Fig. 1

Image analysis in three dimensions using Acquiarium software. a Automatic detection of the cell nucleus (blue) marked with a yellow border line and counting of 21 γH2AX foci (red) inside the cell nucleus, visualized by yellow dots. The green regions emerge as EdU is newly incorporated during DNA synthesis. b A significantly higher count of γH2AX foci is seen in the nucleus of the cell in the middle of the field than in the adjacent cells. c The cell in the middle is strongly positive for EdU (green), suggesting that the cell passes through the S or G2 phase, and γH2AX foci result from replication stress. The hiPSC line CBIA-5 at low passage, non-irradiated control, γH2AX. A merge of 30 3-μm slices is shown. Scale bar = 5 μm. EdU 5-ethynyl-2′-deoxyuridine