Transcription factor-dependent ‘anti-repressive’ mammalian enhancers exclude H3K27me3 from extended genomic domains
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE98724 | GEO | 2018/01/11
SECONDARY ACCESSION(S): PRJNA386029
REPOSITORIES: GEO
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Project description:Compacted chromatin and nucleosomes are known barriers to gene expression; the nature and relative importance of other transcriptional constraints remain unclear, especially at distant enhancers. Polycomb repressor complex 2 (PRC2) places the histone mark H3K27me3 predominantly at promoters, where its silencing activity is well documented. In adult tissues, enhancers lack H3K27me3, and it is unknown whether intergenic H3K27me3 deposits affect nearby genes. In primary intestinal villus cells, we identified hundreds of tissue-restricted enhancers that require the transcription factor (TF) CDX2 to prevent the incursion of H3K27me3 from adjoining areas of elevated basal marking into large well-demarcated genome domains. Similarly, GATA1-dependent enhancers exclude H3K27me3 from extended regions in erythroid blood cells. Excess intergenic H3K27me3 in both TF-deficient tissues is associated with extreme mRNA deficits, which are significantly rescued in intestinal cells lacking PRC2. Explaining these observations, enhancers show TF-dependent binding of the H3K27 demethylase KDM6A. Thus, in diverse cell types, certain genome regions far from promoters accumulate H3K27me3, and optimal gene expression depends on enhancers clearing this repressive mark. These findings reveal new "anti-repressive" function for hundreds of tissue-specific enhancers.
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Project description:<p>Transcription factor p63 is a key regulator of epidermal keratinocyte proliferation and differentiation. Mutations in the p63 DNA-binding domain are associated with Ectrodactyly Ectodermal Dysplasia Cleft Lip/Palate (EEC) syndrome. Underlying molecular mechanism of these mutations however remain unclear. Here we characterized the transcriptome and epigenome of p63 mutant keratinocytes derived from EEC patients. The transcriptome of p63 mutant keratinocytes deviated from the normal epidermal cell identity. Epigenomic analyses showed an altered enhancer landscape in p63 mutant keratinocytes contributed by loss of p63-bound active enhancers and by unexpected gain of enhancers. The gained enhancers were frequently bound by deregulated transcription factors such as RUNX1. Reversing RUNX1 overexpression partially rescued deregulated gene expression and the altered enhancer landscape. Our findings identify an unreported disease mechanism whereby mutant p63 rewires the enhancer landscape and affects epidermal cell identity, consolidating the pivotal role of p63 in controlling the enhancer landscape of epidermal keratinocytes.</p>
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Project description:Differential effect of PRC2 loss on gene repression in intestinal stem cells, transit amplifying cells, and differentiated villus cells in intestine is explained by disparity in the rate of cell division and resulting difference in H3K27me3 loss.
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Project description:Mediator complex regulates transcription by connecting enhancers to promoters. High Mediator binding density defines super enhancers, which regulate cell-identity genes and oncogenes. Protein interactions of Mediator may explain its role in these processes but have not been identified comprehensively. Here we purify Mediator from neural stem cells (NSCs) and identify 75 protein-protein interaction partners. We identify super enhancers in NSCs and show that Mediator-interacting chromatin modifiers colocalise with Mediator at enhancers and super enhancers. Transcription factor families with high affinity for Mediator dominate enhancers and super enhancers and can explain genome-wide Mediator localization. We identify E-box transcription factor Tcf4 as a key regulator of NSCs. Tcf4 interacts with Mediator, colocalises with Mediator at super enhancers and regulates neurogenic transcription factor genes with super enhancers and broad H3K4me3 domains. Our data suggest that high binding-affinity for Mediator is an important organizing feature in the transcriptional network that determines NSC identity.
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Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.
2024-04-09 | GSE225896 | GEO
Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.
2024-04-09 | GSE225894 | GEO
Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.
2024-04-09 | GSE225897 | GEO
Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.
2024-04-09 | GSE225895 | GEO
Project description:BackgroundHistone modifications play a critical role in chromatin remodelling and regulate gene expression in health and disease. Histone methyltransferases EZH1, EZH2, and demethylases UTX, JMJD3, and UTY catalyse trimethylation of lysine 27 on histone H3 (H3K27me3). This study was designed to investigate whether H3K27me3 triggers hyperglycemia-induced oxidative and inflammatory transcriptional programs in the endothelium.MethodsWe studied human aortic endothelial cells exposed to high glucose (HAEC) or isolated from individuals with diabetes (D-HAEC). RT-qPCR, immunoblotting, chromatin immunoprecipitation (ChIP-qPCR), and confocal microscopy were performed to investigate the role of H3K27me3. We determined superoxide anion (O2-) production by ESR spectroscopy, NF-κB binding activity, and monocyte adhesion. Silencing/overexpression and pharmacological inhibition of chromatin modifying enzymes were used to modulate H3K27me3 levels. Furthermore, isometric tension studies and immunohistochemistry were performed in aorta from wild-type and db/db mice.ResultsIncubation of HAEC to high glucose showed that upregulation of EZH2 coupled to reduced demethylase UTX and JMJD3 was responsible for the increased H3K27me3. ChIP-qPCR revealed that repressive H3K27me3 binding to superoxide dismutase and transcription factor JunD promoters is involved in glucose-induced O2- generation. Indeed, loss of JunD transcriptional inhibition favours NOX4 expression. Furthermore, H3K27me3-driven oxidative stress increased NF-κB p65 activity and downstream inflammatory genes. Interestingly, EZH2 inhibitor GSK126 rescued these endothelial derangements by reducing H3K27me3. We also found that H3K27me3 epigenetic signature alters transcriptional programs in D-HAEC and aortas from db/db mice.ConclusionsEZH2-mediated H3K27me3 represents a key epigenetic driver of hyperglycemia-induced endothelial dysfunction. Targeting EZH2 may attenuate oxidative stress and inflammation and, hence, prevent vascular disease in diabetes.
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