A slot blot method for detection of ultraviolet photoproducts in DNA.

A simple new method was established to detect the major uv photoproducts in DNA. A slot blot method, involving the use of T4 DNA polymerase-associated (3'--> 5') exonuclease digestion of uv-irradiated DNA, was used to detect (primarily) cyclobutane pyrimidine dimers and pyrimidine-pyrimidone (6-4) dimers. Hydrolysis of DNA by this enzyme is quantitatively blocked by both of these photoproducts. To detect (primarily) (6-4) dimers, Escherichia coli DNA photolyase was utilized to specifically reverse cyclobutane pyrimidine dimers.