Similar Datasets
Project description:Nucleation and spreading rejuvenate polycomb domains every cell cycle
| PRJNA862526 | ENA
Project description:The Polycomb repressive complex 2 (PRC2) is an essential epigenetic regulator that deposits repressive H3K27me3 for transcriptional gene silencing in eukaryotes. The PRC2-mediated gene silencing process occurs in two steps: the initial H3K27me3 deposition at the nucleation region, and the subsequent spreading of H3K27me3 over the entire gene. Lack of H3K27me3 spreading gives rise to a metastable state that could lead to loss of silencing. H3K27me3 spreading is thus a key step critical for the establishment of stable long-term Polycomb silencing in both animals and plants.Here, we uncover that Arabidopsis thaliana PICKLE (PKL), a member of the conserved Chromodomain Helicase DNA-binding (CHD) family of chromatin remodeling ATPase13, is dispensable for the nucleation but especially required for the efficient spreading of H3K27me3 at thousands of Polycomb target genes. PKL localizes to the spreading regions in a non-DNA-sequence-specific manner through its SANT-SILDE domain. PKL then upregulates the chromatin density by its CHROMODOMAIN and ATPase domain , enabling the H3K27me3 methyltransferase CURLY LEAF (CLF) to deposit H3K27me3 on nucleosomes in the spreading regions to facilitate the H3K27me3 spreading.
2024-10-02 | GSE201375 | GEO
Project description:The Polycomb repressive complex 2 (PRC2) is an essential epigenetic regulator that deposits repressive H3K27me3 for transcriptional gene silencing in eukaryotes. The PRC2-mediated gene silencing process occurs in two steps: the initial H3K27me3 deposition at the nucleation region, and the subsequent spreading of H3K27me3 over the entire gene. Lack of H3K27me3 spreading gives rise to a metastable state that could lead to loss of silencing. H3K27me3 spreading is thus a key step critical for the establishment of stable long-term Polycomb silencing in both animals and plants.Here, we uncover that Arabidopsis thaliana PICKLE (PKL), a member of the conserved Chromodomain Helicase DNA-binding (CHD) family of chromatin remodeling ATPase13, is dispensable for the nucleation but especially required for the efficient spreading of H3K27me3 at thousands of Polycomb target genes. PKL localizes to the spreading regions in a non-DNA-sequence-specific manner through its SANT-SILDE domain. PKL then upregulates the chromatin density by its CHROMODOMAIN and ATPase domain , enabling the H3K27me3 methyltransferase CURLY LEAF (CLF) to deposit H3K27me3 on nucleosomes in the spreading regions to facilitate the H3K27me3 spreading.
2024-10-02 | GSE201374 | GEO
Project description:Nucleation and spreading of H3K27me3 are critical steps for the initiation and maintenance, respectively, of mitotically inheritable Polycomb-mediated repressive chromatin states in cell identity memory, in both animals and plants. Although a semiconservative read-and-write mechanism is proposed to play a key role in H3K27me3 propagation, the specific determinant and underlying mechanism by which the Polycomb Repressive Complex 2 (PRC2) accesses unmodified nucleosomes for propagating H3K27me3 remain enigmatic. Using Arabidopsis thaliana as a model, we show that the chromatin remodeling activity of PICKLE (PKL) has a specialized role in H3K27me3 spreading to safeguard cell identity during differentiation. PKL specifically binds to H3K27me3 spreading regions but not nucleation sites of Polycomb target genes and physically interacts with the MSI1 subunit of PRC2. Loss of PKL abolishes the occupancy of the PRC2 catalytic subunit CLF in spreading regions and leads to aberrant differentiation. Nucleosome condensing endowed by the ATPase function of PKL ensures that unmodified nucleosomes are accessible to PRC2 catalytic activity. Our findings highlight that PKL-dependent nucleosome compaction is critical for PRC2-mediated H3K27me3 read-and-write functions in H3K27me3 spreading, thus revealing a mechanism by which repressive chromatin domains are established and propagated.
