title: Hepatitis C virus genotype 5a subgenomic replicons for evaluation of direct-acting antiviral agents.
abstract: Hepatitis C virus (HCV) exists as six major genotypes that differ in geographical distribution, pathogenesis, and response to antiviral therapy. In vitro replication systems for all HCV genotypes except genotype 5 have been reported. In this study, we recovered genotype 5a full-length genomes from four infected voluntary blood donors in South Africa and established a G418-selectable subgenomic replicon system using one of these strains. The replicon derived from the wild-type sequence failed to replicate in Huh-7.5 cells. However, the inclusion of the S2205I amino acid substitution, a cell culture-adaptive change originally described for a genotype 1b replicon, resulted in a small number of G418-resistant cell colonies. HCV RNA replication in these cells was confirmed by quantification of viral RNA and detection of the nonstructural protein NS5A. Sequence analysis of the viral RNAs isolated from multiple independent cell clones revealed the presence of several nonsynonymous mutations, which were localized mainly in the NS3 protein. These mutations, when introduced back into the parental backbone, significantly increased colony formation. To facilitate convenient monitoring of HCV RNA replication levels, the mutant with the highest replication level was further modified to express a fusion protein of firefly luciferase and neomycin phosphotransferase. Using such replicons from genotypes 1a, 1b, 2a, 3a, 4a, and 5a, we compared the effects of various HCV inhibitors on their replication. In conclusion, we have established an in vitro replication system for HCV genotype 5a, which will be useful for the development of pan-genotype anti-HCV compounds.
authors: Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA Laboratory of Virology, Department of Biological Sciences, School of Environmental and Health Sciences, North-West University, Mafikeng Campus, South Africa.
authors: Constance N
authors: CN
authors: Wose Kinge
authors: Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA.
authors: Christine
authors: C
authors: Espiritu
authors: Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Sandringham, Johannesburg, South Africa.
authors: Nishi
authors: N
authors: Prabdial-Sing
authors: Laboratory of Virology, Department of Biological Sciences, School of Environmental and Health Sciences, North-West University, Mafikeng Campus, South Africa.
authors: Nomathamsaqa Patricia
authors: NP
authors: Sithebe
authors: Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA msaeed@mail.rockefeller.edu ricec@mail.rockefeller.edu.
authors: Mohsan
authors: M
authors: Saeed
authors: Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA msaeed@mail.rockefeller.edu ricec@mail.rockefeller.edu.
authors: Charles M
authors: CM
authors: Rice
mesh_terms: D019943:Amino Acid Substitution / Q000187:drug effects / Q000235:genetics; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D005838:Genotype; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D009154:Mutation / Q000187:drug effects / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D012093:Replicon / Q000187:drug effects* / Q000235:genetics*; D014779:Virus Replication / Q000187:drug effects / Q000235:genetics
chemical_list: D000998:Antiviral Agents; D012367:RNA, Viral