Mutant del20NLS-NP defect is exacerbated as vRNA template length is increased. 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 (top panels) or GFP-NS vRNA (bottom panels) template, as indicated. A. GFP protein was visualized with a Nikon Eclipse TS100 (Nikon Intensilight C-HGFI for fluorescence). B. Total RNA was isolated, DNase treated, and 1 μg subjected to reverse transcription with oligo dT and PCR with gene specific primers for M and NS. Shown is a representative experiment, repeated in triplicate.