Scientists Identify Protein that Helps Dengue Virus Grow
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23 April 2009
By silencing genes one by one, scientists have identified dozens of proteins that help the dengue fever virus to grow and spread among mosquitoes and humans. The research paves the way to potentially prevent or treat the disease, which infects millions worldwide every year.
Dengue is a mosquito–borne illness that can cause debilitating sickness and death.
“Dengue is a nasty disease, and right now, there is no treatment for it and no way to prevent it,” said Mariano Garcia–Blanco, professor of molecular genetics and microbiology at Duke University Medical Centre (DUMC) and study co–author.
“But if we can find a weakness in the virus, we can design a strategy to fight it. This study has helped us identify some gaps in dengue’s armour,” he said.
Almost half the people in the world are vulnerable to the dengue virus, says the World Health Organisation. Public health officials are worried because dengue appears to be popping up in places where it has rarely appeared before. It may be fuelled by global warming.
Garcia–Blanco, used RNA interference (RNAi) to unlock dengue’s secrets.
RNA interference is a normal biological process cells use to turn gene expression on or off depending upon which gene products, or proteins, are needed at any given moment.
“That very same system proved to be the perfect investigative tool for our study,” said Garcia–Blanco.
Garcia–Blanco and colleagues in Duke’s RNAi facility were able to knock down gene function in fruit fly cells infected with a strain of the dengue virus known as DENV–2.
Silencing one gene at a time allowed researchers to pinpoint which genes, or host factors, were essential to viral growth and which ones were not.
They used fruit flies as a model because the genetic tools needed for the same work in mosquitoes have not been developed as yet. The process yielded 116 host factors that appeared to be important for successful dengue infection in fruit flies.
In testing several of these host factors in mosquitoes at Johns Hopkins University, researchers subsequently discovered that at least one – and possibly a second – was necessary for dengue infection to occur in the insects, said a DUMC release.