FIG. 5.

Viral replication, but not de novo host gene expression, is required for the VRP-mediated STAT1 blockade. (A) Vero-81 cells were either mock infected or infected with untreated VRP or VRP that had been exposed to UV light for 1 min (UV-VRP). At 6 h postinfection, cells were stimulated with 1,000 U of IFN/ml and analyzed as in Fig. 3. (B and C) Vero-81 cells were pretreated for 1 h in the absence or presence of the inhibitor ActD or CHx prior to infection with VRP (MOI = 10 IU/cell) or diluent (mock). Virus was allowed to bind to cells in the indicated treatment groups in the presence of each inhibitor for 1 h, after which the inoculum was replaced with medium containing the inhibitor. At 6 h postinfection (7 h of inhibitor treatment), cells were stimulated with IFN-β (1,000 U/ml) for 20 min, and STAT phosphorylation was assessed as described in Fig. 3.