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Journal of Virology, November 2009, p. 11890-11901, Vol. 83, No. 22
0022-538X/09/$08.00+0 doi:10.1128/JVI.00864-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Evolutionary Dynamics of GII.4 Noroviruses over a 34-Year Period
,
Karin Bok,*
Eugenio J. Abente,
Mauricio Realpe-Quintero,
Tanaji Mitra,
Stanislav V. Sosnovtsev,
Albert Z. Kapikian, and
Kim Y. Green
Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
Received 29 April 2009/ Accepted 2 September 2009
Noroviruses are a major cause of epidemic gastroenteritis in children and adults, and GII.4 has been the predominant genotype since its first documented occurrence in 1987. This study examined the evolutionary dynamics of GII.4 noroviruses over more than three decades to investigate possible mechanisms by which these viruses have emerged to become predominant. Stool samples (n = 5,424) from children hospitalized at the Children's Hospital in Washington, DC, between 1974 and 1991 were screened for the presence of noroviruses by a custom multiplex real-time reverse transcription-PCR. The complete genome sequences of five GII.4 noroviruses (three of which predate 1987 by more than a decade) in this archival collection were determined and compared to the sequences of contemporary strains. Evolutionary analysis determined that the GII.4 VP1 capsid gene evolved at a rate of 4.3 x 10–3 nucleotide substitutions/site/year. Only six sites in the VP1 capsid protein were found to evolve under positive selection, most of them located in the shell domain. No unique mutations were observed in or around the two histoblood group antigen (HBGA) binding sites in the P region, indicating that this site has been conserved since the 1970s. The VP1 proteins from the 1974 to 1977 noroviruses contained a unique sequence of four consecutive amino acids in the P2 region, which formed an exposed protrusion on the modeled capsid structure. This protrusion and other observed sequence variations did not affect the HBGA binding profiles of recombinant virus-like particles derived from representative 1974 and 1977 noroviruses compared with more recent noroviruses. Our analysis of archival GII.4 norovirus strains suggests that this genotype has been circulating for more than three decades and provides new ancestral strain sequences for the analysis of GII.4 evolution.
* Corresponding author. Mailing address: Norovirus Gastroenteritis Unit, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive, Bldg. 50, Room 6316, Bethesda, MD 20892. Phone: (301) 594-1633. Fax: (301) 480-5031. E-mail: bokk{at}niaid.nih.gov
Published ahead of print on 16 September 2009.
Supplemental material for this article may be found at http://jvi.asm.org/.
Present address: Research & Development Department, Boehringer-Ingelheim Vetmedica, Guadalajara, Jalisco, Mexico.
Journal of Virology, November 2009, p. 11890-11901, Vol. 83, No. 22
0022-538X/09/$08.00+0 doi:10.1128/JVI.00864-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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