抄録
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.
