Fig. 4

The phosphorylation level of DNA repair-associated proteins. a Quantification of the numbers of γ-H2AX foci in lv-iPSCs, ESCs and MEFs. Error bars represent the standard error of the mean (SEM) for the numbers of γ-H2AX foci per nucleus based on 4–5 fields, each containing approximately 20–30 cells. Significance of differences was assessed using Student’s t test. **P < 0.01 (three independent experiments). b Western blot analysis of phosphorylated ATM (p-ATM) and phosphorylated catalytic subunit of DNA protein kinase (p-DNA-PKcs) in lv-iPSCs and ESCs before and after ionizing irradiation. c Western blot analysis of the trimethylation level of H3K9 in lv-iPSCs and ESCs before and after ionizing irradiation