Potential Involvement of Trophinin, Bystin, and Tastin in Embryo Implantation

Defining the cellular and molecular bases of embryo implantation is an important yet extremely difficult problem in developmental biology because of the lack of an appropriate in vitro model for implantation. In this regard two human cell lines, HT-H and SNG-M, are noteworthy, as these cells appear to mimic some, if not all, of the mechanisms involved in implantation. In particular, their unique manner of initial attachment at their respective apical cell surfaces and subsequent morphological changes leading to stronger adhesive interactions resemble the trophectoderm cells of blastocyst and endometrial epithelial cells at the implantation stage (1).