Figure 3.

p53 does not directly regulate mitochondrial biogenesis induced by γ-rays. (a) Electropherograms of the HPS11 cells inactivating TP53 mutation (p.156R>P) within the DNA binding domain of the protein. (b) Schematic representation of p53 domains. (c) Western blot analysis of p53 and its target gene p21 in HCT116^TP53KO, HCT116^TP53KO complemented with wild-type p53 (HCT116^p53) and with p.156R>P mutated p53 (HCT116^p53_R156P). Gamma tubulin was used as a loading control. One representative experiment of three is shown. (d) Relative mtDNA copy number and mtRNA transcription, in HPS11 and HCT116^TP53KO cells upon irradiation (IR). Data are mean±S.D. (n=3, t-test, *P<0.05 versus T0). (e) Relative mRNA quantification of PGC-1β in HPS11 and HCT116^TP53KO cells after irradiation. Data are mean±S.D. (n=3, t-test, *P<0.05 versus T0). (f) Western blot analysis of mitochondrial proteins upon IR. (g and h) MitoTracker Red (MTR) and Calcein-AM staining of HPS11 (g) and HCT116^TP53KO (h) cells to evaluate mitochondrial mass and network morphology prior (T0) and after irradiation (REC). Magnification × 63/1.4. Length bar corresponds to 25 μm