Binding of H2A.Z within gene bodies in cancer cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE101427 | GEO | 2017/07/15
SECONDARY ACCESSION(S): PRJNA394200
REPOSITORIES: GEO
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Project description:The regulation of eukaryotic chromatin relies on interactions between many epigenetic factors, including histone modifications, DNA methylation, and the incorporation of histone variants. H2A.Z, one of the most conserved but enigmatic histone variants that is enriched at the transcriptional start sites of genes, has been implicated in a variety of chromosomal processes. Recently, we reported a genome-wide anticorrelation between H2A.Z and DNA methylation, an epigenetic hallmark of heterochromatin that has also been found in the bodies of active genes in plants and animals. Here, we investigate the basis of this anticorrelation using a novel h2a.z loss-of-function line in Arabidopsis thaliana. Through genome-wide bisulfite sequencing, we demonstrate that a loss of H2A.Z in Arabidopsis does not affect the level or profile of DNA methylation in genes, and we propose that the global anticorrelation between DNA methylation and H2A.Z is caused by the exclusion of H2A.Z from methylated DNA. RNA-seq and genomic mapping of H2A.Z show that H2A.Z enrichment across gene bodies, rather than at the TSS, is correlated with lower transcription levels and higher measures of gene responsiveness. We find that a loss of H2A.Z causes misregulation of many genes that are disproportionately associated with response to both endogenous and exogenous stimuli. We propose that H2A.Z deposition in gene bodies promotes variability in levels and patterns of gene expression, and that a major function of genic DNA methylation is to exclude H2A.Z from constitutively expressed genes. Examination of DNA methylation and transcription in an h2a.z mutant
2012-12-13 | E-GEOD-39045 | biostudies-arrayexpress
Project description:The regulation of eukaryotic chromatin relies on interactions between many epigenetic factors, including histone modifications, DNA methylation, and the incorporation of histone variants. H2A.Z, one of the most conserved but enigmatic histone variants that is enriched at the transcriptional start sites of genes, has been implicated in a variety of chromosomal processes. Recently, we reported a genome-wide anticorrelation between H2A.Z and DNA methylation, an epigenetic hallmark of heterochromatin that has also been found in the bodies of active genes in plants and animals. Here, we investigate the basis of this anticorrelation using a novel h2a.z loss-of-function line in Arabidopsis thaliana. Through genome-wide bisulfite sequencing, we demonstrate that a loss of H2A.Z in Arabidopsis does not affect the level or profile of DNA methylation in genes, and we propose that the global anticorrelation between DNA methylation and H2A.Z is caused by the exclusion of H2A.Z from methylated DNA. RNA-seq and genomic mapping of H2A.Z show that H2A.Z enrichment across gene bodies, rather than at the TSS, is correlated with lower transcription levels and higher measures of gene responsiveness. We find that a loss of H2A.Z causes misregulation of many genes that are disproportionately associated with response to both endogenous and exogenous stimuli. We propose that H2A.Z deposition in gene bodies promotes variability in levels and patterns of gene expression, and that a major function of genic DNA methylation is to exclude H2A.Z from constitutively expressed genes.
2012-12-13 | GSE39045 | GEO
Project description:Gene regulatory programs in different cell types are largely defined through cell-specific enhancers activity. The histone variant H2A.Z has been shown to play important roles in transcription mainly by controlling proximal promoters, but its effect on enhancer functions remains unclear. Here, we demonstrate by genome-wide approaches that H2A.Z is present at a subset of active enhancers bound by the estrogen receptor alpha (ERα). We also determine that H2A.Z does not influence the local nucleosome positioning around ERα-enhancers using ChIP-sequencing at nucleosomal resolution and unsupervised pattern discovery. We further highlight that H2A.Z-enriched enhancers are associated with chromatin accessibility, H3K122ac enrichment and hypomethylated DNA. Moreover, upon estrogen stimulation, the enhancers occupied by H2A.Z produce enhancer RNAs (eRNAs), and recruit RNA polymerase II as well as RAD21, a member of the cohesin complex involved in chromatin interactions between enhancers and promoters. Importantly, their recruitment and eRNAs production are abolished by H2A.Z depletion, thereby revealing a novel functional link between H2A.Z occupancy and enhancer activity. Taken together, our findings suggest that H2A.Z acts as an important player for enhancer functions by establishing and maintaining a chromatin environment required for RNA polymerase II recruitment, eRNAs transcription and enhancer-promoters interactions, all essential attributes of enhancer activity. The MNase ChIP-seqs in this study measure the genome-wide binding landscape of H2A.Z, H3K4me1, H3K27ac and H3K4me3 in MCF-7 cells in the absence or presence of E2. Two biological replicates were done for each ChIP-seq experiment and for each condition, as well as, control input.
