Tight junction biogenesis in the early Xenopus embryo
Tight junction biogenesis in the early Xenopus embryo
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DOI：
10.1016/s0925-4773(00)00368-3
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发表时间：
2000-08-01
影响因子：
2.6
通讯作者：
Hausen, P
中科院分区：
文献类型：
--
作者：
Fesenko, I;Kurth, T;Hausen, P
紧密连接（TJ）在非洲爪蟾卵裂过程中形成的初级上皮的运输功能和形态发生活性中起着关键作用。通过TJ相关蛋白（扣带蛋白、ZO-1和occludin）的免疫定位和体内生物素扩散试验研究了这些连接的生物发生。使用受精卵同步在第一次分裂周期，我们发现，膜组装的TJ开始在动物波罗对合子胞质分裂结束，并涉及顺序结合扣带蛋白，ZO-1和occludin的组件。这三种成分似乎是从母体商店招募，并有针对性的新生TJ网站通过不同的途径。TJ蛋白组装精确地集中在细胞质分裂过程中产生的卵膜衍生的顶膜和新插入的基底外侧膜之间的边界，并最终在两细胞胚胎中形成功能性TJ，从而保持扩散屏障。因此，新的膜形成和细胞表面极性的产生先于TJ形成的开始。此外，TJ标志物蛋白的组装精确地在顶侧-基底侧膜边界被保存在完全不存在细胞间接触和粘附的情况下。因此，非洲爪蟾早期胚胎TJ生物发生的机制依赖于细胞自主机制的内在线索。这些数据揭示了非洲爪蟾和哺乳动物早期胚胎的起源和机制的上皮细胞极化和TJ形成卵裂过程中的区别。(C)2000爱思唯尔科学爱尔兰有限公司保留所有权利。
Tight junctions (TJs) perform a critical role in the transport functions and morphogenetic activity of the primary epithelium formed during Xenopus cleavage. Biogenesis of these junctions was studied by immunolocalization of TJ-associated proteins (cingulin, ZO-1 and occludin) and by an in vivo biotin diffusion assay. Using fertilized eggs synchronized during the first division cycle, we found that membrane assembly of the TJ initiated at the animal polo towards the end of zygote cytokinesis and involved sequential incorporation of components in the order cingulin, ZO-1 and occludin. The three constituents appeared to be recruited from maternal stores and were targeted to the nascent TJ site by different pathways. TJ protein assembly was focused precisely to the border between the oolemma-derived apical membrane and newly-inserted basolateral membrane generated during cytokinesis and culminated in the formation of functional TJs in the two-cell embryo, which maintained a diffusion barrier. New membrane formation and the generation of cell surface polarity therefore precede initiation of TJ formation. Moreover, assembly of TJ marker protein precisely at the apical-basolateral membrane boundary was preserved in the complete absence of intercellular contacts and adhesion. Thus, the mechanism of TJ biogenesis in the Xenopus early embryo relies on intrinsic cues of a cell autonomous mechanism. These data reveal a distinction between Xenopus and mammalian early embryos in the origin and mechanisms of epithelial cell polarization and TJ formation during cleavage of the egg. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.