer) under the control of regulatory elements of the probasin gene on a BAC. These mouse lines show high organ specificity, high transgene expression in anterior, dorsal and lateral prostate lobes, no background Cre recombination using a reporter strain and adjustable amounts of Cre-induced recombination upon tamoxifen induction. Together with two recently reported transgenic lines expressing the Cre-ERT2 protein from small prostate-specific promoters, these mouse lines will be useful in research focused on prostate-specific disorders such as benign hyperpla...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Andreas Birbach, Emilio Casanova, Johannes A. Schmid Source Type: journals

Oligodendroglial and pan-neural crest expression of Cre recombinase directed by Sox10 enhancerEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Utilizing a recently identified Sox10 distal enhancer directing Cre expression, we report S4F:Cre, a transgenic mouse line capable of inducing recombination in oligodendroglia and all examined neural crest derived tissues. Assayed using R26R:LacZ reporter mice expression was detected in neural crest derived tissues including the forming facial skeleton, dorsal root ganglia, sympathetic ganglia, enteric nervous system, aortae, and melanoblasts, consistent with Sox10 expression. LacZ reporter expression was also detected in non-neural crest derived tissues including the oligodendrocytes and the ventral neural tube. This line...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Zachary E. Stine, Jimmy L. Huynh, Stacie K. Loftus, David U. Gorkin, Amirali H. Salmasi, Thomas Novak, Todd Purves, Ronald A. Miller, Anthony Antonellis, John P. Gearhart, William J. Pavan, Andrew S. McCallion Source Type: journals

New hemocyte-specific enhancer-reporter transgenes for the analysis of hematopoiesis in DrosophilaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Based on environmental challenges or altered genetic composition, Drosophila larvae can produce up to three types of blood cells that express genetic programs essential for their distinct functions. Using transcriptional enhancers for genes expressed exclusively in plasmatocytes, crystal cells, or lamellocytes, several new hemocyte-specific enhancer-reporter transgenes were generated to facilitate the analysis of Drosophila hematopoiesis. This approach took advantage of fluorescent variants of insulated P-element reporter vectors for multilabeling cell analyses; two additional color variants were generated in these studies...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Tsuyoshi Tokusumi, Douglas A. Shoue, Yumiko Tokusumi, Jessica R. Stoller, Robert A. Schulz Source Type: journals

Generation and analysis of a mouse line harboring GFP in the Eomes/Tbr2 locusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
During mouse embryonic development, the T-box transcription factor Eomes/Tbr2 is expressed in highly dynamic patterns in various progenitor cell types. Those include the undifferentiated cells of the trophectoderm, ingressing nascent mesoderm at the primitive streak, and intermediate progenitor cells of the developing cerebral cortex. We generated an EomesGFP- targeted allele to follow the highly dynamic patterns of Eomes expression and to allow for the identification of novel expression domains. We show that our novel allele recapitulates endogenous gene expression at known sites of expression and confirm our results by a...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Sebastian J. Arnold, Jacintha Sugnaseelan, Matthias Groszer, Shankar Srinivas, Elizabeth J. Robertson Source Type: journals

Placenta-specific gene activation and inactivation using integrase-defective lentiviral vectors with the Cre/LoxP systemEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Transgenic and knockout studies have advanced our understanding of the genetic control of embryonic development over the past decades. However, interpretation of the phenotype of mutant mice is potentially complicated, since the commonly used knockout approach modifies both the fetal and placental genome. To circumvent this problem, we previously developed a placenta-specific gene manipulation system by lentiviral vector transduction of embryos at the blastocyst stage. In the present study, by combination with the Cre/LoxP system, we successfully demonstrate placenta-specific gene activation and inactivation in EGFP report...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Yuka Morioka, Ayako Isotani, Robert G. Oshima, Masaru Okabe, Masahito Ikawa Source Type: journals

Generation of aggrecan-CreERT2 knockin mice for inducible Cre activity in adult cartilageEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, we have generated a mouse model in which genes implicated in cartilage degenerative diseases can be inactivated in a spatial and temporal fashion in postnatal and adult mice. genesis 00:1-10, 2009. © 2009 Wiley-Liss, Inc. (Source: genesis)
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Stephen P. Henry, Chuan-Wei Jang, Jian Min Deng, Zhaoping Zhang, Richard R. Behringer, Benoit deCrombrugghe Source Type: journals

