title: Membrane transfer from oocyte to sperm occurs in two CD9-independent ways that do not supply the fertilising ability of Cd9-deleted oocytes.
abstract: Spermatozoa undergo regulation of their functions along their lifespan through exchanges via vesicles or interactions with epithelial cells, in the epididymis, in the seminal fluid and in the female genital tract. Two different ways of oocyte membrane transfer to spermatozoa have been described: trogocytosis and exosomes. We here report an analysis of in vitro exchanges between the membranes of unfertilised oocytes and capacitated spermatozoa. We showed that optimum conditions are fulfilled when unfertilised oocytes interact with acrosome-reacted spermatozoa, a scenario mimicking the events occurring when the fertilising spermatozoon is inside the perivitelline space. Although CD9 tetraspanin is an essential molecule for fertilisation, exosome and trogocytosis transfer persists in Cd9-null oocytes in spite of their dramatic fusion failure. These exchanges are CD9 tetraspanin independent. We also confirm that mice sperm express CD9 tetraspanin and that when Cd9-null oocytes were inseminated with sperm covered with oocyte membrane materials, including CD9 tetraspanin, no rescue of the oocytes' fertilisability could be obtained. Thus, the existence of two ways of exchange between gametes during fertilisation suggests that these events could be of a physiological importance in this process.
authors.affiliation: Service d'Histologie Embryologie, Biologie de la Reproduction, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, 123, Boulevard Port Royal, 75013 Paris, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Barraud-Lange
authors.forename: Céline
authors.initials: C
authors.lastname: Chalas Boissonnas
authors.forename: Catherine
authors.initials: C
authors.lastname: Serres
authors.forename: Jana
authors.initials: J
authors.lastname: Auer
authors.forename: Alain
authors.initials: A
authors.lastname: Schmitt
authors.forename: Brigitte
authors.initials: B
authors.lastname: Lefèvre
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Wolf
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ziyyat
mesh_terms: D020101:Acrosome Reaction; D000818:Animals; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology*; D005260:Female; D005306:Fertilization / Q000502:physiology*; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure*; D013075:Sperm Capacitation; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology / Q000648:ultrastructure*; D060245:Tetraspanin 29 / Q000172:deficiency / Q000502:physiology*; D059470:Tetraspanins / Q000032:analysis
chemical_list: D060245:Tetraspanin 29; D059470:Tetraspanins