Fig. 5.
Brca1 and Chk1 mediate the mitotic exit DNA damage checkpoint. (A) Western blot analysis of the levels of Brca1 (Left) and Chk1 (Right) in the asynchronously growing control and knockdown cells. (B) FACS profiles of the control (Top), Brca1 knockdown (Middle), and Chk1 (Bottom) knockdown cells. The cells were arrested with nocodazole and mitotic cells were collected, irradiated, and released for 2.5 h. (C) Western blot analysis of cyclin B1 in the control (Upper) and Chk1 (Lower) knockdown cells. The cells were treated the same way as in B. (D) Quantitation of the data in C. (E) Western blot analysis of Cdh1 in cells from C. Notice the disappearance of the slower migrating form of Cdh1 in the irradiated samples.