Structure-based mutational analysis of the LLOV NP. (a) Transmission electron microscopy images of the negatively stained purified helical structure of the LLOV NP(full) mutant–RNA complex. A myc tag was fused to the C-terminus of the native and mutant LLOV NPs. Scale bar, 50 nm. (b) The assessment of the function of the LLOV NP-myc mutants on genome transcription and replication, evaluated via minigenome assays. The experiments were performed in pentaplicates (n = 5). Significance was set at P < 0.05 (*) and P < 0.001 (***).