Generation of an allele to inactivate Wnt4 gene function conditionally in the mouseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Wnt family member Wnt4 is critical for the development of several organs, including the kidney, gonad, and adrenal, mammary, and pituitary glands. To study its potential postnatal functions, we generated a floxed Wnt4 allele. A single loxP site was targeted to the second intron, while a loxP-Neo-loxP cassette was placed 3[prime] from Exon 5. The floxed Neo cassette was subsequently removed by crossing with MeuCre40 transgenic mice. The Wnt4 gene was specifically inactivated with CAGCre and another Wnt4 allele, Wnt4EGFPCre, in which the Cre is driven by the endogenous Wnt4 promoter. Deletion of Wnt4 gene function with C...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Jingdong Shan, Tiina Jokela, Hellevi Peltoketo, Seppo Vainio Source Type: journals

Cre activity in fetal albCre mouse hepatocytes: Utility for developmental studiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The albCre transgene, having Cre recombinase driven by the serum albumin (alb) gene promoter, is commonly used to generate adult mice having reliable hepatocyte-specific recombination of loxP-flanked ("floxed") alleles. Based on previous studies, it has been unclear whether albCre transgenes are also reliable in fetal and juvenile mice. Perinatal liver undergoes a dynamic transition from being predominantly hematopoietic to predominantly hepatic. We evaluated Cre activity during this transition in albCre mice using a sensitive two-color fluorescent reporter system. From fetal through adult stages, in situ patterns of Cre-d...
Source: genesis - October 13, 2009 Category: Genetics & Stem Cells Authors: Carla M. Weisend, Jean A. Kundert, Elena S. Suvorova, Justin R. Prigge, Edward E. Schmidt Source Type: journals

Dual fluorescent protein reporters for studying cell behaviors in vivoEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Fluorescent proteins (FPs) are useful tools for visualizing live cells and their behaviors. Protein domains that mediate subcellular localization have been fused to FPs to highlight cellular structures. FPs fused with histone H2B incorporate into chromatin allowing visualization of nuclear events. FPs fused to a glycosylphosphatidylinositol anchor signal sequence label the plasma membrane, highlighting cellular shape. Thus, a reporter gene containing both types of FP fusions would allow for effective monitoring of cell shape, movement, mitotic stage, apoptosis, and other cellular activities. Here, we report a binary color-...
Source: genesis - October 7, 2009 Category: Genetics & Stem Cells Authors: M. David Stewart, Chuan-Wei Jang, Nicholas W. Hong, Anthony P. Austin, Richard R. Behringer Source Type: journals

Generation of an OMgp allelic series in miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The very limited ability to regenerate axons after injury in the mature mammalian central nervous system (CNS) has been partly attributed to the growth restrictive nature of CNS myelin. Oligodendrocyte myelin glycoprotein (OMgp) was identified as a major myelin-derived inhibitor of axon growth. However, its role in axon regeneration in vivo is poorly understood. Here we describe the generation and molecular characterization of an OMgp allelic series. With a single gene targeting event and Cre/FLP mediated recombination, we generated an OMgp null allele with a LacZ reporter, one without a reporter gene, and an OMgp conditio...
Source: genesis - August 11, 2009 Category: Genetics & Stem Cells Authors: Jae K. Lee, Lauren C. Case, Andrea F. Chan, Yuhong Zhu, Marc Tessier-Lavigne, Binhai Zheng Source Type: journals

Membrane domain modulation by Spectrins in Drosophila photoreceptor morphogenesisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Spectrins are major proteins in the cytoskeletal network of most cells. In Drosophila, [beta]Heavy-Spectrin encoded by the karst gene functions together with Crb during photoreceptor morphogenesis. However, the roles of two other Spectrins ([alpha]- and [beta]-Spectrins) in developing photoreceptor cells have not been studied. Here, we analyzed the effects of spectrin mutations on developing eyes to determine their roles in photoreceptor morphogenesis. We found that the Spectrins are dispensable for retinal differentiation in eye imaginal discs during larval stage. However, photoreceptors deficient in [alpha]- or [beta]-Sp...
Source: genesis - August 10, 2009 Category: Genetics & Stem Cells Authors: Tony W. Chen, Geng Chen, Lisa J. Funkhouser, Sang-Chul Nam Source Type: journals

