A Cbx8-containing Polycomb complex facilitates gene activation during ES cell differentiation
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE54053 | GEO | 2014/11/04
SECONDARY ACCESSION(S): PRJNA234481
REPOSITORIES: GEO
Similar Datasets
Project description:Polycomb proteins play an essential role in maintaining the repression of developmental genes in self-renewing embryonic stem cells. The exact mechanism allowing the derepression of polycomb target genes during cell differentiation remains unclear. Our project aimed to identify Cbx8 binding sites in differentiating mouse embryonic stem cells. Therefore, we used a genome-wide chromatin immunoprecipitation of endogenous Cbx8 coupled to direct massive parallel sequencing (ChIP-Seq). Our analysis identified 171 high confidence peaks. By crossing our data with previously published microarray analysis, we show that several differentiation genes transiently recruit Cbx8 during their early activation. Depletion of Cbx8 partially impairs the transcriptional activation of these genes. Both interaction analysis, as well as chromatin immunoprecipitation experiments support the idea that activating Cbx8 acts in the context of an intact PRC1 complex. Prolonged gene activation results in eviction of PRC1 despite persisting H3K27me3 and H2A ubiquitination. The composition of PRC1 is highly modular and changes when embryonic stem cells commit to differentiation. We further demonstrate that the exchange of Cbx7 for Cbx8 is required for the effective activation of differentiation genes. Taken together, our results establish a function for a Cbx8-containing complex in facilitating the transition from a Polycomb-repressed chromatin state to an active state. As this affects several key regulatory differentiation genes this mechanism is likely to contribute to the robust execution of differentiation programs.
| S-EPMC4263398 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-11-04 | E-GEOD-54053 | biostudies-arrayexpress
Project description:Polycomb proteins play an essential role in maintaining the repression of developmental genes in self-renewing embryonic stem cells. The exact mechanism allowing the derepression of polycomb target genes during cell differentiation remains unclear. Here, we show that several differentiation genes transiently recruit a Cbx8-containing Polycomb repressive complex (PRC) 1 during their early activation. Depletion of Cbx8 partially impairs the transcriptional activation of these genes. This correlates with a reduction in low but detectable levels of histone H3 lysine 27 acetylation. Prolonged gene activation results in eviction of PRC1 despite persisting H3K27me3. The composition of PRC1 is highly modular and changes when ES cells commit to differentiation. We further demonstrate that the exchange of Cbx7 for Cbx8 is required for the effective activation of differentiation genes. Taken together our results establish a function for a Cbx8-containing complex in facilitating the transition from a Polycomb-repressed chromatin state to an active state. As this affects several key regulatory differentiation genes this mechanism is likely to contribute to the robust execution of differentiation programs. Examination of cbx8 in ES E14 mouse cells in 2 condition before and after 72h stimulation with retinoic acid compared with IgG
2014-11-04 | E-GEOD-54052 | biostudies-arrayexpress
Project description:Polycomb proteins play an essential role in maintaining the repression of developmental genes in self-renewing embryonic stem cells. The exact mechanism allowing the derepression of polycomb target genes during cell differentiation remains unclear. Here, we show that several differentiation genes transiently recruit a Cbx8-containing Polycomb repressive complex (PRC) 1 during their early activation. Depletion of Cbx8 partially impairs the transcriptional activation of these genes. This correlates with a reduction in low but detectable levels of histone H3 lysine 27 acetylation. Prolonged gene activation results in eviction of PRC1 despite persisting H3K27me3. The composition of PRC1 is highly modular and changes when ES cells commit to differentiation. We further demonstrate that the exchange of Cbx7 for Cbx8 is required for the effective activation of differentiation genes. Taken together our results establish a function for a Cbx8-containing complex in facilitating the transition from a Polycomb-repressed chromatin state to an active state. As this affects several key regulatory differentiation genes this mechanism is likely to contribute to the robust execution of differentiation programs. Four biological replicates were used for each condition (untreated and after 72h of retinoic acid stimulation) and samples were prepared and hybridized to SurePrint G3 Gene Expression Microarrays (Agilent technologies) following the supplier's instructions. Analyses were essentially performed as described (Uribesalgo et al. 2011) selecting differentially expressed probes with a FDR of 0.05 and fold change of > 1.5.
2014-11-04 | E-GEOD-54051 | biostudies-arrayexpress
Project description:Polycomb proteins play an essential role in maintaining the repression of developmental genes in self-renewing embryonic stem cells. The exact mechanism allowing the derepression of polycomb target genes during cell differentiation remains unclear. Here, we show that several differentiation genes transiently recruit a Cbx8-containing Polycomb repressive complex (PRC) 1 during their early activation. Depletion of Cbx8 partially impairs the transcriptional activation of these genes. This correlates with a reduction in low but detectable levels of histone H3 lysine 27 acetylation. Prolonged gene activation results in eviction of PRC1 despite persisting H3K27me3. The composition of PRC1 is highly modular and changes when ES cells commit to differentiation. We further demonstrate that the exchange of Cbx7 for Cbx8 is required for the effective activation of differentiation genes. Taken together our results establish a function for a Cbx8-containing complex in facilitating the transition from a Polycomb-repressed chromatin state to an active state. As this affects several key regulatory differentiation genes this mechanism is likely to contribute to the robust execution of differentiation programs.
