Figure 6. Human- but not avian-like virus growth depends on importin-α1 and -α7.

(A–D) Virus growth in importin silenced human cells. A549 cells were silenced using siRNA for importin-α1, -α3 or -α7 and infected at MOI of 0.001 with WSN-PB2_627K (A and B) or WSN-PB2_627E (C and D). Unsilenced (Mock) and control siRNA transfected cells (Ctrl) were used as a control. Virus titres were determined by plaque assay 72 and 96 hours post infection. As a further control negative siRNA silenced cells were infected (Ctrl). Data shown represent means of three to six independent experiments +/− standard deviations (SD) (*p<0.05, **p<0.01, ***p<0.001, by students t-test). (E) Confirmation of importin-α silencing in human A549 cells by Western blot analysis. GAPDH was used as a loading control.