Replication of SINV WT and nsP3MD mutants in mouse neuronal NSC34 cells. NSC34 cells were infected with SINV WT (TE strain) and nsP3 MD mutants N24A, G32A, G32E, G32S, Y114A, and TM (G32E/I113R/Y114N) at an MOI of 10. (A) Virus production was measured by plaque formation in Vero cells. The data are presented as means ± the SD obtained from three independent experiments *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 (TE versus nsP3 MD mutants N24A, G32A, G32E, Y114A, and TM). (B) Cell viability after infection was determined by trypan blue exclusion. The data are presented as means ± the SD obtained from three independent experiments of the numbers of viable cells compared to day 0 expressed as a percentage. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 (G32E versus TE and nsP3 MD mutants N24A, G32A, G32S, Y114A, and TM). Significance was determined by two-way ANOVA with Tukey’s multiple-comparison test.