Project description:We performed ChIP-sequencing for both H2A.Z and H3 RITE after 4 hours in G1-arrest. In addition, we report H2A.Z and H3 ChIP-sequencing data for samples of replicating cells.
Project description:While it has been clearly established that well positioned H2A.Z-containing nucleosomes flank the nucleosome depleted region (NDR) at the transcriptional start site (TSS) of active mammalian genes, how this chromatin-based information is transmitted through the cell cycle is unknown. We show here that in trophoblast stem (TS) cells, the level of H2A.Z at promoters decreases during S phase coinciding with homotypic (H2A.Z/H2A.Z) nucleosomes flanking the TSS becoming heterotypic (H2A.Z/H2A). Surprisingly, these nucleosomes remain heterotypic at M phase. At the TSS, we identify an unstable heterotypic H2A.Z-containing nucleosome in G1 which, strikingly, is lost following DNA replication. These dynamic changes in H2A.Z at the TSS mirror a global expansion of the NDR at S and M which, unexpectedly, is unrelated to transcriptional activity. Coincident with the loss of H2A.Z at promoters, it is targeted to the centromere when mitosis begins We performed ChIP-Seq experiments (on mouse Trophoblast Stem cells arrested at G1; S and M stages of thecell cycle) using antibodies against histone variant H2A.Z and sequentional ChIP-re-ChIP-Seq experiments using H2A.Z antibody and H2A antibody in sequence. Combining those data sets with microarray gene expression expression data allowed us to see H2A.Z distribution over promoters of mouse coding genes in cell cycle dependant manner. Interestingly, Input also showed cell-cycle dependent effects, but histone H3 could be used as a cell-cycle independent normalisation factor. We also performed ChIP-seq with a CTCF pull-down to investigate its cell-cycle dependent relationship with heterochromatin.
Project description:To investigate the influence of the AtChz1A/B and ARP6 in H2A.Z incorporation, we analysed genome-wide H2A.Z density in the mutant and wild-type by ChIP-seq. We then performed H2A.Z occupancy analysis using data obtained from ChIP-seq of 3 different plants including mutants and wild-type.
Project description:To investigate the effect of the OsINO80, we analysed OsINO80 binding regions and analysed genome-wide H3, H2A, H2A.Z, H2Aub, H3K9me2, H3K4me2, H3K4me3, H3K27me3, and H3K36me3 in the mutant and WT by ChIP-seq.
Project description:After finding a QTL hotspot in a fission yeast cross of strains 968xY0036 that was apparently driven by frame shift mutation in swc5 (swc5-fs), we have determined the genome-wide occupancy of the histone variant H2AZ (PhT1). Indeed swc5 has been shown to affect H2AZ occupancy. To test the impact of swc5-fs on H2A.Z deposition, we performed genome-wide chromatin immuno-precipitation of H2A.Z coupled with deep sequencing (ChIP-seq) in the two parental strains (968, Y0036) and in a swc5 deletion strain. We also assed the histone H3 occupancy as a positive control. We generated pht1-myc tagged strains to precipitate H2AZ with Myc antibody. Several negative controls have been performed, in particular pulldowns with the non tagged strains. Results show a reduced H2A.Z occupancy at the +1 histone in both Y0036 and swc5-deletion strains.
