Figure 3: Premature senescence is cell-type-specific.

(a) Representative images of IF staining for γH2AX foci in WT and BRCA1^mut/+ HMFs on day 100 in culture (same day in culture as proliferating HMECs). Graph under the images shows the average number of γH2AX foci per field (avg number of cells per field WT=278, BRCA1=182). (b) Representative images and summary table of significant genetic and chromosomal events determined by karyotype analysis in WT and BRCA1^mut/+ HMFs on day 100 in culture (same day in culture as proliferating HMECs). (c) Representative growth curves of WT (n=3) and BRCA1^mut/+(n=3) HMFs. (d) Western blot analysis of p16^INK4a, total p53, p53 (Ser15) and p21 levels in WT and BRCA1^mut/+ HMFs at indicated PDs. M1, senescence. (e) Representative growth curves of WT (n=3) and BRCA1^mut/+(n=3) HDEs. (f) LOH analysis in M* BRCA1^mut/+ HDEs from two patient samples. (g) Telomere erosion rate in WT (n=3) and BRCA1^mut/+ (n=3) HDEs. (h) Western blot analysis of p16^INK4a, total p53, p53 (Ser15) and p21 levels in WT and BRCA1^mut/+ HDEs at indicated PDs. M0, stasis. 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.