1887

Abstract

Investigation of the mechanisms underlying hepatitis C virus (HCV) envelope glycoprotein gene evolution will greatly assist rational development of broadly neutralizing antibody-based vaccines or vaccine components. Previously, comprehensive cross-genotype evolutionary studies of E1E2 have not been possible due to the paucity of full-length envelope gene sequences representative of all major HCV genotypes (1–6) deposited in international sequence databases. To address this shortfall, a full-length E1E2 clone panel, corresponding to genotypes of HCV that were previously under-represented, was generated. This panel, coupled with divergent isolates available via international sequence databases, was subjected to high-resolution methods for determining codon-substitution patterns, enabling a fine-scale dissection of the selective pressures operating on HCV E1E2. Whilst no evidence for positive selection was observed in E1, the E2 protein contained a number of sites under strong positive selection. A high proportion of these sites were located within the first hypervariable region (HVR1), and statistical analysis revealed that cross-genotype adaptive mutations were restricted to a subset of homologous positions within this region. Importantly, downstream of HVR1, a differential genotype-specific distribution of adaptive mutations was observed, suggesting that subtly different evolutionary pressures shape present-day genotype diversity in E2 outside HVR1. Despite these observations, it is demonstrated that purifying selection due to functional constraint is the major evolutionary force acting on HCV E1E2. These findings are important in the context of neutralizing-antibody vaccine targeting, as well as in contributing to our understanding of E1E2 function.

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2007-02-01
2020-01-21
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References

  1. Alter, M. J., Margolis, H. S., Krawczynski, K., Judson, F. N., Mares, A., Alexander, W. J., Hu, P. Y., Miller, J. K., Gerber, M. A. & other authors ( 1992; ). The natural history of community-acquired hepatitis C in the United States. The Sentinel Counties Chronic non-A, non-B Hepatitis Study Team. N Engl J Med 327, 1899–1905.[CrossRef]
    [Google Scholar]
  2. Anisimova, M., Bielawski, J. P. & Yang, Z. ( 2001; ). Accuracy and power of the likelihood ratio test in detecting adaptive molecular evolution. Mol Biol Evol 8, 1585–1592.
    [Google Scholar]
  3. Anisimova, M., Nielsen, R. & Yang, Z. ( 2003; ). Effect of recombination on the accuracy of the likelihood method for detecting positive selection at amino acid sites. Genetics 164, 1229–1236.
    [Google Scholar]
  4. Bartosch, B., Verney, G., Dreux, M., Donot, P., Morice, Y., Penin, F., Pawlotsky, J. M., Lavillette, D. & Cosset, F. L. ( 2005; ). An interplay between hypervariable region 1 of the hepatitis C virus E2 glycoprotein, the scavenger receptor BI, and high-density lipoprotein promotes both enhancement of infection and protection against neutralizing antibodies. J Virol 79, 8217–8229.[CrossRef]
    [Google Scholar]
  5. Beaumont, T., Quakkelaar, E., van Nuenen, A., Pantophlet, R. & Schuitemaker, H. ( 2004; ). Increased sensitivity to CD4 binding site-directed neutralization following in vitro propagation on primary lymphocytes of a neutralization-resistant human immunodeficiency virus IIIB strain isolated from an accidentally infected laboratory worker. J Virol 78, 5651–5657.[CrossRef]
