Figure 2

The budding defect resulting from S40F mutation becomes more apparent when PR is inactive. COS-1 cells were transfected with plasmids expressing HA-tagged HIV-1 Gag-WT (panels A and B) or Gag-S40F (panels C and D). Cells were prepared for examination by electron microscopy as described in Methods. Panels A and C , solid arrows, immature particles; open arrows, extended or tethered particles. Bars in panels A and C measure 500 nm; bars in panel B and D measure 100 nm. The relative frequencies of typical spherical particles and filopodia-like particles are summarized (panel E).