Similar mutational property of 8-hydroxy-dGTP during DNA replication by cellular extracts with and without DNA polymerase eta

Abstract

Oxidative nucleotide lesions as well as oxidative DNA lesions appear to contribute to mutagenesis induced by ionizing radiation. We have studied roles of Y-family DNA polymerases, which are involved in translesional synthesis, in mutations induced by oxidative nucleotide lesions. In this study, we compared mutational property of 8-hydroxy-dGTP (8-OH-dGTP) during DNA replication by cellular extracts with and without DNA polymerase (pol) eta. Plasmid DNA containing the SV40 ori and the supF gene, the unmodified dNTPs, the SV40 large T antigen, and extracts of XP-V cells lacking DNA pol eta were incubated with and without 8-OH-dGTP. Replicated DNA was then transfected into an indicator E. coli strain KS40/pOF105, and the supF mutant frequency was measured. Extracts of HeLa cells were used as controls. Although the supF mutant frequency was increased by addition of 8-OH-dGTP, the frequency of mutation induced by 8-OH-dGTP was similar for XP-V and HeLa cell extracts. Thus, DNA pol eta is not major DNA pol which promotes incorporation of 8-OH-dGTP.