FIG. 5.

Replication efficiencies of NS5B insertion sequence mutants. (A) Structures of replicons PI-JT/Xba and PI-JT/1b-1a. The XbaI site introduced after the stop codon of the HCV open reading frame and an NcoI site present at the same position in the 1a and 1b isolates are indicated. The sequence corresponding to the genotype 1a isolate is shaded in gray. The adaptive mutations E1202G, T1280I, and 2202ΔS are indicated by black dots. PI, poliovirus IRES; luc, firefly luciferase; EI, encephalomyocarditis virus IRES. (B) Different replicon RNAs, as specified at the bottom, were transfected into Huh-7 cells by electroporation. Luciferase activities were determined for the cell lysates and are given as percentages of the relative light units at 24, 48, and 72 h in comparison to those 4 h after transfection (100%). Replicon PI-luc/GND, which harbors an inactivating mutation in the GDD motif of NS5B, was used as a negative control.