Chk1 and Chk2 are not activated in induced pluripotent stem cells in response to MNNG, but p53 is.
A, Western blot analysis of phospho-Chk1, phospho-Chk2, total Chk1, and total Chk2 in HeLa and YK26 cells with or without 2 μm MNNG treatment for 24 h. B, Western blot analysis of phospho-Chk1, phospho-Chk2, total Chk1, total Chk2, phospho-p53, and total p53 in H1, CT-2, and Rx13 cells with or without 2 μm MNNG treatment for 24 h. C, Western blot analysis of phospho-Chk1, phospho-Chk2, total Chk1, total Chk2, and γH2AX in YK26 cells originally synchronized in mitosis with nocodazole and then, with or without a 4-h treatment with 2 μm MNNG, harvested at different time points after release. D, quantitation of Western blots represented in C. E, Western blot analysis of phospho-p53 (Ser-15) and total p53 in control or MSH2 knockdown (KD) YK26 cells with or without 2 μm MNNG treatment for 24 h. Actin is included as a loading control. F, quantitation of Western blots represented in E. The values represent the means of three independent experiments. Error bars represent S.E.