2024-10-02 | GSE267571 | GEO
Project description:Nucleation and spreading of H3K27me3 are critical steps for the initiation and maintenance, respectively, of mitotically inheritable Polycomb-mediated repressive chromatin states in cell identity memory, in both animals and plants. Although a semiconservative read-and-write mechanism is proposed to play a key role in H3K27me3 propagation, the specific determinant and underlying mechanism by which the Polycomb Repressive Complex 2 (PRC2) accesses unmodified nucleosomes for propagating H3K27me3 remain enigmatic. Using Arabidopsis thaliana as a model, we show that the chromatin remodeling activity of PICKLE (PKL) has a specialized role in H3K27me3 spreading to safeguard cell identity during differentiation. PKL specifically binds to H3K27me3 spreading regions but not nucleation sites of Polycomb target genes and physically interacts with the MSI1 subunit of PRC2. Loss of PKL abolishes the occupancy of the PRC2 catalytic subunit CLF in spreading regions and leads to aberrant differentiation. Nucleosome condensing endowed by the ATPase function of PKL ensures that unmodified nucleosomes are accessible to PRC2 catalytic activity. Our findings highlight that PKL-dependent nucleosome compaction is critical for PRC2-mediated H3K27me3 read-and-write functions in H3K27me3 spreading, thus revealing a mechanism by which repressive chromatin domains are established and propagated.
2024-10-02 | GSE267567 | GEO
Project description:Polycomb-group proteins play critical roles in gene silencing through the deposition of histone H3 lysine 27 trimethylation (H3K27me3) and chromatin compaction. This process is essential for embryonic stem cells (ESCs) pluripotency, differentiation, and development. Polycomb repressive complex 2 (PRC2) can both read and write H3K27me3, enabling processive spread of H3K27me3 on linear genome and epigenetic memory. Long-range Polycomb-associated DNA contacts have also been described, but their regulation and role in gene silencing remains unclear. Here, we develop H3K27me3 HiChIP and apply optical reconstruction of chromatin architecture to reveal long-range Polycomb-associated DNA loops that span tens to hundreds of megabases and across multiple topological associated domains in mouse ESCs and human induced pluripotent stem cells. H3K27me3 loop anchors are enriched for Polycomb nucleation points and coincide with key developmental genes, such as Hmx1, Wnt6 and Hoxa. Genetic deletion of H3K27me3 loop anchors causes spatially proximal partner chromosomal loci to break apart, and alters H3K27me3 deposition, both locally and megabases away on the same chromosome. A selective EZH2 mutant deficient in RNA binding but intact H3K27me3 enzymatic activity leads to global alteration in H3K27me3 loops, decreased spatial proximity, and failure to spread Polycomb from PRC2 nucleation points to partner loci at developmental genes. Together, these results suggest PRC2 acts as a “genomic wormhole”, using RNA binding to enhance long range chromosome folding and H3K27me3 spreading. Developmental gene loci have novel roles in Polycomb spreading, emerging as key architectural elements of the epigenome.
2022-05-13 | GSE150906 | GEO
Project description:Polycomb-group proteins play critical roles in gene silencing through the deposition of histone H3 lysine 27 trimethylation (H3K27me3) and chromatin compaction. This process is essential for embryonic stem cells (ESCs) pluripotency, differentiation, and development. Polycomb repressive complex 2 (PRC2) can both read and write H3K27me3, enabling processive spread of H3K27me3 on linear genome and epigenetic memory. Long-range Polycomb-associated DNA contacts have also been described, but their regulation and role in gene silencing remains unclear. Here, we develop H3K27me3 HiChIP and apply optical reconstruction of chromatin architecture to reveal long-range Polycomb-associated DNA loops that span tens to hundreds of megabases and across multiple topological associated domains in mouse ESCs and human induced pluripotent stem cells. H3K27me3 loop anchors are enriched for Polycomb nucleation points and coincide with key developmental genes, such as Hmx1, Wnt6 and Hoxa. Genetic deletion of H3K27me3 loop anchors causes spatially proximal partner chromosomal loci to break apart, and alters H3K27me3 deposition, both locally and megabases away on the same chromosome. A selective EZH2 mutant deficient in RNA binding but intact H3K27me3 enzymatic activity leads to global alteration in H3K27me3 loops, decreased spatial proximity, and failure to spread Polycomb from PRC2 nucleation points to partner loci at developmental genes. Together, these results suggest PRC2 acts as a “genomic wormhole”, using RNA binding to enhance long range chromosome folding and H3K27me3 spreading. Developmental gene loci have novel roles in Polycomb spreading, emerging as key architectural elements of the epigenome.
