FIG 4.

Effect of GPS1 downregulation on influenza virus polymerase activity. (A) Virus polymerase activities in GPS1-downregulated cells were assessed by using a minireplicon assay. The luciferase activity of the AllStars siRNA-transfected cells was set at 100%. The expression of PB2, PB1, PA NP, and GPS1 was examined by Western blotting. The tests were performed in triplicate, and the error bars represent the standard deviation for triplicate samples. Statistical analysis was carried out by using ANOVA, followed by Dunnett’s test. ***, P < 0.001 for three independent experiments. (B) The stability of the viral proteins was examined. siRNA-treated cells were transfected with HA, NP, M1, or M2 protein-expressing plasmids. The cell lysates were harvested 24 h after the plasmid transfection, and viral proteins were detected by Western blotting.