Researchers find innate immune defense against RNA viruses
The researchers believe the quality control mechanism may be one of the oldest defense mechanisms against viruses in evolutionary history, ScienceDaily reports.
The team, led by Professor of Biochemistry Ari Helenius, discovered the mechanism while researching human cells in relation to the Semliki Forest virus. The researchers found that cells were more susceptible to the virus when genes of a cellular quality control system for RNA, called nonsense-mediated mRNA decay (NMD), were turned off, according to ScienceDaily.
"Viruses and their hosts are engaged in an endless battle, of which the NMD system is a previously unsuspected yet significant component," Olivier Voinnet, a professor of RNA biology at ETH Zurich, said, ScienceDaily reports. "In this battle, the NMD mechanism likely contributed to shape the genomes of RNA viruses as we see them today."
The study found that NMD acts against viruses with a genome in the form of single-stranded, positive-sense RNA. Many diseases including polio, hepatitis C, SARS and yellow fever belong to that group.
The researchers said, however, that the NMD system is not totally efficient. If it were, RNA viruses would not exist at all, according to ScienceDaily.