Fig. 5

Enhanced Gag-Pol auto-cleavage reduces virus yields and Gag-Pol viral incorporation. a Schematic representations of HIV-1 Gag-Pol expression constructs in a gag-pol frame shift (fs) mutation backbone are as described in the Fig. 4 caption. Striped (Wz) box denotes leucine zipper (LZ). Dashed line indicates deleted Gag coding sequence. “X” denotes a PR-inactivated mutation. Remaining C-terminal p6* residues are in boldface. Altered or additional residues are shown in italics. b, c Leucine zipper-induced Gag-Pol auto-cleavage enhancement leads to reductions in virion yields and Gag-Pol packaging. Indicated amounts of designated plasmids were co-expressed with 15 μg of an HIV-1 protease-defective (D25) Gag/Gag-Pol expression vector (panel b) or co-expressed with pGAG (panel c) at a DNA ratio of 1:10. Culture supernatants and cells were collected at 48–72 h post-transfection and subjected to Western immunoblotting. Indicated are HIV-1 Gag-Pol, 66/51RT, Pr55gag, p41gag and p24gag positions