Mutational analysis of the hepatitis C virus E1 glycoprotein in retroviral pseudoparticles and cell-culture-derived H77/JFH1 chimeric infectious virus particles

Authors

  • R. S. Russell,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • K. Kawaguchi,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • J.-C. Meunier,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • S. Takikawa,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • K. Faulk,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • J. Bukh,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
    2. Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, and Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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  • R. H. Purcell,

    1. Hepatitis Viruses, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • S. U. Emerson

    1. Molecular Hepatitis Sections, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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  • RSR and KK contributed equally to this work.

R. S. Russell, Memorial University, Faculty of Medicine, Immunology & Infectious Diseases Program, Rm. H1815, 300 Prince Philip Drive, St John’s, Newfoundland, Canada A1B 3V6. E-mail: rodney.russell@med.mun.ca

Abstract

Summary.  Cell entry by enveloped viruses is mediated by viral glycoproteins, and generally involves a short hydrophobic peptide (fusion peptide) that inserts into the cellular membrane. An internal hydrophobic domain within E1 (aa262–290) of hepatitis C virus (HCV) may function as a fusion peptide. Retrovirus-based HCV-pseudotyped viruses (HCVpp; genotype 1a) containing Ala or Pro substitutions at conserved amino acid positions within this putative fusion peptide were generated. Mutation of conserved residues significantly reduced efficiency of HCVpp entry into Huh-7 cells. The majority of amino acid substitutions appeared to disrupt necessary interactions between E1 and E2. For some mutants, reductions in HCVpp-associated E1 were associated with the incorporation of a high molecular weight, hyperglycosylated E2 that displayed decreased CD81-binding. Other entry-deficient mutants displayed normal E1E2 incorporation into pseudoparticles and normal CD81-binding, and therefore might affect viral fusion. One mutant (S283P) consistently displayed two- to threefold higher infectivity than did wild-type. Three mutations that decreased HCVpp infectivity also reduced levels of HCVcc infectious virus production. However, the S283P mutation had a different effect in the two systems as it did not increase production of infectious HCVcc. This comprehensive mutational analysis of the putative HCV fusion peptide provides insight into the role of E1 in its interaction with E2 and in HCV entry.

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