title: Hypomethylation of repair patches in HeLa cells.
abstract: In HeLa cells, under conditions where normal semiconservative synthesis is suppressed by hydroxyurea, the excision repair process after irradiation by UV results in a small amount of incorporation of nucleotides into nonreplicated DNA. By labelling the cytosine moieties of these repair patches, and measuring the ratio between cytosine and 5-methylcytosine, we have found that the level of methylation of cytosine in repair patches five hours after UV-irradiation of the cells is about half of that observed in normal semiconservatively synthesized DNA.
mesh_terms: D044503:5-Methylcytosine; D003596:Cytosine / Q000031:analogs & derivatives / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D004260:DNA Repair / Q000528:radiation effects; D006367:HeLa Cells / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D008745:Methylation; D014466:Ultraviolet Rays
chemical_list: D044503:5-Methylcytosine; D003596:Cytosine; D004247:DNA