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The genetics of virus particle shape in equine influenza A virus

Elton, Debra; Bruce, Emily A.; Bryant, Neil; Wise, Helen M.; MacRae, Shona; Rash, Adam; Smith, Nikki; Turnbull, Matthew L.; Medcalf, Liz; Daly, Janet M.; Digard, Paul

Authors

Debra Elton

Emily A. Bruce

Neil Bryant

Helen M. Wise

Shona MacRae

Adam Rash

Nikki Smith

Matthew L. Turnbull

Liz Medcalf

Janet M. Daly

Paul Digard

Abstract

Background Many human strains of influenza A virus produce highly pleomorphic virus particles that at the extremes can be approximated as either spheres of around 100 nm diameter or filaments of similar cross-section but elongated to lengths of many microns. The role filamentous virions play in the virus life cycle remains enigmatic.

Objectives/Methods Here, we set out to define the morphology and genetics of virus particle shape in equine influenza A virus, using reverse genetics and microscopy of infected cells.

Results and Conclusions The majority of H3N8 strains tested were found to produce filamentous virions, as did the prototype H7N7 A/eq/Prague/56 strain. The exception was the prototype H3N8 isolate, A/eq/Miami/63. Reassortment of equine influenza virus M genes from filamentous and non-filamentous strains into the non-filamentous human virus A/PR/8/34 confirmed that segment 7 is a major determinant of particle shape. Sequence analysis identified three M1 amino acid polymorphisms plausibly associated with determining virion morphology, and the introduction of these changes into viruses confirmed the importance of two: S85N and N231D. However, while either change alone affected filament production, the greatest effect was seen when the polymorphisms were introduced in conjunction. Thus, influenza A viruses from equine hosts also produce filamentous virions, and the major genetic determinants are set by the M1 protein. However, the precise sequence determinants are different to those previously identified in human or porcine viruses.

Journal Article Type Article
Publication Date Nov 14, 2013
Journal Influenza and Other Respiratory Viruses
Print ISSN 1750-2640
Electronic ISSN 1750-2640
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 7
Issue s4
Institution Citation Elton, D., Bruce, E. A., Bryant, N., Wise, H. M., MacRae, S., Rash, A., …Digard, P. (2013). The genetics of virus particle shape in equine influenza A virus. Influenza and Other Respiratory Viruses, 7(s4), doi:10.1111/irv.12197
DOI https://doi.org/10.1111/irv.12197
Keywords Budding, Filamentous, Influenza, Matrix
Publisher URL http://onlinelibrary.wiley.com/doi/10.1111/irv.12197/abstract
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0




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