The Mouse Egg's Receptor for Sperm: What Is It and How Does It Work?

Abstract

Fertilization is the process by which sperm and eggs unite to form a zygote, the true beginning of a new individual. In mammals, sperm first make contact with eggs at the surface of the egg's extracellular coat, or zona pellucida (Fig. 1a). This contact can lead to binding of sperm to eggs via species-specific sperm receptors present in the zona pellucida. Bound sperm then undergo changes that enable them to penetrate the zona pellucida and to fuse with the egg's plasma membrane. This fusion results in activation of eggs, and development of the organism ensues (for review, see Gwatkin 1977; Yanagimachi 1981; Bedford 1982; Wassarman 1983a; Wassarman et al. 1984a).