Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA213241 | ENA |
REPOSITORIES: ENA
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Project description:Histone variant H2A.Z-containing nucleosomes are incorporated at most eukaryotic promoters. This incorporation is mediated by the conserved SWR1 complex, which replaces histone H2A in canonical nucleosomes with H2A.Z in an ATP-dependent manner. Here, we show that promoter-proximal nucleosomes are highly heterogeneous for H2A.Z in Saccharomyces cerevisiae, with substantial representation of nucleosomes containing one, two, or no H2A.Z molecules. SWR1-catalyzed H2A.Z replacement in vitro occurs in a stepwise and unidirectional fashion, one H2A.Z-H2B dimer at a time, producing heterotypic nucleosomes as intermediates and homotypic H2A.Z nucleosomes as end products. The ATPase activity of SWR1 is specifically stimulated by H2A-containing nucleosomes without ensuing histone H2A eviction. Remarkably, further addition of free H2A.Z-H2B dimer leads to hyperstimulation of ATPase activity, eviction of nucleosomal H2A-H2B and deposition of H2A.Z-H2B. These results suggest that the combination of H2A-containing nucleosome and free H2A.Z-H2B dimer acting as both effector and substrate for SWR1 governs the specificity and outcome of the replacement reaction. Total nucleosomes from MNase-treated nuclear extracts were fractionated by sequential immunoprecipitation into homotypic H2A/H2A (AA), heterotypic H2A/H2A.Z (AZ), and homotypic H2A.Z/H2A.Z (ZZ) nucleosomes.
2010-10-12 | E-GEOD-24618 | biostudies-arrayexpress
Project description:Histone variant H2A.Z-containing nucleosomes are incorporated at most eukaryotic promoters. This incorporation is mediated by the conserved SWR1 complex, which replaces histone H2A in canonical nucleosomes with H2A.Z in an ATP-dependent manner. Here, we show that promoter-proximal nucleosomes are highly heterogeneous for H2A.Z in Saccharomyces cerevisiae, with substantial representation of nucleosomes containing one, two, or no H2A.Z molecules. SWR1-catalyzed H2A.Z replacement in vitro occurs in a stepwise and unidirectional fashion, one H2A.Z-H2B dimer at a time, producing heterotypic nucleosomes as intermediates and homotypic H2A.Z nucleosomes as end products. The ATPase activity of SWR1 is specifically stimulated by H2A-containing nucleosomes without ensuing histone H2A eviction. Remarkably, further addition of free H2A.Z-H2B dimer leads to hyperstimulation of ATPase activity, eviction of nucleosomal H2A-H2B and deposition of H2A.Z-H2B. These results suggest that the combination of H2A-containing nucleosome and free H2A.Z-H2B dimer acting as both effector and substrate for SWR1 governs the specificity and outcome of the replacement reaction.
2010-10-12 | GSE24618 | GEO
Project description:The site-specific chromatin incorporation of eukaryotic histone variant H2A.Z is driven by the multi-component chromatin remodeling complex SWR1/SRCAP/ p400. The budding yeast SWR1 complex replaces the H2A-H2B dimer in the canonical nucleosome with the H2A.Z-H2B dimer, but the mechanism governing the directionality of H2A-to-H2A.Z exchange remains elusive. Here, we use single-molecule force spectroscopy to dissect the disassembly/ reassembly of H2A-nucleosome and H2A.Z-nucleosome. We find that the N-terminal 1-135 residues of yeast SWR1-complex-protein-2 (previously termed Swc2-Z) facilitate the disassembly of nucleosomes containing H2A but not H2A.Z. The Swc2-mediated nucleosome disassembly/reassembly requires the inherently unstable H2A-nucleosome, whose instability is conferred by three H2A α2-helix residues Gly47, Pro49 and Ile63 as they selectively weaken the structural rigidity of H2A-H2B dimer. It also requires Swc2-ZN (residues 1-37) that directly anchors to H2A-nucleosome and functions in the SWR1-catalyzed H2A.Z replacement in vitro and yeast H2A.Z deposition in vivo. Our findings providecrucial insights into how SWR1 complex discriminates between the H2A-nucleosome and H2A.Z-nucleosome, establishing a simple paradigm for the governace of unidirectional H2A.Z exchange.
2021-04-12 | GSE171844 | GEO
Project description:The histone variant H2A.Z is a genome-wide signature of nucleosomes proximal to eukaryotic regulatory DNA. While the multi-subunit SWR1 chromatin remodeling complex is known to catalyze ATP-dependent deposition of H2A.Z, the mechanism of recruitment to S. cerevisiae promoters has been unclear. A sensitive assay for competitive binding of di-nucleosome substrates revealed that SWR1 preferentially binds long nucleosome-free DNA adjoining core particles, allowing discrimination of gene promoters over gene bodies. We traced the critical DNA binding component of SWR1 to the conserved Swc2/YL1 subunit, whose activity is required for both SWR1 binding and H2A.Z incorporation in vivo. Histone acetylation by NuA4 enhances SWR1 binding, but the interaction with nucleosome-free DNA is the major determinant. ‘Hierarchical cooperation’ between high affinity DNA- and low affinity histone modification-binding factors may reconcile the large disparity in affinities for chromatin substrates, and unify classical control by DNA-binding factors with post-translational histone modifications and ATP-dependent nucleosome mobility. Swr1 TAP IF of various mutants
2013-09-16 | E-GEOD-49183 | biostudies-arrayexpress
Project description:The histone variant H2A.Z is a genome-wide signature of nucleosomes proximal to eukaryotic regulatory DNA. While the multi-subunit SWR1 chromatin remodeling complex is known to catalyze ATP-dependent deposition of H2A.Z, the mechanism of recruitment to S. cerevisiae promoters has been unclear. A sensitive assay for competitive binding of di-nucleosome substrates revealed that SWR1 preferentially binds long nucleosome-free DNA adjoining core particles, allowing discrimination of gene promoters over gene bodies. We traced the critical DNA binding component of SWR1 to the conserved Swc2/YL1 subunit, whose activity is required for both SWR1 binding and H2A.Z incorporation in vivo. Histone acetylation by NuA4 enhances SWR1 binding, but the interaction with nucleosome-free DNA is the major determinant. ‘Hierarchical cooperation’ between high affinity DNA- and low affinity histone modification-binding factors may reconcile the large disparity in affinities for chromatin substrates, and unify classical control by DNA-binding factors with post-translational histone modifications and ATP-dependent nucleosome mobility.
