Fig. 2: Enhanced reimport of viral polymerase complex proteins and cytoplasmic vRNP accumulation with disrupted segment stoichiometry upon RANBP2 knockdown.

a PB1, PB2, PA and NP protein levels in A549 cells transduced with control or RANBP2 shRNA and infected with IAV (MOI 4) at 6 hpi. b Band intensities normalized to actin and control (mean ± SEM; n = 3). c PB1, PB2 and PA levels in nuclear (N) and cytoplasmic (C) fractions after 2 h KPT-330 treatment and 6 h infection (MOI 0.5); lamin and tubulin used as fractionation controls. d Nuclear band intensities (n = 5) normalized to lamin and control (mean ± SEM; PB1, p = 0.0149; PB2, p = 0.0423; PA, p = 0.0059). e PB1 staining in infected A549 cells at 6 hpi. Scale bar: 20 µm. f Nuclear PB1 fluorescence quantification (n = 3; 32-34 cells per condition; p < 0.0001). g Strand- and segment-specific RTqPCR strategy for vRNA and cRNA amplification. Cytoplasmic and nuclear vRNA abundances for each segment at 6 hpi, expressed as percentages of their sum: representative experiment (h), all segments pooled (i) (n = 2, p = 0.001), or box-and-whisker plots (median, 25th–75th percentiles, min/max, and standard deviation (SD); p = 0.001). Dots represent biological replicates (mean of technical triplicates). Statistical tests: two-tailed unpaired Student’s t-test (b, d, f) or Kolmogorov-Smirnov test (i, j). ns: non-significant.