Acrosomal Proteins of Abalone Spermatozoa

Abstract

Publisher Summary This chapter reviews the work of the laboratory on the two proteins released from the acrosomal vesicle of abalone spermatozoa onto the surface of the egg vitelline envelope. The chapter discovers the mechanism of interaction of these sperm proteins with their specific egg surface receptors, and understands how species-specificity evolves. The understanding of living systems is deeply rooted in the knowledge of how biological molecules interact to create form, physiology, and behavior. In most animal species, whether internally or externally fertilizing, sperm-egg interaction leading to gamete fusion usually exhibits some degree of species specificity. This means that sperm and eggs of the same species are almost always more efficient at forming zygotes than are combinations of sperm and eggs from different species. There is a great range in species specificity with some interspecies cross mixtures of gametes forming zygotes as efficiently as homospecific combinations, and other interspecies combinations yielding no zygotes. The species-specificity of sperm-egg interaction suggests the process is mediated by gamete recognition molecules acting in ligand-receptor combinations. The species specificity of fertilization represents an interesting phenomenon to study by the isolation of interacting cell surface macromolecules. Abalone are large, single-shelled, marine archeogastropod mollusks of separate sexes that yield vast amounts of sperm and eggs, permitting the isolation of the egg VE and the sperm acrosomal vesicle proteins.