BAHD1 couples H3K27me3 to gene silencing via a conserved BAH reader module and associated corepressor complex in mammals (CUT&RUN)
Ontology highlight
ABSTRACT: Trimethylation of histone H3 lysine 27 (H3K27me3) is crucially involved for gene silencing, (epi)genome organization, cell-fate decision-making and development. To date, functional readout of H3K27me3 is viewed to be achieved mainly through a class of H3K27me3-recognizing chromodomains harbored within the chromobox (CBX) subunit of Polycomb repressive complex 1 (PRC1), which causes chromatin compaction and gene repression partly through histone H2A lysine 119 mono-ubiquitination. We here report that engagement of H3K27me3 by an evolutionarily conserved bromo adjacent homology (BAH) domain harbored within BAH domain-containing protein 1 (BAHD1) significantly contributes to optimal repression of the H3K27me3-demarcated genes in mammalian cells. BAHD1 assembles a NurD-like transcriptional corepressor complex. Abolishing the BAHD1BAH:H3K27me3 interaction by point mutagenesis interferes with BAHD1 binding to chromatin, leading to chromatin remodeling and derepression of Polycomb target genes. Mice carrying an H3K27me3-binding-defective mutation of Bahd1BAH causes marked embryonic lethality, indicating a requirement of this pathway for development. Altogether, this work demonstrates an H3K27me3-initiated signaling cascade that operates through a conserved BAH ‘reader’ module class in mammals.
Project description:Trimethylation of histone H3 lysine 27 (H3K27me3) is crucially involved for gene silencing, (epi)genome organization, cell-fate decision-making and development. To date, functional readout of H3K27me3 is viewed to be achieved mainly through a class of H3K27me3-recognizing chromodomains harbored within the chromobox (CBX) subunit of Polycomb repressive complex 1 (PRC1), which causes chromatin compaction and gene repression partly through histone H2A lysine 119 mono-ubiquitination. We here report that engagement of H3K27me3 by an evolutionarily conserved bromo adjacent homology (BAH) domain harbored within BAH domain-containing protein 1 (BAHD1) significantly contributes to optimal repression of the H3K27me3-demarcated genes in mammalian cells. BAHD1 assembles a NurD-like transcriptional corepressor complex. Abolishing the BAHD1BAH:H3K27me3 interaction by point mutagenesis interferes with BAHD1 binding to chromatin, leading to chromatin remodeling and derepression of Polycomb target genes. Mice carrying an H3K27me3-binding-defective mutation of Bahd1BAH causes marked embryonic lethality, indicating a requirement of this pathway for development. Altogether, this work demonstrates an H3K27me3-initiated signaling cascade that operates through a conserved BAH ‘reader’ module class in mammals.
Project description:Trimethylation of histone H3 lysine 27 (H3K27me3) is crucially involved for gene silencing, (epi)genome organization, cell-fate decision-making and development. To date, functional readout of H3K27me3 is viewed to be achieved mainly through a class of H3K27me3-recognizing chromodomains harbored within the chromobox (CBX) subunit of Polycomb repressive complex 1 (PRC1), which causes chromatin compaction and gene repression partly through histone H2A lysine 119 mono-ubiquitination. We here report that engagement of H3K27me3 by an evolutionarily conserved bromo adjacent homology (BAH) domain harbored within BAH domain-containing protein 1 (BAHD1) significantly contributes to optimal repression of the H3K27me3-demarcated genes in mammalian cells. BAHD1 assembles a NurD-like transcriptional corepressor complex. Abolishing the BAHD1BAH:H3K27me3 interaction by point mutagenesis interferes with BAHD1 binding to chromatin, leading to chromatin remodeling and derepression of Polycomb target genes. Mice carrying an H3K27me3-binding-defective mutation of Bahd1BAH causes marked embryonic lethality, indicating a requirement of this pathway for development. Altogether, this work demonstrates an H3K27me3-initiated signaling cascade that operates through a conserved BAH ‘reader’ module class in mammals.
