Project description:Polycomb group (PcG) proteins assemble into chromatin modifying complexes that regulate stem cell identity and multicellular development. The trimethylation of lysine 27 on histone H3 (H3K27me3) is catalyzed by the conserved Polycomb Repressive Complex 2 (PRC2). In Neurospora crassa, the typically-subtelomeric pattern of H3K27me3 depends on other chromatin regulators including the H3K36 methyltransferase ASH1, the chromatin remodeling enzyme IMITATION SWITCH, and components of constitutive heterochromatin including the H3K9 methyltransferase DEFECTIVE IN METHYLATION-5 (DIM-5) and the H3K9me3-binding protein HETEROCHROMATIN PROTEIN 1 (HP1). How constitutive heterochromatin impacts PRC2 activity is unclear. We performed a genetic screen to identify histone deacetylase genes required to repress PRC2-methylated genes in N. crassa. We found that HISTONE DEACETYLASE-1 (HDA-1) is required for transcriptional repression in PcG-repressed domains and for normal patterns of H3K27me3. In the absence of HDA-1, H3K27me3 is lost from typical PRC2-methylated domains and instead is enriched at a subset of constitutive heterochromatin domains normally marked for H3K9me3. In addition to altered H3K27me3 patterns, HDA-1-deficient mutants displayed aberrant patterns of H3K9me3, H3K36me3, and lysine acetylation (Kac). Mutants lacking the HP1/HDA-1-interacting protein CHROMO DOMAIN PROTEIN-2 (CDP-2) displayed a similar but non-identical phenotype, and we observed variable patterns of aberrant H3K7me3 enrichment in genetically identical ∆hda-1 strains, raising the possibility that loss of HDA-1 activity leads to progressive changes in H3K27me3 enrichment. Indeed, a newly constructed ∆hda-1 deletion strain displayed a near-wild type H3K27me3 chromatin modification profile that decayed over multiple strain passages corresponding to hundreds of nuclear divisions. Together, our data indicate that HDA-1 is a critical regulator of epigenome stability in N. crassa.
Project description:Polycomb group (PcG) proteins assemble into chromatin modifying complexes that regulate stem cell identity and multicellular development. The trimethylation of lysine 27 on histone H3 (H3K27me3) is catalyzed by the conserved Polycomb Repressive Complex 2 (PRC2). In Neurospora crassa, the typically-subtelomeric pattern of H3K27me3 depends on other chromatin regulators including the H3K36 methyltransferase ASH1, the chromatin remodeling enzyme IMITATION SWITCH, and components of constitutive heterochromatin including the H3K9 methyltransferase DEFECTIVE IN METHYLATION-5 (DIM-5) and the H3K9me3-binding protein HETEROCHROMATIN PROTEIN 1 (HP1). How constitutive heterochromatin impacts PRC2 activity is unclear. We performed a genetic screen to identify histone deacetylase genes required to repress PRC2-methylated genes in N. crassa. We found that HISTONE DEACETYLASE-1 (HDA-1) is required for transcriptional repression in PcG-repressed domains and for normal patterns of H3K27me3. In the absence of HDA-1, H3K27me3 is lost from typical PRC2-methylated domains and instead is enriched at a subset of constitutive heterochromatin domains normally marked for H3K9me3. In addition to altered H3K27me3 patterns, HDA-1-deficient mutants displayed aberrant patterns of H3K9me3, H3K36me3, and lysine acetylation (Kac). Mutants lacking the HP1/HDA-1-interacting protein CHROMO DOMAIN PROTEIN-2 (CDP-2) displayed a similar but non-identical phenotype, and we observed variable patterns of aberrant H3K7me3 enrichment in genetically identical ∆hda-1 strains, raising the possibility that loss of HDA-1 activity leads to progressive changes in H3K27me3 enrichment. Indeed, a newly constructed ∆hda-1 deletion strain displayed a near-wild type H3K27me3 chromatin modification profile that decayed over multiple strain passages corresponding to hundreds of nuclear divisions. Together, our data indicate that HDA-1 is a critical regulator of epigenome stability in N. crassa.
