Figure 3.

Determination of CPD formation in mouse genomic DNA irradiated with various UV wavelengths. Genomic DNA of mouse embryonic fibroblasts was irradiated with a series of UV wavelengths (λ=261–349 nm) at a constant dose of 0.5 J/cm² in comparison with control, as described in Materials and Methods. Aliquots of DNA samples (1 μg) were digested with T4 Endo V enzyme, and subsequently subjected to alkaline agarose gel electrophoresis, followed by standard visualization procedure. M, molecular size marker. A) Digestion buffer plus T4 Endo V enzyme was added to the reaction mix. B) Quantification of results from panel A. Values are expressed as the number of T4 Endo V-sensitive sites per megabase of DNA. Average results from 2 independent experiments are shown for UV-irradiated samples. Error bars = sd. C) Digestion buffer only; no enzyme was added to the reaction mix.