FIG. 3.

Supernatant Mg²⁺-dependent RT activity measured 36 h after transfection of the indicated plasmids in CrFK, HeLa, and 293 cells. Widespread syncytia were present in cells transfected with CT5, CF1, CF1Δpol, or pHCMV-G. The last two plasmids were included as controls for cell lysis to verify the viral specificity of the RT activity. Supernatants from chronically infected CrFK cells and H9 cells (infected 2 weeks earlier with HIV-1 at an MOI of 1) were also assayed for comparison (right side of figure). Each value is the mean of triplicate measurements ± the standard error of the mean.