title: Alpha6beta1 integrin expressed by sperm is determinant in mouse fertilization.
abstract: BACKGROUND
  Based on inhibition tests, the alpha6beta1 integrin was suggested to be a sperm receptor, but further experiments using gene deletion techniques have shown that neither oocyte alpha6, nor beta1 integrin subunits were essential for mouse fertilization.
  
  
  RESULTS
  Using Western blot analysis and immunofluorescence, we showed that the mouse sperm expresses the alpha6beta1 integrin. As for oocyte, binding of GoH3 anti-alpha6 antibody to sperm induces a specific inhibition of sperm fertilizing ability. Comparing zona-intact and zona-free eggs in fusion tests, we showed that the removal of the zona pellucida by acid treatment bypasses fertilizing oocyte alpha6beta1 integrin's function in the adhesion/fusion process.
  
  
  CONCLUSIONS
  These findings show that alpha6beta1 integrin is expressed by both gametes and is functional in their membranes interaction. These results and previous reports, about fertilization of alpha6 or beta1 integrin subunits deleted oocytes by wild type sperm, suggest that the presence of alpha6beta1 integrin on one of the two gamete membranes can rescue the fertilization process. This hypothesis is further supported by the exchange of membrane fragments occurring between gametes prior to fusion that we recently reported.
authors.affiliation: Biologie de la Reproduction, UFR SMBH, Université Paris 13, Bobigny, France, Service d'Histologie-Embryologie-Cytogénétique, Hôpital Jean Verdier (AP-HP), Bondy, France. raud@smbh.univ-paris13.fr
authors.forename: Virginie
authors.initials: V
authors.lastname: Barraud-Lange
authors.forename: Nathalie
authors.initials: N
authors.lastname: Naud-Barriant
authors.forename: Line
authors.initials: L
authors.lastname: Saffar
authors.forename: Liliane
authors.initials: L
authors.lastname: Gattegno
authors.forename: Beatrice
authors.initials: B
authors.lastname: Ducot
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Drillet
authors.forename: Morgane
authors.initials: M
authors.lastname: Bomsel
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Wolf
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ziyyat
mesh_terms: D000818:Animals; D005260:Female; D005306:Fertilization / Q000235:genetics*; D005307:Fertilization in Vitro; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D039121:Integrin alpha6beta1 / Q000235:genetics*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D009865:Oocytes / Q000378:metabolism; D013075:Sperm Capacitation; D013084:Sperm-Ovum Interactions / Q000235:genetics; D013094:Spermatozoa / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism
chemical_list: D039121:Integrin alpha6beta1