Figure 4.

The N terminal of the NP determines the resistance to the restriction of eqMx1. (A) The sequence alignment of NP from H7N9_ZJ13 and H3N8_JL89 showed the differences in AAs at 16 different positions. (B) The schematic presentation of mutant NP sequences generated using overlapping PCR. The NP sequences of H3N8_JL89 and H7N9_ZJ13 were divided into two segments at the N and C terminals (AAs position N = 1–200; C = 201–480). The figure shows the nucleotide positions where the site-directed mutants of NP sequences were generated. (C) The relative luciferase activity of chimeric clones of NP against eqMx1. Constructed site-directed mutants of the NP sequences were tested for their polymerase activities in the presence of an HA-tagged pcDNA-3.1 eqMx1 or pcDNA-3.1-HA empty control vector, transfection complexes of viral polymerases and reporter plasmids were made and the test was performed as described earlier. The expression levels of eqMx1 and NP proteins were assessed using western blotting. (Statistical differences between samples are indicated, according to a one-way ANOVA followed by a Dunnett’s test; NS = not significant, * 0.01 ≤ p < 0.05, *** p < 0.001. Error bars represent the SEM within one representative experiment).