VACV replication in 293T cells expressing APOBEC3G. A: An APOBEC3GmycHis expression plasmid was transiently transfected into 293T cells using the Fugene reagent (Roche, Penzberg) 48 h prior to infection. Transfection efficiency was determined by intracellular staining with a mouse anti-Myc antibody (BDBiosciences, Heidelberg) and a FITC-conjugated anti-mouse IgG antibody (Dianova, Hamburg) followed by FACS analysis, which showed that 59% of cells expressed APOBEC3GmycHis after transfection. B: APOBEC3GmycHis expression does not impair viral replication in 293T cells. 293T cells and 293T cells expressing APOBEC3GmycHis were infected with VACV strain WR at an MOI of 0.05 and viral titers were measured 0 and 24 h post infection by titration on RK13 cells.