FIG. 3.

Growth phenotype of ER-POT1 cells. (A) Growth in the presence of tamoxifen. 1, wild-type DT40; symbols 2 to 4, ER-POT1 clones 37, 16, and 25, respectively. (B) Growth after tamoxifen removal. Symbols 1 and 4, wild-type cells with or without tamoxifen (+Tam or −Tam, respectively); symbols 2 and 3, ER-POT1 clones 37 and 16, respectively, with drug; symbols 5 and 6, clones 37 and 16, respectively, without drug. (C to E) FACS analysis showing DNA content of ER-POT1 cells. (C) Cells were grown for 12, 16, 20, or 48 h without tamoxifen. (D) Caffeine (Caff) was added at the time of tamoxifen removal and the cells were harvested 20 h later. (E) Cells were grown for 20 h without tamoxifen and then caffeine was added for 2 h.