FIGURE 11.

Budding of endosomal Gag is regulated in time and space. A, endosomal exocytosis stimulates the release of endosomal Gag. HT1080 cells transfected with Gag-TC and treated for 8 h with cycloheximide were incubated for 10 min with 3 mm CaCl₂ in the absence (CaCl2) or presence of 10 mm ionomycin (CaCl2 + Iono). Cells were washed, and viral production was assessed after 30 additional minutes. Viral release was normalized to CaCl₂-treated cells. Mean of two experiments done in duplicate (±S.E.). B, inhibition of endosomal trafficking blocks the accumulation of HIV-1 Gag at sites of cellular contacts. HT* cells were treated or not with monensin, and HIV-1 Gag was detected by immunofluorescence with an antibody against CA(p24). The arrows point to sites of cellular contact.