FIG. 1.

Measles virus V protein blocks IFN signal transduction. (A) 293T cells were transfected with an ISRE-luciferase reporter gene and either empty vector or measles virus V protein expression vector as indicated. Cells were treated with 1,000 U of IFN-α per ml for 14 h prior to lysis and luciferase assays (+) or left untreated (−). (B) The same experiment was carried out using a GAS-luciferase reporter gene and treatment with 5 ng of IFN-γ per ml. (C) Murine NIH3T3 fibroblasts were subject to ISRE-luciferase assays as above, but using 1,000 U of murine IFN-β per ml.