FIG. 2.

Protein VP90 is found soluble and associated with membranes in the cells. Cytoplasmic extracts of untreated and infected cells (A) or cells treated for 30 min with TX-100 at room temperature (B) were fractionated by density gradients, and fractions were separated by 7.5% SDS-PAGE and immunoblotted with anti-TYVD antibodies. In vitro-translated VP90 labeled with ³⁵S-Express label in the absence (C) or in the presence (D) of microsomes or in the presence of microsomes but with previous treatment with TX-100 (E) was loaded in the density gradients. ORF1a was in vitro translated in the presence of microsomes, and the p20 amino-terminal product of nsp1a was immunoprecipitated with anti-1a-1 antibodies (F) (16). Viral proteins in panels C to F were separated by SDS-PAGE and detected by autoradiography. The viral proteins VP90, VP70, and p20 are marked at the right.