Fig. 6. p53 modulates BLM function during HR and SCE. (A and B) The absence of wild-type p53 and BLM synergistically enhanced the rate of HR in (A) NHF and (B) BS, BS E6, BS A-15 and BS A-15 E6 cell lines. Cells were transfected with either pBHRF alone or with pBHRF with different expression plasmids, as indicated. At 36 h post-transfection, cells were harvested and analyzed by flow cytometry in a FACS Vantage (Becton Dickinson) machine. The fold difference of the GFP/BFP ratio for different sets of transfections is represented. (C) The absence of wild-type p53 further enhances the rate of SCE in BS cells. SCE measurements (mean ± SD) were carried out in BS, BS E6 (pool), BS E6 (clone 1), BS A-15 and BS A-15 E6 (clone 2) fibroblasts, and a diploid control. The P-values were obtained by Student’s t-test.