FIG. 10.

PolH knockdown suppresses p53 activation at early times but enhances p53 activation at late times after UV irradiation. (A) p53 activation is decreased at early times after UV irradiation when PolH is knocked down. RKO cells that were uninduced or induced to knock down PolH were exposed to 20 J/m² of UV. At the indicated times after UV exposure, cells were collected and PolH, p53, and actin were detected by Western blot analysis. (B) p53 activation is increased at late times after UV irradiation in PolH knockdown cells. The parental and PolH knockdown RKO cells were irradiated with 12 J/m² of UV. At the indicated times, cells were collected and PolH, p53, and actin were detected by Western blot analysis.