title: Genetic heterogeneity of the NS3 protease gene in hepatitis C virus genotype 1 from untreated infected patients.
abstract: NS3 protease is essential for hepatitis C Virus (HCV) replication, and is one of the most promising targets for specific anti-HCV therapy. Its natural polymorphism has not been studied at the quasispecies level. In the present work, the genetic heterogeneity of the NS3 protease gene was analyzed in 17 HCV genotype 1 (5 subtypes 1a and 12 subtypes 1b) samples collected from infected patients before anti-viral therapy. A total of 294 clones were sequenced. Although the protease NS3 is considered to be one of the less variable genes in the HCV genome, variability of both nucleotide and amino acid sequences was found. In variants belonging to 1a and 1b subtypes, 224 and 267 of 543 positions showed one or more nucleotide substitutions, respectively. Forty and 74 of the 181 NS3 amino acid positions showed at least one mutation in HCV-1a and HCV-1b isolates, respectively. Most substitutions were conservative. This substantial polymorphism of the NS3 protease produced by HCV-1a and HCV-1b suggests that, despite the numerous functional and structural constraints, the enzyme is sufficiently flexible to tolerate substitutions.
authors.affiliation: Département de Microbiologie, CHU Morvan, 2 avenue Foch, 19609 Brest cedex, France. sophie.vallet@univ-brest.fr
authors.forename: Sophie
authors.initials: S
authors.lastname: Vallet
authors.forename: Stephanie
authors.initials: S
authors.lastname: Gouriou
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Nousbaum
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Legrand-Quillien
authors.forename: Alain
authors.initials: A
authors.lastname: Goudeau
authors.forename: Bertrand
authors.initials: B
authors.lastname: Picard
mesh_terms: D000595:Amino Acid Sequence; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D016174:Hepacivirus / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D006526:Hepatitis C / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D017422:Sequence Analysis, DNA; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases