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Porcine oocyte activation induced by a cytosolic sperm factor
Author(s) -
Macháty Zoltán,
Bonk Aaron J.,
Kühholzer Birgit,
Prather Randall S.
Publication year - 2000
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 - 10.1002/1098-2795(200011)57:3<290::aid-mrd11>3.0.co;2-#
Subject(s) - biology , oocyte activation , oocyte , cytosol , microbiology and biotechnology , sperm , maturation promoting factor , andrology , genetics , embryo , biochemistry , gene , enzyme , medicine , cyclin dependent kinase 1 , cell cycle
It is not known how the fertilizing sperm elicits the release of Ca 2+ from the oocyte's intracellular stores. We investigated whether a crude extract isolated from boar sperm could induce the Ca 2+ release and trigger subsequent early and late activation events upon injection into matured porcine oocytes. The sperm extract induced an immediate rise in the intracellular free Ca 2+ concentration in all oocytes tested, which was followed by repetitive Ca 2+ transients in 11 out of 14 oocytes. Heat or trypsin treatment of the extract totally abolished the Ca 2+ releasing activity of the sperm factor. The injected oocytes showed cortical granule exocytosis, they resumed meiosis and entered first interphase: pronuclei were formed in 89.2% (132/148) of the cases. Pronuclear formation was accompanied by the appearance of a new 22 kDa protein as normally seen at fertilization. Of the successfully injected oocytes 51.7% (105/203) cleaved and 2.0% (4/203) developed to the blastocyst stage after being cultured for 7 days in NCSU 23 medium. Injection of the carrier medium could not trigger these changes. The results indicate that the sperm might activate porcine oocytes by introducing a soluble factor into the oocyte's cytoplasm after gamete fusion. Mol. Reprod. Dev. 57:290–295, 2000. © 2000 Wiley‐Liss, Inc.