Figure 4. HIS does not correlate with increased p53 signalling pathway activation.

(a) Western blot analysis of p53 (Ser15), total p53, γH2AX, p21 and p27 levels in Prolif and agonescent/HIS (Ag/HIS) WT and BRCA1^mut/+ HMECs and Prolif and M0/HIS WT and BRCA1^mut/+ HDEs. Bar graphs bellow the blots show the average levels of p53 (Ser15), total p53, γH2AX, p21 and p27 levels determined using western blot analysis in Ag WT (n=3) and HIS BRCA1^mut/+ (n=3) HMECs and M0 WT (n=3) and HIS BRCA1^mut/+ (n=3) HDEs. (b) Representative images of IF staining for phospho-ATM/ATR substrates, γH2AX foci, p53BP1 foci in Ag WT and HIS BRCA1^mut/+ HMECs. Bar graphs under the images show the percent of cells positive for phospho-ATM/ATR substrates, the average number of γH2AX foci per field (avg number of cells per field WT=51, BRCA1=78) as well as the number of p53BP1 foci per field (avg number of cells per field WT=79, BRCA1=99). Student's two-tailed t-test was used to calculate P values. (*) indicates P value within the 0.05 level of significance. Error bar, s.e. Scale bar, 10 μm.