Role of phospholipase A2 in mammalian sperm-egg fusion: Development of hamster oolemma fusibility by lysophosphatidylcholine
✍ Scribed by Riffo, Marta S.; Párraga, Mario
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 333 KB
- Volume
- 279
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Phospholipase A 2 (PLA 2 ), its localization on human sperm and its involvement in sperm-egg interaction, was investigated. Sperm-egg interaction was examined using an in vitro assay of the interaction between human sperm and zona-free or zona-intact hamster egg. PLA 2specific antibodies and/or lysophosphatidylcholine (LPC) were added to the coincubation medium. PLA 2 was localized on the anterior tip of the human sperm head by an immunogold silver staining method in light microscopy (IGSS) and TEM. PLA 2 -specific antibodies inhibited human spermzona-free oocyte fusion significantly. LPC treatment allows interspecies fertilization of zona-intact hamster oocytes. PLA 2 plays an important role in membrane-fusion events. This statement is supported by the fact that PLA 2 is localized in the region where an exocytotic event, such as the acrosome reaction, occurs in the spermatozoon. PLA 2 -specific antibodies inhibited sperm-egg fusion, but not sperm-oolemma adhesion. LPC may stimulate the fertilizing ability of spermatozoa and induce changes on the zona pellucida and on the oolemma promoting in sperm-egg fusion. Based on these findings, it is suggested that sperm PLA 2 and one of its modulators, the LPC, may contribute to membrane-fusion events in mammalian fertilization.