Project description:Nucleosomes are decorated with numerous post-translational modifications capable of influencing many DNA processes. Here, we describe a new class of modification, methylation of glutamine, occurring on yeast histone H2A at position 105 (Q105) and human H2A at Q104. We identify Nop1 as the methyltransferase in yeast and we demonstrate that Fibrillarin is the equivalent enzyme in human cells. Glutamine methylation of H2A is restricted to the nucleolus. Global analysis in yeast, using a H2AQ105me specific antibody, show that this modification is exclusively enriched over the 35S rDNA transcriptional unit. We show that the Q105 residue is part of the binding site for the histone chaperone FACT (Facilitator of Transcription) complex. Methylation of Q105 or its substitution to alanine disrupts binding to FACT in vitro. A yeast strain mutated at Q105 exhibits a defect in histone incorporation and shows increased transcription at rDNA genes. This defect is phenocopied by mutations in FACT that decrease its activity. Together these data identify glutamine methylation of H2A as the first histone epigenetic mark dedicated to a specific RNA polymerase and define its function as a regulator of FACT interaction with nucleosomes.
Project description:Nucleosomes are decorated with numerous post-translational modifications capable of influencing many DNA processes. Here we describe a new class of histone modification, methylation of glutamine, occurring on yeast histone H2A at position 105 (Q105) and human H2A at Q104. We identify Nop1 as the methyltransferase in yeast and demonstrate that fibrillarin is the orthologue enzyme in human cells. Glutamine methylation of H2A is restricted to the nucleolus. Global analysis in yeast, using an H2AQ105me-specific antibody, shows that this modification is exclusively enriched over the 35S ribosomal DNA transcriptional unit. We show that the Q105 residue is part of the binding site for the histone chaperone FACT (facilitator of chromatin transcription) complex. Methylation of Q105 or its substitution to alanine disrupts binding to FACT in vitro. A yeast strain mutated at Q105 shows reduced histone incorporation and increased transcription at the ribosomal DNA locus. These features are phenocopied by mutations in FACT complex components. Together these data identify glutamine methylation of H2A as the first histone epigenetic mark dedicated to a specific RNA polymerase and define its function as a regulator of FACT interaction with nucleosomes.
Project description:Chromatin landscapes are disrupted during DNA replication and must be restored faithfully to maintain genome regulation and cell identity. The H3-H4 modification landscape is restored by parental histone recycling and post-replication modification of new histone H3-H4. How DNA replication impact on histone H2A-H2B is unknown. Here, we track H2A-H2B modifications and H2A.Z during DNA replication and across the cell cycle using quantitative genomics. We show that H2AK119ub, H2BK120ub, and H2A.Z are recycled quantitatively and accurately during DNA replication. H2A-H2B are recycled symmetrically to daughter strands largely independent of known H3-H4 recycling pathways. Post-replication, H2A-H2B modifications are rapidly restored, and the rapid wave of H2AK119ub supports accurate restoration of H3K27me3. This work reveals epigenetic transmission of H2A-H2B modification during DNA replication and identifies H3-H4 and H2A-H2B crosstalk in epigenome propagation. We propose that rapid short-term memory of recycled H2A-H2B modifications facilitates reestablishment of slow, long-term chromatin state memory.
Project description:Chromatin landscapes are disrupted during DNA replication and must be restored faithfully to maintain genome regulation and cell identity. The H3-H4 modification landscape is restored by parental histone recycling and post-replication modification of new histone H3-H4. How DNA replication impact on histone H2A-H2B is unknown. Here, we track H2A-H2B modifications and H2A.Z during DNA replication and across the cell cycle using quantitative genomics. We show that H2AK119ub, H2BK120ub, and H2A.Z are recycled quantitatively and accurately during DNA replication. H2A-H2B are recycled symmetrically to daughter strands largely independent of known H3-H4 recycling pathways. Post-replication, H2A-H2B modifications are rapidly restored, and the rapid wave of H2AK119ub supports accurate restoration of H3K27me3. This work reveals epigenetic transmission of H2A-H2B modification during DNA replication and identifies H3-H4 and H2A-H2B crosstalk in epigenome propagation. We propose that rapid short-term memory of recycled H2A-H2B modifications facilitates reestablishment of slow, long-term chromatin state memory.
