Env is a critical determinant of Gag-Pol packaging.

(A) Immunoblot data from pseudo-single cycle assays of the indicated viruses with an intact env (left) or env deletion (right) produced in SupT11-A3G cells. Immunoblots for the indicated proteins in viral particles (top panels) and producer cells (bottom panels) from one experiment representative of 3 biologically independent experiments. (B) Quantification of RT (p66 and p51) packaging levels in the indicated viruses with and without Env produced in SupT11-A3G cells. Viral particle RT band intensities were normalized to levels for WT virus, and then divided by relative p24 levels (mean +/- SD of data from 3 biologically independent experiments).