GC-->CG transversion mutation might be caused by 8-oxoguanine oxidation product.

Oxidation of d(A6GGA6)/d(T6CCT6) with sensitizer under different UV irradiation periods was examined. Enzymatic digestion of photolysate revealed that the amount of 8-oxoG initially increased with decrease of G and then decreased with the formation of Iz. In order to investigate whether Iz was formed by one electron oxidation of 8-oxoG through long-range hole migration, photoirradiation of anthraquinone-linked oligomer was examined. The results clearly demonstrated that 8-oxoG was efficiently converted to Iz under irradiation conditions. These results suggest that Iz generated from 8-oxoG induces GC->CG transversion under oxidative condition.