2015-08-31 | E-GEOD-57436 | biostudies-arrayexpress
Project description:H2A.Z is a highly conserved histone variant involved in several key nuclear processes. It is incorporated into promoters by SWR-C-related chromatin remodeling complexes, but whether it is also actively excluded from non-promoter regions is not clear. Here, we provide genomic and biochemical evidence that RNA polymerase II (RNAPII) elongation-associated histone chaperones FACT and Spt6 both contribute to restricting H2A.Z from intragenic regions. In the absence of FACT or Spt6, the lack of H2A.Z eviction, coupled to its pervasive incorporation by mislocalized SWR-C, alters chromatin composition and contributes to cryptic initiation. Thus, chaperone-mediated H2A.Z removal is crucial for restricting the chromatin signature of gene promoters, which otherwise may license or promote cryptic transcription. We profiled H2A.Z occupancy in S. cerevisiae by ChIP-chip on tiling arrays in different mutants for chromatin remodelers and histone chaperones. In most experiments, H2A.Z ChIP samples (Cy5-labeled) were performed using a polyclonal antibody against H2A.Z and hybridized against H2B ChIP samples (Cy3-labeled), also performed using a polyclonal antibody. Temperature-sensitive mutants for the histone chaperones Spt16 and Spt6 (spt16-197 and spt6-1004 respectively) showed strong H2A.Z localization defects so the role of these factors in H2A.Z localization was further analyzed. H2A.Z ChIP-chip experiments in spt16-197 and spt6-1004 were repeated using different experimental designs [normalized against Input DNA or Mock (IgG) ChIP samples]. The contribution of Spt16 and Spt6 on H2A.Z localization was also confirmed by nuclear depletion of Spt16 and Spt6 using the anchor-away system. H2A.Z ChIP-chip experiments were also performed in sic1Δ and spt16-197/sic1Δ cells in order to rule out any G1-arrest artifact. H2A.Z ChIP-chip experiments were repeated using spike-in controls for normalization, revealing widespread H2A.Z occupancy in Spt16 and Spt6 mutants. In addition, the localization of the chromatin remodeler SWR-C was determined in wild type cells as well as in spt16-197 and spt6-1004 cells. Finally, we also profiled histone H4 occupancy by ChIP-chip in wild type, spt16-197, spt6-1004, spt16-197/htz1Δ and spt6-1004/htz1Δ cells. All ChIP-chip experiments were done in duplicates. Each microarray was normalized using the Lima Loess and replicates were combined using a weighted average method as previously described (Pokholok et al., 2005).
2015-05-12 | E-GEOD-62880 | biostudies-arrayexpress
Project description:The histone variant H2A.Z is evolutionarily conserved from yeast to vertebrates. H2A.Z regulates gene expression when localized to promoter region. Recently, we identified two genes encoding H2A.Z, H2A.Z-1 and H2A.Z-2 in vertebrate genome. However, it is not clear that both H2A.Z-1 and H2A.Z-2 were required for the function of H2A.Z in gene regulation. To address this issue, we generated the H2A.Z-1 and H2A.Z-2 double knock out (KO) cells in chicken DT40 cells. The expression pattern of H2A.Z-1 and H2A.Z-2 double KO cells was compared with WT cells to characterize the genes regulated by H2A.Z-1 and H2A.Z-2. We used microarrays to analysis the alternation of gene expression between WT and H2A.Z double KO cells and identify classes of up or down regulated gene by H2A.Z-1 and H2A.Z-2. In H2A.Z-1 and H2A.Z-2 double KO cells, H2A.Z-2 is knocked out constitutively, but H2A.Z-1 conditionally by tetracycline. The expression of H2A.Z-1 transgene is suppressed completely when H2A.Z-1 and H2A.Z-2 double KO cells culture with tetracycline for three days. For this reason, we prepared the total RNA of WT cells and H2A.Z-1and H2A.Z-2 double KO cells treated with tetracycline for three days and hybridization on Affymetrix microarrays.
2015-11-04 | E-GEOD-35430 | biostudies-arrayexpress
Project description:In this study, we examined the differential RNA profile of alpha amanitin-treated SORBS2-depleted ovarian cancer cells compared with control-treated SORBS2-depleted cells
2018-02-20 | GSE101595 | GEO
Project description:H2A.Z is a highly conserved histone variant involved in several key nuclear processes. It is incorporated into promoters by SWR-C-related chromatin remodeling complexes, but whether it is also actively excluded from non-promoter regions is not clear. Here, we provide genomic and biochemical evidence that RNA polymerase II (RNAPII) elongation-associated histone chaperones FACT and Spt6 both contribute to restricting H2A.Z from intragenic regions. In the absence of FACT or Spt6, the lack of H2A.Z eviction, coupled to its pervasive incorporation by mislocalized SWR-C, alters chromatin composition and contributes to cryptic initiation. Thus, chaperone-mediated H2A.Z removal is crucial for restricting the chromatin signature of gene promoters, which otherwise may license or promote cryptic transcription.
2015-05-12 | GSE62880 | GEO
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| S-EPMC3469445 | biostudies-literature
Project description:Transcriptional profiling of HeLa cells treated with α-amanitin for 9 h. Relative abundance to untreated control cells was used to evaluate the biogenesis of lncRNAs by RNA polymerase II. Two-condition experiment, alpha-amanitin-treated vs. untretated HeLa cells. Biological replicates: 4 with dye-swap
2015-06-30 | E-GEOD-62989 | biostudies-arrayexpress
Project description:Affinity Purification Mass Spectrometry (AP-MS) of Drosophila ovaries expressing an H2A.Z-FlagHA transgene to identify interacting partners of H2A.Z to elucidate potential maternally supplied histone chaperones that deposit H2A.Z on the transcription start site (TSS).
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