Barraud-Lange Virginie, Naud-Barriant Nathalie, Saffar Line, Gattegno Liliane, Ducot Beatrice, Drillet Anne-Sophie, Bomsel Morgane, Wolf Jean-Philippe, Ziyyat Ahmed
Biologie de la Reproduction, UFR SMBH, Université Paris 13, Bobigny, France, Service d'Histologie-Embryologie-Cytogénétique, Hôpital Jean Verdier (AP-HP), Bondy, France.
BMC Dev Biol. 2007 Sep 12;7:102. doi: 10.1186/1471-213X-7-102.
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.
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.
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.
基于抑制试验，α6β1整合素被认为是一种精子受体，但使用基因缺失技术的进一步实验表明，卵母细胞的α6和β1整合素亚基对小鼠受精都不是必需的。
通过蛋白质印迹分析和免疫荧光，我们发现小鼠精子表达α6β1整合素。对于卵母细胞，GoH3抗α6抗体与精子的结合会特异性抑制精子的受精能力。在融合试验中比较有透明带和无透明带的卵子，我们发现酸处理去除透明带可绕过受精时卵母细胞α6β1整合素在黏附/融合过程中的功能。
这些发现表明α6β1整合素在两种配子中均有表达，并且在它们的膜相互作用中发挥作用。这些结果以及之前关于野生型精子使α6或β1整合素亚基缺失的卵母细胞受精的报道表明，两种配子膜之一上存在α6β1整合素可以挽救受精过程。我们最近报道的配子融合前发生的膜片段交换进一步支持了这一假设。
