Figure 5. Transcription of centromeric repeats in response to genotoxic stress requires a wildtype p53 context.

(A) Transcription of minor satellite repeats in WT (NIH3T3; p53^+/+) or null (p53^−/−) p53 contexts following ETOP treatment at the indicated time points, was analyzed as in Fig. 4A. *p < 0.05, **p < 0.01, ***p < 0.001 (unpaired t-test). (B) Enrichment of endogenous p53 at the p53 responsive element found at p21^CIP promoter (p21-p53RE) or at minor satellite repeats in NIH/3T3 cells after a 4 hr treatment with ETOP, Nutlin-3 (N3) or both (N3 + E), analyzed by ChIP-qPCR. Data are normalized to the input then to the control condition. *p < 0.05, **p < 0.01 (unpaired t-test). (C) CENP-A localization in p53^−/− fibroblasts treated with ETOP for 24 hr, analyzed as in Fig. 1A. Percentage of cells with delocalized CENP-A in p53^−/− cells compared to p53^+/+ cells are represented in the adjacent graph (n > 300 cells). Arrows point to the presence of micronuclei. ***p < 0.001 (chi-square test). (D) Percentage of cells with micronuclei in p53^−/− cells compared to p53^+/+ cells (n > 300 cells). ***p < 0.001 (chi-square test). CTRL: untreated cells; E: ETOP; N3: Nutlin-3a. Error bars represent S.E.M of at least three independent experiments. Images represent one focal plan. Scale bar, 10 μm.