FIG. 1.
A substitution that disrupts the PPXY motif but not the overlapping P(T/S)APP motif in the Ebola virus-derived peptide ILPTAPPEYMEA abolishes L domain activity in a minimal Gag context. HeLa (A) or 293T (B) cells were transfected with variants of the highly L domain-dependent Δ-ZWT minimal HIV-1 Gag construct that have either the WT peptide or the Y/G mutant peptide at the C terminus. To compare the levels of VLP formation, particulate material released into the medium during 12 h of metabolic labeling (A) or during a 2-h chase period (B) was pelleted through sucrose and analyzed directly by SDS-PAGE (left panels). Cell-associated Gag protein was detected by immunoprecipitation with anti-CA antiserum (right panels). The positions of migration of molecular weight markers (in kilodaltons) are indicated.