GFP-M protein expression is not recovered by presence of NS1. 293 T cells were transfected with plasmid mixes to express recombinant vRNPs containing influenza RdRP with either WT-NP, del20NLS-NP, or no NP, and either GFP-M vRNA or FLAG-M vRNA in the presence or absence of NS1 as indicated. Total protein was separated by SDS-PAGE and analyzed by Western blotting. Anti-Udorn antibody detects NP and M1 products. Anti-NS1 detects NS1. Anti-tubulin detects tubulin and serves as a loading control. Shown is a representative experiment, repeated in triplicate.