Project description:Trimethylation of histone H3 lysine 27 (H3K27me3) is important for gene silencing, (epi)genome organization and organismal development. In a prevalent model, the functional “readout” of H3K27me3 in mammalian cells is achieved through the H3K27me3-recognizing chromodomain harbored within the chromobox (CBX) component of canonical Polycomb repressive complex 1 (cPRC1), which induces chromatin compaction and gene repression. Here, we report that binding of H3K27me3 by a Bromo Adjacent Homology (BAH) domain harbored within BAH domain-containing protein 1 (BAHD1) is required for overall BAHD1 targeting to chromatin and for optimal repression of the H3K27me3-demarcated genes in mammalian cells. Disruption of direct interaction between BAHD1-BAH and H3K27me3 by point mutagenesis leads to chromatin remodeling, notably, increased histone acetylation, at its Polycomb gene targets. Mice carrying an H3K27me3-interaction-defective mutation of Bahd1BAH causes marked embryonic lethality, showing a requirement of this pathway for normal development. Altogether, this work demonstrates an H3K27me3-initiated signaling cascade that operates through a conserved BAH “reader” module within BAHD1 in mammals.
Project description:The Polycomb Repressive Complex 2 (PRC2) and its trimethylation of histone H3 at lysine 27 (H3K27me3) control gene silencing, genome organization, cell-fate determination, as well as normal and pathological development. To date, functional transduction of H3K27me3 is believed to be achieved through the H3K27me3-‘recognizing’ chromodomain harbored within the chromobox (CBX) subunit of Polycomb Repressive Complex 1 (PRC1), which mediates gene silencing partly through H2A monoubiquitination. Here, we report a novel H3K27me3-readout mechanism in mammal, which utilizes an evolutionarily conserved Bromo-adjacent homology (BAH) domain of BAHCC1 (BAH domain and Coiled-Coil Containing 1) for silencing polycomb gene targets. Biochemical, structural and chromatin-immunoprecipitation followed by sequencing (ChIP-seq) analyses revealed that the BAH domain of BAHCC1 specifically engage H3K27me3 through a hydrophobic trimethyl-lysine-binding cage and multiple intermolecular interactions to its flanking residues, mediating co-localization of BAHCC1 with H3K27me3-marked genomic regions in cells. Additionally, we find that BAHCC1 is overexpressed in several human leukemia subtypes including T-cell acute lymphoblastic leukemia (T-ALL), and interacts with transcriptional repressors SAP30-binding protein (SAP30BP) and histone deacetylase 1 (HDAC1). BAHCC1 loss, or disrupting the BAH-mediated interaction of BAHCC1 with H3K27me3 via structure-based mutagenesis, causes chromatin remodeling at the H3K27me3-targeted loci and reactivates polycomb-related gene-silencing programs intimately associated with tumor suppression and cell differentiation, which leads to significantly suppressed T-ALL tumor growth in vitro and in vivo.
Project description:Tri-methylation of histone H3 lysine 27 (H3K27me3) regulates transcriptional repression, cell-fate determination and differentiation. We report that a conserved Bromo-Adjacent Homology (BAH) module harbored within BAHCC1, a previously uncharacterized chromatin regulator, ‘recognizes’ H3K27me3 specifically and enforces silencing of H3K27me3-demarcated genes in mammalian cells. Biochemical, structural and ChIP-seq-based analyses demonstrate that direct ‘readout’ of H3K27me3 by BAHCC1 is achieved through a hydrophobic trimethyl-lysine-binding ‘cage’ formed by the BAH domain, mediating co-localization of BAHCC1 and H3K27me3-marked genes. BAHCC1 is significantly overexpressed in human acute leukemia and biochemically, BAHCC1 interacts with repressors SAP30BP and HDAC. In acute leukemia, depletion of BAHCC1, or disruption of the BAHCC1 BAH-mediated ‘readout’ of H3K27me3, causes de-repression of H3K27me3-targeted genes that are involved in tumor suppression and cell differentiation, leading to the suppressed tumor growth. In mice, introduction of a germ-line mutation at Bahcc1 to disrupt its H3K27me3 engagement causes postnatal lethality, supporting a role of this pathway in development. Collectively, this study unveils a novel H3K27me3-directed transduction pathway in mammal cells that relies on a conserved BAH ‘reader’, deregulation of which contributes to oncogenesis.
Project description:Tri-methylation of histone H3 lysine 27 (H3K27me3) regulates transcriptional repression, cell-fate determination and differentiation. We report that a conserved Bromo-Adjacent Homology (BAH) module harbored within BAHCC1, a previously uncharacterized chromatin regulator, ‘recognizes’ H3K27me3 specifically and enforces silencing of H3K27me3-demarcated genes in mammalian cells. Biochemical, structural and ChIP-seq-based analyses demonstrate that direct ‘readout’ of H3K27me3 by BAHCC1 is achieved through a hydrophobic trimethyl-lysine-binding ‘cage’ formed by the BAH domain, mediating co-localization of BAHCC1 and H3K27me3-marked genes. BAHCC1 is significantly overexpressed in human acute leukemia and biochemically, BAHCC1 interacts with repressors SAP30BP and HDAC. In acute leukemia, depletion of BAHCC1, or disruption of the BAHCC1 BAH-mediated ‘readout’ of H3K27me3, causes de-repression of H3K27me3-targeted genes that are involved in tumor suppression and cell differentiation, leading to the suppressed tumor growth. In mice, introduction of a germ-line mutation at Bahcc1 to disrupt its H3K27me3 engagement causes postnatal lethality, supporting a role of this pathway in development. Collectively, this study unveils a novel H3K27me3-directed transduction pathway in mammal cells that relies on a conserved BAH ‘reader’, deregulation of which contributes to oncogenesis.
