Figure 1: Cellular transcriptional profiling-based siRNA screen for host factors involved in influenza A virus replication.

(a) Illustration of the siRNA screen procedures. IAVSG, influenza A virus-stimulated genes. (b) Functional classification of identified genes. Numbers of identified genes per category were indicated. (c) Immunofluorescence images of cells treated with control or FMRP-specific siRNA and infected with PR8 virus. Scale bar, 20 μm. (d) The reduction in the FMRP protein level correlated with the extent of NP nuclear accumulation. A549 cells were treated with control or three individual FMRP-specific siRNAs. After 48 h, cells were lysed and subjected to western blot analyses (left), or were infected with PR8 viruses (right, see also Supplementary Fig. 1f), followed by immunofluorescence analysis. Quantitative analyses were calculated by ratios of NP nuclear-retained cells/total infected cells (mean±s.d. of three independent experiments, *P<0.05, **P<0.01, n.s., not significant, two-tailed Student’s t-test). (e) FMRP knockdown resulted in NP nuclear retention in cells infected with H7N9 influenza A virus. A549 cells were treated with the indicated siRNA, infected with H7N9 influenza A virus (A/Anhui/1/2013) at an MOI of 0.1 for 9 h, and were subjected to the immunofluorescence assay and quantitatively analysed (mean±s.d. of three independent experiments, *P<0.05, two-tailed Student’s t-test). Scale bar, 20 μm.