Lack of direct involvement of 8-hydroxy-2′-deoxyguanosine in hypoxanthine-guanine phosphoribosyltransferase mutagenesis in V79 cells treated with N, N′-Bis(2-hydroxyperooxy-2-methoxyethyl)-1,4,5,8- naphthalenetetracarboxylicdiimide (NP-III) or Riboflavin

The object of this study is to investigate the relationship between a typical product of oxidative DNA damage, 8-hydroxy-2′-deoxyguanosine (8OHdG), and mutagenesis in V79 cells through a molecular analysis of hypoxanthine-guanine phosphoribosyltransferase (hprt) gene mutants. We performed a direct sequencing analysis of the cDNA of mutants obtained after treatment with N, N′-bis(2-hydroxyperoxy-2-methoxyethyl)-1,4,5,8- naphthalenetetracarboxylic-diimide (NP-III) or riboflavin, each of which induces the formation of 8OHdG in cellular DNA upon UVA irradiation. The frequency of mutation after both treatments was no more than 2 to 5 times the control value. A considerable number of the mutants could not be amplified by RT-PCR, and this was also the case for the control mutants. Among the mutants analyzed, deletions and a TA→AT transversion occurred predominantly. The reasons for the weak association of induction of 8OHdG with frequency of mutation and the possible mechanism of oxidative-stress-derived mutagenesis are discussed.