    [Google Scholar]
  6. Brown, R. J. P., Juttla, V. S., Tarr, A. W., Finnis, R., Irving, W. L., Hemsley, S., Flower, D. R., Borrow, P. & Ball, J. K. ( 2005; ). Evolutionary dynamics of hepatitis C virus envelope genes during chronic infection. J Gen Virol 86, 1931–1942.[CrossRef]
    [Google Scholar]
  7. Bukh, J., Miller, R. H. & Purcell, R. H. ( 1995; ). Genetic heterogeneity of hepatitis C virus: quasispecies and genotypes. Semin Liver Dis 15, 41–63.[CrossRef]
    [Google Scholar]
  8. Callens, N., Ciczora, Y., Bartosch, B., Vu-Dac, N., Cosset, F. L., Pawlotsky, J. M., Penin, F. & Dubuisson, J. ( 2005).; Basic residues in hypervariable region 1 of hepatitis c virus envelope glycoprotein E2 contribute to virus entry. J Virol 79 , 15331 –15341. [CrossRef]
    [Google Scholar]
  9. Choisy, M., Woelk, C. H., Guegan, J. F. & Robertson, D. L. ( 2004; ). Comparative study of adaptive molecular evolution in different human immunodeficiency virus groups and subtypes. J Virol 78, 1962–1970.[CrossRef]
    [Google Scholar]
  10. Clayton, R. F., Owsianka, A., Aitken, J., Graham, S., Bhella, D. & Patel, A. H. ( 2002; ). Analysis of antigenicity and topology of E2 glycoprotein present on recombinant hepatitis C virus-like particles. J Virol 76, 7672–7682.[CrossRef]
    [Google Scholar]
  11. Cocquerel, L., Quinn, E. R., Flint, M., Hadlock, K. G., Foung, S. K. & Levy, S. ( 2003; ). Recognition of native hepatitis C virus E1E2 heterodimers by a human monoclonal antibody. J Virol 77, 1604–1609.[CrossRef]
    [Google Scholar]
  12. Farci, P., Alter, H. J., Wong, D. C., Miller, R. H., Govindarajan, S., Engle, R., Shapiro, M. & Purcell, R. H. ( 1994; ). Prevention of hepatitis C virus infection in chimpanzees after antibody-mediated in vitro neutralization. Proc Natl Acad Sci U S A 91, 7792–7796.[CrossRef]
    [Google Scholar]
  13. Farci, P., Shimoda, A., Wong, D., Cabezon, T., De Gioannis, D., Strazzera, A., Shimizu, Y., Shapiro, M., Alter, H. J. & Purcell, R. H. ( 1996; ). Prevention of hepatitis C virus infection in chimpanzees by hyperimmune serum against the hypervariable region 1 of the envelope 2 protein. Proc Natl Acad Sci U S A 93, 15394–15399.[CrossRef]
    [Google Scholar]
  14. Farci, P., Shimoda, A., Coiana, A., Diaz, G., Peddis, G., Melpolder, J. C., Strazzera, A., Chien, D. Y., Munoz, S. J. & other authors ( 2000; ). The outcome of acute hepatitis C predicted by the evolution of the viral quasispecies. Science 288, 339–344.[CrossRef]
    [Google Scholar]
  15. Felsenstein, J. ( 1985; ). Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39, 781–783.
    [Google Scholar]
  16. Flint, M., Maidens, C., Loomis-Price, L. D., Shotton, C., Dubuisson, J., Monk, P., Higginbottom, A., Levy, S. & McKeating, J. A. ( 1999; ). Characterization of hepatitis C virus E2 glycoprotein interaction with a putative cellular receptor, CD81. J Virol 73, 6235–6244.
    [Google Scholar]
  17. Fournillier, A., Wychowski, C., Boucreux, D., Baumert, T. F., Meunier, J. C., Jacobs, D., Muguet, S., Depla, E. & Inchauspe, G. ( 2001; ). Induction of hepatitis C virus E1 envelope protein-specific immune response can be enhanced by mutation of N-glycosylation sites. J Virol 75, 12088–12097.[CrossRef]
    [Google Scholar]
  18. Frasca, L., Del Porto, P., Tuosto, L., Marinari, B., Scotta, C., Carbonari, M., Nicosia, A. & Piccolella, E. ( 1999; ). Hypervariable region 1 variants act as TCR antagonists for hepatitis C virus-specific CD4+ T cells. J Immunol 163, 650–658.
