FIG. 1.

Incorporation of mutant glycoprotein into virions. Alanine mutations were substituted for every residue of the cytoplasmic domain of the TM protein from leucine at position 2 to serine at position 33, as described elsewhere (70). Virus-containing supernatants from metabolically labeled COS-1 cells transfected with either wild-type or mutant pSARM4 constructs were centrifuged through a 25% sucrose cushion. The virus pellets were recovered, immunoprecipitated with goat anti-M-PMV serum, and analyzed by SDS-PAGE. The mutant designation is shown above each lane, and the positions of the viral proteins are indicated in the middle.