Xenopus laevis
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PROVIDER: PRJNA176360 | ENA |
REPOSITORIES: ENA
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Project description:Post-translational modifications (PTMs) of histones exert fundamental roles in regulating gene expression. During development, groups of PTMs are constrained by unknown mechanisms into combinatorial patterns, which facilitate transitions from uncommitted embryonic cells into differentiated somatic cell lineages. Repressive histone modifications such as H3K9me3 or H3K27me3 have been investigated in detail, but the role of H4K20me3 in development is currently unknown. Here we show that Xenopus laevis Suv4-20h1 and h2 histone methyltransferases (HMTases) are essential for induction and differentiation of the neuroectoderm. Morpholino-mediated knockdown of the two HMTases leads to a selective and specific downregulation of genes controlling neural induction, thereby effectively blocking differentiation of the neuroectoderm. Global transcriptome analysis supports the notion that these effects arise from the transcriptional deregulation of specific genes rather than widespread, pleiotropic effects. Interestingly, morphant embryos fail to repress the Oct4-related Xenopus gene Oct-25. We validate Oct-25 as direct target of xSu4-20h enzyme-mediated gene repression, showing by chromatin immunoprecipitaton that it is decorated with the H4K20me3 mark downstream of the promoter in normal, but not in double-morphant, embryos. Since knockdown of Oct-25 protein significantly rescues the neural differentiation defect in xSuv4-20h double-morphant embryos, we conclude that the epistatic relationship between Suv4- 20h enzymes and Oct-25 controls the transit from pluripotent to differentiation-competent neural cells. Consistent with these results in Xenopus, murine Suv4-20h1/h2 double-knockout embryonic stem (DKO ES) cells exhibit increased Oct4 protein levels before and during EB formation, and reveal a compromised and biased capacity for in vitro differentiation, when compared to normal ES cells. Together, these results suggest a regulatory mechanism, conserved between amphibian and mammals, in which H4K20me3-dependent restriction of specific POU-V genes directs cell fate decisions, when embryonic cells exit the pluripotent state. Total RNA samples from Xenopus laevis embryos. Transcript levels were analyzed after injection of control or Suv420 morpholinos into blastomeres.
2013-02-06 | E-GEOD-41256 | biostudies-arrayexpress
Project description:Post-translational modifications (PTMs) of histones exert fundamental roles in regulating gene expression. During development, groups of PTMs are constrained by unknown mechanisms into combinatorial patterns, which facilitate transitions from uncommitted embryonic cells into differentiated somatic cell lineages. Repressive histone modifications such as H3K9me3 or H3K27me3 have been investigated in detail, but the role of H4K20me3 in development is currently unknown. Here we show that Xenopus laevis Suv4-20h1 and h2 histone methyltransferases (HMTases) are essential for induction and differentiation of the neuroectoderm. Morpholino-mediated knockdown of the two HMTases leads to a selective and specific downregulation of genes controlling neural induction, thereby effectively blocking differentiation of the neuroectoderm. Global transcriptome analysis supports the notion that these effects arise from the transcriptional deregulation of specific genes rather than widespread, pleiotropic effects. Interestingly, morphant embryos fail to repress the Oct4-related Xenopus gene Oct-25. We validate Oct-25 as direct target of xSu4-20h enzyme-mediated gene repression, showing by chromatin immunoprecipitaton that it is decorated with the H4K20me3 mark downstream of the promoter in normal, but not in double-morphant, embryos. Since knockdown of Oct-25 protein significantly rescues the neural differentiation defect in xSuv4-20h double-morphant embryos, we conclude that the epistatic relationship between Suv4- 20h enzymes and Oct-25 controls the transit from pluripotent to differentiation-competent neural cells. Consistent with these results in Xenopus, murine Suv4-20h1/h2 double-knockout embryonic stem (DKO ES) cells exhibit increased Oct4 protein levels before and during EB formation, and reveal a compromised and biased capacity for in vitro differentiation, when compared to normal ES cells. Together, these results suggest a regulatory mechanism, conserved between amphibian and mammals, in which H4K20me3-dependent restriction of specific POU-V genes directs cell fate decisions, when embryonic cells exit the pluripotent state.
