Myogenic differentiation relies on Pax7 function. We used embryonic stem cells lacking functional Pax7 to follow its role in derivation of skeletal myoblasts.
Myogenic Differentiation of Mouse Embryonic Stem Cells That Lack a Functional Pax7 Gene.
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View SamplesThe Polycomb group (PcG) proteins form chromatin-modifying complexes that are essential for embryonic development and stem cell renewal and are commonly deregulated in cancer. Here, we identify their target genes using genome-wide location analysis in human embryonic fibroblasts. We find that Polycomb-Repressive Complex 1 (PRC1), PRC2, and tri-methylated histone H3K27 co-occupy >1000 silenced genes with a strong functional bias for embryonic development and cell fate decisions. We functionally identify 40 genes derepressed in human embryonic fibroblasts depleted of the PRC2 components (EZH2, EED, SUZ12) and the PRC1 component, BMI-1. Interestingly, several markers of osteogenesis, adipogenesis, and chrondrogenesis are among these genes, consistent with the mesenchymal origin of fibroblasts. Using a neuronal model of differentiation, we delineate two different mechanisms for regulating PcG target genes. For genes activated during differentiation, PcGs are displaced. However, for genes repressed during differentiation, we paradoxically find that they are already bound by the PcGs in nondifferentiated cells despite being actively transcribed. Our results are consistent with the hypothesis that PcGs are part of a preprogrammed memory system established during embryogenesis marking certain key genes for repressive signals during subsequent developmental and differentiation processes.
Genome-wide mapping of Polycomb target genes unravels their roles in cell fate transitions.
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View SamplesPolycomb group (PcG) proteins form multiprotein complexes, called Polycomb repressive complexes (PRCs). PRC2 contains the PcG proteins EZH2, SUZ12, and EED and represses transcription through methylation of lysine (K) 27 of histone H3 (H3). Suz12 is essential for PRC2 activity and its inactivation results in early lethality of mouse embryos.
The polycomb group protein Suz12 is required for embryonic stem cell differentiation.
Specimen part
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TET1 and hydroxymethylcytosine in transcription and DNA methylation fidelity.
Specimen part
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The demethylase JMJD2C localizes to H3K4me3-positive transcription start sites and is dispensable for embryonic development.
Specimen part, Cell line, Treatment
View SamplesEnzymes catalyzing the methylation of the 5-position of cytosine (mC) have essential roles in regulating gene expression, genome stability, and maintaining cellular identity. Recently Tet1, which is highly expressed in embryonic stem (ES) cells, was found to oxidize the methyl group of mC converting it to 5-hydroxymethyl cytosine (hmC)3. Here, we present the genome-wide mapping of Tet1 and hmC in mouse ES cells. We show that Tet1 binds throughout the genome with the majority of binding sites located at transcription start sites (TSSs) and within genes. Similar to Tet1 and mC, also hmC is found throughout the genome and in particular in gene bodies. However, in contrast to mC, hmC is enriched at TSSs. Tet1 and hmC are associated with genes critical for the control of development and differentiation, which become methylated during differentiation. Surprisingly our results also suggest that Tet1 has a role in transcriptional repression. We show that Tet1 binds to a significant proportion of target genes that are positive for the Polycomb repressive histone mark H3K27me3, and that downregulation of Tet1 also leads to increased expression of a group of Tet1 target genes. In agreement with a potential repressive function, we show that Tet1 associates with the Sin3A co-repressor complex, which also co-localises with Tet1 throughout the genome. We propose that Tet1 fulfils dual functions in transcriptional regulation, where it fine-tunes DNA methylation and associates with the Sin3A co-repressor complex to prevent transcriptional activation.
TET1 and hydroxymethylcytosine in transcription and DNA methylation fidelity.
Specimen part
View SamplesWe have mapped transcriptional changes after depletion of the histone demethylases JMJD2C/GASC1/KDM4C and JMJD2A/KDM4A alone or in combination in the esophageal squamous carcinoma cell line, KYSE150. The KYSE150 cell line contains an amplification of the JMJD2C locus.
The demethylase JMJD2C localizes to H3K4me3-positive transcription start sites and is dispensable for embryonic development.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Jarid1b targets genes regulating development and is involved in neural differentiation.
Specimen part
View SamplesThe H3K4me2/3 histone demethylase Jarid1b (Kdm5b/Plu1) is dispensable for embryonic stem cell (ESC) self-renewal, but essential for ESC differentiation along the neural lineage. During neural differentiation, Jarid1b depleted ESCs fail to efficiently silence lineage-inappropriate genes, specifically stem and germ cell genes. Our results delineate an essential role for Jarid1b-mediated transcriptional control during ESC differentiation.
Jarid1b targets genes regulating development and is involved in neural differentiation.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Loss of TET2 in hematopoietic cells leads to DNA hypermethylation of active enhancers and induction of leukemogenesis.
Specimen part
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