Impact of Gene Duplication of B4GALNT2 in Pigs for Xenotransplantation- Technical & Practical.

The B4GALNT2 gene has become an important target for xenotransplantation because its inactivation reduces the antigenicity of porcine tissues. The growing use of organ-source pig models has led to an increased demand for the rapid creation of these animals. However, the physiological role of this gene in pigs remains poorly understood. In 2015, after generating pigs lacking B4GALNT2 expression, researchers observed a third allele for this gene. Subsequently, another gene, described as B4GALNT2-like, was found in the porcine genome. We have collected data over four years since the production of our first line of xenotransplantation pigs lacking B4GALNT2 and B4GALNT2-like expression. In this study, we were able to show that pig cells expressing B4GALNT2-like also reacted to Dolichos biflorus agglutinin (DBA) lectin, which recognizes GalNAc epitopes. Additionally, we demonstrated that B4GALNT2/B4GALNT2-like knockout embryos were able to be carried to term in females with the same genotype. We hypothesized that the presence of both genes in the porcine genome might have occurred due to duplication, inversion, and reinsertion of part of the Phospho1-B4GALNT2 segment. Finally, the pig B4GALNT2-like gene showed greater similarity to the human, bovine, and murine B4GALNT2 genes than the original pig B4GALNT2. These data clarify the importance of targeting both B4GALNT2 and B4GALNT2-like for xenotransplantation studies and have improved our knowledge about their genomic structure and role in pig reproduction.