D471G amino acid substitution does not affect the anti-IFN-I function of LCMV-NP. Human 293T cells were co-transfected in triplicate with 0.5 μg of each of the IFNβ reporter plasmids (pIFNβ-GFP and pIFNβ-FFL), 0.1 μg of the indicated pC-NP HA-tagged expression vector, and 0.1 μg of pRL SV40 expression plasmid to normalize transfection efficiencies. At 16 hpt, cells were mock infected or infected with SeV (moi=3) to induce activation of the IFNβ promoter, and 24 hours later, GFP expression was assessed by fluorescence microscopy (A). Cell lysates were prepared for luciferase activities (B), and to detect expression of wt and mutant NPs by WB using an anti-HA antibody (C). GAPDH was used as a loading control. Reporter gene activation is shown as % of RLUs of a SeV-infected, empty-vector transfected control, after normalization by RL luminescence values. Numbers at the bottom of each WB lane represent the quantification of band intensities normalized to wt NP lane, as described in material and methods.