Reprogramming of Polycomb-mediated gene silencing in embryonic stem cells by the miR-290 family and the methyltransferase Ash1l
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ABSTRACT: Genome-wide analysis of Jarid2, Suz12 and H3K27me3 profiling in DCR-/- and DCRfl/fl ESCs performed by ChIP-seq and transcriptome analysis by RNA-seq
Project description:Members of the miR-290 family are the most abundantly expressed microRNAs (miRNAs) in mouse embryonic stem cells (ESCs). They regulate aspects of differentiation, pluripotency, and proliferation of ESCs, but the molecular program that they control has not been fully delineated. In the absence of Dicer, ESCs fail to express mature miR-290 miRNAs and have selective aberrant overexpression of Hoxa, Hoxb, Hoxc, and Hoxd genes essential for body plan patterning during embryogenesis, but they do not undergo a full differentiation program. Introduction of mature miR-291 into DCR(-/-) ESCs restores Hox gene silencing. This was attributed to the unexpected regulation of Polycomb-mediated gene targeting by miR-291. We identified the methyltransferase Ash1l as a pivotal target of miR-291 mediating this effect. Collectively, our data shed light on the role of Dicer in ESC homeostasis by revealing a facet of molecular regulation by the miR-290 family.
Project description:Genome-wide analysis of Jarid2, Suz12, and c-Maf binding and H3K27me3 profiling in miR-155 KO and WT Th17 performed by ChIP-seq. We found that Jarid2 and c-Maf is differentially expressed in absence of miR-155 and they compete for binding to the Il22 promoter. We highlight targets of Jarid2 and Suz12 in miR-155 KO Th17 cells that are epigenetically silenced by increased H3K27me3 status. Furthermore, genome-wide analysis through Suz12 ChIP-exo in WT and Jarid2fl/fl;CD4cre Th17 reveals defects in PRC2 recruitment in abscence of Jarid2 that results in derepression of genes in Th17 cells. Thus, one main function of miR-155 is to curb epigenetic silencing by targeting Jarid2. Examination of Jarid2, Suz12, c-Maf binding and H3K27me3 changes in miR-155 KO and WT Th17.
Project description:Genome-wide analysis of Jarid2, Suz12, and c-Maf binding and H3K27me3 profiling in miR-155 KO and WT Th17 performed by ChIP-seq. We found that Jarid2 and c-Maf is differentially expressed in absence of miR-155 and they compete for binding to the Il22 promoter. We highlight targets of Jarid2 and Suz12 in miR-155 KO Th17 cells that are epigenetically silenced by increased H3K27me3 status. Furthermore, genome-wide analysis through Suz12 ChIP-exo in WT and Jarid2fl/fl;CD4cre Th17 reveals defects in PRC2 recruitment in abscence of Jarid2 that results in derepression of genes in Th17 cells. Thus, one main function of miR-155 is to curb epigenetic silencing by targeting Jarid2.
Project description:We analyzed the overlap in genome wide binding sites between Jarid2 and Suz12 in mouse ES cells and find that Jarid2 and Suz12 peaks have an high degree (90%) of overlap. Moreover we analyzed the effect of Jarid2 down regulation on genome wide Suz12 binding sites and found that Loss of Jarid2 lead to the loss of 70% of Suz12 binding sites and to a 10 Fold reduction in intensity for 90% of Suz12 binding sites. Overall, these results demonstrate that Jarid2 plays an essential role for Suz12 (PRC2 complex) association to DNA.
Project description:We analyzed the overlap in genome wide binding sites between Jarid2 and Suz12 in mouse ES cells and find that Jarid2 and Suz12 peaks have an high degree (90%) of overlap. Moreover we analyzed the effect of Jarid2 down regulation on genome wide Suz12 binding sites and found that Loss of Jarid2 lead to the loss of 70% of Suz12 binding sites and to a 10 Fold reduction in intensity for 90% of Suz12 binding sites. Overall, these results demonstrate that Jarid2 plays an essential role for Suz12 (PRC2 complex) association to DNA. Examination of two different proteins in two different cell lines
Project description:Molecular mechanisms for the establishment of transcriptional memory are poorly understood. 5,6-dichloro-1-D-ribofuranosyl-benzimidazole (DRB) is a P-TEFb kinase inhibitor that artificially induces the poised RNA polymerase II (RNAPII), thereby manifesting intermediate steps for the establishment of transcriptional activation. Here, using genetics and DRB, we show that mammalian Absent, small, or homeotic discs 1-like (Ash1l), a member of the trithorax group proteins, methylates Lys36 of histone H3 to promote the establishment of Hox gene expression by counteracting Polycomb silencing. Importantly, we found that Ash1l-dependent Lys36 di-, tri-methylation of histone H3 in a coding region and exclusion of Polycomb group proteins occur independently of transcriptional elongation in embryonic stem (ES) cells, although both were previously thought to be consequences of transcription. Genome-wide analyses of histone H3 Lys36 methylation under DRB treatment have suggested that binding of the retinoic acid receptor (RAR) to a certain genomic region promotes trimethylation in the RAR-associated gene independent of its ongoing transcription. Moreover, DRB treatment unveils a parallel response between Lys36 methylation of histone H3 and occupancy of either Tip60 or Mof in a region-dependent manner. We also found that Brg1 is another key player involved in the response. Our results uncover a novel regulatory cascade orchestrated by Ash1l with RAR and provide insights into mechanisms underlying the establishment of the transcriptional activation that counteracts Polycomb silencing.
