FIG. 4.

Protein maturation profile of reconstructed viruses. HeLa cells were transfected with reconstructed viral clones carrying the indicated Gag-PR combinations. Metabolically labelled viral particles released in the supernatant were purified on a sucrose cushion, lysed, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mature Gag proteins—MA, capsid, and NC—as well as mature Pol proteins—integrase (IN) and reverse transcriptase (RT)—are indicated, together with the full-length Gag precursor (Gag pr55) and the mature surface glycoprotein gp120. Identified cleavage intermediates are indicated in italics. Arrows point to additional partially cleaved precursors associated with mutated PR processing. Lane neg corresponds to mock transfected cells; lane mk contains the molecular weight marker proteins (with molecular masses of 220, 97, 66, 46, 30, 21, and 14 kDa).