Fig. 1.

The VP40 proteins of RAVV and MARV inhibit IFN-α/β signaling in human but not mouse cells. Huh7 (A) or Hepa1.6 (B) cells were transfected with hSTAT1-GFP expression plasmid and either empty vector (pCAGGS) or the indicated expression plasmids encoding FLAG-tagged viral proteins. At 24 h posttransfection, the cells were treated with IFN-α/β (1,000 U/ml) for 30 min and analyzed by Western blotting for STAT1 phosphorylation. The total levels of STAT1-GFP were evaluated with an anti-GFP antibody, an anti-β-tubulin blot served as a loading control, and anti-FLAG antibody was used to assess viral protein expression. The asterisk (*) indicates the band that corresponds to FLAG-tagged LGTV NS5. (C) Hepa1.6 cells were either left untransfected or were transfected with empty vector (pCAGGS). At 36 h after transfection, IFN-β was measured by ELISA.