VIRUS PICTURES: West Nile Virus Structure

West Nile Virus Structure cutaway graphic (on a white or black background). Web images measures 450 pixels across, original images are 3876 pixels across

EXPLANATION OF WEST NILE VIRUS PICTURE: West Nile Virus is a small (approx. 50 nm diameter) enveloped + single stranded RNA virus. It belongs to the family Flaviviridae (L. Flavus: yellow) named after Yellow Fever. The red worm-like objects covering the surface are the E (Envelope) Proteins. In the mature virion, these exist as dimers with the two molecules in a "Yin-Yang" or "69" position. The dimers are arranged in an ordered fashion over the surface of the virus (2, 3). The E proteins vary from type to type, as does the state of their glycosylation (9, 10, 11). The illustration above shows the virus with some of the E-Proteins removed to reveal the underlying membrane (bluish green). The E proteins are anchored into this by membrane spanning regions. Also present are M (Membrane) proteins. In this image, the E anchoring regions and the M-Proteins (and their transmembrane regions) look like little nails hammered into the membrane. Beneath the membrane lies the icosahedral nucleocapsid (yellowish glow in middle) that contains the genetic material combined with C (Capsid) Protein. Although generally described as spherical, electron micrographs of West Nile Viruses seem to show a clearly faceted virion.

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REFERENCES:

1. Lindenbach BD, Rice CM. Flaviviridae: The Viruses and Their Replication. Field's Virology

2. Kuhn RJ et al. Structure of Dengue Virus: Implications for Flavivirus Organisation, Maturation and Fusion, Cell, Vol. 108, March 2002, 717-725

3. Kuhn RJ et al. Structure of West Nile Virus, Science, October 2003, 248

4. Lorenz IC, Allison SL, Heinz FX, Helenius A, Folding and Dimerization of Tick-Borne Encephalitis Virus Envelope Proteins prM and E in the Endoplasmic Reticulum. Journal of Virology June 2002: 5480 - 5491

5. De Beeck AO, Molenkamp R, Caron M, Younes AB, Bredenbeek P, Dubuisson J, Role of the Transmembrane Domains of prM and E Proteins in the Formation of Yellow Fever Virus Envelope. Journal of Virology Jan 2003: 813 - 820

6. Beasley DWC, Barrett ADT, Identification of Neutralising Epitopes within Structural Domain III of the West Nile Virus Envelope Protein. Journal of Virology Dec 2002: 13097 - 13100

7. Chu JJH, Choo BGH, Lee JWM, Ng ML, Actin Filaments Participate in West Nile (Sarafend) Virus Maturation Process. Journal of Medical Virology 2003:71: 463 - 472

8. Ng ML, Tan SH, Chu JJH, Transport and Budding at Two Distinct Sites of Visible Nucleocapsids of West Nile (Sarafend) Virus. Journal of Medical Virology 2001:65: 758 - 764

9. Berthet F-X, Zeller HG, Drouet M-T, Rauzier J, Digoutte J-P, Deubel V, Extensive nucleotide changes and deletions within the envelope glycoprotein gene of Euro-African West Nile viruses. Journal of General Virology 1997:78: 2293 - 2297

10. Chambers TJ, Halevy M, Nestorowicz A, Rice CM, Lustig S, West Nile virus envelope proteins: nucleotide sequence analysis of strains differing in mouse neuroinvasiveness. Journal of General Virology 1998:79: 2375 - 2380

11. Scherret JH, Poidinger M, Mackenzie JS, Broom AK, Deubel V, Lipkin WI, Briese T, Gould EA, Hall RA, The Relationship between West Nile and Kunjin Viruses. Emerging Infectious Diseases July-August 2001 Vol. 7 No. 4