(A, B) C2C12 were transfected with a GFP expression vector and either TAp63γ or ΔNp63γ expression vectors. After 24 hr, cells were left untreated (Ct) or treated with FCCP (1 µM) or menadione (1 µM) for 24 hr. Cells were stained with Hoechst and examined with a fluorescence microscope (B). Above, GFP-positive control cells (untreated). Below, dead GFP-positive cell treated with FCCP. C2C12 cells were grown on coverslips coated with poly-ornithine in 24-wells plates. Cells were co-transfected with the indicated expression vectors (200 ng/well) and a GFP-expression vector (50 ng/well) as previously described (Broadley and Hartl, 2008). Cells were cultured for 18 hr with the indicated agents. Cells were subsequently washed with PBS and fixed with 4% paraformaldehyde for 15 min. After two washes, cells were incubated for 10 min with the Hoechst 33,342 staining agent (1 µg/ml, Sigma, Germany). GFP positive cells were then observed with an epi-fluorescent microscope (Zeiss, Germany) to assess the nucleus morphology. (C) C2C12 cells were transfected either with the ∆Np63γ expression vector or siRNA directed against the TA isoforms of Trp63. Cell survival was evaluated using MTT assay after 48 hr of treatment with the indicated drugs at 1 µM. *p<0.01 compared to control, as calculated by a one-way ANOVA test followed by a Tukey post-test.