Effect of p51↓RNH ± T477A mutations on ordered intravirion processing of Gag and Gag-Pol polyproteins. Virus-containing culture supernatants derived from the transfection of COS-7 cells in the presence of various concentrations of ritonavir were subjected to SDS-10% PAGE resolution and Western blotting analysis. (A) Pr160Gag-Pol and (B) Pr55gag polyprotein processing intermediates were visualized with anti-RT and anti-p24 monoclonal antibodies respectively, followed by ECL exposure. Analyses of p51↓RNH mutant viruses containing the wild-type 477T or the mutant 477A are in the left and right panels, respectively. The positions of molecular size markers are shown to the left of each panel. Lines to the right of each panel indicate the positions and estimated molecular masses of predicted polyprotein processing intermediates [24, 27].