Transfections used Lipofectamine 2000 (Life Technologies), preparing it with the DNA in Optimem (Life Technologies) per manufacturer's recommendations. The DNA–lipofectamine complexes were added to cells resuspended in growth media before plating. Transfected cells were placed back in the incubator for 3–5 h after transfection before any further treatment.
Sendai Virus (SeV) (Charles River Laboratories), was centrifuged to clarify the virus and stored at –80°C. For virus infections, we used 50 μl of virus per 1 ml of culture media. Interferon-β (Peprotech, catalog # 300–02BC) was used at 0.1 ng of IFN-β per 1 ml of culture media. These treatments were for 6 h, except for the Luciferase assays, which were for 24 h before prepping the cells for the assay.