FIGURE 3.

p53 is not required for repair of nitric oxide-induced DNA damage. INS 832/13 cells (200,000 cells/400 μl) were transfected with scrambled siRNA or siRNA targeted for p53 (30 nm). Forty-eight hours after transfection, cells were treated with IL-1 (10 units/ml) for 24 h or treated with IL-1 for 24 h followed by the addition of NMMA (2 mm) and 12-h incubation with both IL-1 + NMMA (repair conditions). A, the cells were harvested, and DNA damage was determined using the comet assay. B, alternatively, p53 levels were determined by Western blot analysis to control for gene knockdown. Results are the average ± S.E. (A) or representative of three experiments.