Project description:Tri-methylation of histone H3 lysine 27 (H3K27me3) regulates transcriptional repression, cell-fate determination and differentiation. We report that a conserved Bromo-Adjacent Homology (BAH) module harbored within BAHCC1, a previously uncharacterized chromatin regulator, ‘recognizes’ H3K27me3 specifically and enforces silencing of H3K27me3-demarcated genes in mammalian cells. Biochemical, structural and ChIP-seq-based analyses demonstrate that direct ‘readout’ of H3K27me3 by BAHCC1 is achieved through a hydrophobic trimethyl-lysine-binding ‘cage’ formed by the BAH domain, mediating co-localization of BAHCC1 and H3K27me3-marked genes. BAHCC1 is significantly overexpressed in human acute leukemia and biochemically, BAHCC1 interacts with repressors SAP30BP and HDAC. In acute leukemia, depletion of BAHCC1, or disruption of the BAHCC1 BAH-mediated ‘readout’ of H3K27me3, causes de-repression of H3K27me3-targeted genes that are involved in tumor suppression and cell differentiation, leading to the suppressed tumor growth. In mice, introduction of a germ-line mutation at Bahcc1 to disrupt its H3K27me3 engagement causes postnatal lethality, supporting a role of this pathway in development. Collectively, this study unveils a novel H3K27me3-directed transduction pathway in mammal cells that relies on a conserved BAH ‘reader’, deregulation of which contributes to oncogenesis.
Project description:Tri-methylation of histone H3 lysine 27 (H3K27me3) regulates transcriptional repression, cell-fate determination and differentiation. We report that a conserved Bromo-Adjacent Homology (BAH) module harbored within BAHCC1, a previously uncharacterized chromatin regulator, ‘recognizes’ H3K27me3 specifically and enforces silencing of H3K27me3-demarcated genes in mammalian cells. Biochemical, structural and ChIP-seq-based analyses demonstrate that direct ‘readout’ of H3K27me3 by BAHCC1 is achieved through a hydrophobic trimethyl-lysine-binding ‘cage’ formed by the BAH domain, mediating co-localization of BAHCC1 and H3K27me3-marked genes. BAHCC1 is significantly overexpressed in human acute leukemia and biochemically, BAHCC1 interacts with repressors SAP30BP and HDAC. In acute leukemia, depletion of BAHCC1, or disruption of the BAHCC1 BAH-mediated ‘readout’ of H3K27me3, causes de-repression of H3K27me3-targeted genes that are involved in tumor suppression and cell differentiation, leading to the suppressed tumor growth. In mice, introduction of a germ-line mutation at Bahcc1 to disrupt its H3K27me3 engagement causes postnatal lethality, supporting a role of this pathway in development. Collectively, this study unveils a novel H3K27me3-directed transduction pathway in mammal cells that relies on a conserved BAH ‘reader’, deregulation of which contributes to oncogenesis.
Project description:Here we utilize a forward genetics approach in Neurospora crassa to identify novel effectors of Polycomb repression. We recovered several mutant alleles of a gene (NCU07505),which we deemed effector of Polycomb repression 1 (epr-1), encoding a protein with a bromo-adjacent homology (BAH) domain and plant homeodomain (PHD) finger. Although epr-1mutants display phenotypic and gene expression changes similar to strains lacking PRC2 components, H3K27 methylation is notably unaffected. We demonstrate that EPR-1 forms nuclear foci, reminiscent of Polycomb bodies {Pirrotta:2012br}, and its genomic distribution is limited to and dependent upon H3K27-methylated chromatin, which it recognizes through its BAH domain. Finally, we discover that EPR-1 homologs are widely distributed across eukaryotes, contrary to previous reports {LopezGonzalez:2014id, Li:2018kg}, suggesting an ancient role of EPR-1 homologs in Polycomb repression that was secondarily lost in select lineages.