Transient DNA lesions induced by benzo[a]pyrene in Chinese hamster ovary cells

Alkaline sucrose gradient sedimentation analysis was used to detect DNA lesions induced by benzo[a]pyrene B(a)P in Chinese hamster ovary cells. The number of lesions detected immediately following treatment with 10(-4) M B(a)P was related directly to the duration of treatment. When treated cells were incubated in a B(a)P-free medium, the majority of lesions disappeared rapidly and could no longer be detected 15 min following treatment. These data indicate that a population of B(a)P-induced DNA lesions may be removed by a rapid DNA-repair process. The transient nature of such lesions should be considered when assays for DNA damage or repair are designed and interpreted.