FIG. 1.

Coexpression of the SIVmac239 Gag and Env proteins. HeLa T4 cells were infected with vTF7-3 and transfected with plasmids encoding the Gag and wt Env proteins or SIV Env164RS. For better resolution of gp160 and gp120, an aliquot of the immunoprecipitated proteins was analyzed by SDS–7% PAGE. Fifteen hours posttransfection, the cells were labeled with [³⁵S]methionine/cysteine for 30 min and chased for 3, 5, 8, and 12 h, as indicated above the gels. Samples of cell lysates or media were immunoprecipitated, analyzed by SDS-PAGE, and visualized by autoradiography. Expression of wt SIV Env proteins (A), Env proteins coexpressed with the Gag proteins (B), SIV Env164RS protein (C), and mutant Env164RS coexpressed with Gag (D). gp160 and gp120 denote the Env precursor and surface proteins, respectively. The positions of molecular mass markers (in kilodaltons) used are indicated to the left of the gels.