Polymorphism of the capsid L1 gene of human papillomavirus types 31, 33, and 35 |
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| Authors: | Gilbert Cornut Simon Gagnon Catherine Hankins Deborah Money Karina Pourreaux Eduardo L. Franco François Coutlée for The Canadian Women's HIV Study Group |
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| Affiliation: | 1. Laboratoire de Virologie Moléculaire, Centre de Recherche and Département de Microbiologie‐Infectiologie, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada;2. Département de Médecine Sociale et Préventive, Université de Montréal, Montréal, Québec, Canada;3. Direction de la Santé Publique de Montréal‐Centre, Institut National de Santé Publique du Québec, Montréal, Québec, Canada;4. Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada;5. Division of Cancer Epidemiology, Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Québec, Canada;6. Département de Microbiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada;7. The Canadian Women's HIV Study Group includes the following investigators from across Canada: Halifax: Janet Conners, Rob Grimshaw, David Haase, Lynn Johnston, Wally Schlech, Arlo Yuzicappi‐Fayant. Hamilton: Stephen Landis, Fiona Smaill. London: Tom Austin, Ole Hammerberg, Ted Ralph. Montréal: Fran?ois Coutlée, Julian Falutz, Alex Ferenczy, Catherine Hankins, Marina Klein, Louise Labrecque, Normand Lapointe, Richard Lalonde, John Macleod, Grégoire No?l, Chantal Perron, Jean‐Pierre Routy, and Emil Toma. Ottawa: Claire Touchie, Garry Victor. Québec: Louise Coté, Hélène Senay, Sylvie Trottier. Saskatoon: Kurt Williams. Sherbrooke: Alain Piché. Sudbury: Roger Sandre. Toronto: Louise Binder, Donna Keystone, Anne Phillips, Anita Rachlis, Irving Salit, Cheryl Wagner, Sharon Walmsley. Vancouver: Paula Braitstein, David Burdge, Marianne Harris, Deborah Money, Julio Montaner. |
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| Abstract: | The L1 gene encodes for the major capsid protein of human papillomaviruses (HPV). There is limited information on the polymorphism of L1 for types related to HPV‐16. This report explores the polymorphism of L1 in phylogenetically related types 31, 33, and 35 compared to HPV‐16. Genital specimens collected from 732 HIV‐seropositive and 323 HIV‐seronegative women were screened for HPV DNA with consensus L1 PCR. Cervical samples positive for HPV‐16 (n = 74), HPV‐31 (n = 78), HPV‐33 (n = 37), and HPV‐35 (n = 58) were further characterized by PCR‐sequencing of the complete L1 gene. The number of nucleotide substitutions within L1 ranged from 19 for HPV‐33 to 52 for HPV‐31. The ratio of the number of variants/number of isolates tested was higher for HPV‐31 (56.4%, P = 0.05) and HPV‐35 (60.3%, P = 0.04) compared to HPV‐16 (40.5%), while this ratio was lower for HPV‐33 (24.3%), although not significantly (P = 0.14). The maximal distance between HPV variants was greater in the five putative surface‐exposed loops of L1 than in sequences outside the loops (P < 0.01). Synonymous variations were encountered in 1.7% (95% CI 1.1–2.3) of nucleotides inside the L1 loops and 2.4% (95% CI1.2–3.7) of nucleotides outside the L1 loops. Non‐synonymous variations were encountered in 1.8% (95% CI 1.1–2.5) of nucleotides within the L1 loops and 0.2% (95% CI 0–0.4) of nucleotides outside the loops. dN/dS ratios were below 1.0 in extra‐loop and intra‐loop regions, but they were lower in extra‐loop regions. These results suggest that sequences within and outside the hypervariable loops of L1 were under selective constraint. J. Med. Virol. 82: 1168–1178, 2010. © 2010 Wiley‐Liss, Inc. |
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| Keywords: | HPV polymorphism vaccine capsid cancer HPV‐16 |
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