β-HPV 5 and 8 E6 Disrupt Homology Dependent Double Strand Break Repair by Attenuating BRCA1 and BRCA2 Expression and Foci Formation
Fig 5
A mutant p300 that is resistant to β-HPV E6 mediated degradation rescues homology dependent repair of DSBs.
Immunofluorescence microscopy was used to measure the intensity of (A.) BRCA1 and (B.) BRCA2 as well as foci positive cells for (C.) p-H2AX, (D.) BRCA1, (E.) BRCA2 and (F.) RAD51 foci persistence in HFK cells transfected with p300 expression vectors following exposure to 4 gray of ionizing radiation. These charts depict the percentage of foci positive cells at the indicated time points after irradiation. p300A denotes p300 S1834A mutant. p300E denotes p300 S1834E mutant. For all experiments, error bars depict standard errors of the mean. Similarly, * denote points where β-HPV E6 expressing cells significantly differed from the values of the corresponding control cells determined by student T-test and with a p value ≤ 0.05. # denotes a statistically significant difference within a cell line between cells transfected with p300A and p300E. Finally, all experiments were conducted at least three times independently.