(C) The intensity of γH2AX is increased in cell expressing the E141A mutant following KillerRed-induced oxidative DNA lesions (left panel). Scale bar, 2 μm. The foci were indicated with white arrowheads. Scale bar, 0.5 μm. Right panel: the relative intensity of γH2AX at the site of tetR (intensity of γH2AX at the site of tetR/intensity of γH2AX area away from tetR) was quantified. Mean value with SD is the relative intensity of γH2AX in 20 cells. 