Role of DNA repair in mutagenesis of Chinese hamster ovary cells by 7-bromomethylbenz(a)anthracene

Journal Article · Fri Jan 01 04:00:00 EST 1982 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.79.2.534· OSTI ID:5615026

Thompson, L H; Brookman, K W; Carrano, A V; Dillehay, L E

The role of DNA repair in mutagenesis was studied in normal, repair-proficient Chinese hamster ovary cells and in two mutant strains that are deficient in excision repair. By using the mutagen 7-bromomethylbenz(a)anthracene (7-BrMeBA) and the technique of alkaline elution of DNA, the mutants were found to be defective at or before the incision step of excision repair. Dose-responses were determined for cell killing, mutation induction at three loci, and sister chromatid exchanges over a survival range of 1.0-0.1 after 7-BrMeBA treatment. The mutants were 5-fold more sensitive to killing than were the normal cells, but the degree of hypersensitivity to mutation induction varied depending on the mutant strain, the genetic marker, and the dose of mutagen. In each instance, the dose-response curve for mutations was essentially linear in the repair-deficient cells. In the normal cells, however, the curves for induced resistance to thioguanine and azaadenine were complex and were curvilinear with increasing slope at low doses. This behavior may be attributable to saturation of the excision repair system. No difference was seen in the efficiency of inducing ouabain-resistant mutations in the repair-deficienct cells compared to the normal cells, indicating a qualitatively different behavior of this marker. These results are consistent with excision repair of 7-BrMeBA damage being error-free in Chinese hamster ovary cells. Sister chromatid exchange, another manifestation of DNA damage, also was induced with greater efficiency in the repair-deficient cells.

• Research Organization: Lawrence Livermore National Lab., Livermore, CA
• OSTI ID: 5615026
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 79:2; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550400* -- Genetics
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
AROMATICS
BENZANTHRACENE
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
CHROMOSOMAL ABERRATIONS
CONDENSED AROMATICS
DNA
FEMALE GENITALS
GONADS
HAMSTERS
HYDROCARBONS
MAMMALS
MUTAGENESIS
MUTATIONS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OVARIES
RECOVERY
REPAIR
RODENTS
SISTER CHROMATID EXCHANGES
VERTEBRATES