title: Screening for hepatitis C virus non-nucleotide resistance mutations in treatment-naive women.
abstract: OBJECTIVE
  Hepatitis C virus (HCV) non-nucleoside inhibitors (NNIs) target the viral RNA-dependent RNA polymerase encoded by the NS5B gene. Several NNIs share a similar allosteric binding site, and their antiviral efficacy is attenuated by a cysteine-to-tyrosine mutation at amino acid 316 (C316Y). In the current study, we assessed NS5B resistance mutations in treatment-naive individuals from a prospective natural history study of viral infections in women.
  
  
  METHODS
  Partial NS5B sequences from HCV-positive women were amplified by RT-PCR. Additionally, subcloning was performed to evaluate intrapatient variability in selected samples.
  
  
  RESULTS
  HCV NS5B genotypes were 45 genotype 1a (57.0%), 11 genotype 1b (13.9%), 5 genotype 2a (6.3%), 3 genotype 2b (3.8%), 9 genotype 3a (11.4%) and 6 genotype 4a (7.6%). One HCV genotype 1a-infected patient was found to have the C316Y mutation (1.3%). Clonal analysis further revealed that all NS5B sequences from this individual--representing three serum samples collected 4 years apart--contained the C316Y mutation. In contrast, the S282T resistance mutation was not found in any samples.
  
  
  CONCLUSIONS
  The C316Y polymerase resistance mutation was found in 1.3% of samples from HCV-infected women. The presence of this mutation over time suggests significant replicative fitness of this variant and has implications for development of new specifically targeted antiviral therapies against HCV (STAT-C) targeting this region.
authors.affiliation: Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Dryer
authors.forename: Berkeley N
authors.initials: BN
authors.lastname: Limketkai
authors.forename: Christina M
authors.initials: CM
authors.lastname: Martin
authors.forename: Gang
authors.initials: G
authors.lastname: Ma
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Sherman
authors.forename: Lynn E
authors.initials: LE
authors.lastname: Taylor
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Mayer
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Jamieson
authors.forename: Jason T
authors.initials: JT
authors.lastname: Blackard
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000494:pharmacology*; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D016174:Hepacivirus / Q000187:drug effects*; D006801:Humans; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase