Fig. 3.

Real-time PCR showing the inhibition of IFN-β and luciferase gene transcription by coronavirus nsp1 proteins. Samples were analyzed using primers specific for human IFN-β gene, firefly or Renilla luciferase genes. Numbers represent ΔCt values normalized to endogenous 18S rRNA. The y-axis is inverted to reflect the inverse relationship between ΔCt and mRNA levels. Error bars indicate standard errors of triplicate treatments in three individual experiments. (A) 293 cells were transfected with nsp1-expressing plasmids or control plasmids and cells were stimulated with NDV for 24 h. B, 293 cells were co-transfected with IFN-β promoter-driven firefly luciferase-expressing plasmid and nsp1-expressing plasmids or control plasmids for 24 h. (C) 293 cells were co-transfected with CMV promoter-driven Renilla luciferase-expressing plasmid and nsp1-expressing plasmids or control plasmids for 24 h.