FIGURE 3.

p27 loss collaborates with LT to promote anchorage-independent growth. A, p27 deficiency does not abrogate the confluence-dependent checkpoint in cells expressing LT. Foci were visualized by crystal violet staining. The graph displays the number of foci (mean and S.D.) per plate in three independent experiments with each line. The image is representative of one such experiment. B, p27 deficiency can complement anchorage-independent growth in ST-deficient cells. Representative images of colony growth after 5 weeks are shown. The graph displays the number of colonies (mean and S.D.) per well for three independent WT and p27^D51/D51 cell lines repeated three times. The Student's t test was used to determine the significance. C, first passage primary MEFs isolated from three independently derived WT or p27^D51/D51 embryos (denoted A, B, and C) were infected with SV40 (SV) or DL888 (DL), and the expression of LT and ST was determined by immunoblotting. Lamin B is a loading control.