PhotomorphsTM: A novel light-activated reagent for controlling gene expression in zebrafishEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this report, we describe a novel light- activatable knockdown reagent called PhotoMorphTM. PhotoMorphs can be generated from existing morpholinos by hybridization with a complementary caging strand containing a photocleavable linkage. The caging strand neutralizes the morpholino activity until irradiation of the PhotoMorph with UV light releases the morpholino. We generated PhotoMorphs to target genes encoding enhanced green fluorescent protein, No tail, and E-cadherin to illustrate the utility of this approach. Temporal control of gene expression with PhotoMorphs permitted us to circumvent the early lethal phenotype of...
Source: genesis - July 30, 2009 Category: Genetics & Stem Cells Authors: Amber J. Tomasini, Aaron D. Schuler, John A. Zebala, Alan N. Mayer Source Type: journals

Periphilin is strongly expressed in the murine nervous system and is indispensable for murine developmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Periphilin is involved in multiple processes in vivo. To explore its physiological role from an organismic perspective, we generated mice with a gene trap insertion in the periphilin-1 gene. Based on [beta]-gal reporter activity, a widespread periphilin expression was evident, especially in the developing somites and limbs, the embryonic nervous system, and the adult brain. In accordance with this broad expression, homozygous deficiency of periphilin was lethal in early embryogenesis. Mice with a heterozygous deficiency did not show any abnormalities of brain morphology and function, neither histologically nor regarding th...
Source: genesis - July 20, 2009 Category: Genetics & Stem Cells Authors: Anne S. Soehn, Thu-Trang Pham, Karin Schaeferhoff, Thomas Floss, Daniela M. Vogt Weisenhorn, Wolfgang Wurst, Michael Bonin, Olaf Riess Source Type: journals

Generation of cortactin floxed mice and cellular analysis of motility in fibroblastsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cortactin is an F-actin binding protein that has been suggested to play key roles in various cellular functions. Here, we generated mice carrying floxed alleles of the cortactin (Cttn) gene (Cttnflox/flox mice). Expression of Cre recombinase in mouse embryonic fibroblasts (MEFs) isolated from Cttnflox/flox embryos depleted cortactin within days, without disturbing F-actin distribution and localization of multiple actin-binding proteins. Cre-mediated deletion of Cttn also did not affect cell migration. To obtain mice with a Cttn null allele, we next crossed Cttnflox/flox mice with transgenic mice that express Cre recombinas...
Source: genesis - July 19, 2009 Category: Genetics & Stem Cells Authors: Shinji Tanaka, Masataka Kunii, Akihiro Harada, Shigeo Okabe Source Type: journals

Generation of conditional Hoxc8 loss-of-function and Hoxc8[rarr]Hoxc9 replacement alleles in miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Hox family of transcription factors are expressed at different domains along the rostrocaudal (R-C) body axis during development. To examine the function of Hoxc8 and Hoxc9 in specific cell types and at different developmental times, we have generated and characterized loxP flanked (floxed) Hoxc8 and Hoxc8[rarr]Hoxc9 replacement alleles of mice, with either GFP or LacZ reporters. Although all four alleles of mice behave like wild-type controls in motor behavioral testing, slight differences in endogenous Hox gene expression were observed among these alleles depending on the type of reporters used and the presence of Ho...
Source: genesis - July 19, 2009 Category: Genetics & Stem Cells Authors: Jessica Blackburn, Melissa Rich, Nima Ghitani, Jeh-Ping Liu Source Type: journals

Generation of a conditional CREB Ser133Ala knockin mouseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Phosphorylation of Ser133 in the transcription factor CREB is an important mechanism for regulating its transcriptional activity, however recent work has suggested significant roles for other regulatory inputs into CREB. To allow study of this in vivo, we have generated a Ser133 to alanine knockin mutation in the mouse CREB locus. As CREB knockout is perinatal lethal, a minigene strategy was used to allow conditional knockin of the Ser133Ala mutation in adult mice using Cre recombinase. While some expression of the mutated protein was observed prior to Cre expression, following Cre expression in either T cells or neurons o...
Source: genesis - July 19, 2009 Category: Genetics & Stem Cells Authors: Andrew D. Wingate, Kirsty J. Martin, Chris Hunter, Julia M. Carr, Carol Clacher, J. Simon C. Arthur Source Type: journals

