A team of scientists at the University of Edinburgh’s Roslin Institute, the birthplace of Dolly the Sheep, found that by changing the part of the DNA responsible for producing the ANP32A protein that causes chickens to become infected with avian influenza, part of it can provide protection against the infection. Resist and protect, not spread it. To this end, gene-editing technology is used to alter parts of the chicken’s DNA to limit the spread of avian influenza viruses in the animals. In this way, the researchers were able to limit, but not completely prevent, the virus from infecting chickens by changing a small part of the DNA. Furthermore, there is no indication that the changes in the birds’ DNA have any impact on their health or well-being. The findings, published in Nature Communications, are an encouraging step towards controlling the infection, but experts stress that more genetic modification is needed to produce chicken flocks that are immune to avian influenza, which is One of the most costly animal diseases in the world. world. To make the discovery, scientists from the Roslin Institute, Imperial College London and the Pirbright Institute used gene-editing techniques to alter the ANP32A protein in chickens raised because influenza viruses hijack this protein during infection. molecules to aid in replication. When chickens gene-edited with ANP32A were exposed to normal doses of the H9N2-UDL avian influenza strain, nine out of 10 chickens did not become infected or spread to other chickens. The team then exposed the gene-edited birds to artificially high doses of avian influenza viruses to further test their resistance. When exposed to high doses, half of the group (five out of ten birds) became infected. However, gene editing provided some protection to infected gene-edited chickens, with infection levels being much lower than those typically observed during infection in non-gene-edited chickens. Gene editing also helped limit the spread of the virus to one of the four non-GMO chickens in the same incubator, and none to the gene-edited birds. Therefore, the scientists found that in birds with edited ANP32A genes, the virus has adapted to obtain support from two related proteins, ANP32B and ANP32E, to replicate. After laboratory testing, the scientists found that some mutations allowed the virus to use the human version of ANP32, but its replication rate in human respiratory cell cultures was still low. “Gene editing offers a promising route to achieving permanent disease resistance that can be passed on from generation to generation, protecting poultry and reducing risks to humans and wild birds. Our work shows that stopping avian influenza in chickens Transmission in the genome requires multiple gene edits at the same time. Changes,” said Mike McGrew, a professor at the Roslin Institute. In this sense, the findings suggest that a single version of the ANP32A gene is not sufficient for use in chicken production, the team said. To prevent the emergence of escape viruses—those that have adapted to evade gene editing and cause infection—the team next targeted other parts of the DNA responsible for producing three proteins: ANP32A, ANP32B, and ANP32E. In the laboratory. So the next step will be to try to breed chickens with modifications to these three genes, something that has not yet been done in birds.
