New Image of Dengue Virus Revealed

A new study of the structure of the dengue virus employing the techniques of cryo-electron microscopy and three-dimensional image reconstruction has revealed several surprising features. The report appears in the March 8, 2002 issue of Cell.

Dengue is a member of the flavivirus family, which includes such other dangerous insect-borne diseases as West Nile fever, yellow fever, tick-borne encephalitis, and St. Louis encephalitis. The dengue virus, transmitted to humans through the bites of infected mosquitoes, causes dengue fever, a severe flu-like illness with high fever, rash and extreme pain in the head, muscles, and joints. Dengue hemorrhagic fever is a potentially lethal complication that can cause internal bleeding, vomiting, severe abdominal pain and death.

Researchers at Purdue University (West Lafayette, IN, USA) have revealed a new image of the virus showing how the major protein--called E for envelope protein--organizes itself to form a protective shell around the virus. The protein shell is made up of 60 subunits to form a 20-sided sphere. The shell serves as a cage for the genetic material inside, sheltering it from harm until it is released inside a host cell. While simple viruses consist of only a protein shell and genetic information, more complex viruses, such as flaviviruses, also contain a lipid bilayer that sits between the protein shell and viral genome.

Richard J. Kuhn, a member of the research team, explained that the three-dimensional reconstruction reveals several unexpected features in the dengue virus architecture: "The organization of the shell protein is very different from what we have seen before and what we might have predicted for this type of virus.”

While vaccines have been developed for dengue, control of the virus by vaccination has proved elusive. The detailed information obtained from the new structural data paves the way for the possible development of new vaccines and antiviral agents.





Related Links:
Purdue University