Highly B lymphocyte-specific tamoxifen inducible transgene expression of CreERT2 by using the LC-1 locus BAC vectorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, the LC-1-hCD19-CreERT2 strain is a powerful tool to study gene function specifically in B lymphocytes at any chosen time point in the lifecycle of the mouse. genesis 00:1-7, 2009. © 2009 Wiley-Liss, Inc. (Source: genesis)
Source: genesis - July 19, 2009 Category: Genetics & Stem Cells Authors: Peter Boross, Cor Breukel, Pieter Fokko van Loo, Jos van der Kaa, Jill W. Claassens, Hermann Bujard, Kai Schönig, J. Sjef Verbeek Source Type: journals

Left-right asymmetry in the chick embryo requires core planar cell polarity protein Vangl2Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Consistent left-right patterning is a fascinating and biomedically important problem. In the chick embryo, it is not known how cells determine their position (left or right) relative to the primitive streak, which is required for subsequent asymmetric gene expression cascades. We show that the subcellular localization of Vangl2, a core planar cell polarity (PCP) protein, is consistently polarized, giving cells in the blastoderm a vector pointing toward the primitive streak. Moreover, morpholino-mediated loss-of-function of Vangl2 by electroporation into chicks at very early stages randomizes the normally left-sided express...
Source: genesis - July 19, 2009 Category: Genetics & Stem Cells Authors: Ying Zhang, Michael Levin Source Type: journals

Capn8 promoter directs the expression of Cre recombinase in gastric pit cells of transgenic miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Gastric pit cells are high-turnover epithelial cells of the gastric mucosa. They secrete mucus to protect the gastric epithelium from acid and pepsin. To investigate the genetic mechanisms underlying the physiological functions of gastric pit cells, we generated a transgenic mouse line, namely, Capn8-Cre, in which the expression of Cre recombinase was controlled by the promoter of the intracellular Ca2+-regulated cysteine protease calpain-8. To test the tissue distribution and excision activity of Cre recombinase, the Capn8-Cre transgenic mice were bred with the ROSA26 reporter strain and a mouse strain that carries Smad4 ...
Source: genesis - July 14, 2009 Category: Genetics & Stem Cells Authors: Zengming Zhao, Yanxun Sun, Ning Hou, Yan Teng, Youliang Wang, Xiao Yang Source Type: journals

Analysis of epigenetic alterations to chromatin during developmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Each cell within a multicellular organism has distinguishable characteristics established by its unique patterns of gene expression. This individual identity is determined by the expression of genes in a time and place-dependent manner, and it is becoming increasingly clear that chromatin plays a fundamental role in the control of gene transcription in multicellular organisms. Therefore, understanding the regulation of chromatin and how the distinct identity of a cell is passed to daughter cells during development is paramount. Techniques with which to study chromatin have advanced rapidly over the past decade. Development...
Source: genesis - July 13, 2009 Category: Genetics & Stem Cells Authors: Meghan E. Minard, Abhinav K. Jain, Michelle Craig Barton Source Type: journals

A mouse model for visualization of GABAB receptorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
GABAB receptors are the G-protein-coupled receptors for the neurotransmitter [gamma]-aminobutyric acid (GABA). Receptor subtypes are based on the subunit isoforms GABAB1a and GABAB1b, which combine with GABAB2 subunits to form heteromeric receptors. Here, we used a modified bacterial artificial chromosome (BAC) containing the GABAB1 gene to generate transgenic mice expressing GABAB1a and GABAB1b subunits fused to the enhanced green fluorescence protein (eGFP). We demonstrate that the GABAB1-eGFP fusion proteins reproduce the cellular expression patterns of endogenous GABAB1 proteins in the brain and in peripheral tissue. C...
Source: genesis - July 13, 2009 Category: Genetics & Stem Cells Authors: Emilio Casanova, Nicole Guetg, Réjan Vigot, Riad Seddik, Marcela Julio-Pieper, Niall P. Hyland, John F. Cryan, Martin Gassmann, Bernhard Bettler Source Type: journals

