RNA Silencing May Protect Against Viral Infection

The findings appear in the cover story in the May 17, 2002, issue of Science.

RNA silencing regulates gene expression by specific degradation of that gene's mRNA. After activation, the RNA silencing mechanism has ‘memory,” recognizing which RNA nucleotide sequences to destroy.

"In our experiments, we infected fruit fly cells with an RNA virus,” said Dr. Shou-Wei Ding, assistant professor of plant pathology at the University of California (Riverside, USA). "This triggered strong silencing of the viral RNAs in the fly cells. We further demonstrated that the same virus also directs expression of a protein that suppresses RNA silencing in the fly cells, thus ensuring successful infections.”

RNA silencing has been shown to be a common antiviral mechanism in plants since it was first discovered in transgenic plants in 1990. That it also functions in animal cells suggests the existence of a highly conserved antiviral pathway shared by the animal and plant kingdoms.

The new findings may lead to the development of new treatments for recalcitrant human and animal viral diseases based on the RNA silencing adaptive defense, which differs from adaptive immunity that targets protein antigens of viruses. "For example, blocking the action of viral silencing suppressors should lead to rapid virus elimination by the cell's own antiviral defense,” said Ding.




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