EPITHELIAL AUTONOMY IN THE DEVELOPMENT OF THE INNER-EAR OF A BIRD EMBRYO
EPITHELIAL AUTONOMY IN THE DEVELOPMENT OF THE INNER-EAR OF A BIRD EMBRYO
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DOI：
10.1016/0012-1606(90)90251-d
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发表时间：
1990-02-01
影响因子：
2.7
通讯作者：
LEWIS, J
中科院分区：
文献类型：
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作者：
SWANSON, GJ;HOWARD, M;LEWIS, J
内耳上皮内有大量分化的细胞类型，排列精确。一旦耳囊肿闭合，细胞是根据上皮固有的机制分化还是依赖于外部影响？特别是，它们是否受周围周期间质信号的支配？内耳的封闭结构或耳囊液对模式的形成和分化是否像对成人功能一样重要？我们通过两种嫁接实验检验了这些问题。首先，将早期（E3, 17-18期，或E2, 13-14期）未分化的鹌鹑耳囊剥离其间充质并移植到鸡胚胎的翼芽中。耳上皮虽被外源间充质包围，但仍分化为标准内耳细胞类型。大体形态异常，感觉毛细胞由通常的8个小块排列成几个大块；局部分化细胞类型间的空间关系正常。在第二个实验中，将早期未分化耳囊肿的开放片段（带有粘附的间充质）移植到肢芽表面。在这种暴露在体内的情况下，上皮的顶端表面被羊水而不是耳囊液浸泡，分化也正常进行。因此，这些阶段内耳上皮的分化不需要耳间质的任何特定影响，并且与耳囊肿是开放还是关闭无关。这种上皮细胞的自主性为体外分析创造了特殊的机会。
The epithelium lining the inner ear contains a large number of differentiated cell types, arranged in precise patterns. Once the otocyst has closed, do the cells differentiate according to mechanisms intrinsic to the epithelium or are they dependent on external influences? In particular, are they governed by signals from the surrounding periotic mesenchyme? And is the closed structure of the inner ear or the otocyst fluid that it contains important for pattern formation and differentiation as it is for adult function? We have examined these questions by two types of grafting experiment. In the first, early (E3, stage 17-18, or E2, stage 13-14) undifferentiated quail otocysts were stripped of their mesenchyme and grafted into the wing buds of chick embryos. Although surrounded by a foreign mesenchyme the otic epithelium differentiated into the standard inner ear cell types. The gross morphology was abnormal, and the sensory hair cells were grouped into a few large patches instead of the usual eight smaller patches; locally, however, the spatial relationships between the differentiated cell types appeared normal. In the second experiment, open fragments of early undifferentiated otocyst (with some adhering mesenchyme) were grafted onto the surface of a limb bud. In this exposed in vivo situation, where the apical surface of the epithelium is bathed by amniotic fluid instead of otocyst fluid, differentiation proceeds normally also. Thus differentiation of inner ear epithelium at these stages does not require any specific influence from otic mesenchyme and proceeds independently of whether the otocyst is open or closed. Such epithelial autonomy creates special opportunities for in vitro analysis.