Similar Datasets
Project description:Using a recently established histone turnover sensor, we measured the genome-wide H3 turnover during S-phase in S.cerevisiae.
2022-02-18 | GSE193044 | GEO
Project description:Eviction of histones from nucleosomes and their exchange with newly synthesized or alternative variants is a central mechanism shaping the epigenome. Here, we implemented a recently established sensor system that enables measuring genome-wide incorporation and exchange of canonical and non-canonical histone variants in mouse embryonic stem cells. While exchange of all measured variants scales with transcription, variant-specific patterns are associated with transcription elongation and Polycomb binding. We found considerable exchange rates of canonical H3.1 and H2B in heterochromatin and repeat elements where non-canonical H3.3 is stably incorporated but not exchanged. This unexpected association between H3.3 incorporation and the exchange of H3.1 and H2B is also evident in active promoters and enhancers, which we validated using HIRA knockout cells harboring the sensor system. The sensor system provides a powerful experimental framework with quantitative readout, facilitating functional studies of histone dynamics and epigenetic gene regulation in vivo.
2023-05-24 | GSE213076 | GEO
Project description:Regulators of histone exchange
| PRJNA927495 | ENA
Project description:Oncohistone mutations are crucial drivers for tumorigenesis, but how a living organism responds to and governs the loss-of-function oncohistone remains unclear. Here, we generated a histone H2B triple knockout (3KO) strain in Caenorhabditis elegans, which decreased the embryonic H2B level, disrupted cell divisions, and caused animal sterility. Our genetic screens identified mutations defective in a histone H3-H4 chaperone UNC-85 as suppressors that recovered H2B 3KO fertility. We found that unc-85 mutations reduced chromatin H3-H4 levels and that inhibiting other H3-H4 chaperones or H3-H4 histones also rescued H2B 3KO sterility. The oncohistone H2BE76K mutation disrupts the H2B-H4 interface and causes nucleosome instability, and we showed that blocking H3-H4 chaperones restored cell division defects in C. elegans or human cells carrying H2BE76K. Thus, our results indicate that reducing chromatin H3-H4 rescues H2B loss and suggest that inhibiting H3-H4 chaperones may be a therapeutic strategy to treat cancers resulting from loss-of-function H2B oncohistone.
2022-04-03 | GSE185582 | GEO
Project description:Histone variant H2A.Z is found at promoters and regulates transcription. The ATP-dependent chromatin remodeler SRCAP complex (SRCAP-C) promotes the replacement of canonical histone H2A-H2B dimer with H2A.Z-H2B dimer. Here, we determined structures of human SRCAP-C bound to H2A-containing nucleosome at near-atomic resolution. The SRCAP subunit integrates a 6-subunit actin-related protein (ARP) module and an ATPase-containing motor module. The ATPase-associated ARP module encircles half of the nucleosome along the DNA and may restrain net DNA translocation, a unique feature of SRCAP-C. The motor module adopts distinct nucleosome-binding modes in the apo (nucleotide-free), ADP-bound, and ADP-BeFx-bound states, suggesting that ATPase-driven movement destabilizes H2A-H2B by unwrapping the entry DNA and pulls H2A-H2B out of nucleosome through the ZNHIT1 subunit. Structure-guided chromatin immunoprecipitation (ChIP) sequencing analysis confirmed the requirement of H2A-contacting ZNHIT1 in maintaining H2A.Z occupancy on the genome. Our study provides structural insights into the mechanism of H2A-H2A.Z exchange mediated by SRCAP-C.
2024-02-10 | GSE249825 | GEO
Project description:Histone acetylation is important for the activation of gene transcription but little is known about its direct ‘read/write’ mechanisms. Here, we report cryo-electron microscopy structures in which a p300/CBP multidomain monomer recognizes histone H4 N-terminal tail (NT) acetylation (ac) in a nucleosome and acetylates non-H4 histone NTs within the same nucleosome. p300/CBP not only recognized H4NTac via the bromodomain pocket responsible for ‘reading’, but also interacted with the DNA minor grooves via the outside of that pocket. This directed the catalytic center of p300/CBP to one of the non-H4 histone NTs. The primary target that p300 ‘writes’ by ‘reading’ H4NTac was H2BNT, and H2BNTac promoted H2A-H2B dissociation from the nucleosome. We propose a model in which p300/CBP ‘replicates’ histone NT acetylation within the H3-H4 tetramer to inherit epigenetic storage, and ‘transcribes’ it from the H3-H4 tetramer to the H2B-H2A dimers to activate context-dependent gene transcription through local nucleosome destabilization.
