Xenopus laevis
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA136611 | ENA |
REPOSITORIES: ENA
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Project description:A balance between cell survival and apoptosis is essential for animal development. Although proper development involves multiple interactions between germ layers, little is known about the intercellular and intertissue signaling pathways that promote cell survival in neighboring or distant germ layers . We show that serum- and glucocorticoid-inducible kinase 1 (SGK1) promoted ectodermal cell survival during early Xenopus embryogenesis through a non-cell-autonomous mechanism. Dorsal depletion of SGK1 in Xenopus embryos resulted in shortened axes and reduced head structures with defective eyes, and ventral depletion led to defective tail morphologies. Although the gene encoding SGK1 was mainly expressed in the endoderm and dorsal mesoderm, knockdown of SGK1 caused excessive apoptosis in the ectoderm. SGK1-depleted ectodermal explants showed little or no apoptosis, suggesting non-cell-autonomous effects of SGK1 on ectodermal cells. Microarray analysis revealed that SGK1 knockdown increased the expression of genes encoding FADD and caspase-10, components of the death-inducing signaling complex (DISC). Inhibition of DISC function suppressed excessive apoptosis in SGK1-knockdown embryos. SGK1 acted through the transcription factor nuclear factor kappaB to stimulate production of bone morphogenetic protein 7 (BMP7), and overexpression of BMP7 in SGK1-knockdown embryos reduced the abundance of DISC components. We show that phosphoinositide 3-kinase (PI3K) functioned upstream of SGK1, thus revealing an endodermal and mesodermal pathway from PI3K to SGK1 to NF-kappaB that produces BMP7, which provides a survival signal to the ectoderm by decreasing DISC function.
2011-02-21 | GSE26381 | GEO
Project description:A balance between cell survival and apoptosis is essential for animal development. Although proper development involves multiple interactions between germ layers, little is known about the intercellular and intertissue signaling pathways that promote cell survival in neighboring or distant germ layers . We show that serum- and glucocorticoid-inducible kinase 1 (SGK1) promoted ectodermal cell survival during early Xenopus embryogenesis through a non-cell-autonomous mechanism. Dorsal depletion of SGK1 in Xenopus embryos resulted in shortened axes and reduced head structures with defective eyes, and ventral depletion led to defective tail morphologies. Although the gene encoding SGK1 was mainly expressed in the endoderm and dorsal mesoderm, knockdown of SGK1 caused excessive apoptosis in the ectoderm. SGK1-depleted ectodermal explants showed little or no apoptosis, suggesting non-cell-autonomous effects of SGK1 on ectodermal cells. Microarray analysis revealed that SGK1 knockdown increased the expression of genes encoding FADD and caspase-10, components of the death-inducing signaling complex (DISC). Inhibition of DISC function suppressed excessive apoptosis in SGK1-knockdown embryos. SGK1 acted through the transcription factor nuclear factor kappaB to stimulate production of bone morphogenetic protein 7 (BMP7), and overexpression of BMP7 in SGK1-knockdown embryos reduced the abundance of DISC components. We show that phosphoinositide 3-kinase (PI3K) functioned upstream of SGK1, thus revealing an endodermal and mesodermal pathway from PI3K to SGK1 to NF-kappaB that produces BMP7, which provides a survival signal to the ectoderm by decreasing DISC function. To identify genes whose expression levels are regulated by SGK1 in Xenopus development, we performed genome-wide analysis by using Affymetrix GeneChip oligonucleotide microarrays. We performed two independent experiments. For each microarray experiment, we radially injected control-morpholino or xSGK1-morpholinos into 4-cell embryos, cultured the embryos until stage 12, extracted total RNAs using Trizol (Invitrogen) and purified them on RNeasy columns (Qiagen). Synthesis of cDNA, in vitro transcription and biotin labeling of cRNA, and hybridization to the Xenopus laevis genome array (Affymetrix) were performed according to the Affymetrix protocol (Two-Cycle Target Labeling Assays). Hybridized arrays were scanned using an Affymetrix GeneChip Scanner. Scanned chip images were analyzed with GeneChip Operating Software (GCOS) v. 1.4.
