FIG. 2.

Viral particle release of Gag mutants. (A) RIPA analysis of the expression of Gag polyproteins in transfected cells. Lysates from G418 mass culture of QT6 cells transfected with the mutant plasmids described in Fig. 1 were immunoprecipitated with anti-p10 antisera and electrophoresed on SDS-polyacrylamide gels, as described in Materials and Methods. The specific Gag polyproteins of the expected sizes are indicated by the asterisks. Abbreviations are same as in Fig. 1; untransf., untransfected cells. Two separate ΔMA transfectants are shown. (B) RIPA analysis of pelleted virus-like particles collected from supernatants. (C) Relative efficiency of particle release. The number of PhosphorImager machine units counted for each Gag band detected in the media was divided by the number obtained for the respective Gag band detected in the cells. These ratio were then normalized to the ratio obtained for the intact full-length Gag polyprotein by correcting for the number of methionines in the respective Gag mutants to give a relative efficiency of particle release. Each experiment was done four or five times, and the bars show the standard deviations.