Figure 3: Activity of the polymerase complexes in mouse-adapted H5N8 variants in human cells.

The replication and transcription activity levels of reconstituted viral polymerase complexes were measured. The PA, PB1, and PB2 genes of wild-type H5N8 viruses were substituted with polymerase subunits carrying mutations identified during mouse adaptation. The polymerase activity levels of ma452 variants and their single mutants (A), ma468 variants and their single mutants (B), and recombinant ma452 variants (C) were determined using a luciferase-based minigenome reporter assay in 293T cells. Activity values shown are the means of at least 3 assays. The bold formatting of mutations indicates addition of amino acid changes in the RNP complex. Asterisks indicate p-values (*P < 0.05; ***P < 0.0001) representing a statistically significant difference. Error bars indicate the SDs of the means.