FIGURE 4.

Sensitivity of MEFs to UV light, camptothecin, or hydroxyurea. MEFs produced from PP5^+/+ (circles) or PP5^−/− (squares) animals were treated as indicated. After 24 h, cell viability was measured as described under “Experimental Procedures.” The data represent the means ± S.E. from three separate experiments in which four replicate plates for each condition and cell type were processed simultaneously. * (p < 0.01) and ** (p < 0.05) denote statistically significant differences (two-way ANOVA).