Fig. 2

Visualization of gH2AX foci and variation in the number of foci per cell in Syrian hamster fibroblasts. a Visualization of gH2AX foci in nuclei of cells at different stages of the cell cycle determined by Ki-67 staining (early-passage cells are shown). Bars are 5 µm (shown in G2 cell image for all interphase cells, and in M—for anaphase cell). b Examples of BL-treated (0 h after the treatment) G0 cells at the 1st passage with variable countable numbers of gH2AX foci and a cell containing multiple breakage sites with a uniform staining with the use of anti-gH2AX antibody. Bar is 5 µm. In a and b, maximal projections of confocal sections are shown. In late-passage cells, similar types of gH2AX focus distribution were observed as in G0 early-passage cells. DNA in a and b is counterstained with DAPI. c Bar chart representing average numbers of foci per cell nucleus in control and BL-treated G0, G1 and S-phase cells at the 1st passage collected at 0 h after BL treatment. Around 200 cells were analyzed for each phase of the cell cycle. Error bars represent ±3 SE