2011-02-21 | E-GEOD-26381 | biostudies-arrayexpress
Project description:Genes induced in Xenopus foregut endoderm by mesoderm
| PRJNA168354 | ENA
Project description:The transcription factors Mixer and Sox17beta have well characterized roles in endoderm specification during Xenopus embryogenesis. In order to more thoroughly understand the mechanisms by which these endodermal regulators act, we expressed Mixer and Sox17beta in naïve ectodermal tissue and, using oligonucleotide-based microarrays, compared their genomic transcriptional profile to that of unaffected tissue. Using this novel approach, we identified 71 transcripts that are upregulated by Mixer or Sox17beta, 63 of which have previously uncharacterized roles in endoderm development. Furthermore, an in situ hybridization screen using antisense probes for several of these clones identified six targets of Mixer and/or Sox17beta that are expressed in the endoderm during gastrula stages, providing new and regional markers of the endoderm. Our results contribute further insight into the functions of Mixer and Sox17beta and bring us closer to understanding at the molecular level the pathways that regulate endoderm development.
2007-06-28 | E-GEOD-3334 | biostudies-arrayexpress
Project description:The response of ectodermal explants, neuralized by noggin and treated with cycloheximide, following activation of hormone-inducible zic1 injected into the parent embryos compared to those from beta globin injected embryos as controls, is expected to provide information on the direct targets of the Zic1 transcription factor. Experiment Overall Design: Activation of zic1 in ectodermal explants following inhibition of new protein synthesis allowed the direct targets of zic1 to be identified by comparison with controls. After RNA extraction, purification and checks with PCR with actin primers for any mesoderm contamination samples were prepared for hybridization to Xenopus laevis Affymetrix GeneChip arrays.
2009-07-10 | E-GEOD-12128 | biostudies-arrayexpress
Project description:Derriere targets in Xenopus posterior mesoderm
| PRJNA110353 | ENA
Project description:Foregut organogenesis is regulated by inductive interactions between the endoderm and the adjacent mesoderm. We identified genes induced in the foregut progenitors by the adjacent mesoderm. We used microarrays to detail the global programme of early foregut endoderm gene expression resulting from mesoderm induction and identified distinct classes of up-regulated genes during this process. Xenopus foregut endoderm explants cultured from Stages 15 to 23 either intact with mesoderm or as endoderm alone. Total RNA was isolated from the endoderm of these two culture conditions in quadruplicate and were subjected to Affymetrix microarray analysis.
2012-06-11 | E-GEOD-38654 | biostudies-arrayexpress
Project description:Expression data from ectodermal explants following activation of hormone-inducible zic1
| PRJNA113487 | ENA
Project description:We screened for differentially expressed genes in the developing notochord using the Affymetrix microarray system in Xenopus laevis. At late gastrula, we dissected four regions from the embryo, anterior mesoderm, posterior mesoderm, notochord and presomitic mesoderm. Three types of comparison were carried out to generate a list of predominantly notochord expressed genes: (1) Posterior mesoderm vs. anterior mesoderm; notochord genes are expected to be increased since the notochord is located in the posterior mesoderm. (2) Posterior mesoderm vs. whole embryos; notochord genes are expected to be increased. (3) Notochord vs. somite. This comparison sub-divided the group of posterior mesodermal genes identified in (1) and (2). All tissues are dissected using tungsten needles. We first dissected dorsal tissue above the archenteron from late gastrula to early neurula. To loosen tissue, we treated the dissected dorsal explant in a 1% cysteine solution (pH 7.4) and removed the neuroectodermal layer. Anterior mesoderm was dissected corresponding to about the anterior one-third of the archenteron roof, and the rest was collected as posterior mesoderm. The posterior mesodermal explant was dissected into notochord and somites, following a clearly visible border between the two tissues. The accuracy of all dissection was confirmed by RT-PCR of marker genes.
2006-12-31 | E-MEXP-717 | biostudies-arrayexpress
Project description:Global analysis of the transcriptional network controlling Xenopus endoderm formation
| PRJNA94719 | ENA