Nuclear myosin VI maintains replication fork stability
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Q Exactive Plus
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Permanent Cell Line Cell, Hela Cell
SUBMITTER: 
Petra Beli
LAB HEAD: Petra Beli
PROVIDER: PXD035394 | Pride | 2023-05-04
REPOSITORIES: Pride
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Project description:Background: Chromatin remodeling complexes facilitate the access of enzymes that mediate transcription, replication or repair of DNA by modulating nucleosome position and/or composition. Ino80 is the DNA-dependent Snf2-like ATPase subunit of a complex whose nucleosome remodeling activity requires actin-related proteins, Arp4, Arp5 and Arp8, as well as two RuvB-like DNA helicase subunits. Budding yeast mutants deficient for Ino80 function are not only hypersensitive to reagents that induce DNA double strand breaks, but also to those that impair replication fork progression. Results: To understand why ino80 mutants are sensitive to agents that perturb DNA replication, we used chromatin immunoprecipitation to map the binding sites of the Ino80 chromatin remodeling complex on four budding yeast chromosomes. We found that Ino80 and Arp5 binding sites coincide with origins of DNA replication and tRNA genes. In addition, Ino80 was bound at 67% of the promoters of genes that are sensitive to ino80 mutation. When replication forks were arrested near origins in the presence of hydroxyurea (HU), the presence of the Ino80 complex at stalled forks and at unfired origins increased dramatically. Importantly, the resumption of DNA replication after release from a HU block was impaired in the absence of Ino80 activity. Mutant cells accumulated double-strand breaks as they attempted to restart replication. Consistently, ino80-deficient cells, although proficient for checkpoint activation, delay recovery from the checkpoint response. Conclusions: The Ino80 chromatin remodeling complex is enriched at stalled replication forks where it promotes the resumption of replication upon recovery from fork arrest. Keywords: ChIP-chip • The goal of the experiment Genome-wide localization of Ino80 on chromosome in Saccharomyces cerevisiae • Keywords DNA replication, Saccharomyces cerevisiae, Genome tilling array (chromosome III, IV, V, VI) • Experimental factor Distribution of Ino80 in random culture Distribution of Ino80 in G1 phase Distribution of Ino80 in early S phase • Experimental design ChIP analyses: W303 background cells expressing Myc-tagged Ino80 were used for the ChIP using anti-Myc monoclonal antibody (9E11). ChIP-chip analyses: In all cases, hybridization data for ChIP fraction was compared with WCE (whole cell extract) fraction. Saccharomyces cerevisiae affymetrix genome tiling array (SC3456a520015F for chromosome III, IV, V, VI) was used. • Quality control steps taken Confirmation of several loci by quantitative real time PCR.
2008-04-10 | E-GEOD-9420 | biostudies-arrayexpress
Project description:During transcription, RNA Polymerase II (RNAPII) is spatially organised into clusters that correlate with transcription activity. However, the assembly, organisation and stability of these transcription units remains unknown. Here, we have combined single molecule imaging with genomics approaches in order to explore the role of nuclear myosin VI in the nanoscale organisation of RNAPII. We can reveal that myosin VI acts as the molecular anchor that holds RNAPII into these transcription factories. Perturbation of myosin VI leads to the disruption of RNAPII localisation, changes in chromatin organisation and subsequently a decrease in gene expression. This role of Myosin VI is particularly important for transcription events following stimulation, where multiple genes are simultaneously activated.
