GP enhancement is correlated with the entry susceptibility of the target cells. (A) EGP expression in HeLa cells enhances EGP/HIV transduction. HeLa Tet-On cells with EGP, ΔEGP or control vector were induced with dox and challenged with pseudotyped viruses. The luciferase activities were measured 48 h post-infection and are shown as percentage of the uninduced cells (100%). Data represents an average of at least three independent experiments. Bars, standard deviations. (B) EGP expression in Jurkat Tet-On cells does not enhance EGP/HIV transduction. Jurkat Tet-On cells expressing EGP or ΔEGP or control vector were challenged with luciferase reporter virus and luciferase activity in the cell lysates are shown in relative light units (RLU). Data represents an average of at least three independent experiments. Bars, standard deviations. (C) Enhancement of EGP/MLV pseudovirus transduction in HeLa Tet-On cells. HEK Tet-On cells with EGP, ΔEGP or control vector induced with dox were challenged with ΔEGP/MLV pseudovirion carrying a GFP reporter. The percentage of GFP expressing cells are shown as inserts in each panel.