FIG. 2.

Expression of mutant proteins in stable NIH 3T3 cell lines. (A) Lysates of Env-expressing NIH 3T3 cells were boiled and reduced in sample buffer, separated by SDS-PAGE (11.5% gel), transferred to nitrocellulose, and Western blotted with anti-A tail antibodies. (B) A parallel set of Env-expressing cells were biotinylated with the membrane-impermeant reagent NHS-LC-biotin, lysed, and immunoprecipitated with anti-A tail antibodies as described in Materials and Methods. Immunecomplexes were analyzed by SDS-PAGE (11% gel), transferred to nitrocellulose, probed with streptavidin-HRP, and detected by ECL. The SU, TM, and Pr95 proteins migrated as shown.