FIG. 1.

Bypass of 8-oxoG and m6G lesions by the combined action of Polδ and Polζ. (A) DNA synthesis on an 8-oxoG-containing DNA template. Lanes 1 to 7, undamaged DNA; lanes 8 to 14, 8-oxoG-containing DNA. Sequences adjacent to the primer-template junction are shown for the 40-nt, 5′-³²P-labeled primer and 75-nt template. The position corresponding to the undamaged G or the 8-oxoG site on the template is indicated by ∗G. Yeast Polζ (10 nM), yeast Polδ (10 nM), or a combination of these two enzymes were incubated with the DNA substrate (20 nM) in the presence of each of the four dNTPs (5 or 100 μM) at 30°C for 10 min. The reaction products were resolved on a 15% denaturing polyacrylamide gel and visualized by autoradiography. The gel was analyzed by using a PhosphorImager, and the concentrations of the products of the synthesis past the undamaged G or 8-oxoG are indicated. (B) DNA synthesis on an m6G-containing DNA template. Lanes 1 to 7, undamaged DNA; lanes 8 to 14, m6G-containing DNA. Reactions were carried out as indicated in the legend for panel A, except that the incubation time of the reactions was 15 min.