CONICET | Buscador de Institutos y Recursos Humanos

Mammalian sperm-egg interaction is a multistep process involving sperm penetration through the cumulus oophorus that surrounds the egg, binding to and penetration of the zona pellucida (ZP), and fusion between the sperm plasma membrane and the oolema. Although the structural and physiological aspects of gamete interaction have been extensively studied, during the past years efforts have been made towards elucidating the molecular mechanisms involved in this process. Evidence indicates that many of the fertilization events occur through the interaction of complementary molecules localized on the surface of both gametes. Biochemical and molecular approaches identified several molecules as mediators of gamete interaction, and the participation of few of them has been more recently confirmed through the use of KO models (i.e. SED-1 and ZP2/ZP3 for sperm-ZP interaction, and Izumo and CD9 for gamete fusion). The results from these genetic approaches also suggest that there must be other as yet unidentified components contributing to the fertilization process. For many years, our laboratory has been working on the functional role of protein DE, a sperm epididymal protein described by our group and also known as CRISP1 for being the first member of the Cysteine RIch Secretory Protein (CRISP) family. Evidence supports the involvement of DE/CRISP1 in both sperm-ZP interaction and gamete fusion through its binding to complementary sites on the ZP and egg surface, respectively. Recent results also support the participation of the testicular homologue of DE, known as Tpx-1 or CRISP2, in gamete interaction through its interaction with the same egg binding sites than DE/CRISP1. The results from KO mice for each of these proteins will provide important information for a better understanding of the molecular mechanisms involved in the fertilization process.