FIG. 7.

Dose-dependent inhibition of the IFN-α response against subgenomes by lactacystin and epoxomicin. (A) Cells were incubated with lactacystin and epoxomicin at the indicated concentrations for 7 h and then for an additional 12 h without the drugs. One hour after incubation with the proteasome inhibitors, IFN-α (100 IU/ml) was added for 6 h to a fraction of the cell culture plates (lanes 6 to 10 and 16 to 20). Viral RNA levels were determined by Northern blot analysis. rRNA was used as a control for the amount of RNA present in the samples. (B and C) The amount of viral RNA was measured with a phosphorimager, and values were plotted as percentages of the values obtained with untreated cells.