FIG. 4.

Cell fractionation of MA-mutant Pr55^Gag. HeLa cells were transfected with pNL4-3/PR⁻ or derivatives containing the indicated MA mutations. Postnuclear supernatants were treated with no salt (top panel) or high salt (1 M NaCl; lower panel) and fractionated (Materials and Methods). Pr55^Gag and the transmembrane Env glycoprotein gp41 were detected by Western blotting. The percentage of Pr55^Gag in the pellet fraction, normalized to the wild-type (WT) value, is indicated under each lane. Approximately 70% of wild-type Pr55^Gag was detected in the pellet under either no- or high-salt conditions.