Mutagenic processing and strand-specific repair of solar light-induced dipyrimidine photoproducts in rodent cells
- Hopital Maisonneuve-Rosemont, Montreal (Canada)
- Institut Curie, Paris (France)
Although mutations induced by {open_quotes}UVC-like{close_quotes} dipyrimidine photoproducts during sunlight exposure have been directly implicated in multistage photocarcinogenesis, the utility of 254nm UV as a paradigm for broad spectrum solar mutagenesis is questionable. To address this issue, the spectrum of mutations induced by simulated sunlight (SSL) at the adrenine phosphoribosyltransferase locus of Chinese hamster ovary cells has been characterized, and aligned with that previously established for 254nm UV in the same gene. Virtually all SSL-induced events were recovered at potential dinucleotide target sites, most of which could also be implicated in UVC mutagenesis, confirming a preeminent role for cyclobutane dimers and/or (6-4) photoproducts in sunlight-exposed rodent cells. However, striking differences were also noted in the frequency and distribution of mutational classes generated by SSL vs. UVc. Whereas C->T transitions were clearly the most frequent UVC-induced event (58%), three types of base substitution contributed substantially to the SSL spectrum; C->T transitions (35%), T->G transversions (25%), and tandem double CC->TT events (25%). In addition, a significantly greater fraction of SSL-induced mutations (94%) could be attributed to dipyrimidine photoproducts on the non-transcribed strand of the aprt gene than was observed following treatment with 254nm UV (63%). Taken together, the data indicate remarkable differences between UVC- and sunlight-exposed rodent cells in the distribution, strand-specific repair, and/or metabolic processing of similar premutagenic (dipyrimidine) photoproducts.
- OSTI ID:
- 88810
- Report Number(s):
- CONF-9405324-; ISSN 0893-6692; TRN: 95:004220-0014
- Journal Information:
- Environmental and Molecular Mutagenesis, Vol. 23, Issue Suppl.23; Conference: 25. annual meeting of the Environmental Mutagen Society, Portland, OR (United States), 7-12 May 1994; Other Information: PBD: 1994
- Country of Publication:
- United States
- Language:
- English
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