title: Sequence specificity of cyclobutane pyrimidine dimers in DNA treated with solar (ultraviolet B) radiation.
abstract: Cyclobutane pyrimidine dimers were quantified at the sequence level after irradiation with solar ultraviolet (UVB) and nonsolar ultraviolet (UVC) light sources. The yield of photoproducts at specific sites was dependent on the nucleotide composition in and around the potential lesion as well as on the wavelength of ultraviolet light used to induce the damage. Induction was greater in the presence of 5' flanking pyrimidines than purines; 5' guanine inhibited induction more than adenine. UVB irradiation increased the induction of cyclobutane dimers containing cytosine relative to thymine homodimers. At the single UVC and UVB fluences used, the ratio of thymine homodimers (T mean value of T) to dimers containing cytosine (C mean value of T, T mean value of C, C mean value of C) was greater after UVC compared to UVB irradiation.
authors.affiliation: Laboratory of Radiobiology and Environmental Health, University of California, San Francisco 94143-0750.
authors.forename: D L
authors.initials: DL
authors.lastname: Mitchell
authors.forename: J
authors.initials: J
authors.lastname: Jen
authors.forename: J E
authors.initials: JE
authors.lastname: Cleaver
mesh_terms: D001483:Base Sequence; D003503:Cyclobutanes / Q000032:analysis*; D004279:DNA, Viral / Q000378:metabolism / Q000528:radiation effects*; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases / Q000378:metabolism; D008969:Molecular Sequence Data; D011740:Pyrimidine Dimers / Q000032:analysis*; D012091:Repetitive Sequences, Nucleic Acid / Q000528:radiation effects; D013539:Simian virus 40 / Q000235:genetics; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D003503:Cyclobutanes; D004279:DNA, Viral; D011740:Pyrimidine Dimers; D004706:Endodeoxyribonucleases; D043224:Deoxyribonuclease (Pyrimidine Dimer)