TABLE 1.

Encapsidation of luciferase into virus particlesa

Plasmid transfectedLuciferase activity (counts/s/10 μl)
pFB-ψlucpψEGFPpGag-polpEnvpEnv-luc1pEnv-luc2Cell lysateSupernatantPelletLysed/unlysed ratio
+++0108NDb
+++574,0001,10122ND
+++2,212,00055697515
+++2,022,0003502431
++++ND2,1452,89111
  • a First, 293 cells were transfected with the plasmids indicated, and after 36 h, the supernatants were harvested, passed through a 0.45-μm filter, and tested for luciferase activity. Part of the supernatant (0.25 ml) was overlaid onto a 0.5-ml 20% (wt/vol) sucrose cushion, and pelleted material was collected after 1 h at 16,000 × g. Cells and pellets were lysed by resuspension in 1.0 or 0.1 ml of 1% NP-40, respectively; 10 μl was then used to determine luciferase activity. The lysed/unlysed ratio was determined by dividing the luciferase activity obtained from particles treated with 1% NP-40 by the activity for intact particles.

  • b ND, not determined.