Localization of B4GALNT2 and its role in mouse embryo attachment

Objective: To investigate the location of β-1,4-N- acetylgalactosaminyltransferase II (B4GALNT2) and the involvement of this protein and Sda antigen in embryonic implantation. Design: Cell and animal study. Setting: University. Animal(s): Adult outbred Institute for Cancer Research mice. Intervention(s): B4GALNT2 antibody injected into the uteri of mice in early pregnancy; E3.5 blastocysts and pregnant uterine tissues were collected. Main Outcome Measure(s): Protein expression was detected by immunofluorescence staining and Western blotting. Embryo attachment was assayed via in vitro and in vivo embryo implantation models. Result(s): The b4galnt2 gene expression in the 293T cell line showed the protein localized in the plasma membrane. We confirmed that B4GALNT2 was localized on the surface of E3.5 blastocysts but was an intracellular component in uterine epithelia. Finally, anti-B4GALNT2 and lectins inhibition assays demonstrated the involvement of B4GALNT2 and Sda antigen in embryonic attachment in vitro and in vivo via the mouse system and human endometrial cell line (Ishikawa). Conclusion(s): B4GALNT2 expressed in the blastocyst may interact with a ligand on the endometrial surface, perhaps via Sda also, to permit embryo implantation. Our data suggest that B4GALNT2 and Sda antigen are essential for embryo implantation. ? 2012 American Society for Reproductive Medicine, Published by Elsevier Inc.