Assay of different photoproducts after UVA, B and C irradiation of DNA and human skin explants

A P-32-HPLC method was applied to study the induction of UVB- and UVC-induced DNA lesions (cyclobutane dimers, 6-4 photoproducts and Dewar isomers) in human skin explants. The employed technique was sensitive enough to detect the lesions at a dose of 10 J/m(2) UVB. Comparison of photoadduct formation under UVC and UVB indicated the importance of photosensitization pathways in DNA damage. Dewar isomers were detected only at a high dose of UVB. The compounds were identified by their photochemical reactivity and by spiking with prepared standards, Treatment with nuclease P1 was used to identify the 5'-terminal nucleotide, UVA caused no detectable adducts.