Fig. 1

γH2AX and 53BP1 responses to γ-irradiation and etoposide in bat, human and mouse cells. a Western blot analysis of γH2AX in PaLung, WI-38 and MEF cells exposed to 10 Gy of γ-irradiation. Protein lysates were harvested at the indicated time points. Tubulin was used as a loading control. b Analysis of the average number of 53BP1 foci per cell for PaLung, WI-38 and MEF cells treated with 10 Gy of γ-irradiation. Immunofluorescence staining of 53BP1 was performed at the indicated time points. The number of foci in a minimum of 100 cells was quantified. Bars represent the means ± SDs of three independent experiments. c Western blot analysis of γH2AX in PaLung, WI-38 and MEF cells treated with 50 μM etoposide (Eto) for 3 h, followed by drug-free medium up to 12 h (starting at t = 0 h, indicated by arrow). Protein lysates were harvested at the indicated time points. Tubulin was used as a loading control. N.T stands for no treatment. All Western blot results shown are representative of at least three experimental repeats