Influence of RSV infection on RNA Pol II dependent RSV-F expression levels. 293T cells were cotransfected with a Gaussia luciferase expression plasmid and the indicated RSV-F expression plasmids containing an inframe 3'-terminal myc-tag. Similar transfection efficiencies were controlled by measuring the Gaussia luciferase activity in cell supernatants (not shown). Six hours following transfection cells were infected with the GFP expressing recombinant RSV at an MOI of 2 (+). As negative control, cells were also left uninfected (-). GFP expression analysis revealed similar infection efficiencies (data not shown). Equal amounts of protein were analysed in non-reducing Western blot analysis using a monoclonal antibody to the myc-tag 48 h after transfection.