Project description:Chromatin landscapes are disrupted during DNA replication and must be restored faithfully to maintain genome regulation and cell identity. The H3-H4 modification landscape is restored by parental histone recycling and post-replication modification of new histone H3-H4. How DNA replication impact on histone H2A-H2B is unknown. Here, we track H2A-H2B modifications and H2A.Z during DNA replication and across the cell cycle using quantitative genomics. We show that H2AK119ub, H2BK120ub, and H2A.Z are recycled quantitatively and accurately during DNA replication. H2A-H2B are recycled symmetrically to daughter strands largely independent of known H3-H4 recycling pathways. Post-replication, H2A-H2B modifications are rapidly restored, and the rapid wave of H2AK119ub supports accurate restoration of H3K27me3. This work reveals epigenetic transmission of H2A-H2B modification during DNA replication and identifies H3-H4 and H2A-H2B crosstalk in epigenome propagation. We propose that rapid short-term memory of recycled H2A-H2B modifications facilitates reestablishment of slow, long-term chromatin state memory.
Project description:We report genome-wide distribution of O-GlcNAcylated H2A at serine 40 (H2A-S40Gc) in mouse trophoblast stem cells (TSCs). We found that H2A-S40Gc was mainly located at genic area, positively correlated with the gene expression, and varied the localization during their differentiation. This study using ChIP-seq analysis provides genomic distribution of newly O-GlcNAc histone modification.
Project description:The TRIM37 gene is mutatedin Mulbery nanism, a rare autosomal recessive disorder, and is in the 17q23 chromosomal region that is amplified in up to ~40% of breast cancers. Trim37 contains a RING finger domain, a hallmark of E3 ubiquitin ligases, but the protein substrate(s) of Trim37 is unknown. Mono-ubiquitination of histone H2A is a chromatin modification associated with transcriptional repression and here we report that Trim37 is an H2A ubiquitin ligase. Genome-wide Chip-CHIP experiments indicate that in human breast cancer cells containing amplified 17q23, Trim37 is bound to the promoters of many tumor suppressor genes. RNA interference (RNAi)-mediated knockdown of Trim37 results in loss of ubiquitinated H2A, dissociation of PRC1 and PRC2, and transcriptional reactivation of silenced genes. Knockdown of Trim37 in human breast cancer cells containing amplified 17q23 substantially decreases tumor growth in mouse xenografts. Collectively, our results reveal Trim37 as a new H2A ubiquitin ligase that is overexpressed in a subset of breast cancers and redirects PRC2 to silence tumor suppressors and other genes resulting in oncogenesis. Identification of TRIM37 Binding targets in MCF7 cells from the two replicate experiments
Project description:Total RNA from three replicate cultures of wild-type and mutant strains was isolated and the expression profiles were determined using Affymetrix arrays. Comparisons between the sample groups allow the identification of genes regulated by the histone H2A K4,7G mutant. Keywords: histone H2A mutant, repeat
Project description:Chromatin landscapes are disrupted during DNA replication and need to be restored faithfully to maintain appropriate gene expression, including post-translational modifications (PTMs) of newly deposited histones. Whether histones H2A-H2B are accurately recycled during DNA replication and the behaviour of their associated marks during and post replication is unknown. Here we comprehensively map key modifications on H2A-H2B including H2A.Z during DNA replication. We show that H2AK119ub, H2BK120ub, and H2A.Z are recycled quantitatively and accurately during DNA replication in a symmetrical manner. Recycling occurs independently from H3-H4 chaperone pathways apart from a minor role for Polymerase alpha. H2A-H2B modifications are restored rapidly post replication and are important for timely and accurate restoration of H3-H4 marks, such as H3K27me3. This work uncovers H3-H4 and H2A-H2B crosstalk in epigenome propagation across DNA replication and suggests a model where rapid short-term memory of recycled H2A-H2B marks facilitates reestablishment of slow, long-term memory chromatin states.