Viral switches share a shape

PUBLIC RELEASE DATE:

27-Oct-2014

Contact: Susan Brown sdbrown@ucsd.edu 858-246-0161 University of California - San Diego @UCSanDiego

A hinge in the RNA genome of the virus that causes hepatitis C works like a switch that can be flipped to prevent it from replicating in infected cells. Scientists have discovered that this shape is shared by several other virusesamong them one that kills cancer cells.

That's Seneca Valley virus, which seems harmless to healthy human cells but lethal to cancer stem cells.

"Clearly we'd like to understand it better," said Thomas Hermann, professor of chemistry and biochemistry at the University of California, San Diego.

Hermann's research group has determined the molecular structure of this critical switch in the Seneca Valley virus and found that it matches the L-shaped switch in hepatitis C virus, which his group had previously described.

The similarity was a surprise.

"It wasn't immediately apparent to us from the genome sequence alone," said Mark Boerneke, a graduate student in chemistry and lead author of the report in the Proceedings of the National Academy of Sciences online the week of October 27. "This is a different virus that regulates protein production in a similar fashion."

This kind of viral on-off switch is part of an IRES, for internal ribosome entry site. Ribosomes are the structures inside cells that make proteins. Lacking their own protein-making machinery, viruses use the IRES to hijack the ribosomes of cells they've infected to produce proteins they need to replicate.

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Viral switches share a shape