Gene expression data of Arabidopsis thaliana yaf9a yaf9b double mutant seedlings
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE126020 | GEO | 2019/02/06
REPOSITORIES: GEO
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Project description:In the baker’s yeast Saccharomyces cerevisiae, Swc4, Yaf9, Arp4, and Act1 form a submodule shared by histone acetylation NuA4 complex and chromatin remodeling SWR1 complex (SWR1-C). Act1 and Arp4 are essential for cell survival. Deletion of SWC4, but not YAF9, results in severe growth defect, however, the underlying mechanism remains largely unknown. Here, we show that swc4Δ, but not yaf9Δ, eaf1Δ, or swr1Δ cells display mitotic defects in both faithful chromosome segregation and DNA ploidy, suggesting that the defects observed in swc4Δ cells are independent of the integrity of either NuA4 or SWR1-C. Additionally, loss of Swc4 function results in chromosomal breakage, spindle assembly check-point activation and significant increase of the Rfa1 foci and γ-H2A levels. Notably, both telomeres and rDNA loci in swc4Δ cells become unstable and are highly susceptible to recombination. Mechanistically, Swc4 interacts with chromatin likely through hypoacetylated histone H4. Taking together, we conclude that the chromatin associated Swc4 protects chromatin from breakage to ensure genome integrity.
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Project description:The human NuA4/TIP60 co-activator complex, a fusion of the yeast SWR1 and NuA4 complexes, both incorporates the histone variant H2A.Z into nucleosomes and acetylates histones H4/H2A/H2A.Z to play crucial roles regulating gene expression and maintaining genome stability. Our cryo-EM studies show that within the NuA4/TIP60 complex, the EP400 subunit serves as an architectural scaffold holding the different functional modules in specific positions and giving rise to a novel arrangement of the ARP module. EP400 interacts with the TRRAP subunit using a footprint that overlaps with that of the SAGA acetyltransferase complex, thereby preventing the formation of a hybrid complex. Loss of the TRRAP subunit leads to mislocalization of NuA4/TIP60, resulting in the redistribution of H2A.Z and its acetylation across the genome, emphasizing the dual functionality of NuA4/TIP60 as a single macromolecular assembly.
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Project description:The human NuA4/TIP60 co-activator complex, a fusion of the yeast SWR1 and NuA4 complexes, both incorporates the histone variant H2A.Z into nucleosomes and acetylates histones H4/H2A/H2A.Z to play crucial roles regulating gene expression and maintaining genome stability. Our cryo-EM studies show that within the NuA4/TIP60 complex, the EP400 subunit serves as an architectural scaffold holding the different functional modules in specific positions and giving rise to a novel arrangement of the ARP module. EP400 interacts with the TRRAP subunit using a footprint that overlaps with that of the SAGA acetyltransferase complex, thereby preventing the formation of a hybrid complex. Loss of the TRRAP subunit leads to mislocalization of NuA4/TIP60, resulting in the redistribution of H2A.Z and its acetylation across the genome,emphasizing the dual functionality of NuA4/TIP60 as a single macromolecular assembly.
2024-08-08 | PXD053207 | Pride
Project description:The human NuA4/TIP60 co-activator complex, a fusion of the yeast SWR1 and NuA4 complexes, both incorporates the histone variant H2A.Z into nucleosomes and acetylates histones H4/H2A/H2A.Z to play crucial roles regulating gene expression and maintaining genome stability. Our cryo-EM studies show that within the NuA4/TIP60 complex, the EP400 subunit serves as an architectural scaffold holding the different functional modules in specific positions and giving rise to a novel arrangement of the ARP module. EP400 interacts with the TRRAP subunit using a footprint that overlaps with that of the SAGA acetyltransferase complex, thereby preventing the formation of a hybrid complex. Loss of the TRRAP subunit leads to mislocalization of NuA4/TIP60, resulting in the redistribution of H2A.Z and its acetylation across the genome, emphasizing the dual functionality of NuA4/TIP60 as a single macromolecular assembly.
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Project description:The human NuA4/TIP60 co-activator complex, a fusion of the yeast SWR1 and NuA4 complexes, both incorporates the histone variant H2A.Z into nucleosomes and acetylates histones H4/H2A/H2A.Z to play crucial roles regulating gene expression and maintaining genome stability. Our cryo-EM studies show that within the NuA4/TIP60 complex, the EP400 subunit serves as an architectural scaffold holding the different functional modules in specific positions and giving rise to a novel arrangement of the ARP module. EP400 interacts with the TRRAP subunit using a footprint that overlaps with that of the SAGA acetyltransferase complex, thereby preventing the formation of a hybrid complex. Loss of the TRRAP subunit leads to mislocalization of NuA4/TIP60, resulting in the redistribution of H2A.Z and its acetylation across the genome, emphasizing the dual functionality of NuA4/TIP60 as a single macromolecular assembly.
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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:In the baker’s yeast Saccharomyces cerevisiae, NuA4 and SWR1-C, two multisubunit complexes, are involved in histone acetylation and chromatin remodeling, respectively. Eaf1 is the assembly platform subunit of NuA4, Swr1 is the assembly platform and catalytic subunit of SWR1-C, while Swc4, Yaf9, Arp4 and Act1 form a functional module, and is present in both NuA4 and SWR1 complexes. ACT1 and ARP4 are essential for cell survival. Deletion of SWC4, but not YAF9, EAF1 or SWR1 results in a severe growth defect, but the underlying mechanism remains largely unknown. Here, we show that swc4Δ, but not yaf9Δ, eaf1Δ, or swr1Δ cells display defects in DNA ploidy and chromosome segregation, suggesting that the defects observed in swc4Δ cells are independent of NuA4 or SWR1-C integrity. Swc4 is enriched in the nucleosome-free regions (NFRs) of the genome, including characteristic regions of RDN5s, tDNAs and telomeres, independently of Yaf9, Eaf1 or Swr1. In particular, rDNA, tDNA and telomere loci are more unstable and prone to recombination in the swc4Δ cells than in wild-type cells. Taken together, we conclude that the chromatin associated Swc4 protects nucleosome-free chromatin of rDNA, tDNA and telomere loci to ensure genome integrity.
2023-05-31 | GSE233269 | GEO
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 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 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