Mouse gamete adhesion molecules.
Complementary adhesion molecules are located on the surface of mouse eggs and sperm. These molecules support species-specific interactions between sperm and eggs that lead to gamete fusion (fertilization). Modification of these molecules shortly after gamete fusion assists in prevention of polyspermic fertilization. mZP3, an 83,000-Mr glycoprotein located in the egg extracellular coat, or zona pellucida, serves as primary sperm receptor. Gamete adhesion in mice is carbohydrate-mediated, since sperm recognize and bind to certain mZP3 serine/threonine- (O-) linked oligosaccharides. As a consequence of binding to mZP3, sperm undergo the acrosome reaction, which enables them to penetrate the zona pellucida and fertilize the egg. A 56,000-Mr protein called sp56, which is located in plasma membrane surrounding acrosome-intact mouse sperm heads, is a putative primary egg-binding protein. It is suggested that sp56 recognizes and binds to certain mZP3 O-linked oligosaccharides. Acrosome-reacted sperm remain bound to eggs by interacting with mZP2, a 120,000-Mr zona pellicida glycoprotein. Thus, mZP2 serves as secondary sperm receptor. Perhaps a sperm protease associated with inner acrosomal membrane, possibly (pro)acrosin, serves as secondary egg-binding protein. These and, perhaps, other egg and sperm surface molecules regulate fertilization in mice. Homologous molecules apparently regulate fertilization in other mammals.
Wassarman
P M
PM
Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, New Jersey 07110.
D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D004527:Egg Proteins; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D010063:Ovum / Q000378:metabolism*; D011956:Receptors, Cell Surface; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
D015815:Cell Adhesion Molecules; D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins