title: Chromatin remodeling activities act on UV-damaged nucleosomes and modulate DNA damage accessibility to photolyase.
abstract: Nucleosomes inhibit DNA repair in vitro, suggesting that chromatin remodeling activities might be required for efficient repair in vivo. To investigate how structural and dynamic properties of nucleosomes affect damage recognition and processing, we investigated repair of UV lesions by photolyase on a nucleosome positioned at one end of a 226-bp-long DNA fragment. Repair was slow in the nucleosome but efficient outside. No disruption or movement of the nucleosome was observed after UV irradiation and during repair. However, incubation with the nucleosome remodeling complex SWI/SNF and ATP altered the conformation of nucleosomal DNA as judged by UV photo-footprinting and promoted more homogeneous repair. Incubation with yISW2 and ATP moved the nucleosome to a more central position, thereby altering the repair pattern. This is the first demonstration that two different chromatin remodeling complexes can act on UV-damaged nucleosomes and modulate repair. Similar activities might relieve the inhibitory effect of nucleosomes on DNA repair processes in living cells.
authors.affiliation: Institut für Zellbiologie and Institut für Molekularbiologie, Departement Biologie, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
authors.forename: Hélène
authors.initials: H
authors.lastname: Gaillard
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Fitzgerald
authors.forename: Corey L
authors.initials: CL
authors.lastname: Smith
authors.forename: Craig L
authors.initials: CL
authors.lastname: Peterson
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Richmond
authors.forename: Fritz
authors.initials: F
authors.lastname: Thoma
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D004260:DNA Repair; D004262:DNA Restriction Enzymes / Q000494:pharmacology; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D002843:Chromatin; D005656:Fungal Proteins; C086468:ISWI protein; D009707:Nucleosomes; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D004247:DNA; D004262:DNA Restriction Enzymes; D003850:Deoxyribonuclease I; D000251:Adenosine Triphosphatases; D004255:Deoxyribodipyrimidine Photo-Lyase