Differentiation-related expression of a major 64K corneal keratin in vivo and in culture suggests limbal location of corneal epithelial stem cells.
Differentiation-related expression of a major 64K corneal keratin in vivo and in culture suggests limbal location of corneal epithelial stem cells.
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在体内和培养物中，主要64K角膜角蛋白的分化相关表达表明角膜上皮干细胞的边缘位置。
DOI：
10.1083/jcb.103.1.49
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发表时间：
1986-07
影响因子：
7.8
通讯作者：
Sun, T T
中科院分区：
文献类型：
--
作者：
Schermer, A;Galvin, S;Sun, T T
在本文中，我们提出的角蛋白表达的数据，提供了强有力的支持，角膜上皮成熟的模型中，干细胞位于利姆布斯，角膜和结膜之间的过渡带。使用一种新的单克隆抗体，AE 5，这是高度特异性的64，000-mol-wt角膜角蛋白，指定RK 3，我们证明，这种角蛋白是本地化的所有细胞层的兔角膜上皮，但只在基底层的角膜缘上皮。培养的角膜角质形成细胞的分析表明，它们依次表达三种主要的角蛋白对。由单层“基底”细胞组成的早期培养物主要表达50/58 K角蛋白，指数生长的细胞合成额外的48/56 K角蛋白，汇合后，高度分层的培养物开始表达55/64 K角膜角蛋白。细胞分离实验表明，从汇合后培养物中分离的基底细胞主要含有50/58 K对，而基底上细胞含有额外的55/64 K和48/56 K对。然而，旧的，postconfluent文化的基底细胞，可以成为AE 5阳性，表明基底上的位置是不是一个先决条件的64 K角蛋白的表达。总之，这些结果表明，酸性55 K和碱性64 K角蛋白代表角膜上皮分化的晚期阶段的标志物。因此，中央角膜的上皮基底细胞而不是利姆布斯的上皮基底细胞具有64 K角蛋白的事实表明，角膜基底细胞比角膜缘基底细胞处于更分化的状态。这些发现，加上已知的角膜上皮细胞的向心迁移，强烈表明角膜上皮干细胞位于利姆布斯，角膜基底细胞对应于“干细胞-瞬时扩增细胞-终末分化细胞”方案中的“瞬时扩增细胞”。"
In this paper we present keratin expression data that lend strong support to a model of corneal epithelial maturation in which the stem cells are located in the limbus, the transitional zone between cornea and conjunctiva. Using a new monoclonal antibody, AE5, which is highly specific for a 64,000-mol-wt corneal keratin, designated RK3, we demonstrate that this keratin is localized in all cell layers of rabbit corneal epithelium, but only in the suprabasal layers of the limbal epithelium. Analysis of cultured corneal keratinocytes showed that they express sequentially three major keratin pairs. Early cultures consisting of a monolayer of "basal" cells express mainly the 50/58K keratins, exponentially growing cells synthesize additional 48/56K keratins, and postconfluent, heavily stratified cultures begin to express the 55/64K corneal keratins. Cell separation experiments showed that basal cells isolated from postconfluent cultures contain predominantly the 50/58K pair, whereas suprabasal cells contain additional 55/64K and 48/56K pairs. Basal cells of the older, postconfluent cultures, however, can become AE5 positive, indicating that suprabasal location is not a prerequisite for the expression of the 64K keratin. Taken together, these results suggest that the acidic 55K and basic 64K keratins represent markers for an advanced stage of corneal epithelial differentiation. The fact that epithelial basal cells of central cornea but not those of the limbus possess the 64K keratin therefore indicates that corneal basal cells are in a more differentiated state than limbal basal cells. These findings, coupled with the known centripetal migration of corneal epithelial cells, strongly suggest that corneal epithelial stem cells are located in the limbus, and that corneal basal cells correspond to "transient amplifying cells" in the scheme of "stem cells----transient amplifying cells----terminally differentiated cells."