Cell adhesive affinity does not dictate primitive endoderm segregation and positioning during murine embryoid body formationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The classical cell sorting experiments undertaken by Townes and Holtfreter described the intrinsic propensity of dissociated embryonic cells to self-organize and reconcile into their original embryonic germ layers with characteristic histotypic positioning. Steinberg presented the differential adhesion hypothesis to explain these patterning phenomena. Here, we have reappraised these issues by implementing embryoid bodies to model the patterning of epiblast and primitive endoderm layers. We have used combinations of embryonic stem (ES) cells and their derivatives differentiated by retinoic acid treatment to model epiblast a...
Source: genesis - July 13, 2009 Category: Genetics & Stem Cells Authors: Robert Moore, Kathy Q. Cai, Diogo O. Escudero, Xiang-Xi Xu Source Type: journals

A Cre/LoxP conditional luciferase reporter transgenic mouse for bioluminescence monitoring of tumorigenesisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report the generation of a bioluminescent reporter strain that allows monitoring of tumor development in preexisting conditional mouse tumor models. We demonstrate that, in a Cre-dependent glioblastoma multiforme model, tumor initiation and progression is readily monitored over time and that luminescent output is related to tumor volume. Our results show that this reporter strain may be combined with various Cre/loxP mouse tumor models to allow for noninvasive longitudinal monitoring of tumor growth and therapeutic response in vivo. genesis 00:1-8, 2009. © 2009 Wiley-Liss, Inc. (Source: genesis)
Source: genesis - July 13, 2009 Category: Genetics & Stem Cells Authors: Steve Woolfenden, Haihao Zhu, Al Charest Source Type: journals

Misexpression of Gbx2 throughout the mesencephalon by a conditional gain-of-function transgene leads to deletion of the midbrain and cerebellum in miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe here a conditional Gbx2 gain-of-function transgenic mouse line, Gbx2-GOF, which expresses Gbx2 and red fluorescence protein, mCherry, upon Cre-mediated recombination. In the absence of Cre, [beta]-galactosidase is broadly expressed in mouse embryos and adult brains carrying the transgene. By combining Gbx2-GOF and En1Cre knock-in allele, we activated expression of Gbx2 and mCherry throughout the mesencephalon (mes) and rhombomere 1 (r1). The ectopic expression of Gbx2 causes an anterior shift of the mes/r1 junction at embryonic day 10.5. Interestingly, we found that persistent expression of Gbx2 throughout the ...
Source: genesis - July 13, 2009 Category: Genetics & Stem Cells Authors: N. Abimbola Sunmonu, Li Chen, James Y.H. Li Source Type: journals

Sox17-2A-iCre: A knock-in mouse line expressing Cre recombinase in endoderm and vascular endothelial cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Sox17 encodes an SRY-related high-mobility group (HMG) box transcription factor that is essential for endoderm formation and fetal hematopoietic stem cell maintenance. In the mouse, expression of Sox17 is first observed in the extraembryonic endoderm and is subsequently seen in the definitive endoderm as well as in blood and the endothelial cells of the developing vasculature. To conditionally inactivate genes in these domains, we have targeted the Sox17 locus to generate a bicistronic mRNA linking Sox17 to a codon improved Cre recombinase (iCre) via a viral 2A sequence. Here we report a new Cre knock-in mouse line, Sox17-...
Source: genesis - June 24, 2009 Category: Genetics & Stem Cells Authors: Silvia Engert, W. Perry Liao, Ingo Burtscher, Heiko Lickert Source Type: journals

Generation of mice with a conditional allele for G6pcEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Glucose-6-phosphatase-[alpha] (G6Pase-[alpha] or G6PC) catalyzes the hydrolysis of glucose-6-phosphate to glucose and is a key enzyme in interprandial glucose homeostasis. Mutations in the human G6PC gene, expressed primarily in the liver, kidney, and intestine, cause glycogen storage disease Type Ia (GSD-Ia), an autosomal recessive disorder characterized by a disturbed glucose homeostasis. For better understanding of the roles of G6Pase-[alpha] in different tissues and in pathological conditions, we have generated mice harboring a conditional null allele for G6pc by flanking Exon 3 of the G6pc gene with loxP sites. We con...
Source: genesis - June 21, 2009 Category: Genetics & Stem Cells Authors: Wen-Tao Peng, Chi-Jiunn Pan, Eric J. Lee, Heiner Westphal, Janice Y. Chou Source Type: journals

