Fig. 3.

Amount of RPA foci per nucleus induced by charged particle and X-ray irradiation. The amount of RPA foci per nucleus induced by different ion species compared with the X-ray data from Figure 1 allocates the nuclear charged particle doses at ∼2 Gy of X-rays or lower. The indicated calculated nuclear particle doses and the corresponding foci numbers per nucleus are standardized to a total length of all traversals per nucleus of 18 μm. Error bars indicate the SEM. Inlay: U2OS cell nucleus irradiated with carbon ions under a low angle. The nucleus was hit by a single carbon ion as visualized by immunocytochemical staining of RPA (green). The RPA foci form typical streaks. The DNA is counterstained with ToPro3 (blue).