Fig. 2.
Susceptibility to anti-Fas antibody–induced apoptosis is increased in c-FlipF/F;Alb-Cre mice. (A) Serum ALT concentrations. Sera were collected from c-FlipF/F and c-FlipF/F;Alb-Cre mice of the indicated ages. Results are means ± SEM of six to eight mice of each genotype. (B) Analysis of c-FLIP protein in the liver (L), spleen (S), and hepatocytes. Extracts of livers, spleens, and hepatocytes were prepared from 8-week-old c-FlipF/F and c-FlipF/F;Alb-Cre mice and were analyzed by Western blotting with antibodies against the indicated proteins. Results are representative of three independent experiments. (C to F) c-FlipF/F mice (n = 8) and c-FlipF/F;Alb-Cre mice (n = 5) mice were injected with anti-Fas antibody. Sera were collected, and mice were sacrificed 6 and 24 hours after injection. (C) Serum ALT concentrations were determined. Results are means ± SEM of five to eight mice of each genotype. (D) H&E-stained liver sections 6 and 24 hours after injection with anti-Fas antibody. Images are representative of five to eight mice of each genotype. Arrowheads indicate pyknotic nuclei. (E) Liver sections frozen 6 hours after injection with anti-Fas antibody were stained with anti–active caspase-3 antibody (red), and nuclei were stained with Hoechst 33258 (blue). Lower panels show merged images. Images are representative of two mice of each genotype. (F) Liver extracts harvested at the indicated times were analyzed by Western blotting with antibodies specific for the indicated proteins. Data are representative of three to four mice of each genotype. P and C indicate the proform and the cleaved form of caspase-3, respectively. *P < 0.05; **P < 0.01; ns, not significant. Scale bars, 100 µm.