Ultrastructural localization of lectin-binding sites on the zonae pellucidae and plasma membranes of mammalian eggs.
Ultrastructural localization of lectin-binding sites on the zonae pellucidae and plasma membranes of mammalian eggs.
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DOI：
10.1083/jcb.66.2.263
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发表时间：
1975-08
期刊：
影响因子：
--
通讯作者：
Yanagimachi H
中科院分区：
文献类型：
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作者：
Nicolson GL;Yanagimachi R;Yanagimachi H
蓖麻凝集素 I (RCAI)、刀豆球蛋白 A (Con A) 和麦芽凝集素 (WGA) 的受体通过铁蛋白-凝集素缀合物定位于仓鼠、小鼠和大鼠卵的透明带和质膜上。用铁蛋白结合物标记的完整鸡蛋在透明带的最外层区域显示出密集的RCAI和WGA受体浓度，而Con A受体在整个透明带中分布稀疏。铁蛋白-凝集素标记是特异性的，因为抑制性糖有效地阻断了标记。通过机械分离的透明带的铁蛋白-RCAI 和荧光素-RCAI 标记证实了跨带的 RCAI 受体的不对称密度，表明 RCAI 结合位点更密集地分布在外部带区域。啮齿动物卵的质膜含有 RCAI、WGA 和 Con A 受体。研究发现，这些受体或多或少随机分布在醛固定蛋的表面或在 0 摄氏度附近标记的蛋上。然而，在 25 摄氏度下孵育的蛋在其质膜上显示出聚集的 WGA 和 Con A 结合位点分布。这表明凝集素诱导的受体重新分布发生在该温度下。讨论了质膜受体移动性是精卵融合的必要条件的可能性。
Receptors for Ricinus communis agglutinin I (RCAI), concanavalin A (Con A), and wheat germ agglutinin (WGA) were localized on the zonae pellucidae and plasma membranes of hamster, mouse, and rat eggs with ferritin-lectin conjugates. Intact eggs labeled with the ferritin conjugates showed dense concentrations of RCAI and WGA receptors in the outermost regions of their zonae pellucidae and sparse distributions of Con A receptors throughout the zonae. Ferritin-lectin labeling was specific, since inhibitory saccharides effectively blocked labeling. The asymmetric density of RCAI receptors across the zona was confirmed by ferritin-RCAI and fluorescein-RCAI labeling of mechanically isolated zonae pellucidae, indicating that the RCAI-binding sites are more densely distributed in the exterior zona regions. Plasma membranes of rodent eggs contained RCAI, WGA, and Con A receptors. These receptors were found to be more or less randomly distributed on surfaces of aldehyde-fixed eggs or on eggs labeled near 0 degrees C. However, eggs incubated at 25 degrees C showed aggregated WGA- and Con A-binding site distributions on their plasma membranes. This indicates that lectin- induced receptor redistribution occurs at this temperature. The possibility that plasma membrane receptor mobility is a requirement for sperm-egg fusion is discussed.