FIGURE 3.

OGG1 stimulates the poly(ADP-ribosyl)ation activity of PARP-1. A and B, PARP-1 activity was measured by determining the amount of PAR deposited on immobilized histones in an ELISA assay. The addition of OGG1 (0.5 μg) increased the amount of PAR synthesis by PARP-1 (2 ng). B, ELISA assays were performed with or without activated DNA. The histograms show the averages + S.E. from triplicate (A) and quadruplicate (B) experiments. **, p < 0.01 compared with untreated control by Student's t test for A. *, p < 0.05 and ***, p < 0.001 for the indicated comparisons in B using one-way analysis of variance and Tukey's post-hoc test.