title: Transient conformation changes in chromatin during excision repair of ultraviolet damage to DNA.
abstract: DNA labeled for 15 minutes during UV induced repair synthesis is two-fold more sensitive to micrococcal nuclease than the bulk nuclear DNA. As the length of the labeling period increases from 15 minutes to 4 hours the nuclease sensitivity of repair labeled DNA approaches that of bulk chromatin. Pulse-chase experiments indicate that the nuclease sensitivity of the repaired DNA labeled during a brief pulse decreases with a half-life of about 15 minutes. In contrast to previous interpretations, we consider these results to mean that immediately after synthesis, chromatin labeled during repair has a conformation which renders it more susceptible to nuclease digestion than the bulk chromatin. With time these repaired regions are assembled into a nucleosome structure with normal nuclease sensitivity.
mesh_terms: D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D002843:Chromatin / Q000378:metabolism / Q000528:radiation effects*; D004247:DNA / Q000528:radiation effects*; D004260:DNA Repair; D004262:DNA Restriction Enzymes; D007668:Kidney; D007700:Kinetics; D008836:Micrococcal Nuclease / Q000378:metabolism; D008970:Molecular Weight; D014466:Ultraviolet Rays
chemical_list: D002843:Chromatin; D004247:DNA; D004262:DNA Restriction Enzymes; D008836:Micrococcal Nuclease