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Mechanistic studies of the plasma membrane block to polyspermy in mouse eggs
Author(s) -
Horvath Peter M.,
Kellom Theresa,
Caulfield Jeanne,
Boldt Jeffrey
Publication year - 1993
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080340111
Subject(s) - polyspermy , cortical granule , oocyte activation , zona pellucida , biology , microbiology and biotechnology , sperm , human fertilization , exocytosis , vitelline membrane , membrane , penetration (warfare) , biophysics , anatomy , biochemistry , oocyte , botany , embryo , operations research , engineering
The mechanisms responsible for the plasma membrane associated block to polyspermy in mouse eggs were studied. Reinsemination experiments using zona‐free eggs indicated that, after fertilization, the egg plasma membrane is altered such that sperm binding to the egg plasma membrane is blocked, except in the region of the second polar body. Activation of the egg with either ethanol or strontium chloride did not result in a block to polyspermic penetration, as artificially activated eggs displayed identical penetration levels as to nonactivated control eggs. The penetrability of activated eggs was not altered by the presence or absence of the zona pellucida during activation. Lectin staining for egg cortical granule material indicated that activation did cause cortical granule exocytosis; however, activated eggs remained penetrable. These data support the following conclusions: (1) an alteration in the ability of the egg plasma membrane to allow sperm adherence accounts for the block to polyspermy; (2) establishment of the plasma membrane block to polyspermy is sperm dependent, since artificial egg activation does not result in a block response; (3) the contents of the egg's cortical granules do not play a role in the establishment of the plasmalemma block response. © 1993 Wiley‐Liss, Inc.