FIG. 5.

ICP27 transactivates the gC gene when its transcription is driven by the CMV IE promoter. (A) Induction of protein expression from the transiently transfected gCΔpro gene. Vero cells were transfected with pUC19 only (lane 2) or with pgC (lanes 3 to 6) or pgCΔpro (lanes 7 to 10). Transfections also included pSG1, which encodes ICP4 and ICP0 (lanes 4 and 8); pC27, which encodes ICP27 (lanes 5 and 9); or pSG1 plus pC27 (lanes 6 and 10). Protein analysis was carried out as done for Fig. 2. (B) Induction of mRNA from the transiently transfected gCΔpro gene. Vero cells were transfected with the plasmids indicated, as in panel A. RNA was prepared at 2 days posttransfection, and equal amounts were subjected to Northern analysis using a gC gene-specific probe. Lane 1 contains RNA from HSV-1-infected Vero cells. A shorter autoradiographic exposure of this lane is shown. (C) Expression of an intronless CMV-β-galactosidase gene is unaffected by ICP27. Vero cells were transfected with pUC19 only (lane 1) or with pCMVβ-c (lanes 2 to 5). Increasing amounts of pC27 were added to the indicated transfections (lanes 3 to 5). Protein analysis was carried out as in Fig. 2, except that detection was done using a monoclonal antibody specific for β-galactosidase. (D) Induction of the stably transfected gCΔpro gene. VgC3, VgC14 and VgC16 cells were transfected with pUC19 only (lane 2) or with 4 μg of each of the following plasmids: pK1-2 and pSHX, which encode ICP4 and ICP0, respectively (lane 4); pC27, which encodes ICP27 (lane 5); and pC27, pK1-2, and pSHZ (lane 6). No plasmid was added to the transfection shown in lane 3. Protein analysis was carried out as done for Fig. 2. Lane 1 contains protein extract from HSV-1-infected Vero cells.