FIGURE 2.

Extension of ³²P-labeled primers opposite G and N²- and O⁶-G adducts by human REV1 in the presence of all four dNTPs. A, opposite G, N²-MeG, N²-EtG, N²-IbG, N²-BzG, N²-NaphG, N²-AnthG, N²-BPG, and N²,N²-diMeG; B, opposite G, O⁶-MeG, O⁶-BzG, and O⁶-PobG. Primer (24-mer) was annealed with each of the 12 different 36-mer templates (Table 1) containing an unmodified G or N²- or O⁶-modified G placed at the 25th position from the 3′-end (see Fig. 1). Reactions were performed for 15 min with increasing concentrations of REV1 (0–50 nm) and a constant concentration of DNA substrate (100 nm primer-template) as indicated. ³²P-Labeled 24-mer primer was extended in the presence of all four dNTPs. The reaction products were analyzed by denaturing gel electrophoresis with subsequent phosphorimaging analysis.