A research group led by Senior Associate Professor Yoshihiko Araki of Juntendo University Graduate School of Medicine and Institute of Environmental Medicine found that the membrane protein TEX101 / Ly6k complex on germ cells in the testis is extremely important for the production of fertilizing sperm in vivo. It was announced that it was clarified at the molecular level that it would play a key role.The results of this research can be a clue to elucidate a part of the cause of "unexplained" human infertility, which has been said to account for one-third of all infertility.
Glycosylphosphatidylinositol (GPI), a membrane protein anchored to the cell surface membrane using a lipid as an anchor, exists in male germ cells of mammals and is called a GPI-anchored protein.Among them, the TEX101 / Ly6k complex is important for the reproductive process, and mice lacking TEX101 and Ly6k are said to be infertile because sperm do not work normally.
In this study, we analyzed the expression dynamics of Ly101k in Tex6-deficient knockout (KO) mice regarding the role of TEX101 / Ly6k in the reproductive mechanism.As a result, in the absence of the complementary molecule TEX101, Ly6k is normally transcribed and translated and produced, but this membrane protein cannot be stably present in germ cells and can be rapidly degraded. It was revealed.It was also found that when cultured cells in which these two molecules are stably expressed are used to inhibit the action of each gene, the expression of the complementary molecule is dramatically reduced.According to this result, TEX101 and Ly6k do not function independently, but the stable formation of these GPI-anchored protein complexes is extremely important for normal sperm function in vivo.
This achievement puts a stone in the conventional research that considers the cause of infertility as a single molecule, and is important in elucidating the pathophysiology of male infertility and constructing a treatment strategy for which the cause was unknown.