2023-05-08 | PXD040835 | Pride
Project description:Chd proteins are ATP-dependent chromatin remodeling enzymes implicated in biological functions from transcriptional elongation to control of pluripotency. Here, we examine roles of Chd1 in replication- independent dynamics of histone H3 in yeast. Using genome-wide ChIP on chip analysis, we find that Chd1 influences histone turnover at the 5M-bM-^@M-^Y and 3M-bM-^@M-^Y ends of genes, accelerating H3 replacement at the 5M-bM-^@M-^Y ends of genes while protecting the 3M-bM-^@M-^Y ends of genes from excessive H3 turnover. Although consistent with a direct role for Chd1 in exchange, these results may indicate that Chd1 stabilizes nucleosomes perturbed by transcription. Curiously, we observe a strong effect of gene length on Chd1M-bM-^@M-^Ys effects on H3 turnover. Finally, we show that Chd1 also affects histone H3K4 and H3K36 methylation patterns over genes, likely as a consequence of its effects on histone replacement. In control experiments, we measure effects of deletion of CHD1 on RNA polymerase II distribution across the genome and on gene expression. We also examine the effect of deleting the TOP1 gene, alone and in combination with deletion of CHD1, on histone replacement. Taken together, our results emphasize a role for Chd1 in histone replacement in both budding yeast and Drosophila, and surprisingly show that the major effects of Chd1 on turnover occur at the 3M-bM-^@M-^Y ends of genes. ChIP on chip experiments, compares IP of newly expressed, Flag-tagged histone H3 to total histone H3.
2012-06-07 | E-GEOD-38491 | biostudies-arrayexpress
Project description:Nucleosome composition actively contribute to the chromatin structure and accessibility. To preserve chromatin state during replication, transcription and DNA repair, cells have evolved mechanisms to evict or recycle histones, generating a landscape of differentially aged nucleosomes. To map the stability of nucleosomes, we have adapted the recombination induced tag exchange (RITE) method to Schizosaccharomyces pombe histone H3. The RITE method allows us to study replication-independent protein turnover both through the occurrence of, in our case, new histone H3 and the disappearance or preservation of old histone H3. We contrast the RITE system to nucleosome turnover measured by chromatin incorporation of an epitope-tagged H3 under an inducible promoter. We confirm previous findings that stable nucleosomes are found at heterochromatin, but also at coding regions of actively transcribed genes. Genome-wide comparisons with several chromatin marks showed that high turnover nucleosomes correlate with H2A.Z, acetylated H4 and H3K4me2. The histones with high turnover are primarily found at the nucleosomes on the 5´and/or 3´ edges of the transcribed unit. In addition, in this study we have determined genome-wide maps of all three methylation marks at H4K20. All methylation of H4K20 appeared in low turnover nucleosomes and particularly in euchromatic regions. H4K20me1 marks stable nucleosomes at loci proximal to nucleosome depleted regions (NDR) and H4K20me2/3 were found further inside of transcribed units, especially at coding regions of long genes expressed at low levels. Further, this transcription-dependent accumulation of histone methylations was dependent on the histone chaperone complex FACT (Facilitates Chromatin Transcription), as predicited from its role in recycling nucleosomes during transcription.
2015-03-06 | GSE59461 | GEO
Project description:Nucleosome composition actively contribute to the chromatin structure and accessibility. To preserve chromatin state during replication, transcription and DNA repair, cells have evolved mechanisms to evict or recycle histones, generating a landscape of differentially aged nucleosomes. To map the stability of nucleosomes, we have adapted the recombination induced tag exchange (RITE) method to Schizosaccharomyces pombe histone H3. The RITE method allows us to study replication-independent protein turnover both through the occurrence of, in our case, new histone H3 and the disappearance or preservation of old histone H3. We contrast the RITE system to nucleosome turnover measured by chromatin incorporation of an epitope-tagged H3 under an inducible promoter. We confirm previous findings that stable nucleosomes are found at heterochromatin, but also at coding regions of actively transcribed genes. Genome-wide comparisons with several chromatin marks showed that high turnover nucleosomes correlate with H2A.Z, acetylated H4 and H3K4me2. The histones with high turnover are primarily found at the nucleosomes on the 5´and/or 3´ edges of the transcribed unit. In addition, in this study we have determined genome-wide maps of all three methylation marks at H4K20. All methylation of H4K20 appeared in low turnover nucleosomes and particularly in euchromatic regions. H4K20me1 marks stable nucleosomes at loci proximal to nucleosome depleted regions (NDR) and H4K20me2/3 were found further inside of transcribed units, especially at coding regions of long genes expressed at low levels. Further, this transcription-dependent accumulation of histone methylations was dependent on the histone chaperone complex FACT (Facilitates Chromatin Transcription), as predicited from its role in recycling nucleosomes during transcription.
2015-03-13 | GSE66865 | GEO
Project description:In Penicillium oxalicum, histone H2B (PDE_01489) was one of the interacting proteins with the methyltransferase LaeA. It suggests that histone H2B may be a direct target of LaeA/Lae1. To verify whether histone H2B is one of the LaeA targets, an in vitro catalytic experiment was performed using Homo sapiens recombinant histone H2B (HsH2B, expressed in Escherichia coli, without histone modification), SAM as substrates, and LaeA. The products were analyzed by LC-MS/MS for histone modifications. Results showed that the mono and di-methylation of lysine 108 and the mono-methylation of lysine 116 were detected.
2021-07-08 | PXD027171 |