(A) Distribution of Gag-GFP in 293T cells at 24-h post-transfection. Examples of cells exhibiting diffuse Gag only (left), PM accumulations (center), or PM + internal (Int; right) accumulations are shown. Samples were stained with Hoechst 33258 (blue). Scale bars indicate 4 μm.
(B) Quantification of Gag-GFP distribution in 293T cells. The number of cells in which Gag-GFP accumulation was observed at the PM, as internal and PM accumulations, or as a diffuse cytoplasmic signal only was counted. Approximately 100 cells were evaluated at each time point.
(C) Gag-GFP accumulates at both early and late endosomes. 293T cells expressing Gag-GFP (green) were fixed at 24-h post-transfection and stained with anti-CD63, anti-Lamp1, or anti-EEA1 antibodies (red). Alternatively, cells were co-transfected with CherryFP-Rab5a (red). Cells were stained with Hoechst 33258 (blue). Insets show expanded views of individual Gag puncta. Scale bars, from top to bottom, indicate 4 μm, 2 μm, 8 μm, and 2 μm.
(D) Quantification of Gag-GFP distribution in 293T in the presence of endocytosis inhibitors. 293T cells expressing Gag-GFP together with the indicated proteins were fixed at 24-h post-transfection and the proportion of cells (out of 100 counted) in which Gag was found at the PM, or both at internal accumulations and at the PM was determined.
(E) Western blot analysis of 293T cells expressing HIV-1 Gag-Pol in the presence of endocytosis inhibitors. Samples were collected at 24-h post-transfection as indicated, and cell and virion lysates were probed with anti-HIV-1 CA antibodies. Numerical values below the blots indicate VLP p24CA signal intensities, derived by densitometry.