Structural dynamics and function of early embryonic coats
Structural dynamics and function of early embryonic coats
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DOI：
10.1159/000016732
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发表时间：
2000-01-01
影响因子：
2.7
通讯作者：
Denker, HW
中科院分区：
文献类型：
--
作者：
Denker, HW
早期哺乳动物胚胎周围的细胞外胚皮（胚胎/囊胚覆盖物）通常仍被称为透明带。从许多早期和最近的研究中积累的证据清楚地表明，这是一种过度简化的说法，至少在许多物种中是如此。被毛的结构变化发生在卵裂和囊胚阶段；这在许多具有中心型着床的物种中最为明显，与此相关的是囊胚高度膨胀，尤其是兔子和马。在这篇文章中，将回顾各种层的形成和转化（兔子的透明带，粘蛋白层，新生层和胶膜，马的胶囊），以及在海豹（亚区层）和狒狒中看到的类似结构。这些现象将在其他物种中发现的结构上更微妙的变化的背景下进行讨论，包括那些具有小囊胚和其他类型植入的物种，特别是可能在生理学上相当重要的生化修饰。本文将简要介绍涂层沉积及其转化和脱落/溶解的分子机制。本文将讨论外壳及其转化的可能功能意义（机械、形态发生和免疫作用、分子运输控制、囊胚定位、植入、信号分子的捕获和储存功能）。版权所有(C) 2000 S. Karger AG，巴塞尔。
The extracellular embryonic coats (embryo/blastocyst coverings) that surround early mammalian embryos are most often still referred to as zona pellucida. Accumulating evidence from a number of earlier and recent studies clearly indicates that this is an oversimplification which cannot be defended anymore, at least in many species. Structural modifications of the coats occur during cleavage and blastocyst stages; these are most obvious in a number of species with the central type of implantation and, related to this, a high degree of blastocyst expansion, notably the rabbit and the horse. In this contribution, formation and transformation of the various layers of coats (zona pellucida, mucoprotein layer, neozona and gloiolemma in the rabbit, capsule in the horse) will be reviewed, as will be comparable structures seen, e.g., in the fur seal (subzonal layer) and the baboon. These phenomena will be discussed in the context of structurally more subtle changes found in other species, including those with small blastocysts and other types of implantation, in particular with biochemical modifications which may be physiologically quite important. The molecular mechanisms of deposition of coats and their transformation and shedding/dissolution will be briefly addressed. The possible functional significance of the coats and their transformation will be discussed (mechanical, morphogenetic and immunological role, molecular transport control, blastocyst positioning, implantation, trap and reservoir function for signalling molecules).Copyright (C) 2000 S. Karger AG, Basel.