Expression data from Ring1A(-/-);Ring1B(fl/fl);R26::CreERT2 ES cells expressing either of mock, WT or mutant Ring1B construct before or after OHT treatment
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ABSTRACT: We used microarrays to investigate the restoration of repression of PRC1 target gene expression in Ring1A/B-dKO ES cells stably expressing either of mock, WT or mutant Ring1B construct. Total RNAs were extracted from the respective ES cells, and were subjected to microarray analysis using Affymetrix GeneChip Mouse Genome 430A 2.0 arrays
Project description:Two distinct Polycomb complexes, PRC1 and PRC2, collaborate to maintain epigenetic repression of key developmental loci in embryonic stem cells (ESCs). PRC1 and PRC2 have histone modifying activities, catalyzing mono-ubiquitination of histone H2A (H2AK119u1) and trimethylation of H3 lysine 27 (H3K27me3) respectively. Compared to H3K27me3, localization and role of H2AK119ub1 is not fully understood in ESCs. Here we present genome-wide H2AK119u1 maps in ESCs and identify a group of genes at which H2AK119u1 is deposited in a Ring1-dependent manner. These genes are a distinctive subset of genes with H3K27me3 enrichment and are the central targets of Polycomb silencing that are required to maintain ESC identity. We further show that the H2A ubiquitination activity of PRC1 is dispensable for its target binding and its activity to compact chromatin at Hox loci, but is indispensable for efficient repression of target genes and thereby ESC maintenance. These data demonstrate that multiple effector mechanisms including H2A ubiquitination and chromatin compaction combine to mediate PRC1-dependent repression of genes that are crucial for the maintenance of ESC identity. Utilization of these diverse effector mechanisms might provide a means to maintain a repressive state that is robust yet highly responsive to developmental cues during ES cell self-renewal and differentiation. This SuperSeries is composed of the following subset Series: GSE38224: Expression data from Ring1A(-/-);Ring1B(fl/fl);R26::CreERT2 ES cells expressing either of mock, WT or mutant Ring1B construct before or after OHT treatment GSE38504: ChIP-on-chip analysis of Ring1B, Ring1A, H2AK119u1 and H3K27me3 in mouse ES cells Total RNAs were extracted from the respective ES cells, and were subjected to microarray analysis using Affymetrix GeneChip Mouse Genome 430A 2.0 arrays. ChIP on chip analysis was carried out using the Mouse Promoter ChIP-on-chip Microarray Set (G4490A, Agilent, Palo Alto, Calif., USA). MEFs were subjected to ChIP assay using various antibodies. Purified immunoprecipitated and input DNA was subjected to T7 RNA polymerase-based amplification. Labeling, hybridization and washing were carried out according to the Agilent mammalian ChIP-on-chip protocol (ver.9.0). Scanned images were quantified with Agilent Feature Extraction software under standard conditions.
Project description:We used microarrays to investigate the restoration of repression of PRC1 target gene expression in Ring1A/B-dKO ES cells stably expressing either of mock, WT or mutant Ring1B construct.
Project description:ChIP-on-chip analysis was carried out to determine targets of Ring1B, Ring1A, H2AK119u1 and H3K27me3 in mouse ES cells. ChIP-on-chip analysis was carried out using the Mouse Promoter ChIP-on-chip Microarray Set (G4490A, Agilent, Palo Alto, Calif., USA). ESCs were subjected to ChIP assay using specific antibodies. Purified immunoprecipitated and input DNA was subjected to T7 RNA polymerase-based amplification as described previously (van Bakel et al., 2008). Labeling, hybridization and washing were carried out according to the Agilent mammalian ChIP-on-chip protocol (ver.9.0). Scanned images were quantified with Agilent Feature Extraction software under standard conditions.
Project description:The chromatin modifying activities inherent to polycomb repressive complexes PRC1 and PRC2 play an essential role in gene regulation, cellular differentiation, and development. However, the mechanisms by which these complexes recognize their target sites and function together to form repressive chromatin domains remain poorly understood. Recruitment of PRC1 to target sites has been proposed to occur through a hierarchical process, dependent on the prior nucleation of PRC2 and placement of H3K27me3. Here, using a de novo targeting assay in mouse embryonic stem cells we unexpectedly discover that PRC1-dependent H2AK119ub1 leads to the recruitment of PRC2 and H3K27me3 to effectively initiate a polycomb domain. Genetic ablation of catalytic subunit of the PRC1 complex (RINGA/B) and ChIP-seq analysis of PRC1 and PRC2 components confirmed genome-wide decreases in PRC2 occupancy and H3K27me3 levels at PRC target sites. This activity is restricted to variant PRC1 complexes and genetic ablation experiments reveal that targeting of the variant PCGF1/PRC1 complex by KDM2B to CpG islands is required for polycomb domain formation and normal development. Together these observations provide a surprising new PRC1-dependent logic for PRC2 occupancy and polycomb domain formation. RING1A-/-;RING1Bfl/fl ES cells were treated with 800M-BM-5M tamoxifen for 48hours and compared to untreated control cells by ChIP-seq for RING1B, SUZ12, EZH2 and H3K27me3.