    [Google Scholar]
  19. Goffard, A. & Dubuisson, J. ( 2003; ). Glycosylation of hepatitis C virus envelope proteins. Biochimie 85, 295–301.[CrossRef]
    [Google Scholar]
  20. Goffard, A., Callens, N., Bartosch, B., Wychowski, C., Cosset, F. L., Montpellier, C. & Dubuisson, J. ( 2005; ). Role of N-linked glycans in the functions of hepatitis C virus envelope glycoproteins. J Virol 79, 8400–8409.[CrossRef]
    [Google Scholar]
  21. Hadlock, K. G., Lanford, R. E., Perkins, S., Rowe, J., Yang, Q., Levy, S., Pileri, P., Abrignani, S. & Foung, S. K. ( 2000; ). Human monoclonal antibodies that inhibit binding of hepatitis C virus E2 protein to CD81 and recognize conserved conformational epitopes. J Virol 74, 10407–10416.[CrossRef]
    [Google Scholar]
  22. Heo, T. H., Chang, J. H., Lee, J. W., Foung, S. K., Dubuisson, J. & Kang, C. Y. ( 2004; ). Incomplete humoral immunity against hepatitis C virus is linked with distinct recognition of putative multiple receptors by E2 envelope glycoprotein. J Immunol 173, 446–455.[CrossRef]
    [Google Scholar]
  23. Hsu, M., Zhang, J., Flint, M., Logvinoff, C., Cheng-Mayer, C., Rice, C. M. & McKeating, J. A. ( 2003; ). Hepatitis C virus glycoproteins mediate pH-dependent cell entry of pseudotyped retroviral particles. Proc Natl Acad Sci U S A 100, 7271–7276.[CrossRef]
    [Google Scholar]
  24. Huang, X., Barchi, J. J., Jr, Lung, F. D., Roller, P. P., Nara, P. L., Muschik, J. & Garrity, R. R. ( 1997; ). Glycosylation affects both the three-dimensional structure and antibody binding properties of the HIV-1IIIB GP120 peptide RP135. Biochemistry 36, 10846–10856.[CrossRef]
    [Google Scholar]
  25. Kiepiela, P., Leslie, A. J., Honeyborne, I., Ramduth, D., Thobakgale, C., Chetty, S., Rathnavalu, P., Moore, C., Pfafferott, K. J. & other authors ( 2004; ). Dominant influence of HLA-B in mediating the potential co-evolution of HIV and HLA. Nature 432, 769–775.[CrossRef]
    [Google Scholar]
  26. Kumar, S., Tamura, K. & Nei, M. ( 2004; ). mega3: integrated software for Molecular Evolutionary Genetics Analysis and sequence alignment. Brief Bioinform 5, 150–163.[CrossRef]
    [Google Scholar]
  27. Lanford, R. E., Guerra, B., Chavez, D., Bigger, C., Brasky, K. M., Wang, X. H., Ray, S. C. & Thomas, D. L. ( 2004; ). Cross-genotype immunity to hepatitis C virus. J Virol 78, 1575–1581.[CrossRef]
    [Google Scholar]
  28. Lavillette, D., Tarr, A. W., Voisset, C., Donot, P., Bartosch, B., Bain, C., Patel, A. H., Dubuisson, J., Ball, J. K. & Cosset, F. L. ( 2005; ). Characterization of host-range and cell entry properties of the major genotypes and subtypes of hepatitis C virus. Hepatology 41, 265–274.[CrossRef]
    [Google Scholar]
  29. Li, Y., Luo, L., Rasool, N. & Kang, C. Y. ( 1993; ). Glycosylation is necessary for the correct folding of human immunodeficiency virus gp120 in CD4 binding. J Virol 67, 584–588.
    [Google Scholar]
  30. Lindenbach, B. D. & Rice, C. M. ( 2001; ). Flaviviridae: the viruses and their replication. In Fields Virology, 4th edn, pp. 991–1041. Edited by B. N. Fields, D. M. Knipe & P. M. Howley. New York: Lippincott Williams & Wilkins.
  31. Lole, K. S., Bollinger, R. C., Paranjape, R. S., Gadkari, D., Kulkarni, S. S., Novak, N. G., Ingersoll, R., Sheppard, H. W. & Ray, S. C. ( 1999; ). Full-length human immunodeficiency virus type 1 genomes from subtype C-infected seroconverters in India, with evidence of intersubtype recombination. J Virol 73, 152–160.
    [Google Scholar]
  32. Majid, A., Jackson, P., Lawal, Z., Pearson, G. M. J., Parker, H., Alexander, G. J. M., Allain, J.-P. & Petrik, J. ( 1999; ). Ontogeny of hepatitis C virus (HCV) hypervariable region 1 (HVR1) heterogeneity and HVR1 antibody responses over a 3 year period in a patient infected with HCV type 2b. J Gen Virol 80, 317–325.
    [Google Scholar]
  33. Martell, M., Esteban, J. I., Quer, J., Genesca, J., Weiner, A., Esteban, R., Guardia, J. & Gomez, J. ( 1992; ). Hepatitis C virus (HCV) circulates as a population of different but closely related genomes: quasispecies nature of HCV genome distribution. J Virol 66, 3225–3229.
