Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Genomic maps of homotypic H2Av, heterotypic H2Av, input and 80mM salt soluble chromatin from Drosophila S2 cells

ABSTRACT: Nucleosomes that contain the histone variant H2A.Z are enriched around transcriptional start sites in many organisms. A single octameric nucleosome can contain two H2A.Z histones (homotypic) or one H2A.Z and one canonical H2A (heterotype). We generated high-resolution maps of homotypic and heterotypic Drosophila H2A.Z (H2Av) nucleosomes. Although homotypic and heterotypic H2Av nucleosomes map throughout most of the genome, homotypic nucleosomes are enriched and heterotypic nucleosomes are depleted downstream of active promoters and intron/exon boundaries. The distribution of homotypic H2A.Z nucleosomes resembles that of salt-soluble nucleosomes and shows evidence of displacement during transcriptional elongation. Homotypic nucleosomes are also depleted downstream of paused polymerases, where salt-soluble nucleosomes are conspicuously depleted. Our results suggest a model whereby H2A.Z enrichment patterns result from different structural interactions within the core of heterotypic and homotypic nucleosomes following disruption during transcriptional elongation. We analyzed two replicates for input, heterotypic and homotypic purifications. We sequenced one library for each of the single H2Av pulldown and 80mM salt soluble samples.

ORGANISM(S): Drosophila melanogaster

SUBMITTER: Jorja Henikoff

PROVIDER: E-GEOD-21615 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

H2A.Z nucleosomes enriched over active genes are homotypic.

Weber Christopher M CM Henikoff Jorja G JG Henikoff Steven S

Nature structural & molecular biology 20101107 12

Nucleosomes that contain the histone variant H2A.Z are enriched around transcriptional start sites, but the mechanistic basis for this enrichment is unknown. A single octameric nucleosome can contain two H2A.Z histones (homotypic) or one H2A.Z and one canonical H2A (heterotypic). To elucidate the function of H2A.Z, we generated high-resolution maps of homotypic and heterotypic Drosophila H2A.Z (H2Av) nucleosomes. Although homotypic and heterotypic H2A.Z nucleosomes mapped throughout most of the ...[more]

PMID: 21057526

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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 1,2, 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 surveyed whole genome expression using microarrays, in combination with H2A.Z ChIP-Seq (Illumina) data, to study the H2A.Z distribution on promoters of coding genes in different stages of the cell cycle in Trophoblast Stem (TS) cells. These data are published in Nekrasov et al., H2AZ inheritance during the cell cycle and it's impact on promoter organization and dynamics, Nature Structural and Molecular Biology (in press: accepted for publication on 24 Sep 2012). Mouse Trophoblast stem (TS) cells were grown in cell culture medium. By adding specific drugs cells were arrested at particular stages of the cell cycle: G1; S and M. Total RNA was extracted from TS cells arrested at G1; S and M stages of cell cycle using TRizol (Invitrogen) extraction protocol and purified further the by RNAeasy Extraction Kit (Qiagen). RNA quality was assesed on Bioanalyzer total RNA chip. RNA samples were reverse transcribed and resulted cDNA samples were subjected to DNA microarray analysis (in triplicate) using the GeneChip Mouse Gene 1.0 ST Array (Affymetrix). Robust Multichip Average (RMA) correction and probe set summaries were obtained using Affymetrix Power Tools software annotation (Affymetrix) based on the mm9 mouse genome. Unless otherwise stated, all subsequent expression analyses (see Supplementary Methods) were performed in the R statistical computing environment (version 2.11.1).

Dataset Information

Genomic maps of homotypic H2Av, heterotypic H2Av, input and 80mM salt soluble chromatin from Drosophila S2 cells

Publications

H2A.Z nucleosomes enriched over active genes are homotypic.

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