Int. J. Dev. Biol. 52: 511 - 522 (2008)

https://doi.org/10.1387/ijdb.072532mb

Vol 52, Issue 5-6

Special Issue: Fertilization

The role of the acrosomal matrix in fertilization

Published: 1 July 2008

Mariano G. Buffone¹, James A. Foster³ and George L. Gerton^1,2,*

¹Center for Research on Reproduction and Women's Health, ²Department of Obstetrics and Gynecology,University of Pennsylvania School of Medicine, Philadelphia, PA, USA and ³Department of Biology, Randolph-Macon College, Ashland, VA, USA

Abstract

Mammalian sperm must have properly formed acrosomes to be fully functional in the process of binding and penetrating the zona pellucida (ZP), the extracellular matrix surrounding the egg. There is much evidence to raise doubts about the old "bag of enzymes" paradigm of acrosomal function, although this is the model that seems to prevail. We concur with other scientists that acrosomal exocytosis is not an all or none event where the acrosome is either "intact" or "reacted". As determined by transmission electron microscopy of human sperm undergoing acrosomal exocytosis, six stages can be identified, with the intermediate ones involving loss of acrosomal matrix material. In the mouse, there is a temporal relationship among four stages of acrosomal exocytosis. Numerous evidences suggest a more complex role for the acrosome in fertilization in which the acrosomal matrix is a scaffold for sperm-ZP interactions that self-regulates by a controlled disassembly mechanism.

Keywords

acrosome, sperm, zona binding, zona pellucida, sp56