Fig. 3.

Lethal virus production. (A) Schematic for the method for producing viruses harboring fusion-defective G proteins. Step 1, recombinant viruses were produced using the previously established method (42); however, a New Jersey G protein (shown in red) was included to complement the fusion-defective phenotype of the viruses. Step 2, viruses containing lethal mutations were passaged in cells expressing New Jersey G protein. Step 3, viruses which only expressed the altered G protein were produced, with a final round of amplification in the absence of New Jersey G. (B) A Coomassie-stained 10% low-bis SDS-PAGE gel of equal amounts of wild-type and altered VSIV G viruses. L, G, N, P, and M refer to the five viral proteins. The G/M ratio was determined and is an average of three experiments. (C) Plaque assays of samples shown in panel B. The assayed plaques were incubated for 24 h at 37°C.