Enzymatic comparison and expression pattern of pig B4GALNT2 and B4GALNT2-like proteins

The final step in the production of the human Sd(a) antigen is catalyzed by beta-1,4-N-acetyl-galactosamine transferase 2 (B4GALNT2). This is done by adding a N-acetylgalactosamine residue via a beta-1,4 linkage to a subterminal galactose residue that has been substituted with an alpha-2,3-linked sialic acid. The final stage of the production of the Cad antigen is also catalyzed by B4GALNT2. Knocking out pig B4GALNT2 gene decreased human serum antibodies binding to pig cells, which greatly reduces the immunological rejection in clinical xenotransplantation trials. Interestingly, gene region LOC110255214 (hereafter named B4GALNT2-like) showed high similarity with the B4GALNT2 gene in the pig genome in our previous work, but whether B4GALNT2-like shares similar biological properties like B4GALNT2 remains to be elucidated, whether B4GALNT2-like is a potential immune gene in xenotransplantation remains to be determined.