FIG. 1.

Effects of mutations introduced in the PPT of an HIV-1-based retroviral vector on viral titer. Viruses containing mutations in the PPT were generated as described in Materials and Methods. Left columns, the names of the mutants (the wild-type control is labeled WT and is at the top row of each panel); middle columns, DNA sequences of the mutations in the PPT (mutated bases are underlined and shown in bold); right columns, virus titers (normalized to the amount of p24 in the virus-containing supernatants). The relative virus titers were determined from the linear range of dilution, as described in Materials and Methods. (A) Effects of G-to-A transition mutations on virus titer. (B) Effects of G-to-C transversion mutations on virus titer. (C) Effects of G-to-T transversion mutations on virus titer.