Stem-loop structures II-IV of the 5' untranslated sequences are required for the expression of the full-length hepatitis C virus genome

Arch Virol. 2003 Mar;148(3):449-67. doi: 10.1007/s00705-002-0933-0.


The 5' and 3' untranslated regions (UTR) of the hepatitis C virus (HCV) genome contain stem-loop structures, which are important in viral gene expression and replication. In this study, the functional roles of the predicted stem-loop structures of HCV 5' UTR and 3' UTR in viral gene expression were examined using a chimeric clone of full-length HCV genomic cDNA clone and the gene for green fluorescent protein (GFP). High level expression of the HCV-GFP chimera in Huh-7 cells was accomplished by using a replication defective adenovirus that expresses T7 RNA polymerase and transcription plasmid containing full-length HCV-GFP chimera under the control of a T7 promoter. The HCV-GFP clone, with deletion of stem-loop I, expressed proteins in transfected Huh-7 cells at comparable levels to the wild type HCV clone. Other mutations of the 5' UTR, which either deleted or altered the base pairing of stem-loops II to IV, completely abolished the expression of HCV-GFP chimera. In contrast, deletion of 3' UTR sequences had no effect on HCV protein expression. These findings suggest that the stem-loop structures II to IV of HCV 5' UTR are necessary for protein expression, but that stem loop I is dispensable for protein translation. The stem-loop structures of 3' UTR of HCV genome appear to have no direct role in viral gene expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3' Untranslated Regions / chemistry
  • 3' Untranslated Regions / genetics
  • 5' Untranslated Regions / chemistry*
  • 5' Untranslated Regions / genetics
  • Base Sequence
  • Cell Line
  • Gene Expression Regulation, Viral*
  • Genome, Viral*
  • Green Fluorescent Proteins
  • Hepacivirus / genetics
  • Hepacivirus / metabolism*
  • Humans
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Molecular Sequence Data
  • Mutation
  • Protein Biosynthesis
  • RNA, Viral / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Viral Proteins / genetics
  • Viral Proteins / metabolism*


  • 3' Untranslated Regions
  • 5' Untranslated Regions
  • Luminescent Proteins
  • RNA, Viral
  • Recombinant Fusion Proteins
  • Viral Proteins
  • Green Fluorescent Proteins