Project description:Polycomb Repressive Complex 2 (PRC2) has been shown to play a key role in hematopoietic stem and progenitor cell (HSPC) function. Analyses of mouse mutants harboring deletions of core components have implicated PRC2 in fine-tuning multiple pathways that instruct HSPC behavior, yet how PRC2 is targeted to specific genomic loci within HSPCs remains unknown. Here we use shRNA-mediated knockdown to survey the function of known PRC2 accessory factors in HSPCs by testing the competitive reconstitution capacity of transduced murine fetal liver cells. We find that similar to the phenotype observed upon depletion of core subunit Suz12, depleting Jarid2 enhances the competitive transplantation capacity of both fetal and adult, mouse and human HSPCs. Gene expression profiling revealed common Suz12 and Jarid2 target genes that are enriched for the H3K27me3 mark established by PRC2. These data implicate Jarid2 as an important component of PRC2 that has a central role in coordinating HSPC function. RNA-seq of jarid knockdown, suz knockdown and control from HSPC in 16 week old mice.
Project description:Polycomb Repressive Complex 2 (PRC2) has been shown to play a key role in hematopoietic stem and progenitor cell (HSPC) function. Analyses of mouse mutants harboring deletions of core components have implicated PRC2 in fine-tuning multiple pathways that instruct HSPC behavior, yet how PRC2 is targeted to specific genomic loci within HSPCs remains unknown. Here we use shRNA-mediated knockdown to survey the function of known PRC2 accessory factors in HSPCs by testing the competitive reconstitution capacity of transduced murine fetal liver cells. We find that similar to the phenotype observed upon depletion of core subunit Suz12, depleting Jarid2 enhances the competitive transplantation capacity of both fetal and adult, mouse and human HSPCs. Gene expression profiling revealed common Suz12 and Jarid2 target genes that are enriched for the H3K27me3 mark established by PRC2. These data implicate Jarid2 as an important component of PRC2 that has a central role in coordinating HSPC function.
Project description:We report on mechanism of interaction between PRC2 complex and Jarid2 and their role in pluripotent cells Examination of PRC2 genomic localization by analysis of Jarid2, Ezh2, Suz12 and Jarid1a occupancy
Project description:Polycomb repressive complex 2 (PRC2) maintains developmental regulator genes in a repressed state through methylation of histone H3 at lysine 27 (H3K27me3) and is necessary for cell differentiation. We and others have previously found that the PRC2 subunit Suz12 interacts with RNA in vitro and other studies have shown that Ezh2 and Jarid2 also possess RNA binding function. The interaction of PRC2 with RNA has been suggested to regulate PRC2 targeting or enzymatic activity, but the RNAs directly bound by PRC2 in cells, and the role of each PRC2 RNA binding subunit, remain unclear. We have used different CLIP techniques, which use UV-crosslinking to allow detection of direct Suz12-RNA interactions as they occur in living mouse ES cells. Suz12 binds nascent RNA and has a preference for interaction with the 3’UTR, showing it does have binding specificity in cells. RNAs bound by Suz12 at the 3’UTR encode developmental regulator genes. Suz12 remains bound to RNA upon deletion of Ezh2 or Jarid2 showing that it binds RNA independently of other PRC2 subunits. We also show that binding of Suz12 to RNA or chromatin is mutually inhibitory. Although Ezh2 and Jarid2 also bind RNA, Ezh2 and Jarid2 deletion causes an increase in Suz12 RNA binding, without changing its specificity, which reflects the loss of Suz12 from chromatin. Similarly, disruption of Suz12-RNA interactions by RNA polymerase II inhibition or RNase treatment increases Suz12 binding to chromatin. These results therefore suggest that Suz12 acts as an RNA sensor, binding to the 3’UTR of nascent RNAs and modulating the interaction of PRC2 with chromatin.