Correlation of UV-induced mutational spectra and the in vitro damage distribution at the human hprt gene.
We have determined the in vitro DNA damage distribution induced by 254 mm UV in the human hprt gene. The sequence-specific nature of the DNA damage for both main classes of UV-induced photoproducts, i.e., cyclobutane pyrimidine dimers (CPDs) and the pyrimidine <6-4> pyrimidone photoproducts (64PyPy), was evaluated. Utilizing an automated DNA sequencer plus auxiliary software, semi-automated analyses were performed for peak quantitation and retention-time to sequence-position correlation. 64PyPy were predominantly formed at 5'-YTC-3' sites (p < 0.02; where Y = C,T). The effect of the 3'flanking nucleotide on the 64PyPy formation at 5'-TC-3' sites was 64PyPy at 5'-TCT-3' sites were induced at lower frequencies compared to 5'-TCM-3' sites (where M = A or C; p < 0.03). No effect of flanking nucleotides was detected for CPDs recovered at 5'-TT-3' sites. Sites of mutations in the hprt gene were compared to the sites of DNA damage. Two regions of frequently mutated nucleotides corresponded to sites of high deposition of damage. The two sites either had a high frequency of CPDs or 64PyPy, which implicated both types of photoproducts as premutagenic lesions.
Kotturi
G
G
Stratagene, La Jolla, CA 92037, USA.
de Boer
J G
JG
Koop
B F
BF
Glickman
B W
BW
D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage; D004252:DNA Mutational Analysis / Q000379:methods / Q000592:standards; D017931:DNA Primers / Q000235:genetics; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009154:Mutation; D010777:Photochemistry; D011740:Pyrimidine Dimers / Q000235:genetics / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*
D017931:DNA Primers; D011740:Pyrimidine Dimers; D004247:DNA; D007041:Hypoxanthine Phosphoribosyltransferase