Figure 3. XPC^KD cells display increased proliferative capacity associated with an increased fraction of S phase cells and decreased length of S phase following an initial stalled phase.

(A) The proliferation capacities of shCtrl- or shXPC-transduced keratinocytes were measured by serial cell counts on different days after transduction. (B) The distribution of cells in the G₁, S, and G₂ phases was measured at the indicated time intervals after transduction using 7-AAD and BrdU staining. (C) Graphic representation of the distribution of cells in the G₁, S, and G₂ phases. The percentage of cells in each phase for shCtl-transduced keratinocytes was considered to be 100%. The results were then compared with the shCtrl and are expressed as the mean ± SD of 3 independent experiments. (D) DNA synthesis time was measured by a BrdU pulse assay. Results are shown as the average percentages of shCtrl ± SD of 3 independent experiments. *P < 0.05 for shXPC-transduced cells versus shCtrl-transduced cells at the indicated time points. (E) Total protein extracts were assessed for cell-cycle regulators by Western blot analysis. β-actin was used as a loading control.