DNA replication-coupled histone modification maintains Polycomb gene silencing in plants [RNA-seq]
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE101219 | GEO | 2017/08/20
SECONDARY ACCESSION(S): PRJNA393891
REPOSITORIES: GEO
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Project description:Propagation of patterns of gene expression through the cell cycle requires prompt restoration of epigenetic marks after the twofold dilution caused by DNA replication. Here, we show that the transcriptional repressive mark histone H3K27 trimethylation (H3K27me3) is restored in replicating plant cells through DNA replication-coupled modification of histone variant H3.1. Plants evolved a mechanism for efficient K27 trimethylation on H3.1, which is essential for inheritance of the silencing memory from mother to daughter cells. We illustrate how this mechanism establishes H3K27me3 mediated silencing during the developmental transition to flowering. Our study reveals transmission of H3K27me3 in plant cells through cell divisions, enabling H3K27me3 to function as an epigenetic mark.
2017-08-20 | GSE101220 | GEO
Project description:Trimethylation of histone H3 lysine 27 (H3K27me3) regulates gene repression, cell-fate determination and differentiation. We report that a conserved Bromo-Adjacent Homology (BAH) module of BAHCC1 (BAHCC1BAH) ‘recognizes’ H3K27me3 specifically and enforces silencing of H3K27me3-demarcated genes in mammalian cells. Biochemical, structural and ChIP-seq-based analyses demonstrate that direct readout of H3K27me3 by BAHCC1 is achieved through a hydrophobic trimethyl-lysine-binding ‘cage’ formed by BAHCC1BAH, mediating co-localization of BAHCC1 and H3K27me3-marked genes. BAHCC1 is overexpressed in human acute leukemias and interacts with transcriptional co-repressors. In leukemia, depletion of BAHCC1, or disruption of the BAHCC1BAH:H3K27me3 interaction, causes de-repression of H3K27me3-targeted genes that are involved in tumor suppression and cell differentiation, leading to suppression of oncogenesis. In mice, introduction of a germ-line mutation at Bahcc1 to disrupt its H3K27me3 engagement causes partial postnatal lethality, supporting a role in development. This study unveils a novel H3K27me3-directed transduction pathway in mammals that relies on a conserved BAH ‘reader’.
2020-11-05 | PXD021679 | Pride
Project description:Histone modifications are associated with distinct transcriptional states, but it is unclear whether they instruct gene expression. To investigate this, we mutated histone H3.3 K9 and K27 residues in mouse embryonic stem cells (mESCs). Here, we find that H3.3K9 is essential for controlling specific distal intergenic regions and for proper H3K27me3 deposition at promoters. The H3.3K9A mutation resulted in decreased H3K9me3 at regions encompassing endogenous retroviruses and induced a gain of H3K27ac and nascent transcription. These changes in the chromatin environment unleashed cryptic enhancers, resulting in the activation of distinctive transcriptional programs and culminating in protein expression normally restricted to specialized immune cell types. The H3.3K27A mutant disrupted deposition and spreading of the repressive H3K27me3 mark, particularly impacting bivalent genes with higher basal level of H3.3 at promoters. Therefore, H3.3K9 and K27 crucially orchestrate repressive chromatin states at cis-regulatory elements and bivalent promoters, respectively, and instruct proper transcription in mESCs.
2024-06-24 | MSV000095134 | MassIVE
Project description:Epigenetic environment of histone H3.3 on promoters revealed by integration of imaging and genome-scale chromatin and methyl-DNA immunoprecipitation information. Chromatin regions with different transcriptional outputs are distinguished by the deposition of histone variants. Histone H3.3 is incorporated into chromatin in a replication-independent manner; yet the relationship between H3.3 deposition, chromatin environment is incompletely understood. We have integrated imaging and genome-scale chromatin and methyl-DNA immunoprecipitation approaches to investigate the genomic distribution of epitope-tagged H3.3 in relation to histone modifications, DNA methylation and transcription. Results: Imaging shows that H3.3, in contrast to replicative H3.1 or H2B, is enriched in chromatin marked by histone modifications of active genes. A genome-wide survey identifies 1,649 H3.3-enriched promoters, only a subset of which is co-enriched in H3K4me3, H3K9me3 and/or H3K27me3, with a preference for H3K4me3, corroborating imaging data. H3.3-enriched promoters are depleted of H3.3 at the TSS in a transcription-independent manner. H3.3 is found predominantly on CpG-rich unmethylated promoters, creating a condition favourable for transcription. In undifferentiated mesenchymal stem cells, H3.3 target genes are linked to signaling and mesodermal differentiation, suggesting that H3.3 may be a mark of lineage priming. Conclusions: A minor fraction of H3.3 is targeted to promoters, which are predominantly CpG-rich, DNA unmethylated and devoid of detectable trimethylated H3K4, K9 and K27. Among H3.3 target promoters co-marked by methylated H3, H4K4me3 is preferred, with or without H3K27me3, arguing that in mesenchymal stem cells H3.3 marks transcriptionally active or potentially active promoters. Key words: Imaging, ChIP-chip, MeDIP-chip, histone H3.3, mesenchymal stem cells ChIP-chip and MeDIP-chip experiments: Performed with two independent biological replicates. Gene expression profiling experiments: Total RNA obtained from H3.3-EGFP transfected or empty-EGFP transfected mesenchymal stem cells compared to untransfected mesenchymal stem cells. Raw expression data linked below as supplementary file (GSE17053_Illumina_non-normalized_data.txt).
