A genotype 2b NS5B polymerase with novel substitutions supports replication of a chimeric HCV 1b:2b replicon containing a genotype 1b NS3-5A background

Antiviral Res. 2006 Jan;69(1):24-30. doi: 10.1016/j.antiviral.2005.08.005. Epub 2005 Nov 4.

Abstract

HCV diversity suggests that evaluation of HCV inhibitors for broad genotypic efficacy is warranted. The replicon system enables cell-culture compound efficacy evaluation against an active replication complex, and a functional replicon dependent upon a genotype 2b polymerase would augment existing cell-culture efficacy studies that are presently limited to genotype 1a, 1b, and 2a replicons. We made a chimeric Neo(r) 1b:2b replicon where genotype 2b NS5B was inserted into a genotype 1b NS3-5A background and transfected replicon RNA to generate Neo(r) cell lines. All cell lines contained novel substitutions within NS5B which were subsequently engineered into the parental 1b:2b replicon and shown to enhance replication to various degrees. A single NS5B M31I substitution enhanced replication to levels sufficiently robust to quantify sensitivity to HCV inhibitors in a transient replication assay. The M31I 1b:2b replicon was similarly sensitive to an active-site nucleoside inhibitor of NS5B as genotype 1b replicons, but was insensitive to two non-nucleoside inhibitors which were otherwise efficacious against the genotype 1b replicons. This work describes a novel HCV replicon sustained by a genotype 2b polymerase that is sufficiently robust for quantifiable analysis in a transient replication assay, and demonstrates its utility in characterizing anti-HCV compounds for cross-genotypic efficacy.

MeSH terms

  • Adenosine / analogs & derivatives
  • Adenosine / pharmacology
  • Cell Line
  • Hepacivirus / genetics*
  • Hepacivirus / physiology
  • Humans
  • Models, Molecular
  • RNA-Dependent RNA Polymerase / antagonists & inhibitors
  • RNA-Dependent RNA Polymerase / chemistry
  • RNA-Dependent RNA Polymerase / genetics*
  • Replicon*
  • Ribonucleoside Diphosphate Reductase / pharmacology
  • Species Specificity
  • Viral Nonstructural Proteins / antagonists & inhibitors
  • Viral Nonstructural Proteins / chemistry
  • Viral Nonstructural Proteins / genetics*
  • Virus Replication

Substances

  • Viral Nonstructural Proteins
  • Ribonucleoside Diphosphate Reductase
  • NS-5 protein, hepatitis C virus
  • RNA-Dependent RNA Polymerase
  • Adenosine