A team of researchers from the University of Missouri (MU), Kansas State University (KSU), and biotechnology company, Genus, have successfully produced a litter of pigs genetically resistant to a deadly porcine virus through gene editing. Transmissible gastroenteritis virus (TGEV), a coronavirus, is highly contagious and commonly infects pig intestines. “Previous research had identified an enzyme called ANPEP as a potential receptor for TGEV, meaning it could be an important factor in allowing the virus to take hold in pigs,” said Randall Prather, professor of animal sciences in the College of Agriculture, Food, and Natural Resources. “We were able to breed a litter of pigs who did not produce this enzyme, and as a result, they did not get sick when we exposed them to the virus.” The team edited the gene responsible for making the ANPEP enzyme, resulting in a litter of seven pigs with a null gene that did not produce the enzyme. When exposed to the TGEV, these pigs did not become infected, meaning the presence of the ANPEP enzyme is necessary for infection, and gene editing can create pigs who are resistant. In comparison to the scores of gene mutations occurring naturally during the reproductive process, researchers only altered the expression of a single gene. Those pigs lacking the enzyme were healthy and experienced no changes in development. The study also sought to determine whether editing out ANPEP would produce resistance to porcine epidemic diarrhea virus, however, pigs lacking the enzyme still contracted the virus. “Porcine coronaviruses are a global threat to the pig industry. One of the greatest concerns for U.S. producers are outbreaks of new coronaviral diseases. Genetic modification to protect pigs from endemic and emerging diseases is the future of the pork industry,” said Raymond Rowland, professor of diagnostic medicine and pathobiology at KSU and co-author of the study. MU has partnered with Genus to commercialize this method of producing virus-resistant pigs. Genus is currently seeking U.S. Food and Drug Administration (FDA) approval for the use of gene editing technology for use in eradicating the PRRS virus. The study, "Resistance to coronavirus infection in amino peptidase N-deficient pigs, was published in Transgenic Research", and is available here.
