FIG. 7.
N-dINS-L8P mutant characterization. (A) N-dINS and N-dINS-L8P mutant focus formation. A focus-forming assay was performed as described in Materials and Methods. Mean plaque diameters ± standard errors of the mean are shown. (B) Western blot analysis of NS3 and NS2-3 expression. Cell lysates from cells infected with wt NADL, N-dINS, N-L8P, and N-dINS-L8P at an MOI of 18 for 18 h were analyzed in a Western blot probed with anti-NS3 monoclonal 20.10.6. The positions of NS2-3 protein, NS3 (arrowheads), and nonspecific bands (*) are indicated. (C) IFN production analysis in acute infection by BVDV Npro mutants. Bovine testicle cells were infected with the different BVDV strains at an MOI of 1. The supernatants were removed from infected cells after 24 h, clarified by centrifugation, added to the ISRE-Luc-Hygro reporter cell line, and incubated for 8 h. The luciferase assay was realized as described in Materials and Methods. The induction was calculated based on the mock-infected cells. The error bars indicate standard deviations.