Project description:Polycomb Repressive Complex 2 (PRC2) plays crucial roles in transcriptional regulation and stem cell development. However, the context-specific functions associated with alternative subunits remain largely unexplored. Here we show that the related enzymatic subunits EZH1 and EZH2 undergo an expression switch during hematopoiesis. We examine the in vivo stoichiometry of the PRC2 complexes by quantitative proteomics and reveal the existence of an EZH1-SUZ12 sub-complex lacking EED. We provide evidence that EZH1 together with SUZ12 form a non-canonical PRC2 complex, occupy active chromatin domains in the absence of H3K27me3, and positively regulate gene expression. Loss of EZH2 expression leads to global repositioning of EZH1 chromatin occupancy to EZH2 targets. Moreover, we demonstrate that an erythroid-specific enhancer mediates transcriptional activation of EZH1, and a switch from GATA2 to GATA1 controls the developmental EZH1/2 switch by differential association with EZH1 enhancers during erythropoiesis. Thus, the lineage- and developmental stage-specific regulation of PRC2 expression and subunit composition leads to a switch from canonical silencing to non-canonical PRC2 functions during blood stem cell specification. Transcriptional profiling in primary human fetal liver proerythroblasts upon lentiviral shRNA-mediated knockdown of EZH1, EZH2, EED, or SUZ12 by RNA-seq analysis.
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:This SuperSeries is composed of the following subset Series: GSE22366: Primary human erythroid progenitor cells HDAC1 and HDAC2 shRNA knockdown samples GSE22367: Primary human erythroid progenitor cells SAHA treatment samples GSE22368: Primary human erythroid progenitor cells NK57 treatment samples Refer to individual Series
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:The histone methyltransferase complex PRC2 controls key steps in developmental transitions and cell fate choices. However, its roles in vertebrate eye development remain unknown. Here we report that in Xenopus PRC2 regulates the progression of retinal progenitors from proliferation to differentiation. We show that the PRC2 core components are enriched in retinal progenitors and downregulated with differentiation. Knockdown of the PRC2 core component Ezh2 leads to reduced retinal progenitor proliferation in part due to upregulation of the cdk inhibitor p15Ink4b. In addition, while PRC2 knockdown does not alter eye patterning, retinal progenitor gene expression or expression of the neural competence factor Sox2, it does cause suppression of proneural bHLH gene expression, indicating that PRC2 is critical for the initiation of neural differentiation in the retina. Consistent with this, knocking down or blocking PRC2 function constrains the generation of most retinal neural cell types and promotes a Mueller glial cell fate decision. We also show that Wnt/?-catenin signaling acting through the receptor Frizzled 5, but independent of Sox2, regulates expression of key PRC2 subunits in the developing retina. This is consistent with a role for this pathway in coordinating proliferation and the transition to neurogenesis in the Xenopus retina. Our data establishes PRC2 as a regulator of proliferation and differentiation during eye development. Xenopus embryos were injected at the 8-cell stage with 5ng Ezh2 ATG MO or 5ng control MO (scrambled sequence of Ezh2 ATG MO) together with 400 pg mRNA for GFP as a lineage tracer. At stage 27, GFP-positive eyes were isolated by microdissection. Pools of 20-25 eyes were used to prepare total RNA for each sample on the microarray. 4 control and 4 Ezh2 ATG MO samples were hybridized to Agilent 1-color microarrays.
Project description:The histone methyltransferase complex PRC2 controls key steps in developmental transitions and cell fate choices. However, its roles in vertebrate eye development remain unknown. Here we report that in Xenopus PRC2 regulates the progression of retinal progenitors from proliferation to differentiation. We show that the PRC2 core components are enriched in retinal progenitors and downregulated with differentiation. Knockdown of the PRC2 core component Ezh2 leads to reduced retinal progenitor proliferation in part due to upregulation of the cdk inhibitor p15Ink4b. In addition, while PRC2 knockdown does not alter eye patterning, retinal progenitor gene expression or expression of the neural competence factor Sox2, it does cause suppression of proneural bHLH gene expression, indicating that PRC2 is critical for the initiation of neural differentiation in the retina. Consistent with this, knocking down or blocking PRC2 function constrains the generation of most retinal neural cell types and promotes a Mueller glial cell fate decision. We also show that Wnt/β-catenin signaling acting through the receptor Frizzled 5, but independent of Sox2, regulates expression of key PRC2 subunits in the developing retina. This is consistent with a role for this pathway in coordinating proliferation and the transition to neurogenesis in the Xenopus retina. Our data establishes PRC2 as a regulator of proliferation and differentiation during eye development.