    [Google Scholar]
  34. Meunier, J.-C., Fournillier, A., Choukhi, A., Cahour, A., Cocquerel, L., Dubuisson, J. & Wychowski, C. ( 1999; ). Analysis of the glycosylation sites of hepatitis C virus (HCV) glycoprotein E1 and the influence of E1 glycans on the formation of the HCV glycoprotein complex. J Gen Virol 80, 887–896.
    [Google Scholar]
  35. Moore, C. B., John, M., James, I. R., Christiansen, F. T., Witt, C. S. & Mallal, S. A. ( 2002; ). Evidence of HIV-1 adaptation to HLA-restricted immune responses at a population level. Science 296, 1439–1443.[CrossRef]
    [Google Scholar]
  36. Muller, R. ( 1996; ). The natural history of hepatitis C: clinical experiences. J Hepatol 24 (Suppl. 2), 52–54.[CrossRef]
    [Google Scholar]
  37. Owsianka, A., Clayton, R. F., Loomis-Price, L. D., McKeating, J. A. & Patel, A. H. ( 2001; ). Functional analysis of hepatitis C virus E2 glycoproteins and virus-like particles reveals structural dissimilarities between different forms of E2. J Gen Virol 82, 1877–1883.
    [Google Scholar]
  38. Owsianka, A., Tarr, A. W., Juttla, V. S., Lavillette, D., Bartosch, B., Cosset, F. L., Ball, J. K. & Patel, A. H. ( 2005; ). Monoclonal antibody AP33 defines a broadly neutralizing epitope on the hepatitis C virus E2 envelope glycoprotein. J Virol 79, 11095–11104.[CrossRef]
    [Google Scholar]
  39. Penin, F., Combet, C., Germanidis, G., Frainais, P. O., Deleage, G. & Pawlotsky, J.-M. ( 2001; ). Conservation of the conformation and positive charges of hepatitis C virus E2 envelope glycoprotein hypervariable region 1 points to a role in cell attachment. J Virol 75, 5703–5710.[CrossRef]
    [Google Scholar]
  40. Pinter, A., Honnen, W. J., He, Y., Gorny, M. K., Zolla-Pazner, S. & Kayman, S. C. ( 2004; ). The V1/V2 domain of gp120 is a global regulator of the sensitivity of primary human immunodeficiency virus type 1 isolates to neutralization by antibodies commonly induced upon infection. J Virol 78, 5205–5215.[CrossRef]
    [Google Scholar]
  41. Posada, D. & Crandall, K. A. ( 1998; ). modeltest: testing the model of DNA substitution. Bioinformatics 14, 817–818.[CrossRef]
    [Google Scholar]
  42. Pugach, P., Kuhmann, S. E., Taylor, J., Marozsan, A. J., Snyder, A., Ketas, T., Wolinsky, S. M., Korber, B. T. & Moore, J. P. ( 2004; ). The prolonged culture of human immunodeficiency virus type 1 in primary lymphocytes increases its sensitivity to neutralization by soluble CD4. Virology 321, 8–22.[CrossRef]
    [Google Scholar]
  43. Pybus, O. G., Drummond, A. J., Nakano, T., Robertson, B. H. & Rambaut, A. ( 2003; ). The epidemiology and iatrogenic transmission of hepatitis C virus in Egypt: a Bayesian coalescent approach. Mol Biol Evol 20, 381–387.[CrossRef]
    [Google Scholar]
  44. Pybus, O. G., Cochrane, A., Holmes, E. C. & Simmonds, P. ( 2005; ). The hepatitis C virus epidemic among injecting drug users. Infect Genet Evol 5, 131–139.[CrossRef]
    [Google Scholar]
  45. Ray, S. C., Wang, Y. M., Laeyendecker, O., Ticehurst, J. R., Villano, S. A. & Thomas, D. L. ( 1999; ). Acute hepatitis C virus structural gene sequences as predictors of persistent viremia: hypervariable region 1 as a decoy. J Virol 73, 2938–2946.
