Influence of Siah1 on DNA damage in response to IR. A: transfected SKBR3 cells were irradiated with a single dose of 4 Gy followed by immunofluorescence at the 3 and 6 h after IR. Unirradiated cells were used as control. Siah1L significantly increased γH2AX foci at 3 h and the latter were more persistent and numerous 6 h post-IR. Quantitative analysis of γH2AX foci per cell averaged over 100 cells per data point. Columns, mean; bars, SE; *, P < 0.01. B: Representative merged images of DAPI (blue) and γH2AX (red) at 3 h and 6 h post-IR are shown. Scale bars, 10 μm.