2014-11-04 | GSE54052 | GEO
Project description:Polycomb proteins play an essential role in maintaining the repression of developmental genes in self-renewing embryonic stem cells. The exact mechanism allowing the derepression of polycomb target genes during cell differentiation remains unclear. Here, we show that several differentiation genes transiently recruit a Cbx8-containing Polycomb repressive complex (PRC) 1 during their early activation. Depletion of Cbx8 partially impairs the transcriptional activation of these genes. This correlates with a reduction in low but detectable levels of histone H3 lysine 27 acetylation. Prolonged gene activation results in eviction of PRC1 despite persisting H3K27me3. The composition of PRC1 is highly modular and changes when ES cells commit to differentiation. We further demonstrate that the exchange of Cbx7 for Cbx8 is required for the effective activation of differentiation genes. Taken together our results establish a function for a Cbx8-containing complex in facilitating the transition from a Polycomb-repressed chromatin state to an active state. As this affects several key regulatory differentiation genes this mechanism is likely to contribute to the robust execution of differentiation programs.
2014-11-04 | GSE54051 | GEO
Project description:A Cbx8-containing Polycomb complex facilitates gene activation during ES cell differentiation
| PRJNA234481 | ENA
Project description:Huntington's disease (HD) is caused by expansion of the polymorphic polyglutamine segment in the huntingtin protein. Full-length huntingtin is thought to be a predominant HEAT repeat alpha-solenoid, implying a role as a facilitator of macromolecular complexes. Here we have investigated huntingtin's domain structure and potential intersection with epigenetic silencer polycomb repressive complex 2 (PRC2), suggested by shared embryonic deficiency phenotypes. Analysis of a set of full-length recombinant huntingtins, with different polyglutamine regions, demonstrated dramatic conformational flexibility, with an accessible hinge separating two large alpha-helical domains. Moreover, embryos lacking huntingtin exhibited impaired PRC2 regulation of Hox gene expression, trophoblast giant cell differentiation, paternal X chromosome inactivation and histone H3K27 tri-methylation, while full-length endogenous nuclear huntingtin in wild-type embryoid bodies (EBs) was associated with PRC2 subunits and was detected with trimethylated histone H3K27 at Hoxb9. Supporting a direct stimulatory role, full-length recombinant huntingtin significantly increased the histone H3K27 tri-methylase activity of reconstituted PRC2 in vitro, and structure-function analysis demonstrated that the polyglutamine region augmented full-length huntingtin PRC2 stimulation, both in Hdh(Q111) EBs and in vitro, with reconstituted PRC2. Knowledge of full-length huntingtin's alpha-helical organization and role as a facilitator of the multi-subunit PRC2 complex provides a novel starting point for studying PRC2 regulation, implicates this chromatin repressive complex in a neurodegenerative disorder and sets the stage for further study of huntingtin's molecular function and the impact of its modulatory polyglutamine region.
| S-EPMC2807366 | biostudies-literature
Project description:Polycomb Repressive Complex 2 (PRC2) catalyzes histone H3 lysine 27 tri-methylation (H3K27me3), an epigenetic modification associated with gene repression. H3K27me3 is enriched at the promoters of a large cohort of developmental genes in embryonic stem cells (ESCs). Loss of H3K27me3 leads to a failure of ESCs to properly differentiate, making it difficult to determine the precise roles of PRC2 during lineage commitment. Moreover, while studies suggest that PRC2 prevents DNA methylation, how these two epigenetic regulators coordinate to regulate lineage programs is poorly understood. Using several PRC2 mutant ESC lines that maintain varying levels of H3K27me3, we found that partial maintenance of H3K27me3 allowed for proper temporal activation of lineage genes during directed differentiation of ESCs to spinal motor neurons (SMNs). In contrast, genes that function to specify other lineages failed to be repressed in these cells, suggesting that PRC2 is also necessary for lineage fidelity. We also found that loss of H3K27me3 leads to a modest gain in DNA methylation at PRC2 target regions in both ESCs and in SMNs. Our study demonstrates a critical role for PRC2 in safeguarding lineage decisions and in protecting genes against inappropriate DNA methylation.
| S-EPMC4204901 | biostudies-literature
Project description:Master regulatory genes require stable silencing by the polycomb group (PcG) to prevent misexpression during differentiation and development. Some PcG proteins covalently modify histones, which contributes to heritable repression. The role for other effects on chromatin structure is less understood. We characterized the organization of PcG target genes in ESCs and neural progenitors using 5C and super-resolution microscopy. The genomic loci of repressed PcG targets formed discrete, small (20-140 Kb) domains of tight interaction that corresponded to locations bound by canonical polycomb repressive complex 1 (PRC1). These domains changed during differentiation as PRC1 binding changed. Their formation depended upon the Polyhomeotic component of canonical PRC1 and occurred independently of PRC1-catalyzed ubiquitylation. PRC1 domains differ from topologically associating domains in size and boundary characteristics. These domains have the potential to play a key role in transmitting epigenetic silencing of PcG targets by linking PRC1 to formation of a repressive higher-order structure.
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