The R150A NP mutant shows different activities in H5 and WSN(H1) polymerase backgrounds.

<p>(A) SPR of different concentrations of NP R150A mutant against immobilized RNA. (B) Co-immunoprecipitation of flag-tagged NP mutants with their myc-tagged counterparts. ‘+’ refers to the presence of the anti-myc antibodies while ‘−’ indicates their absence. (C) The wild-type and R150A mutant NP were subjected to RNP reconstitution assay in an H5 background and viral RNA (NA) levels were quantified by primer extension. A representative result of three independent experiments is shown. RNA levels of the NP R150A mutant were compared to those of wild-type NP, which was set to 100%. 5S rRNA was used to normalize the m-, c- and v-RNA levels. The quantitation represents the mean percentage ± standard deviations from three experiments. (D) RNP reconstitution assay of wild-type and R150A mutant NP in an WSN(H1) background (*, <i>P</i><0.05; **, <i>P</i><0.005).