Project description:Polycomb group proteins assemble into chromatin modifying complexes that regulate stem cell identity and multicellular development. The trimethylation of lysine 27 on histone H3 (H3K27me3) is catalyzed by the conserved Polycomb Repressive Complex 2 (PRC2). In Neurospora crassa, the typically-subtelomeric pattern of H3K27me3 depends on other chromatin regulators including the H3K36 methyltransferase ASH1, the chromatin remodeling enzyme IMITATION SWITCH, and components of constitutive heterochromatin including the H3K9 methyltransferase DEFECTIVE IN METHYLATION-5 and the H3K9me3-binding protein HETEROCHROMATIN PROTEIN 1 (HP1). How constitutive heterochromatin impacts PRC2 activity is unclear. HP1 forms multiple protein complexes including the HCHC complex, which removes acetyl groups from histones in constitutive heterochromatin, and contains the proteins Histone Deacetylase 1(HDA-1) and Chromodomain Protein-2 (CDP-2). To identify genes required for Polycomb repression in N. crassa, we performed a genetic screen and identified HDA-1 as necessary for PRC2-targeted gene silencing. In the absence of HDA-1, H3K27me2/3 is lost from the subtelomeres and aberrantly accumulates at constitutive heterochromatin domains normally enriched for H3K9me3; CDP-2 is also important for wildtype H3K27me3 localization. The H3K27me2/3 redistribution in Δhda-1 or Δcdp-2 strains is variable and incomplete, and mutant progeny obtained following a sexual cross displayed wild-type H3K27me3 patterns, consistent with HCHC loss leading to progressive changes in H3K27me3 enrichment. Indeed, a newly constructed ∆hda-1 deletion strain displays a wild-type H3K27me3 pattern that relocalizes to constitutive heterochromatic regions after sequential passages. Thus, HCHC-specific deacetylation prevents aberrant recruitment of PRC2 to constitutive heterochromatin.
Project description:Polycomb group proteins assemble into chromatin modifying complexes that regulate stem cell identity and multicellular development. The trimethylation of lysine 27 on histone H3 (H3K27me3) is catalyzed by the conserved Polycomb Repressive Complex 2 (PRC2). In Neurospora crassa, the typically-subtelomeric pattern of H3K27me3 depends on other chromatin regulators including the H3K36 methyltransferase ASH1, the chromatin remodeling enzyme IMITATION SWITCH, and components of constitutive heterochromatin including the H3K9 methyltransferase DEFECTIVE IN METHYLATION-5 and the H3K9me3-binding protein HETEROCHROMATIN PROTEIN 1 (HP1). How constitutive heterochromatin impacts PRC2 activity is unclear. HP1 forms multiple protein complexes including the HCHC complex, which removes acetyl groups from histones in constitutive heterochromatin, and contains the proteins Histone Deacetylase 1(HDA-1) and Chromodomain Protein-2 (CDP-2). To identify genes required for Polycomb repression in N. crassa, we performed a genetic screen and identified HDA-1 as necessary for PRC2-targeted gene silencing. In the absence of HDA-1, H3K27me2/3 is lost from the subtelomeres and aberrantly accumulates at constitutive heterochromatin domains normally enriched for H3K9me3; CDP-2 is also important for wildtype H3K27me3 localization. The H3K27me2/3 redistribution in Δhda-1 or Δcdp-2 strains is variable and incomplete, and mutant progeny obtained following a sexual cross displayed wild-type H3K27me3 patterns, consistent with HCHC loss leading to progressive changes in H3K27me3 enrichment. Indeed, a newly constructed ∆hda-1 deletion strain displays a wild-type H3K27me3 pattern that relocalizes to constitutive heterochromatic regions after sequential passages. Thus, HCHC-specific deacetylation prevents aberrant recruitment of PRC2 to constitutive heterochromatin.
Project description:This SuperSeries is composed of the following subset Series: GSE33596: Histone Deacetylase 3 is an Epigenomic Brake in Macrophage Alternative Activation (ChIP-Seq) GSE33608: Histone Deacetylase 3 is an Epigenomic Brake in Macrophage Alternative Activation (microarray) Refer to individual Series
Project description:Macrophages, a key cellular component of inflammation, become functionally polarized in a signal- and context-specific manner. Th2 cytokines such as IL-4 polarize macrophages to a state of alternative activation that limits inflammation and promotes wound healing. Alternative activation is mediated by a transcriptional program that is influenced by epigenomic modifications including histone acetylation. To determine if Histone Deacetylase 3 (HDAC3) has a role in macrophage polarization including alternative activation, we have performed global gene expression analysis in macrophages with and without HDAC3 and with or without IL-4 exposure. From this data, we conclude that macrophages lacking histone deacetylase 3 (HDAC3) display a polarization phenotype similar to IL-4 induced alternative activation and furthermore are hyper-responsive to IL-4 stimulation. Mouse bone marrow derived macrophages were obtained from both control and HDAC3 KO animals and treated with vehicle control (BSA) or IL-4 for 24 hours. RNA was isolated and subjected to analysis using an Agilent Whole Genome Microarray Kit.