FIG. 2.

Cellular DNA repair characteristics. (A) UV-induced (15 J/m² UVC) unscheduled DNA repair synthesis capacity (UDS) of primary homozygous Xpb^XPCS MEFs. A representative experiment (three experiments total) is depicted. The P value indicates the significance of the difference between WT and Xpb^XPCS within the representative experiment. Error bars indicate the SEM. (B) Recovery of RNA synthesis after UV (10 J/m² UVC) irradiation (RRS). A representative experiment (three experiments total) is depicted. The P value indicates the significance of the difference between WT and Xpb^XPCS within the representative experiment. Error bars indicate the SEM. (C) UV survival curves averaged from four independent experiments. At least 2 cell lines per genotype were included. Error bars indicate SEM between experiments. (D) Gamma ray survival curves averaged from five independent experiments with two cell lines per genotype. Error bars indicate the SEM between experiments. (E) Reduction of TFIIH protein levels in Xpb^XPCS, Xpd^TTD single-mutant, and Xpb^XPCS Xpd^TTD double-mutant primary MEFs by comparative immunofluorescence analysis of p62 subunit of TFIIH. Quantification of the immunofluorescence signal is based on analysis of at least 50 nuclei per genotype in two separate experiments with two independent cell lines per genotype. WT cells are labeled with latex beads, mixed with the mutant cells, and cultured and immunostained on the same microscopic slide. Bars representing cell lines analyzed on the same microscopic slide are depicted side by side. The P value indicates the minimum significant difference between WT versus mutant cell lines analyzed on the same microscopic slide within one experiment. (F) UV survival curves averaged from four independent experiments. At least two cell lines per genotype were included. Error bars indicate the SEM between experiments. (G) Hypersensitivity of the indicated cells to acute oxidative damage. Gamma ray survival curves averaged from two independent experiments with two cell lines per genotype. Error bars indicate the SEM between experiments and lie within the symbol size. (H) Hypersensitivity of Xpb^XPCS Xpd^TTD and Xpa Xpb^XPCS cells to chronic oxidative injury. MEF cells of the indicated genotype were cultured in the continuous presence of the indicated concentration of paraquat for 3 days. Two cell lines per genotype were tested. For reasons of simplicity, on the depicted representative survival experiment, results from two independent cell lines for Xpb^XPCS and Xpa Xpb^XPCS cells were averaged and error bars depict the SEM between two independent cell lines within the given experiment. For the other genotypes in the given experiment, one cell line per genotype was used and error bars depict the SEM within the experiment.