title: Nucleosome positioning, nucleotide excision repair and photoreactivation in Saccharomyces cerevisiae.
abstract: The position of nucleosomes on DNA participates in gene regulation and DNA replication. Nucleosomes can be repressors by limiting access of factors to regulatory sequences, or activators by facilitating binding of factors to exposed DNA sequences on the surface of the core histones. The formation of UV induced DNA lesions, like cyclobutane pyrimidine dimers (CPDs), is modulated by DNA bending around the core histones. Since CPDs are removed by nucleotide excision repair (NER) and photolyase repair, it is of paramount importance to understand how DNA damage and repair are tempered by the position of nucleosomes. In vitro, nucleosomes inhibit NER and photolyase repair. In vivo, nucleosomes slow down NER and considerably obstruct photoreactivation of CPDs. However, over-expression of photolyase allows repair of nucleosomal DNA in a second time scale. It is proposed that the intrinsic abilities of nucleosomes to move and transiently unwrap could facilitate damage recognition and repair in nucleosomal DNA.
authors.affiliation: Département de Microbiologie et Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Guintini
authors.affiliation: Département de Microbiologie et Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
authors.forename: Romain
authors.initials: R
authors.lastname: Charton
authors.affiliation: Département de Microbiologie et Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Peyresaubes
authors.affiliation: Department of Biology, ETH Zürich, 8093 Zürich, Switzerland. Electronic address: fritz.thoma@cell.biol.ethz.ch.
authors.forename: Fritz
authors.initials: F
authors.lastname: Thoma
authors.affiliation: Département de Microbiologie et Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada. Electronic address: Antonio.Conconi@usherbrooke.ca.
authors.forename: Antonio
authors.initials: A
authors.lastname: Conconi
mesh_terms: D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal / Q000378:metabolism / Q000528:radiation effects; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000378:metabolism*; D009707:Nucleosomes / Q000378:metabolism*; D011740:Pyrimidine Dimers / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D004271:DNA, Fungal; D009707:Nucleosomes; D011740:Pyrimidine Dimers; D029701:Saccharomyces cerevisiae Proteins; D004255:Deoxyribodipyrimidine Photo-Lyase
keywords: 6,4 Pyrimidine–pyrimidone dimers; Chromatin; Cyclobutane pyrimidine dimers; Nucleosome positioning; Nucleotide excision repair; Photolyase