Figure 5
The PB1 structure model derived peptides inhibit influenza virus polymerase activity and virus replication.
(A) Polymerase inhibitory activity of 10 model-derived peptide-GFP fusion proteins in influenza A virus minireplicon systems. The activity detected with samples containing Flag-GFP was set to 100%. PB11-25-GFP (1–25) was used as positive control. A transfection mixture without PB2 used as negative control.* indicates p < 0.05 (Student t-test). Error bars mean standard deviation (n = 3). (B) Location of these 10 peptides on the PB1 model. Five peptides with remarkable inhibitory effects were marked and colored with red while other five peptides with green. The N- and C- terminus of each peptide was marked with scissors. (C–D) The inhibitory effects of PB1481-515-GFP to H1N1 (A/WSN/33) (C) and H9N2 (A/Quail/HK/G1/97) (D) viruses replication in A549 cells. The activity detected with samples containing Flag-GFP (Flag-GFP) was set to 100% after subtracting background of uninfected samples (Mock). PB11-25 was used as positive control. (E). PB1481-515 can inhibit influenza virus IAV-Luc replication. 293T cells were transfected with PX/PB11-25/PB1481-515-GFP expressing plasmids, respectively. 24 h post transfection, cells were challenged with influenza virus (IAV-Luc) carrying Gaussia luciferase reporter gene at MOI = 0.25. 12 or 24 h p.i., activity of Gaussia luciferase from supernatant was detected using microplate reader. The activity from samples containing PX-GFP was set to 100%. (F). PB1481-515 can inhibit influenza virus (A/WSN/33) replication. 293T cells were transfected with PX/PB11-25/PB1481-515-GFP expressing plasmids. 24 h post transfection, cells were challenged with influenza virus (A/WSN/33) at MOI = 0.02. 12 h p.i., Western blot of whole cells extracts were conducted to determine the expression level of actin, GFP fusion proteins and influenza virus NP.
