FIG. 8.
m38.5 inhibits Bax- but not Bak-mediated cell death. (A) Fibroblasts from wt, Bax knockout, Bak knockout, or double-knockout mice were infected with the indicated viruses and treated with STS. The percent viabilities of STS-treated cells versus dimethyl sulfoxide-treated control cells are shown. Δm38.5, MCMVΔm38.5. (B) Fibroblasts expressing only Bak were transduced with retroviral vectors encoding m38.5, Bcl-XL, or GFP as a negative control. Bcl-XL but not m38.5 protected cells against STS-induced cell death. Two different concentrations of STS were used. (C) In fibroblasts expressing only Bax, Bcl-XL and m38.5 both protected against STS-induced apoptosis. (D) wt and Bax−/− fibroblasts were infected with the indicated viruses. Lysates of infected cells were subjected to Western blotting and immunoprecipitation (IP) with an anti-HA antibody to precipitate HA-tagged m38.5 and UL37x1 proteins. Bax was detected as a coprecipitating protein, indicating an interaction between the viral mitochondrial proteins and Bax. (E) Results of an experiment similar to that described in the legend to panel D. A recombinant MCMV expressing HA-tagged m41 protein (Rm41) was used as a negative control.