Tools for the genetic analysis of germ cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Germ cells are essential for the propagation of individual species. Studies on germ cell development in mice highlight important biological paradigms. Beginning with their first appearance around embryonic day 7 (E7), germ cells undergo specific cellular changes at different stages of their embryonic and adult development. Germ cells migrate through the hind-regions of the embryo to eventually home into the developing gonads. Further differentiation and development of germ cells differ in males and females. The processes involved in germ cell development and their eventual differentiation into sperm and oocytes have been u...
Source: genesis - June 21, 2009 Category: Genetics & Stem Cells Authors: Shirley S. Hammond, Angabin Matin Source Type: journals

Targeted disruption of Sonic Hedgehog in the mouse adrenal leads to adrenocortical hypoplasiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Development of the mammalian adrenal gland is regulated by a diverse network of growth and transcription factors. Disruptions in these pathways often result in adrenal insufficiency because of adrenal hypoplasia. Several lines of evidence have suggested that the Hedgehog signaling pathway, which controls many aspects of tissue and organ patterning, may play a direct role in adrenal morphogenesis as well. Therefore, we examined the role of Sonic Hedgehog (Shh), a member of the Hedgehog family, in mouse adrenal development. We show that Shh and its downstream effectors Gli1, Gli2, and Gli3 are expressed in the adrenal cortex...
Source: genesis - June 16, 2009 Category: Genetics & Stem Cells Authors: Saunders Ching, Eric Vilain Source Type: journals

Functional dissection of Timekeeper (Tik) implicates opposite roles for CK2 and PP2A during Drosophila neurogenesisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Repression by E(spl)M8 during inhibitory Notch (N) signaling (lateral inhibition) is regulated, in part, by protein kinase CK2, but the involvement of a phosphatase has been unclear. The studies we report here employ Tik, a unique dominant-negative (DN) mutation in the catalytic subunit of CK2, in a Gal4-UAS based assay for impaired lateral inhibition. Specifically, overexpression of Tik elicits ectopic bristles in N+ flies and suppresses the retinal defects of the gain-of-function allele Nspl. Functional dissection of the two substitutions in Tik (M161K and E165D), suggests that both mutations contribute to its DN effects...
Source: genesis - June 16, 2009 Category: Genetics & Stem Cells Authors: Ezgi Kunttas-Tatli, Anasua Bose, Bhaskar Kahali, Clifton P. Bishop, Ashok P. Bidwai Source Type: journals

Generation of mice that conditionally express the activation domain of Notch2Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this report we describe the construction of a transgenic mouse strain that expresses the Notch2 intracellular domain in response to cell lineage specific expression of Cre recombinase. This approach bypasses the requirement for ligand- receptor interaction and allows the direct determination of the consequences of Notch2 activation in vivo. Exogenous expression of the Notch2 intracellular domain resulted in the developmental arrest of secondary heart field derived cardiomyocytes during the transition from immature [alpha]-Smooth Muscle Actin expressing cells to mature [alpha]-Actinin positive cardiomyocytes. In contrast...
Source: genesis - June 14, 2009 Category: Genetics & Stem Cells Authors: Prajakta A. Varadkar, Matthew Kraman, Brent McCright Source Type: journals

Changes in allele-specific association of histone modifications at the imprinting control regions during mouse preimplantation developmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we first revealed the allelic enrichment of histone modifications and variant histones at the imprinting control regions (ICRs) of four-cell to blastocyst stage preimplantation embryos by using carrier chromatin immunoprecipitation and sequence polymorphism analysis of immunoprecipitated DNA. We found relative enrichment of histone H3 lysine 9 dimethylation at the imprinted alleles of ICRs and obtained the results suggesting that histone modifications at ICRs are established during a late preimplantation stage. genesis, 00:1-6, 2009. © 2009 Wiley-Liss, Inc. (Source: genesis)
Source: genesis - June 14, 2009 Category: Genetics & Stem Cells Authors: Jin-Moon Kim, Atsuo Ogura Source Type: journals

Microinjection of Cre recombinase protein into zygotes enables specific deletion of two eukaryotic selection cassettes and enhances the expression of a DsRed2 reporter gene in Ccr2/Ccr5 double-deficient miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The chemokine receptors CCR2 and CCR5 represent potential novel therapeutic targets to treat important inflammatory and infectious diseases, including atherosclerosis and HIV infection. To study the functions of both receptors in vivo, we aimed to generate Ccr2/Ccr5 double-deficient mice. As these genes are separated by (Source: genesis)
Source: genesis - June 9, 2009 Category: Genetics & Stem Cells Authors: Bruno Luckow, Amy Hänggli, Holger Maier, Silvia Chilla, Robert P. Loewe, Stefan Dehmel, Detlef Schlöndorff, Pius Loetscher, Hans-Günter Zerwes, Matthias Müller Source Type: journals

