A group of researchers including one porcine reproductive and respiratory syndrome expert from Kansas State have discovered a new gene expression mechanism in the PRRS virus — a swine pathogen that costs the U.S. pork industry more than $600 million a year.
The discovery provides a new avenue for scientists to explore strategies to control and prevent the disease.
The research recently appeared in the Proceedings of the National Academy of Sciences.
The study builds on a 2012 PNAS study that Ying Fang, associate professor of diagnostic medicine and pathobiology at K-State, and her collaborators conducted while she was at South Dakota State University.
In the previous study, researchers identified the nsp2TF protein in the PRRS virus. The protein is expressed through a new gene expression mechanism called -2 ribosomal frameshifting.
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"Frameshifting occurs when a ribosome encounters a 'slippery' sequence and downstream signal in messenger RNA," Fang said. "This causes the ribosome to shift two nucleotides backward, which results in all the genetic codons downstream of the shifted site to be read differently and produce a new protein that has a different function."
With the most recent study, Fang and colleagues have shown that this -2 frameshifting requires a PRRS virus protein, nsp1beta. It is the first time a virus's genetic mechanism has been found to require the action of a transacting viral protein rather than a RNA structure to induce a ribosomal frameshifting, which is novel in the protein translation field.
The function of the nsp2TF protein is currently under investigation, Fang said. The protein contains a genetic element that may be responsible for suppressing the pig's immune system.
The newly identified ribosomal frameshifting mechanism may provide an additional antiviral target. Fang's research lab cloned the PRRS virus and then genetically engineered nsp2TF protein knockout viruses.
"These knockout viruses could be potentially used to develop vaccines," Fang said. "Additionally, this novel mechanism of gene expression may also be used by other viruses or in cellular gene expression."
Fang joined Kansas State University in 2013.