2020-05-31 | GSE149448 | GEO
Project description:Background: Chromatin remodeling complexes facilitate the access of enzymes that mediate transcription, replication or repair of DNA by modulating nucleosome position and/or composition. Ino80 is the DNA-dependent Snf2-like ATPase subunit of a complex whose nucleosome remodeling activity requires actin-related proteins, Arp4, Arp5 and Arp8, as well as two RuvB-like DNA helicase subunits. Budding yeast mutants deficient for Ino80 function are not only hypersensitive to reagents that induce DNA double strand breaks, but also to those that impair replication fork progression. Results: To understand why ino80 mutants are sensitive to agents that perturb DNA replication, we used chromatin immunoprecipitation to map the binding sites of the Ino80 chromatin remodeling complex on four budding yeast chromosomes. We found that Ino80 and Arp5 binding sites coincide with origins of DNA replication and tRNA genes. In addition, Ino80 was bound at 67% of the promoters of genes that are sensitive to ino80 mutation. When replication forks were arrested near origins in the presence of hydroxyurea (HU), the presence of the Ino80 complex at stalled forks and at unfired origins increased dramatically. Importantly, the resumption of DNA replication after release from a HU block was impaired in the absence of Ino80 activity. Mutant cells accumulated double-strand breaks as they attempted to restart replication. Consistently, ino80-deficient cells, although proficient for checkpoint activation, delay recovery from the checkpoint response. Conclusions: The Ino80 chromatin remodeling complex is enriched at stalled replication forks where it promotes the resumption of replication upon recovery from fork arrest. Keywords: ChIP-chip • The goal of the experiment Genome-wide localization of Ino80 and Arp5 on chromosome in Saccharomyces cerevisiae • Keywords DNA replication, Saccharomyces cerevisiae, Genome tilling array (chromosome III, IV, V, VI) • Experimental factor Distribution of Ino80 and Arp5 in wild type in random culture Distribution of Ino80 in G1 cells Distribution of Ino80 in early S phase cells • Experimental design ChIP analyses: W303 background cells expressing Myc tagged Ino80 were used for the ChIP using anti-Myc monoclonal antibody (9E11). ChIP analyses: W303 background cells expressing Myc tagged Ino80 were used for the ChIP using anti-Arp5 polyclonal antibody. ChIP-chip analyses: In all cases, hybridization data for ChIP fraction was compared with WCE (whole cell extract) fraction. Saccharomyces cerevisiae affymetrix genome tiling array (SC3456a520015F for chromosome III, IV, V, VI) was used. • Quality control steps taken Confirmation of several loci by quantitative real time PCR.
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Project description:Nuclear myosin 1c (NM1) is emerging as regulator of transcription and chromatin organization. Using a genome-wide approach we report here that NM1 binds across the mammalian genome with occupancy peaks at class II gene promoters, correlating with distributions of RNA Polymerase II (Pol II) and active epigenetic marks. We show that NM1 synergizes with polymerase-associated actin to maintain active Pol II at gene promoters. NM1 also co-localizes with the nucleosome remodeler SNF2h at class II promoters where they assemble together with WSTF as part of the B-WICH complex to remodel chromatin. Following B-WICH assembly, NM1 mediates physical recruitment of the histone acetyl transferase PCAF and the histone methyl transferase Set1/Ash2 to maintain and preserve H3K9acetylation and H3K4trimethylation for active transcription. We propose a novel genome-wide mechanism where myosin synergizes with Pol II-associated actin to link the polymerase machinery with permissive chromatin for transcription activation. Association of nuclear myosin 1 (NM1) with the genome in mouse embryonic fibroblasts
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Project description:Oncoproteins of the MYC family drive the development of numerous human tumors. In unperturbed cells, MYC proteins bind to virtually all active promoters and control transcription by RNA Polymerase II (RNAPII). MYC proteins can also coordinate transcription with DNA replication and promote the repair of transcription-associated DNA damage, but how they exert these mechanistically diverse functions is unknown. Here we show that MYC dissociates from many of its binding sites in active promoters and forms multimeric, often sphere-like structures in response to perturbation of transcription elongation, mRNA splicing or inhibition of the proteasome. Multimerization is accompanied by a global change in the MYC interactome towards proteins involved in transcription termination and RNA processing. MYC multimers accumulate on chromatin immediately adjacent to stalled replication forks and surround FANCD2, ATR and BRCA1 proteins, which are located at stalled forks. MYC multimerization is triggered in a HUWE1- and ubiquitylation-dependent manner. At active promoters, MYC multimers block antisense transcription and stabilize FANCD2 association with chromatin. This limits DNA double-strand break formation during S phase, suggesting that multimerization of MYC enables tumor cells to proliferate under stressful conditions.
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