Fig 6.

(A) HSV γ₁34.5 inhibits IFN-β expression independently of PKR. PKR^−/− MEFs were either mock infected or infected with indicated viruses (5 PFU/cell). At 3 and 6 h after infection, total RNA extracted from cells was subjected to quantitative real-time PCR amplification. The level of IFN-β mRNA was normalized to the level of 18S rRNA, and fold induction was calculated as described in Materials and Methods. Results are representative of three independent experiments with standard deviations among triplicate samples. (B) Deletion of the γ₁34.5 amino terminus has no effect on HSV resistance to IFN-α. Vero cells were untreated or pretreated with IFN-α (Sigma) for 20 h. Cells were then infected with indicated viruses at 0.05 PFU per cell, and viral yields were determined at 48 h postinfection.