Figure 5 Analysis of the activities of various NS3/4A proteases by polyprotein expression in transfected cells (A) and replication of viral RNA (B). (A) Analysis of polyprotein processing using NS3 to NS5B constructs containing given 1073–1081 epitope mutations. Huh‐7/T7 cells were transfected with the control plasmid, wild type (wt) construct, or plasmids containing the 1073–1081 epitope mutants. Four hours later proteins were radiolabelled metabolically with [³⁵S] methionine. Hepatitis C virus specific proteins were isolated from cell lysates by immunoprecipitation using given antisera and proteins were detected after sodium dodecyl sulphate‐polyacrylamide gel electrophoresis by autoradiography. (B) Transient replication of replicons carrying the luciferase reporter gene and given mutations in the NS3 1073–1081 epitope. Highly permissive Huh‐7 cells were transfected with 5 µg of replicon RNA, and luciferase activity was determined in cell lysates 4, 24, 48, 72, and 96 hours after transfection. RNA transfections and luciferase assays were performed in duplicate.