5C with wild type mESC, wild type NPC and mESC with various PcG components knocked-out
Ontology highlight
ABSTRACT: Master regulatory genes require stable silencing by the Polycomb-Group (PcG) to prevent improper expression during differentiation and development. Some PcG proteins covalently modify histones, which contributes to heritable repression. The role for other effects on chromatin structure is less understood. We characterized the organization of PcG target genes in mouse ES cells and neural progenitors using high-resolution 5C technology and super-resolution microscopy. The genomic loci of repressed PcG target genes formed discrete, small domains of tight interaction that corresponded to locations bound by canonical Polycomb Repressive Complex 1 (PRC1). These domains changed during differentiation as PRC1 binding changed. Their formation depended upon the Polyhomeotic component of canonical PRC1, and occurred independently of PRC1-catalyzed ubiquitylation. PRC1 domains differ from topologically associating domains in numerous aspects . These domains have the potential to play a key role in transmitting epigenetic silencing of PcG targets by linking PRC1 to formation of a repressive higher order structure.
Project description:Master regulatory genes require stable silencing by the Polycomb-Group (PcG) to prevent improper expression during differentiation and development. Some PcG proteins covalently modify histones, which contributes to heritable repression. The role for other effects on chromatin structure is less understood. We characterized the organization of PcG target genes in mouse ES cells and neural progenitors using high-resolution 5C technology and super-resolution microscopy. The genomic loci of repressed PcG target genes formed discrete, small domains of tight interaction that corresponded to locations bound by canonical Polycomb Repressive Complex 1 (PRC1). These domains changed during differentiation as PRC1 binding changed. Their formation depended upon the Polyhomeotic component of canonical PRC1, and occurred independently of PRC1-catalyzed ubiquitylation. PRC1 domains differ from topologically associating domains in numerous aspectsá. These domains have the potential to play a key role in transmitting epigenetic silencing of PcG targets by linking PRC1 to formation of a repressive higher order structure.
Project description:Master regulatory genes require stable silencing by the Polycomb-Group (PcG) to prevent improper expression during differentiation and development. Some PcG proteins covalently modify histones, which contributes to heritable repression. The role for other effects on chromatin structure is less understood. We characterized the organization of PcG target genes in mouse ES cells and neural progenitors using high-resolution 5C technology and super-resolution microscopy. The genomic loci of repressed PcG target genes formed discrete, small domains of tight interaction that corresponded to locations bound by canonical Polycomb Repressive Complex 1 (PRC1). These domains changed during differentiation as PRC1 binding changed. Their formation depended upon the Polyhomeotic component of canonical PRC1, and occurred independently of PRC1-catalyzed ubiquitylation. PRC1 domains differ from topologically associating domains in numerous aspects . These domains have the potential to play a key role in transmitting epigenetic silencing of PcG targets by linking PRC1 to formation of a repressive higher order structure.
Project description:Polycomb group (PcG) proteins play critical roles during development. H2Aub and H3K27me3 are deposited by Polycomb-repressive Complex 1 and 2 (PRC1/2) respectively, and largely overlap in the genome due to mutual recruitment of the two complexes. However, whether PRC1/H2Aub and PRC2/H3K27me3 also function independently remains elusive. Here we uncovered a large-scale decoupling of H2Aub and H3K27me3 in preimplantation mouse embryos, at both canonical PcG targets and broad distal domains. H2Aub represses future bivalent genes without H3K27me3 but does not contribute to maintenance of H3K27me3-dependent non-canonical imprinting. Our study thus revealed their distinct and independent functions in early mammalian development.
Project description:Polycomb repressive complexes-1 and -2 (PRC1 and 2), silence developmental genes in spatiotemporally regulated manner during metazoan embryogenesis. How PcG proteins contribute to down-regulation of target genes upon differentiation, however, remains elusive. Here, by differentiating embryonic stem cells into embryoid bodies, we reveal a crucial role of a PCGF1 (Polycomb group RING finger protein 1)-containing variant PRC1 complex (PCGF1-PRC1) to facilitate induced down-regulation of a group of genes. Binding of PCGF1-PRC1 results in down-regulation of transcriptional activity, followed by Histone H2AK119 mono-ubiquitination (H2AK119ub1) and subsequent recruitment of PRC2, to initiate PcG-repressive domain formation. Based on these findings, we propose that PCGF1-PRC1 mediates establishment of PcG-repressive domains at target genes during differentiation.
