FIGURE 2.

Expression of a miR-424 mimic inhibits RNA virus infection. (A) HeLa cells were transfected with a duplex RNA mimic of miR-424, the broadly antiviral miR-199a-3p, an siRNA against the DENV2 genome (DENV2 siRNA), or a negative control miRNA mimic (miR-Ct). Two days post-transfection, cells were infected with DENV2 (MOI = 10 ffu/cell) or WNV (MOI = 3 ffu/cell). Two (WNV) or 3 (DENV2) days p.i., cells were fixed and incubated with anti-flavivirus E antibody, and infected cells visualized with an Alexa Fluor–conjugated anti-mouse immunoglobulin antibody (green). Cell nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI) (blue). (B) Supernatants were collected from the above infected cells at 2 h, 1 day, and 2 days p.i., and infectious viral titers [displayed as focus-forming unit (ffu)/ml] determined by focus-forming assay on Vero cells. (C) HeLa cells transfected with the miR-424 mimic or negative control miRNA mimic were infected with CHKV, vesicular stomatitis virus (VSV), herpes simplex virus (HSV), or vaccinia virus (VacV) (MOI = 0.5 pfu/cell). Supernatants were collected 3 days p.i., and titers [displayed as plaque-forming unit (pfu)/ml] determined by plaque-forming assay on Vero cells. Results are representative of at least three independent experiments. (* p-value < 0.05, ** p-value < 0.01, **** p-value < 0.001).