In vivo genetic manipulation of the rat trophoblast cell lineage using lentiviral vector deliveryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this report, we have adapted a lentiviral gene delivery technique for genetic modification of the rat trophoblast cell lineage. Blastocysts were incubated with lentiviral particles and transferred into the uteri of pseudopregnant female rats, harvested at various times during gestation, and then analyzed. Two test systems were evaluated: (1) delivery of an enhanced green fluorescent protein (EGFP) gene under the control of constitutive promoters to rat blastocysts; (2) delivery of EGFP short hairpin RNA (shRNA) to rat blastocysts constitutively expressing EGFP. Lentiviral packaged gene constructs were efficiently and sp...
Source: genesis - May 15, 2009 Category: Genetics & Stem Cells Authors: Dong-Soo Lee, M.A. Karim Rumi, Toshihiro Konno, Michael J. Soares Source Type: journals

Characterization of teleost Mdga1 using a gene-trap approach in medaka (Oryzias latipes)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
MAM domain containing glycosilphosphatidilinositol anchor 1 (MDGA1) is an IgCAM protein present in many vertebrate species including humans. In mammals, MDGA1 is expressed by a subset of neurons in the developing brain and thought to function in neural cell migration. We identified a fish ortholog of mdga1 by a gene-trap screen utilizing the Frog Prince transposon in medaka (Japanese killifish, Oryzias latipes). The gene-trap vector was inserted into an intronic region of mdga1 to form a chimeric protein with green fluorescent protein, allowing us to monitor mdga1 expression in vivo. Expression of medaka mdga1 was seen in ...
Source: genesis - May 7, 2009 Category: Genetics & Stem Cells Authors: Shinya Sano, Shigeo Takashima, Hitomi Niwa, Hayato Yokoi, Atsuko Shimada, Alexander Arenz, Joachim Wittbrodt, Hiroyuki Takeda Source Type: journals

The non-conserved C-terminal segments of Sine Oculis Homeobox (SIX) proteins confer functional specificityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Sine Oculis Homeobox (SIX) proteins play critical roles in organogenesis and are defined by the presence of two evolutionarily conserved functional motifs: a homeobox DNA binding domain and the SIX protein-protein interaction domain. Members of this transcription factor family can be divided into three subgroups: Six1/2, Six4/5, and Six3/6. This partitioning is based mainly on protein sequence similarity and genomic architecture, and not on specificities of DNA binding or binding partners. In fact, it is well demonstrated that members of the different subgroups can bind to and activate common transcriptional targets as...
Source: genesis - May 6, 2009 Category: Genetics & Stem Cells Authors: Brandon P. Weasner, Justin P. Kumar Source Type: journals

Transgenic analysis of the physiological functions of Mahogunin ring finger-1 isoformsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mahogunin Ring Finger-1 (Mgrn1) null mutant mice have a pleiotropic phenotype that includes the absence of yellow hair pigment, abnormal head shape, reduced viability, and adult-onset spongiform neurodegeneration. Mgrn1 encodes a highly conserved E3 ubiquitin ligase with four different isoforms which are differentially expressed and predicted to localize to different subcellular compartments. To test whether loss of specific isoforms causes different aspects of the mutant phenotype, we generated transgenes for each isoform and bred them onto the null mutant background. Mice expressing only isoform I or III appeared complet...
Source: genesis - May 6, 2009 Category: Genetics & Stem Cells Authors: Jian Jiao, Hae Young Kim, Roy R. Liu, Carolyn A. Hogan, Kaihua Sun, Lori Mon Tam, Teresa M. Gunn Source Type: journals