Project description:Polycomb repressive complexes-1 and -2 (PRC1 and 2), silence developmental genes in spatiotemporally regulated manner during metazoan embryogenesis. How PcG proteins contribute to down-regulation of target genes upon differentiation, however, remains elusive. Here, by differentiating embryonic stem cells into embryoid bodies, we reveal a crucial role of a PCGF1 (Polycomb group RING finger protein 1)-containing variant PRC1 complex (PCGF1-PRC1) to facilitate induced down-regulation of a group of genes. Binding of PCGF1-PRC1 results in down-regulation of transcriptional activity, followed by Histone H2AK119 mono-ubiquitination (H2AK119ub1) and subsequent recruitment of PRC2, to initiate PcG-repressive domain formation. Based on these findings, we propose that PCGF1-PRC1 mediates establishment of PcG-repressive domains at target genes during differentiation.
Project description:Polycomb repressive complexes-1 and -2 (PRC1 and 2), silence developmental genes in spatiotemporally regulated manner during metazoan embryogenesis. How PcG proteins contribute to down-regulation of target genes upon differentiation, however, remains elusive. Here, by differentiating embryonic stem cells into embryoid bodies, we reveal a crucial role of a PCGF1 (Polycomb group RING finger protein 1)-containing variant PRC1 complex (PCGF1-PRC1) to facilitate induced down-regulation of a group of genes. Binding of PCGF1-PRC1 results in down-regulation of transcriptional activity, followed by Histone H2AK119 mono-ubiquitination (H2AK119ub1) and subsequent recruitment of PRC2, to initiate PcG-repressive domain formation. Based on these findings, we propose that PCGF1-PRC1 mediates establishment of PcG-repressive domains at target genes during differentiation.
Project description:The Polycomb group (PcG) proteins are fundamental epigenetic regulators that control the repressive state of target genes in multicellular organisms. One of the open questions is defining the mechanisms of PcG recruitment to chromatin. In Drosophila, the crucial role in PcG recruitment is thought to belong to DNA-binding proteins associated with Polycomb response elements (PREs). However, current data suggests that not all PRE-binding factors have been identified. Here, we report the identification of the transcription factor Crooked legs (Crol) as a novel PcG recruiter. Crol is a C2H2-type Zinc Finger protein that directly binds to poly(G)-rich DNA sequences. Mutation of Crol binding sites as well as crol CRISPR/Cas9 knockout diminish the repressive activity of PREs in transgenes. Like other PRE-DNA binding proteins, Crol co-localizes with PcG proteins inside and outside of H2K27me3 domains. Crol knockout impairs the recruitment of the PRC1 subunit Polyhomeotic and the PRE-binding protein Combgap at a subset of sites. The decreased binding of PcG proteins is accompanied by dysregulated transcription of target genes. Overall, our study identified Crol as a new important player in PcG recruitment and epigenetic regulation.
Project description:The Polycomb group (PcG) proteins are fundamental epigenetic regulators that control the repressive state of target genes in multicellular organisms. One of the open questions is defining the mechanisms of PcG recruitment to chromatin. In Drosophila, the crucial role in PcG recruitment is thought to belong to DNA-binding proteins associated with Polycomb response elements (PREs). However, current data suggests that not all PRE-binding factors have been identified. Here, we report the identification of the transcription factor Crooked legs (Crol) as a novel PcG recruiter. Crol is a C2H2-type Zinc Finger protein that directly binds to poly(G)-rich DNA sequences. Mutation of Crol binding sites as well as crol CRISPR/Cas9 knockout diminish the repressive activity of PREs in transgenes. Like other PRE-DNA binding proteins, Crol co-localizes with PcG proteins inside and outside of H2K27me3 domains. Crol knockout impairs the recruitment of the PRC1 subunit Polyhomeotic and the PRE-binding protein Combgap at a subset of sites. The decreased binding of PcG proteins is accompanied by dysregulated transcription of target genes. Overall, our study identified Crol as a new important player in PcG recruitment and epigenetic regulation.
Project description:Polycomb group (PcG) proteins are essential epigenetic transcriptional regulators. Traditionally, PcG proteins function as two multi-subunit complexes, Polycomb repressive complex 1 (PRC1) and PRC2, which largely overlap in their genomic binding and cooperate to establish repressive chromatin domains demarcated by H2AK119ub and H3K27me3. Here, using the developing skin epidermis as a paradigm, we uncovered a functional redundancy between Polycomb complexes in the repression of unwanted non-lineage genes.
Project description:Polycomb group (PcG) proteins are essential epigenetic transcriptional regulators. Traditionally, PcG proteins function as two multi-subunit complexes, Polycomb repressive complex 1 (PRC1) and PRC2, which largely overlap in their genomic binding and cooperate to establish repressive chromatin domains demarcated by H2AK119ub and H3K27me3. Here, using the developing skin epidermis as a paradigm, we uncovered a functional redundancy between Polycomb complexes in the repression of unwanted non-lineage genes.