FIG. 2.

NIH 3T3 cells expressing vIRF-1 showed resistance to TNF-α-mediated apoptosis. (A) Expression of vIRF-1 mRNA in the clone (3T3/vIRF-1) selected for studies of apoptosis (Northern blot). The NIH 3T3 cell line expressing vIRF-1 was generated as described in Materials and Methods. (B) Comparison of TNF-α-induced cell killing in control NIH 3T3 cells and NIH 3T3/vIRF-1 cells. Cells were treated with the indicated concentrations of mouse TNF-α and actinomycin D (1 μg/ml) for 24 h, and the cell viability was determined by MTT assay. The data represent an average (± the standard error of the mean) of two separate experiments done in triplicate.