FIG. 2.

vAcIE2 can activate both CMV and SV40, with an effective dosage as low as an MOI of 5. (A) Fluorescence microscopy showed that IE2 strongly activated both CMV and SV40 promoters for gene expression. All viruses were added at an MOI of 150, and photos were taken at 43 h p.t. −, minus; +, plus. (B and C) vAcE at an MOI of 20 was added with vAcIE2 at an MOI of 0, 5, 10, 20 or 50. A vAcE control at an MOI of 200 was also included as a comparison. Significant upregulation of the CMV promoter was seen with an MOI as low as 5 for both Vero E6 (B, panel a) and U-2OS (C, panel a) cells by fluorescence microscopy. Flow cytometry analysis was used to calculate the fluorescence intensity (B and C, panels b) and transduction efficiency (B and C, panels c) of cells from each sample.