FIG. 6.

IFN-α can repress endogenous Qp activity in type I cells. (A) Repression of endogenous Qp by IFN-α in Eli-BL cells. Lanes 1 and 2, undigested GAPDH and EBNA-1 probes, respectively; lanes 3 to 8, RNAs from Eli-BL (lanes 3 to 5) or Rael (lanes 6 to 8) cells were used for RPA; lanes 3 and 6, mock treatment; lanes 4 and 7, IFN-α treatment (500 U/ml, 48 h); lanes 5 and 8, IFN-γ treatment (500 U/ml, 48 h). The reduction of EBNA-1 mRNA by IFN-α was 53%. Data were obtained by normalizing EBNA-1 levels to the GAPDH level with the use of a PhosphorImager. One representative experiment of two independent experiments performed is shown. (B) IFN-α induces the expression of IRF-7 in Eli-BL cells. Protein lysates from Rael (lanes 1 to 3) or Eli-BL (lanes 4 to 6) cells from the same experiment as shown in panel A were separated by SDS-PAGE (8% gel) and stained with Ponceau S red after transfer of protein to the membrane. Lanes 1 and 4, mock treatment; lanes 2 and 5, IFN-α treatment; lanes 3 and 6, IFN-γ treatment. Western blots with IRF-7 and γ-tubulin antibodies were performed. (C) IFN-α induces ISG-15 expression in Rael cells. Equal amounts of protein lysates from Rael with IFN-α treatment (lanes 2 and 3) or mock treatment (lane 1) were separated by SDS-PAGE (12% gel) and stained with Ponceau S red after transfer of protein to the membrane. Western blotting with ISG-15 antibody was performed. ns, nonspecific band.