Sensitivity of Mrad9b+/+, Mrad9b+/− and Mrad9b−/− mouse ES cells to DNA damaging agents. Continuous lines, closed circles, Mrad9b+/+ ES cells; Continuous lines, closed triangles, Mrad9b−/− ES cells; Dashed lines, closed squares, Mrad9b+/− ES cells #341; Dashed lines, closed diamonds, Mrad9b+/− ES cells #350. (A) Gamma rays; (B) Mitomycin C; (C) Hydroxyurea; (D) Cisplatin; (E) Ethyl methanesulfonate (EMS). Points are the mean of three to four experiments. Error bars indicate standard deviation.