Figure 1.

Generation of a Chk1^Tg strain. (A) Region including Chk1 that was subcloned from the mouse genome. (B) Southern blot with an internal Chk1 probe, illustrating the presence of an integration site (8 kb) on the Chk1^Tg strain. The 5-kb band corresponds to the endogenous Chk1. (C) Representative picture of 4-mo-old WT and Chk1^Tg littermates. (D) Weight distribution of 1-mo-old WT and Chk1^Tg mice. (E) Chk1 Western blot in testis, spleen, and purified B cells after a 2-d stimulation with lipopolysaccharide from WT and Chk1^Tg mice. Data are representative of four independent analyses. (F) ATR, Chk1-P, Chk1, RPA-P, and Rad17-P Western blot in WT and Chk1^Tg littermate MEF, either untreated (C) or upon treatment with 2 mM HU for 3 h or 10 Gy IR for 1 h. Data are representative of two independent analyses. (G) Chk1-P, RPA-P, and Rad17-P Western blot in WT and Chk1^Tg littermate MEF upon treatment with 2 mM HU for 3 h in the presence or absence of 1 µM of ATR inhibitor (ATRi; ETP-46464). Data are representative of two independent analyses. β-Actin was used as a loading control in all Western blots. In D, center lines indicate mean values.