Project description:Here we report a novel role for H2A.Z.2 (H2AFV) as a mediator of cell proliferation and sensitivity to targeted therapies in malignant melanoma. While both H2A.Z.1 and H2A.Z.2 are highly expressed in metastatic melanoma and correlate with decreased patient survival, only H2A.Z.2 deficiency results in impaired cellular proliferation of melanoma cells, which occurs via a G1/S arrest. Integrated gene expression and ChIP-seq analyses revealed that H2A.Z.2 positively regulates E2F target genes, and that such genes acquire a distinct H2A.Z occupancy signature over the promoter and gene body in metastatic melanoma cells. We further identified the BET family member BRD2 as an H2A.Z-interacting protein in melanoma cells, and demonstrate that H2A.Z.2 silencing cooperates with BET inhibition to induce cell death. Cross-linked ChIP in SKmel147 melamoma cell line for E2F1 and BRD2
Project description:Here we report a novel role for H2A.Z.2 (H2AFV) as a mediator of cell proliferation and sensitivity to targeted therapies in malignant melanoma. While both H2A.Z.1 and H2A.Z.2 are highly expressed in metastatic melanoma and correlate with decreased patient survival, only H2A.Z.2 deficiency results in impaired cellular proliferation of melanoma cells, which occurs via a G1/S arrest. Integrated gene expression and ChIP-seq analyses revealed that H2A.Z.2 positively regulates E2F target genes, and that such genes acquire a distinct H2A.Z occupancy signature over the promoter and gene body in metastatic melanoma cells. We further identified the BET family member BRD2 as an H2A.Z-interacting protein in melanoma cells, and demonstrate that H2A.Z.2 silencing cooperates with BET inhibition to induce cell death. Mononucleosomes from SK-mel147 (wt and stably expressing eGFP-H2A. eGFP-H2A.Z.1 and eGFP-H2A.Z.2) and melanocytes were isolated for ChIP with H2A.Z antibody or GFP trap beads (Chromotek).
Project description:The histone variant H2A.Z plays key roles in gene expression, DNA repair, and centromere function. H2A.Z deposition is controlled by SWR-C chromatin remodeling enzymes that catalyze the nucleosomal exchange of canonical H2A with H2A.Z. Here we report that acetylation of histone H3 lysine 56 (H3-K56Ac) alters the substrate specificity of SWR-C, leading to promiscuous dimer exchange where either H2A.Z or H2A can be exchanged from nucleosomes. This result is confirmed in vivo, where genome-wide analysis demonstrates widespread decreases in H2A.Z levels in yeast mutants with hyperacetylated H3K56. Our work also suggests that a conserved SWR-C subunit may function as a M-bM-^@M-^\lockM-bM-^@M-^] that prevents removal of H2A.Z from nucleosomes. Our study identifies a histone modification that regulates a chromatin remodeling reaction and provides insights into how histone variants and nucleosome turnover can be controlled by chromatin regulators. H2A.Z ChIP seq experiments in mutants with constitutive H3K56ac
Project description:Histone variant H2A.Z occupies the promoters of active and poised, bivalent genes in ESCs to regulate developmental programs, yet how it contributes to these contrasting states is poorly understood. Here, we investigate the function of H2A.Z.1 mono-ubiquitylation (H2A.Z.1ub) by mutation of the PRC1 target residues (H2A.Z.1K3R3). We show that H2A.Z.1K3R3 is properly incorporated at target promoters in murine ESCs (mESCs), however, loss of mono-ubiquitylation leads to de-repression of bivalent genes, loss of Polycomb binding, and to faulty lineage commitment. Using quantitative proteomics, we find that tandem bromodomain proteins, including the BET family member Brd2, are enriched in H2A.Z.1 chromatin. We further show that Brd2 is gained at de-repressed promoters in H2A.Z.1K3R3 mESCs whereas Brd2 inhibition restores gene silencing at these sites. Together, our study reveals an antagonistic relationship between H2A.Z.1ub and Brd2 to regulate the transcriptional balance at bivalent genes to enable proper execution of developmental programs. ChIP-Seq analysis on mouse embryonic stem cells harboring H2A.Z or H2A.Z.K3R3 (3 C-terminal lysines mutated to arginines) tagged with YFP, in the presence of a knockdown hairpin targeting the endogenous H2A.Z transcript.
Project description:At genome-wide level, loss of OsChz1 causes mis-regulation of thousands of genes and broad alterations of nucleosome occupancy as well as reduction of H2A.Z-enrichment within chromatin along the gene body and at TSS. While OsChz1 associates with chromatin regions enriched of repressive histone marks (H3K27me3 and H4K4me2), its loss does not affect the genome landscape of DNA methylation.