Functional analysis of Pcipg2 from the straminopilous plant pathogen Phytophthora capsiciEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Phytophthora capsici causes serious diseases in numerous crop plants. Polygalacturonases (PGs) are cell wall-degrading enzymes that play an important role in pathogenesis in straminopilous pathogens. To understand PGs as they relate to the virulence of P. capsici, Pcipg2 was identified from a genomic library of a highly virulent P. capsici strain. Pcipg2 was strongly expressed during symptom development after the inoculation of pepper leaves with P. capsici. The wild protein (PCIPGII) was obtained from the expression of pcipg2 and found that increasing activity of PGs in PCIPGII-treated pepper leaves was consistent with in...
Source: genesis - May 6, 2009 Category: Genetics & Stem Cells Authors: Wen Xiu Sun, Yong Jian Jia, Bao Zhen Feng, Nichole R. O'Neill, Xiao Ping Zhu, Bing Yan Xie, Xiu Guo Zhang Source Type: journals

Cre/lox recombination in the lower urinary tractEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tbx18 is a T-Box transcription factor that has specific expression and indispensible function in the lower urinary tract. Here, we report the generation and characterization of a bacterial artificial chromosome (BAC) transgene expressing Cre under the control of Tbx18 regulatory elements. When crossed to the ROSA26R-lacZ reporter mice, the Tbx18-Cre transgene mediates loxP recombination in the mesenchymal derivatives in the lower urinary tract, especially in the smooth muscle cells (SMCs) and the stromal cells. There is no expression of this transgene in the urothelium or in the kidney. This Tbx18-Cre transgene recapitulat...
Source: genesis - May 4, 2009 Category: Genetics & Stem Cells Authors: Yinqiu Wang, Piyush Tripathi, Qiusha Guo, Matthew Coussens, Liang Ma, Feng Chen Source Type: journals

Generation of mice with a conditional allele for transforming growth factor beta 1 geneEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Transforming growth factor [beta]1 (TGF[beta]1) is a multifunctional growth factor involved in wound healing, tissue fibrosis, and in the pathogenesis of many syndromic diseases (e.g., Marfan syndrome, Camurati-Engelmann disease) and muscular, neurological, ophthalmic, cardiovascular and immunological disorders, and cancer. Since the generation of Tgfb1 knockout mice, there has been extraordinary progress in understanding its physiological and pathophysiological function. Here, we report the generation of a conditional knockout allele for Tgfb1 in which its exon 6 is flanked with LoxP sites. As proof of principle, we cross...
Source: genesis - May 4, 2009 Category: Genetics & Stem Cells Authors: Mohamad Azhar, Moying Yin, Ramireddy Bommireddy, John J. Duffy, Junqi Yang, Sharon A. Pawlowski, Gregory P Boivin, Sandra J. Engle, L.P. Sanford, Christina Grisham, Ram R. Singh, George F. Babcock, Thomas Doetschman Source Type: journals

Generation of a mouse line expressing Sox17-driven Cre recombinase with specific activity in arteriesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The HMG-box transcription factor Sox17 has been shown to play important roles in both endoderm formation and cardiovascular development. To conditionally inactivate genes in these domains, we have targeted a codon improved Cre Recombinase (iCre) into exon 1 of the Sox17 gene. Surprisingly, Cre-mediated recombination in the Rosa26 reporter mouse line revealed largely specific activity within the vasculature rather than in endoderm-derived tissues. Here we report a new Cre knock-in mouse line, Sox17iCre with activity in the vascular endothelial cells of arteries in the cardiovascular system but not in veins. Cre-mediated rec...
Source: genesis - May 4, 2009 Category: Genetics & Stem Cells Authors: W. Perry Liao, Lena Uetzmann, Ingo Burtscher, Heiko Lickert Source Type: journals

Transthyretin mouse transgenes direct RFP expression or Cre-mediated recombination throughout the visceral endodermEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Transthyretin (Ttr) is a thyroid hormone transport protein secreted by cells of the visceral yolk sac and fetal liver in developing embryos, and by hepatocytes and the choroid plexus epithelium of the brain in adult mice. Spatiotemporal localization of Ttr mRNA during embryogenesis suggested that Ttr regulatory elements might drive transgene expression throughout the visceral endoderm of early mouse embryos. We use Ttr cis-regulatory elements to generate Ttr::RFP and Ttr::Cre strains of mice, driving red fluorescent protein (RFP) and a nuclear-localized Cre recombinase, respectively. Visualization of RFP fluorescence in Tt...
Source: genesis - May 4, 2009 Category: Genetics & Stem Cells Authors: Gloria S. Kwon, Anna-Katerina Hadjantonakis Source Type: journals