Figure 6. The cdN activity but not its protein amount was increased after interferon treatment in HCV replicon cells.

(A) HuH7 cells (lanes 1 and 2) or HCV replicon cells (lanes 3-6) were mock-treated (lanes 1, 3 and 5) or treated with interferon-α (10⁴ U/ml in lanes 2 and 6; 10³ U/ml in lane 4). At 72 hrs after treatment, proteins derived from these cells were analyzed using antibodies against NS5A to reflect HCV replication (upper panel), against cdN protein (middle panel) or against Erk-2 as a loading control (bottom panel). (B) The 5′(3′)-deoxyribonucleotidase activity was analyzed using cell lysates derived from (A).