<i>In vitro</i> polymerase activities of vRNPs and plaque formation of recombinant viruses.

<p>(A) Polymerase activities of reconstituted HB04 and HN05 vRNP complexes composed of the indicated plasmids. 293T cells were transfected with the pPolI-NS-Luc plasmid and pRL-TK (internal control plasmid) as well as plasmids expressing PB2, PB1, PA and NP derived from either the HB04 or HN05 virus. Cells were incubated at 37°C for 24 h, and Firefly and Renilla luciferase activities were measured in the cell lysates. The data are represented as the means ± SD of the three independent experiments, expressed as log₁₀ relative fold to HB04 RNP activity. (B) Plaque formation after virus titration in MDCK cells.