title: Re-establishment of nucleosome occupancy during double-strand break repair in budding yeast.
abstract: Homologous recombination (HR) is an evolutionarily conserved pathway in eukaryotes that repairs a double-strand break (DSB) by copying homologous sequences from a sister chromatid, a homologous chromosome or an ectopic location. Recombination is challenged by the packaging of DNA into nucleosomes, which may impair the process at many steps, from resection of the DSB ends to the re-establishement of nucleosomes after repair. However, nucleosome dynamics during DSB repair have not been well described, primarily because of a lack of well-ordered nucleosomes around a DSB. We designed a system in budding yeast Saccharomyces cerevisiae to monitor nucleosome dynamics during repair of an HO endonuclease-induced DSB. Nucleosome occupancy around the break is lost following DSB formation, by 5'-3' resection of the DSB end. Soon after repair is complete, nucleosome occupancy is partially restored in a repair-dependent but cell cycle-independent manner. Full re-establishment of nucleosome protection back to the level prior to DSB induction is achieved when the cell cycle resumes following repair. These findings may have implications to the mechanisms by which cells sense the completion of repair.
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Tsabar
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States.
authors.forename: Wade M
authors.initials: WM
authors.lastname: Hicks
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States.
authors.forename: Olga
authors.initials: O
authors.lastname: Tsaponina
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States. Electronic address: haber@brandeis.edu.
authors.forename: James E
authors.initials: JE
authors.lastname: Haber
mesh_terms: D001681:Biological Assay; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004271:DNA, Fungal / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006657:Histones / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism*; D059767:Recombinational DNA Repair; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D006657:Histones; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins
keywords: Cell cycle; Chromatin; Chromatin dynamics; Double-strand break; Nucleosome