A. A549 cells were transfected with control plasmid pcDNA 3.1 or plasmids encoding FLAG-tagged WT or mutant NS5 proteins. At 48 hrs post-transfection cells were treated with IFN-α (100 U/mL) for 2 hrs and then processed for indirect immunofluorescence. Images were acquired on a spinning disk confocal microscope with a 40X objective. NS5 positive cells are indicated by dashed white circles. Representative panels are shown. The experiment was repeated three times.B. Quantification of nuclearSTAT2 was performed using Volocity image analyses software. A minimum of 20 cells were counted for each sample. N.D.= not detected. Values are expressed as mean ± standard error. *P<0.05, **P<0.01 (Student's t-test); N=3 