Detection of tandem CC-->TT mutations induced by oxygen radicals using mutation-specific PCR.

DNA lesions caused by reactive oxygen species (ROS) are considered to be one of the major contributors to DNA damage and mutagenesis. In this study, we developed a modification of allele-specific PCR to detect CC-->TT mutations caused by oxidative damage. These tandem mutations have been previously demonstrated to be indicative of oxygen damage in the absence of UV-irradiation. Using a CC target site in the rat DNA polymerase beta (pol beta) gene and a thermostable restriction enzyme that cuts the wild type sequence but not the TT mutation, we demonstrate that the TT mutation can be preferentially amplified from plasmid DNA damaged by oxygen radicals but not other DNA-damaging agents. We evaluated the potential utility of this assay in screening for mutations in cells and in analyzing those that arise during clonal proliferation in carcinogenesis.