Fig. 1.

UV sensitivity of TK6 and MCF-7 cells as a function of loss of BER factors in the absence of XPA. (A–C) Colony survival of human TK6 (A and B) and MCF-7 cells (C) carrying the indicated genotypes following exposure to UV. The dose of DNA-damaging agents is displayed on the x axis on a linear scale, while the percent fraction of surviving cells is displayed on the y axis on a logarithmic scale. Error bars show the SD of mean for three independent experiments. Percent survival was calculated as the percentage of surviving cells treated with DNA-damaging agents relative to the untreated surviving cells.