NS5A and NS5B sequence alignment from RBV-resistant and RBV-sensitive replicon-containing cell lines. RNA was isolated from colony-derived cell lines, and the NS5 regions of the replicons were amplified by RT-PCR and sequenced. Cloned regions from different isolates were chosen randomly for sequencing. (A and B) Two separate RNA pools from RBV-resistant isolate 4-7. (C) RBV-resistant isolate 4-3. (D) RBV-sensitive control isolate 4-17. Gray circles, nonconserved amino acid changes; black squares, stop codon; open squares, existing adaptive change S232I; A, R246C; B, P351L; C, G404S; D, Q399L; E, S434P; F, E442G; G, L384H; H, I432T. Silent mutations are not shown.