Fig. 3.

Nsp1 mutant viral protein expression and processing. Cytoplasmic lysates were generated from radiolabeled DBT-9 cells that were either mock-infected (m) or infected with icwt or nsp1 mutant viruses. Labeled proteins were immunoprecipitated from cytoplasmic lysates with the indicated polyclonal antisera. Proteins were resolved by SDS-PAGE in 5–18% polyacrylamide gradient gels and visualized following fluorography. Images were obtained following 4-day film exposure. Bands corresponding to unique or predicted proteins are indicated on the right of the fluorograms, and molecular weight standards (in kilodaltons) are shown on the left. The MHV structural proteins are designated as follows: spike (S), nucleocapsid (N), and membrane (M). The antisera used for immunoprecipitation are indicated: (A) α-nsp1; (B) α-nsp2; (C) α-nsp8; and (D) α-MHV.