    [Google Scholar]
  46. Robertson, D. L., Hahn, B. H. & Sharp, P. M. ( 1995; ). Recombination in AIDS viruses. J Mol Evol 40, 249–259.[CrossRef]
    [Google Scholar]
  47. Robertson, B., Myers, G., Howard, C., Brettin, T., Bukh, J., Gaschen, B., Gojobori, T., Maertens, G., Mizokami, M. & other authors ( 1998; ). Classification, nomenclature, and database development for hepatitis C virus (HCV) and related viruses: proposals for standardization. International Committee on Virus Taxonomy. Arch Virol 143, 2493–2503.[CrossRef]
    [Google Scholar]
  48. Roccasecca, R., Ansuini, H., Vitelli, A., Meola, A., Scarselli, E., Acali, S., Pezzanera, M., Bruni Ercole, B., McKeating, J. & other authors ( 2003; ). Binding of the hepatitis C virus E2 glycoprotein to CD81 is strain specific and is modulated by a complex interplay between hypervariable regions 1 and 2. J Virol 77, 1856–1867.[CrossRef]
    [Google Scholar]
  49. Saito, I., Miyamura, T., Ohbayashi, A., Harada, H., Katayama, T., Kikuchi, S., Watanabe, Y., Koi, S., Onji, M. & other authors ( 1990; ). Hepatitis C virus infection is associated with the development of hepatocellular carcinoma. Proc Natl Acad Sci U S A 87, 6547–6549.[CrossRef]
    [Google Scholar]
  50. Saitou, N. & Nei, M. ( 1987; ). The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol 4, 406–425.
    [Google Scholar]
  51. Scarselli, E., Ansuini, H., Cerino, R., Roccasecca, R. M., Acali, S., Filocamo, G., Traboni, C., Nicosia, A., Cortese, R. & Vitelli, A. ( 2002; ). The human scavenger receptor class B type I is a novel candidate receptor for the hepatitis C virus. EMBO J 21, 5017–5025.[CrossRef]
    [Google Scholar]
  52. Schønning, K., Jansson, B., Olofsson, S. & Hansen, J.-E. S. ( 1996; ). Rapid selection for an N-linked oligosaccharide by monoclonal antibodies directed against the V3 loop of human immunodeficiency virus type 1. J Gen Virol 77, 753–758.[CrossRef]
    [Google Scholar]
  53. Sheridan, I., Pybus, O. G., Holmes, E. C. & Klenerman, P. ( 2004; ). High-resolution phylogenetic analysis of hepatitis C virus adaptation and its relationship to disease progression. J Virol 78, 3447–3454.[CrossRef]
    [Google Scholar]
  54. Shimizu, Y. K., Hijikata, M., Iwamoto, A., Alter, H. J., Purcell, R. H. & Yoshikura, H. ( 1994; ). Neutralizing antibodies against hepatitis C virus and the emergence of neutralization escape mutant viruses. J Virol 68, 1494–1500.
    [Google Scholar]
  55. Shimizu, Y. K., Igarashi, H., Kiyohara, T., Cabezon, T., Farci, P., Purcell, R. H. & Yoshikura, H. ( 1996; ). A hyperimmune serum against a synthetic peptide corresponding to the hypervariable region 1 of hepatitis C virus can prevent viral infection in cell cultures. Virology 223, 409–412.[CrossRef]
    [Google Scholar]
  56. Simmonds, P. ( 2001a; ). 2000 Fleming Lecture. The origin and evolution of hepatitis viruses in humans. J Gen Virol 82, 693–712.
    [Google Scholar]
  57. Simmonds, P. ( 2001b; ). Reconstructing the origins of human hepatitis viruses. Philos Trans R Soc Lond B Biol Sci 356, 1013–1026.[CrossRef]
    [Google Scholar]
  58. Simmonds, P. ( 2004; ). Genetic diversity and evolution of hepatitis C virus – 15 years on. J Gen Virol 85, 3173–3188.[CrossRef]
    [Google Scholar]
  59. Simmonds, P., Bukh, J., Combet, C., Deleage, G., Enomoto, N., Feinstone, S., Halfon, P., Inchauspe, G., Kuiken, C. & other authors ( 2005; ). Consensus proposals for a unified system of nomenclature of hepatitis C virus genotypes. Hepatology 42, 962–973.[CrossRef]
    [Google Scholar]
  60. Sullivan, J., Swofford, D. L. & Naylor, G. J. P. ( 1999; ). The effect of taxon sampling on estimating rate heterogeneity parameters of maximum-likelihood models. Mol Biol Evol 16, 1347–1356.[CrossRef]
    [Google Scholar]
  61. Swofford, D. L. ( 2003; ). paup*: phylogenetic analysis using parsinomy (*and other methods).: Version 4. Sunderland, MA: Sinauer Associates.
