Autoradiographic visualization of the mouse egg's sperm receptor bound to sperm

Journal Article · Tue Apr 01 04:00:00 EST 1986 · J. Cell Biol.; (United States)

DOI:https://doi.org/10.1083/jcb.102.4.1363· OSTI ID:5617662

Bleil, J D; Wassarman, P M

The extracellular coat, or zona pellucida, of mammalian eggs contains species-specific receptors to which sperm bind as a prelude to fertilization. In mice, ZP3, one of only three zona pellucida glycoproteins, serves as sperm receptor. Acrosome-intact, but not acrosome-reacted, mouse sperm recognize and interact with specific O-linked oligosaccharides of ZP3 resulting in sperm-egg binding. Binding, in turn, causes sperm to undergo the acrosome reaction; a membrane fusion event that results in loss of plasma membrane at the anterior region of the head and exposure of inner acrosomal membrane with its associated acrosomal contents. Bound, acrosome-reacted sperm are able to penetrate the zona pellucida and fuse with the egg's plasma membrane (fertilization). In the present report, we examined binding of radioiodinated, purified, egg ZP3 to both acrosome intact and acrosome reacted sperm by whole-mount autoradiography. Silver grains due to bound 125I-ZP3 were found localized to the acrosomal cap region of heads of acrosome-reacted sperm. Under the same conditions, 125I-fetuin bound at only background levels to heads of both acrosome-intact and -reacted sperm, and 125I-ZP2, another zona pellucida glycoprotein, bound preferentially to acrosome-reacted sperm. These results provide visual evidence that ZP3 binds preferentially and specifically to heads of acrosome intact sperm; properties expected of the mouse egg's sperm receptor.

• Research Organization: Roche Research Center, Nutley, NJ
• OSTI ID: 5617662
• Journal Information: J. Cell Biol.; (United States), Journal Name: J. Cell Biol.; (United States) Vol. 4; ISSN JCLBA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
CARBOHYDRATES
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL BONDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
FERTILIZATION
GAMETES
GERM CELLS
GLUCOPROTEINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MICE
NUCLEI
ODD-EVEN NUCLEI
OOCYTES
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RECEPTORS
RODENTS
SACCHARIDES
SPERMATOZOA
VERTEBRATES