Expression and putative function of fibronectin and its receptor (integrin α5β1) in male and female gametes during bovine fertilization in vitro
Expression and putative function of fibronectin and its receptor (integrin α5β1) in male and female gametes during bovine fertilization in vitro
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DOI：
10.1530/rep-09-0094
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发表时间：
2009-09-01
期刊：
影响因子：
3.8
通讯作者：
Van Soom, Ann
中科院分区：
文献类型：
--
作者：
Thys, Mirjan;Nauwynck, Hans;Van Soom, Ann
纤连蛋白（Fn）是一种分子量为440 kDa的糖蛋白，被认为参与人类精子与卵子的相互作用。最近，Fn -在牛体外受精过程中被证明能强烈抑制精子穿透。本研究首先利用间接免疫荧光技术评价Fn及其整合素受体(α (5) β(1))在雄性和雌性牛配子上的表达，其次确定Fn在牛体外受精中的功能。内源性Fn在透明带（ZP）和卵膜上的整合素α(5)下检测到。顶体反应后，牛精子赤道段显示整合素α(5)。我们发现外源补充Fn的主要抑制作用位于精子-卵膜结合处，同时对融合有影响，这可能是由于Fin在赤道段与精子结合，如Alexa Fluor 488偶联Fn所示。综上所述，外源补充Fn的抑制作用似乎是通过顶体反应后与暴露的整合素α (5) β(1)受体结合而对雄性配子产生的。内源性Fn在ZP下方的存在以及整合素α(5)在卵膜和顶体反应（AR）精子细胞表面的表达表明，内源性Fn配体与AR精子细胞和卵膜上的相应受体之间存在“魔术贴”相互作用，启动了精子-卵子结合。复制（2009）138 471-482
Fibronectin (Fn) is a 440 kDa glycoprotein assumed to participate in sperm-egg interaction in human. Recently, it has been demonstrated that Fn - when present during bovine IVF - strongly inhibits sperm penetration. The present study was conducted firstly to evaluate the expression of Fn and its integrin receptor (alpha(5)beta(1)) on male and female bovine gametes using indirect immunofluorescence and secondly, to determine the function of Fn during bovine IVF. Endogenous Fn was detected underneath the zona pellucida (ZP) and integrin alpha(5) on the oolemma of cumulus-denuded oocytes. Bovine spermatozoa displayed integrin alpha(5) at their equatorial segment after acrosome reaction. We established that the main inhibitory effect of exogenously supplemented Fn was located at the sperm-oolemma binding, with a (concurrent) effect on fusion, and this can probably be attributed to the binding of Fin to spermatozoa at the equatorial segment, as shown by means of Alexa Fluor 488-conjugated Fn. Combining these results, the inhibitory effect of exogenously supplemented Fn seemed to be exerted on the male gamete by binding to the exposed integrin alpha(5)beta(1), receptor after acrosome reaction. The presence of endogenous Fn underneath the ZP together with integrin alpha(5) expression on oolemma and acrosome-reacted (AR) sperm cell surface suggests a 'velcro' interaction between the endogenous Fn ligand and corresponding receptors on both (AR) sperm cell and oolemma, initiating sperm-egg binding. Reproduction (2009) 138 471-482