  62. Tamura, K. & Nei, M. ( 1993; ). Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees. Mol Biol Evol 10, 512–526.
    [Google Scholar]
  63. Tarr, A. W., Owsianka, A. M., Timms, J. M., McClure, C. P., Brown, R. J. P., Hickling, T. P., Pietschmann, T., Bartenschlager, R., Patel, A. H. & Ball, J. K. ( 2006; ). Characterization of the hepatitis C virus E2 epitope defined by the broadly neutralizing monoclonal antibody AP33. Hepatology 43, 592–601.[CrossRef]
    [Google Scholar]
  64. Triyatni, M., Vergalla, J., Davis, A. R., Hadlock, K. G., Foung, S. K. & Liang, T. J. ( 2002; ). Structural features of envelope proteins on hepatitis C virus-like particles as determined by anti-envelope monoclonal antibodies and CD81 binding. Virology 298, 124–132.[CrossRef]
    [Google Scholar]
  65. Wang, H. & Eckels, D. D. ( 1999; ). Mutations in immunodominant T cell epitopes derived from the nonstructural 3 protein of hepatitis C virus have the potential for generating escape variants that may have important consequences for T cell recognition. J Immunol 162, 4177–4183.
    [Google Scholar]
  66. Wei, X., Decker, J. M., Wang, S., Hui, H., Kappes, J. C., Wu, X., Salazar-Gonzalez, J. F., Salazar, M. G., Kilby, J. M. & other authors ( 2003; ). Antibody neutralization and escape by HIV-1. Nature 422, 307–312.[CrossRef]
    [Google Scholar]
  67. WHO ( 1999; ). Global surveillance and control of hepatitis C. Report of a WHO Consultation organized in collaboration with the Viral Hepatitis Prevention Board, Antwerp, Belgium. J Viral Hepat 6, 35–47.[CrossRef]
    [Google Scholar]
  68. Wu, Z., Kayman, S. C., Honnen, W., Revesz, K., Chen, H., Vijh-Warrier, S., Tilley, S. A., McKeating, J., Shotton, C. & Pinter, A. ( 1995; ). Characterization of neutralization epitopes in the V2 region of human immunodeficiency virus type 1 gp120: role of glycosylation in the correct folding of the V1/V2 domain. J Virol 69, 2271–2278.
    [Google Scholar]
  69. Yagnik, A. T., Lahm, A., Meola, A., Roccasecca, R. M., Ercole, B. B., Nicosia, A. & Tramontano, A. ( 2000; ). A model for the hepatitis C virus envelope glycoprotein E2. Proteins 40, 355–366.[CrossRef]
    [Google Scholar]
  70. Yang, Z. ( 1994a; ). Estimating the pattern of nucleotide substitution. J Mol Evol 39, 105–111.
    [Google Scholar]
  71. Yang, Z. ( 1994b; ). Maximum likelihood phylogenetic estimation from DNA sequences with variable rates over sites: approximate methods. J Mol Evol 39, 306–314.[CrossRef]
    [Google Scholar]
  72. Yang, Z. ( 1997; ). paml: a program package for phylogenetic analysis by maximum likelihood. Comput Appl Biosci 13, 555–556.
    [Google Scholar]
  73. Yang, Z. & Bielawski, J. P. ( 2000; ). Statistical methods for detecting molecular adaptation. Trends Ecol Evol 15, 496–503.[CrossRef]
    [Google Scholar]
  74. Yang, Z., Nielsen, R., Goldman, N. & Pedersen, A. M. ( 2000; ). Codon-substitution models for heterogeneous selection pressure at amino acid sites. Genetics 155, 431–449.
    [Google Scholar]
  75. Zhang, J., Randall, G., Higginbottom, A., Monk, P., Rice, C. M. & McKeating, J. A. ( 2004; ). CD81 is required for hepatitis C virus glycoprotein-mediated viral infection. J Virol 78, 1448–1455.[CrossRef]
    [Google Scholar]
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