Project description:Genome organization influences transcriptional regulation by facilitating interactions between gene promoters and distal regulatory elements. To analyse distal promoter contacts mediated by the PRC1 complex we used Capture Hi-C (CHi-C) to enrich for promoter-interactions in a HiC library in Ring1a KO and Ring1a/b dKO mouse ES cells.
Project description:Embryonic stem (ES) cells express pluripotency-associated genes and repress differentiation-inducible genes. The activities of these genes are coordinately reversed during differentiation. The changes in the transcriptome upon conditional KAP1 knockout in ES cells overlapped with the changes during embryoid body formation. KAP1 repressed differentiation-inducible genes and derepressed pluripotency-associated genes in ES cells. KAP1 formed complexes with polycomb repressive complexes 1 (PRC1) through an interaction that was mediated by the KAP1 coiled-coil region. KAP1 and PRC1 bound cooperatively at the promoters of differentiation-inducible genes and repressed their transcription. In contrast, KAP1 bound the transcribed and flanking sequences of pluripotency-associated genes, did not enhance PRC1 binding, and derepressed their transcription. KAP1 had opposite effects on differentiation-inducible and pluripotency-associated gene transcription both in ES cells and in differentiating embryoid bodies. The region of KAP1 that mediated the interaction with PRC1 was required for KAP1 enhancement of PRC1 binding and for KAP1 repression of transcription at differentiation-inducible promoters. This region of KAP1 was not required for KAP1 suppression of PRC1 binding or for KAP1 derepression of transcription at pluripotency-associated promoters. The opposite effects of KAP1 on transcription of differentiation-inducible versus pluripotency-associated genes contributed to the reciprocal changes in their transcription during differentiation. Analysis of the regions occupied by KAP1(TRIM28/TIF1beta) and by Ring1b(Rnf2) in mouse embryonic stem cells before and after conditional KAP fl/fl and Ring1b fl/fl knockout
Project description:Nuclear RNA was isolated from all three cell types to enable differential expression analysis of both coding and non-coding RNA shortly after tamoxifen treatment, that resulted in conditional knock-out of Ring1b in the Ring1a -/- background.
Project description:The histone lysine demethylase protein, KDM2B, associates with the PCGF1/PRC1 complex and binds to non-methylated DNA through its ZF-CxxC domain, providing a possible molecular link between CpG island elements and polycomb nucleation (Farcas et al., 2012, Wu et al., 2013). Here, a novel genetic system was designed in which PCGF1/PRC1 targeting could be disrupted in vivo through the ablation of KDM2B-mediated DNA binding. To ablate PCGF1/PRC1 targeting, an exon that encodes most of the KDM2B ZF-CxxC domain and is shared by both the long and short form of the protein was flanked by loxP sites (Kdm2bfl/fl). Homozygous mouse ES cell lines were derived that also stably express a tamoxifen inducible form of CRE-recombinase. CRE induced deletion of the ZF-CxxC domain by the addition of tamoxifen yields KDM2B long and short form proteins that are incapable of binding to CpG island DNA but still remain associated with the PCGF1/PRC1 variant complex. We then assessed genome-wide occupancy of the PRC1 component RING1B and the PRC2 component SUZ12 to examine the impact of losing KDM2B-dependent targeting of polycomb. KDM2Bfl/fl ES cells were treated with 800M-BM-5M tamoxifen for 72hours and compared to untreated control cells by ChIP-seq for KDM2B, RING1B and SUZ12, and RNA-seq.
Project description:H3K4me1 (ab8895 Abcam) and H3K27ac (ab4729 Abcam) antibodies were used for ChIP-seq in Ring1a-/- mouse ES cells and after 48h tamoxifen treatment in conditional knock-out of Ring1b in the Ring1a -/- background.