FIG. 6.

Compensatory mutations in NS proteins are isolated by passaging. (A) Putative topology diagram of the p7 to NS3 region of the HCV polyprotein. Positions of isolated mutations are designated. (B) Infectious virus production at 48 h postelectroporation of core alanine-substitution mutants with or without compensatory mutations. Infectious virus was detected by immunohistostaining for NS5A at 48 h postinoculation of naive cells. Nuclei were counterstained with hemotoxylin-2. Core mutations are designated on the left; additional mutations are described above. All mutations are according to J6/JFH polyprotein numbering.