2010-05-12 | E-GEOD-17053 | biostudies-arrayexpress
Project description:Normal cell growth is characterized by a regulated epigenetic program that drives cellular activities such as gene transcription, DNA replication and DNA damage repair. Perturbation of this epigenetic program can lead to events such as mis-regulation of gene transcription and diseases such as cancer. To begin to understand the epigenetic program correlated to the development of melanoma, we performed a quantitative mass spectrometric analysis of histone posttranslational modifications mis-regulated in melanoma cell culture. Aggressive melanoma cells were found to have elevated histone H3 lysine 27 trimethylation (H3K27me3) as well as over-expressed methyltransferase EZH2 that adds the specific modification. The altered epigenetic program that led to elevated H3K27me3 in melanoma cell culture was found to directly silence transcription of the tumor suppressor gene RUNX3. The elevated level of H3K27me3 and silencing of RUNX3 transcription was also validated in advanced stage human melanoma tissues. The study presented underscores the utility of using high resolution mass spectrometry to identify mis-regulated epigenetic programs in diseases such as cancer, which could ultimately lead to the identification of biological markers for diagnostic and prognostic applications.
2015-12-02 | PXD002471 | Pride
Project description:Normal cell growth is characterized by a regulated epigenetic program that drives cellular activities such as gene transcription, DNA replication and DNA damage repair. Perturbation of this epigenetic program can lead to events such as mis-regulation of gene transcription and diseases such as cancer. To begin to understand the epigenetic program correlated to the development of melanoma, we performed a quantitative mass spectrometric analysis of histone posttranslational modifications mis-regulated in melanoma cell culture. Aggressive melanoma cells were found to have elevated histone H3 lysine 27 trimethylation (H3K27me3) as well as over-expressed methyltransferase EZH2 that adds the specific modification. The altered epigenetic program that led to elevated H3K27me3 in melanoma cell culture was found to directly silence transcription of the tumor suppressor gene RUNX3. The elevated level of H3K27me3 and silencing of RUNX3 transcription was also validated in advanced stage human melanoma tissues. The study presented underscores the utility of using high resolution mass spectrometry to identify mis-regulated epigenetic programs in diseases such as cancer, which could ultimately lead to the identification of biological markers for diagnostic and prognostic applications.
2016-07-22 | MSV000079979 | MassIVE
Project description:BRAHMA (BRM) is a conserved SWI/SNF-type chromatin remodeling ATPase implicated in many key nuclear events. Histone H3 Lysine 27 (H3K27) demethylases specifically remove the repressive histone mark, trimethylation of H3K27 (H3K27me3). Both proteins are thought to play active roles in regulating gene activities at the chromatin level, but their genome-wide coordination remains to be determined. In Arabidopsis thaliana, RELATIVE OF EARLY FLOWERING 6 (REF6, also known as JMJ12) is the first identified plant H3K27 demethylase. Here, genome-wide analyses revealed that REF6 targets to thousands of genes across the Arabidopsis genome and co-localizes with BRM at more than 1,000 genes, many of which are genes involved in response to various stimuli, especially plant hormones. Loss of REF6 activity results in decreased BRM occupancy at hundreds of BRM-REF6 co-targets, indicating that REF6 is required for the recruitment of BRM to chromatin. Further, REF6 targets to genomic loci that contains the CTCTGTTT motif in vivo
2016-03-31 | PXD003583 | Pride
Project description:Nucleosomes package eukaryotic DNA and are composed of four different histone proteins, H3, H4, H2A and H2B. Histone H3 has two main variants, H3.1 and H3.3, which show different genomic localization patterns in animals. We profiled H3.1 and H3.3 variants in the genome of the plant Arabidopsis thaliana and show that the localization of these variants shows broad similarity in plants and animals, in addition to some unique features. H3.1 was enriched in silent areas of the genome including regions containing the repressive chromatin modifications H3 lysine 27 methylation, H3 lysine 9 methylation, and DNA methylation. In contrast, H3.3 was enriched in actively transcribed genes, especially peaking at the 3’ end of genes, and correlated with histone modifications associated with gene activation such as histone H3 lysine 4 methylation, and H2B ubiquitylation, as well as by RNA Pol II occupancy. Surprisingly, both H3.1 and H3.3 were enriched on defined origins of replication, as was overall nucleosome density, suggesting a novel characteristic of plant origins. Our results are broadly consistent with the hypothesis that H3.1 acts as the canonical histone that is incorporated during DNA replication, whereas H3.3 acts as the replacement histone that can be incorporated outside of S-phase during chromatin disrupting processes like transcription. ChIP-seq - 4 samples: 2 experiment and 2 controls RNA-seq - 1 sample
2012-03-05 | E-GEOD-34840 | biostudies-arrayexpress
Project description:Transcription factor (TF)-induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF-induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF-induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF-dependent cell reprogramming. Genechip microarray analysis was performed respectively on 4 Ezh2 +/+ iPSC clones (control), 4 Ezh2 M-bM-^HM-^FSET/M-bM-^HM-^FSET iPSC clones (experimental), 3 independent preparations of wild type MEF (reference) and one sample of E14Tg2a embryonic stem cells (reference) using Affymetrix Mouse Gene 1.0 ST arrays. Labeling, hybridization, and washing were performed according to Affymetrix guidelines
2013-03-09 | E-GEOD-44972 | biostudies-arrayexpress
Project description:Transcription factor (TF)-induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF-induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF-induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF-dependent cell reprogramming.
2013-03-09 | GSE44972 | GEO