2013-02-06 | GSE41256 | GEO
Project description:Identification of genes regulated by XOct-25 overexpression in Xenopus ectoderm
| PRJNA132629 | ENA
Project description:Analysis of whole body of unfertilized eggs and two-cell stage, 16-cell stage, stage 8, stage 9, stage 10.5, stage 12, stage 15, stage 20, stage 25, stage 30, stage 35 and stage 40 embryos. Results provide insight into the global molecular changes in Xenopus embryogenesis.
2015-09-05 | GSE40620 | GEO
Project description:Comparative temporal analysis of wild-type Ptf1a, Neurog2 and mutant Ptf1a (Ptf1aW224A/W242A) overexpressing Xenopus explant transcriptomes after 6 and 25 hours of DEX induction.
| PRJNA342823 | 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:Analysis of whole body of unfertilized eggs and two-cell stage, 16-cell stage, stage 8, stage 9, stage 10.5, stage 12, stage 15, stage 20, stage 25, stage 30, stage 35 and stage 40 embryos. Results provide insight into the global molecular changes in Xenopus embryogenesis. Gene expressions in intact whole unfertilized eggs and whole embryos at two-cell stage, 16-cell stage, stage 8, stage 9, stage 10.5, stage 12, stage 15, stage 20, stage 25, stage 30, stage 35 and stage 40.
2015-09-05 | E-GEOD-40620 | biostudies-arrayexpress
Project description:In the embryo, inductive cues are interpreted by competent tissues in a spatially and temporally restricted manner, and the mechanisms for the loss of responsiveness are not well understood. To test the hypothesis that loss of competence is associated with changes in chromatin accessibility, we adapted the assay for transposase-accessible chromatin with high throughput sequencing (ATAC-seq) for use in Xenopus laevis to evaluate genome-wide changes in chromatin accessibility in early and late gastrula stages. ATAC-seq was performed on presumptive ectoderm (animal caps) explanted at the blastula stage and cultured until siblings reached early (stage 10) or late (stage 12) gastrula stage. Approximately 70,000 accessible regions were identified at intergenic regions, introns, promoters, and transcription termination sites at both stages. Accessibility decreased from stage 10 to stage 12 at 279 promoters, including developmental regulators such as Foxh1, chordin, and VegT. Accessible chromatin domains overlap extensively with previously reported p300 binding sites, consistent with putative cis-regulatory modules (pCRMs), and these pCRMs are enriched for binding motifs for pluripotency factors, including Sox, Oct/Pou, and KLF binding motifs. Dorsal Wnt target gene promoters are not accessible after the loss of competence, but inhibition of histone deacetylases increases acetylation at these promoters and extends competence for dorsal gene induction by Wnt signaling. In contrast, the promoters for genes involved in mesoderm and neural crest development remain open through gastrulation, and histone deacetylase inhibition does not extend competence for mesoderm or neural crest induction. These data suggest that chromatin state regulates the loss of competence to inductive signals in a context-dependent manner.
2020-02-26 | GSE138905 | GEO
Project description:Suv4-20h1/2 are histone methyltransferases that write the H4K20me2 and H4K20me3 marks. We knocked down these enzymes using translation blocking morpholinos in X. tropicalis animal caps and performed RNA-seq in order to investigate the impact of altering H4K20me state on epidermal differentiation. Knocking down Suv4-20h1/2 leads to a strong increase of H4K20me1 in bulk chromatin. To determine whether increased H4K20me1 is responsible for transcriptional changes in suv4-20h KD animal caps, we performed RNA-Seq for a rescue experiment with PHF8, an H4K20me1 demethylase.
2021-09-01 | GSE161250 | GEO
Project description:Suv4-20h1/2 are histone methyltransferases that write the H4K20me2 and H4K20me3 marks. We knocked down these enzymes using translation blocking morpholinos in X. tropicalis animal caps and performed RNA-seq in order to investigate the impact of altering H4K20me state on epidermal differentiation. Knocking down Suv4-20h1/2 leads to a strong increase of H4K20me1 in bulk chromatin. To determine whether increased H4K20me1 is responsible for transcriptional changes in suv4-20h KD animal caps, we performed RNA-Seq for a rescue experiment with PHF8, an H4K20me1 demethylase.
2021-09-01 | GSE161249 | GEO