Fig. 1

ZSCAN4 expression is reversely correlated with the extent of DSBs in mESCs. A Immunofluorescence images of the pZscan4-GFP mESCs. Note only a small subpopulation of cells (boxed in top row) express ZSCAN4 at a given time. Scale bar: 10 µm. B Left: western blot of γH2AX, PARP1, and ZSCAN4 the GFP⁺ (indicative of ZSCAN4 expressing) and GFP⁻ (indicative of ZSCAN4-negative) mESCs. Middle and right: quantitative levels of γH2AX and PARP1. Data are normalized to the GFP⁻ group and are represented as mean ± SEM. C Left: western blot of γH2AX, PARP1, and ZSCAN4 in the wildtype mESCs transiently expressing FLAG-ZSCAN4. Middle and right: quantitative levels of γH2AX and PARP1. Data are normalized to the GFP⁻ group and are represented as mean ± SEM. D Left: IF images of FLAG and γH2AX in wildtype mESCs transiently overexpressing FLAG-ZSCAN4. Scale bar: 20 µm. Right: quantitative percentage of cells with ≧10 γH2AX foci. Data are represented as mean ± SEM. E Left: IF images of FLAG and γH2AX in wildtype mESCs transiently overexpressing FLAG-ZSCAN4 with 0.01% H₂O₂ treatment. Scale bar: 20 µm. Middle: quantitative percentage of cells with ≧10 γH2AX foci. Data are represented as mean ± SEM. Right: fold change of the percentage of cells with ≧10 γH2AX foci after the H₂O₂ treatment. See also Additional file 1: Figs. S1, S2 and Table S2