Fig 7.

Polymerase activity of Norwegian viruses measured in a minigenome replicon assay. Four protein expression plasmids for PB2, PB1, PA, and NP derived from Norway3487 or Norway3568, pPolI-WNA-Flu expressing the NA gene encoding the firefly luciferase gene, and the pGL4.74[hRuc/TK] control plasmid were transfected into 293T cells and assayed for luciferase activity after a 24-h incubation at 37°C. Since Norway3487 and Norway3568 viruses do not differ in their PA and NP sequences, only combinations of PB1 and PB2 proteins were tested. 3487 and 3568, Norway3487 and Norway3568 viruses, respectively. The values shown are means ± standard deviations for the results of three independent experiments and are standardized to the activities of the expression plasmids for the Norway3568 RNP complex proteins (100%). Polymerase activities of replication complexes possessing the PB2 protein from Norway3487 virus were higher than those possessing PB2 from Norway3568 virus (P < 0.001).