Figure 1.

Translesion synthesis past 8oxodG by ϕ29 DNA polymerase. The assay was carried out as described in the Materials and Methods section. Twenty-four nanomolar of either wild-type or mutant D12A/D66A (Exo⁻) DNA polymerase were incubated with ³²P-labelled primer/template DNA hybrid molecules, containing at the +3 position of the template either dG (X=G) or 8oxodG (X=8oxodG), and in the presence of the indicated concentration of the four dNTPs. After incubation for 5 min at 25°C, samples were analysed by 8 M urea–20% PAGE and autoradiography. Polymerization or 3′–5′ exonuclease activity are detected as an increase or decrease, respectively, in the size (13-mer) of the 5′-labelled primer.