2013-09-16 | GSE49183 | GEO
Project description:The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription. Here we analysed the transcription profiles of single and double mutants and wild-type cells by whole-genome microarray analysis. Our results indicate that genome-wide transcriptional misregulation in htz1∆ can be partially or totally suppressed if SWR1 is not formed (swr1∆), if it forms but cannot bind to chromatin (swc2∆), or if it binds to chromatin but has no histone replacement activity (swc5∆). These results suggest that in htz1∆ the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter. Three biological independent replicates were use for each strain
2011-05-18 | E-GEOD-21571 | biostudies-arrayexpress
Project description:The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription. Here we analysed the transcription profiles of single and double mutants and wild-type cells by whole-genome microarray analysis. Our results indicate that genome-wide transcriptional misregulation in htz1∆ can be partially or totally suppressed if SWR1 is not formed (swr1∆), if it forms but cannot bind to chromatin (swc2∆), or if it binds to chromatin but has no histone replacement activity (swc5∆). These results suggest that in htz1∆ the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter.
2011-05-18 | GSE21571 | GEO
Project description:The SWR1 chromatin remodeling complex (SRCAP in humans) is recruited to +1 nucleosomes downstream of transcription start sites of eukaryotic promoters, where it exchanges histone H2A for the specialized variant H2A.Z. Here we use cryo-EM to resolve the structural basis of the SWR1 interaction with free DNA, revealing a distinct open conformation of the Swr1 ATPase that enables sliding from accessible DNA to nucleosomes. A complete structural model of the SWR1-nucleosome complex illustrates critical structure-function roles for Swc2 and Swc3 subunits in oriented nucleosome engagement by SWR1. Moreover, an extended DNA-binding α -helix within the Swc3 subunit enables sensing of nucleosome linker length and is essential for SWR1 promoter-specific recruitment and activity. The previously unresolved N-SWR1 subcomplex forms a flexible extended structure enabling multivalent recognition of acetylated histone tails by reader domains to further direct SWR1 towards the +1 nucleosome. Altogether, our findings provide a generalizable mechanism for promoter-specific targeting of chromatin and transcription complexes.
2024-08-26 | GSE275429 | GEO
Project description:The histone variant H2A.Z marking permissive chromatin is preferentially deposited at promoter-proximal +1 nucleosomes by the multicomponent SWR1 chromatin remodeler. Although SWR1 targeting to nucleosome-depleted regions (NDRs) is directed by its free DNA length sensing module, how the remodeler is guided preferentially to flanking +1 nucleosomes has been enigmatic. Here, we show by live-cell, single-molecule tracking (SMT) that SWR1 subunits Bdf1 and Yaf9 harboring bromo and YEATS acetyl-histone reader domains are required for quantitative chromatin binding via distinct kinetic mechanisms: Bdf1 increases SWR1 association, Yaf9-YEATS reduces disassociation. Notably, SMT and genome-wide ChIP-exo reveals Bdf1 and Yaf9 contributions to SWR1 targeting globally and histone exchange at +1 nucleosomes. Our findings highlight the native biochemistry of histone readers and suggest a broadly applicable, two-stage mechanism wherein acetyl-histone interactions initially constrain 3D diffusion of SWR1 to increase local concentration, followed by stochastic 1D diffusion at NDRs with directional capture by acetylated +1 nucleosomes.
2024-07-29 | GSE273028 | GEO
Project description:The histone variant H2A.Z is important for transcriptional regulation across eukaryotes, where it can alternately promote or repress transcription. Actively transcribed genes show H2A.Z enrichment in nucleosomes immediately downstream of the transcription start site (TSS), while silent genes show H2A.Z enrichment across the gene body. In plants, previous work shows that silent genes responsive to temperature and light lose gene body H2A.Z upon activation, but whether H2A.Z loss is generally required for transcription is not clear. We profiled H2A.Z and components of its deposition complex, SWR1, before and after treating Arabidopsis thaliana with the hormone abscisic acid (ABA). Our results show that transcribed genes with TSS-enriched H2A.Z have high SWR1 binding, indicating continuous replacement of H2A.Z, while silent genes with gene body H2A.Z show lower SWR1 binding. Surprisingly, upon ABA treatment, thousands of previously silent genes activate, correlating with recruitment of SWR1 and retention of gene body H2A.Z enrichment. We also found that the SWR1-interacting protein MBD9 is not required for SWR1 recruitment to activated genes. These results provide new insights into the relationship between H2A.Z and transcription and the mechanics of H2A.Z targeting to chromatin.
2025-06-01 | GSE269876 | GEO