Figure 3.

Radiation-induced DSBs visualized by immunofluorescence staining of γH2AX and 53BP1. Cultured A549 lung cancer cells were immunostained for γH2AX and 53BP1 at 30 min or 24 h post-irradiation using X-rays at a dose of 1 Gy. DSBs are identified as foci of γH2AX and 53BP1. Merged images show high consistency between γH2AX foci and 53BP1 foci. A markedly smaller number of γH2AX and 53BP1 foci at 24 h compared with 30 min indicate the high capacity of the X-ray-resistant cell line for DSB repair.