FIG 3.

Expression of lncRNA IFITM4P is regulated by IFN signaling during viral infection. (A and B) A549 cells were transfected with poly(I·C) at the indicated concentrations for 4 h. The levels of lncRNA IFITM4P were examined by RT-PCR (A) and qRT-PCR (B). (C) Total RNAs were extracted from A549 cells infected or not infected with WSN for 14 h. The RNAs were then treated with or without calf intestine alkaline phosphatase (CIAP) and transfected into A549 cells for 4 h. Levels of lncRNA IFITM4P were examined by RT-PCR. (D and E) Knockout efficiency of RIG-I in A549 cells was assessed by Western blotting (D). RT-PCR (D) and qRT-PCR (E) were applied to examine lncRNA IFITM4P expression in RIG-I knockout or knockdown cells infected or not infected with WSN for 14 h (MOI of 0.5). (F and G) A549 cells were treated with BAY 11-7082 (8 μM) or the DMSO control 30 min before IAV infection. The RNA levels of lncRNA IFITM4P in A549 cells infected or not infected with WSN for 14 h were determined by RT-PCR (F) and qRT-PCR (G). (H) In A549 cells, knockdown efficiency of the NF-κB p65 subunit using siRNA was evaluated by Western blotting. The lncRNA IFITM4P levels in p65 knockdown or control cells infected or not infected with WSN for 14 h were detected by RT-PCR. (I) Native A549 cells were stimulated with supernatants from A549 cells infected or not infected with WSN for 14 h or were infected with WSN directly for 2 or 14 h. lncRNA IFITM4P expression was examined by RT-PCR. (J and K) A549 cells were treated with IFN-β at indicated concentrations for 2 h, and expression of lncRNA IFITM4P was examined by RT-PCR (J) and qRT-PCR (K). (L) lncRNA IFITM4P levels in IFNAR knockout or A549 control cells infected or not infected with WSN for 14 h were detected by RT-PCR. Data represent the mean values ± SEM (n = 3; *, P < 0.05; **, P < 0.01).