Figure 1

Effect of p53 , p21 ^Cip1 and Rb deficiency on hepatocyte sensitivity to TGFβ-induced apoptosis. Where appropriate cells were treated with TGFβ from 24 hours in culture. For apoptosis curves in A, B & C, each time point is the average percentage of apoptotic cells +/- SDV obtained from two cultures where 500 cells were counted. The experiment was repeated 3 times with similar results. Control cells are shown in all graphs; in blue control cells treated with TGFβ. Untreated controls are shown with open symbols. The tables show the p values of statistical analysis for pairwise comparison of apoptosis in the genotype of interest (see text and methods). A: p53 &Rb deficiency increase sensitivity to apoptosis. The curves show the % of apoptotic cells in control (▲,△); p53-/- (□,■); Rb-/- (○,●); and p53-/- Rb-/-(◇, ◆) cells treated (plain) or not (open) with TGFβ. B: p21 ^Cip1-deficiency has no effect on Rb -/- cells. The curve shows the percentage of apoptosis in cells of indicated genotypes either wild type (black/blue) or deleted for p21 ^Cip1 (red) treated or not with TGFβ. C: Cells deficient in both p53 and p21 ^Cip1 are less sensitive to TGFβ-induced apoptosis. Compare black symbols (single nulls for p53 or p21 ^Cip1) with red symbols (deficient in both p53 and p21 ^Cip1).