2022-05-13 | GSE150905 | GEO
Project description:Polycomb-group proteins play critical roles in gene silencing through the deposition of histone H3 lysine 27 trimethylation (H3K27me3) and chromatin compaction. This process is essential for embryonic stem cells (ESCs) pluripotency, differentiation, and development. Polycomb repressive complex 2 (PRC2) can both read and write H3K27me3, enabling processive spread of H3K27me3 on linear genome and epigenetic memory. Long-range Polycomb-associated DNA contacts have also been described, but their regulation and role in gene silencing remains unclear. Here, we develop H3K27me3 HiChIP and apply optical reconstruction of chromatin architecture to reveal long-range Polycomb-associated DNA loops that span tens to hundreds of megabases and across multiple topological associated domains in mouse ESCs and human induced pluripotent stem cells. H3K27me3 loop anchors are enriched for Polycomb nucleation points and coincide with key developmental genes, such as Hmx1, Wnt6 and Hoxa. Genetic deletion of H3K27me3 loop anchors causes spatially proximal partner chromosomal loci to break apart, and alters H3K27me3 deposition, both locally and megabases away on the same chromosome. A selective EZH2 mutant deficient in RNA binding but intact H3K27me3 enzymatic activity leads to global alteration in H3K27me3 loops, decreased spatial proximity, and failure to spread Polycomb from PRC2 nucleation points to partner loci at developmental genes. Together, these results suggest PRC2 acts as a “genomic wormhole”, using RNA binding to enhance long range chromosome folding and H3K27me3 spreading. Developmental gene loci have novel roles in Polycomb spreading, emerging as key architectural elements of the epigenome.
2022-05-13 | GSE150904 | GEO
Project description:Polycomb-group proteins play critical roles in gene silencing through the deposition of histone H3 lysine 27 trimethylation (H3K27me3) and chromatin compaction. This process is essential for embryonic stem cells (ESCs) pluripotency, differentiation, and development. Polycomb repressive complex 2 (PRC2) can both read and write H3K27me3, enabling processive spread of H3K27me3 on linear genome and epigenetic memory. Long-range Polycomb-associated DNA contacts have also been described, but their regulation and role in gene silencing remains unclear. Here, we develop H3K27me3 HiChIP and apply optical reconstruction of chromatin architecture to reveal long-range Polycomb-associated DNA loops that span tens to hundreds of megabases and across multiple topological associated domains in mouse ESCs and human induced pluripotent stem cells. H3K27me3 loop anchors are enriched for Polycomb nucleation points and coincide with key developmental genes, such as Hmx1, Wnt6 and Hoxa. Genetic deletion of H3K27me3 loop anchors causes spatially proximal partner chromosomal loci to break apart, and alters H3K27me3 deposition, both locally and megabases away on the same chromosome. A selective EZH2 mutant deficient in RNA binding but intact H3K27me3 enzymatic activity leads to global alteration in H3K27me3 loops, decreased spatial proximity, and failure to spread Polycomb from PRC2 nucleation points to partner loci at developmental genes. Together, these results suggest PRC2 acts as a “genomic wormhole”, using RNA binding to enhance long range chromosome folding and H3K27me3 spreading. Developmental gene loci have novel roles in Polycomb spreading, emerging as key architectural elements of the epigenome.
2022-05-13 | GSE196526 | GEO
Project description:Heterochromatin spreading, the expansion of gene-silencing structures from DNA-encoded nucleation sites, occurs in distinct settings. Spreading re-establishes gene-poor constitutive heterochromatin every cell cycle, but also invades gene-rich euchromatin de novo to steer cell fate decisions. How chromatin context, i.e. euchromatic, heterochromatic, or different nucleator types, influences the determinants of this process remains poorly understood. Previously, we documented distinct behaviors of heterochromatin spreading in different contexts using a single-cell heterochromatin spreading sensor (Greenstein et al. 2018). In this work, building on this sensor system, we now genetically identify the factors that positively or negatively alter the propensity of a nucleation site to spread heterochromatin. We find that different chromatin contexts are dependent on unique sets of genes for the regulation of heterochromatin spreading. Further, we find that spreading in constitutive heterochromatin requires Clr6 histone deacetylase complexes containing the Fkh2 transcription factor, while the Clr3 deacetylase is globally required for silencing. Fkh2 acts by recruiting Clr6 to nucleation-distal chromatin sites. Our results segregate the pathways that control lateral heterochromatin spreading from those that instruct DNA-directed assembly in nucleation.
2021-09-24 | GSE184379 | GEO