GENESIS OF CELL MEMBRANE POLARITY IN CORNEAL EPITHELIUM

角膜上皮是一种极化的多层组织， 高效率地实现了许多生理和 快速眼科手术对角膜健康至关重要的保护作用 更换细胞。提高对生理学的认识 参与保存正常上皮的活动，这 这项为期5年的研究考察了一些基本事件， A)替换角膜表面的细胞， 和b)细胞膜极性的成熟。 它们在上皮层中的迁移。对这些人来说至关重要 研究是最近发展起来的一种方法 一层层地剥离上皮细胞。这个 方法允许将上皮解剖成5个可区分的 分层，从而促进了对许多 性质或功能随着细胞沿着基底部到基底部的方向发展 地表层结轴线。 紧密连接(T.J.)在成熟表面之间 细胞将通过电子显微镜进行测定。然后，在 诱导这些细胞的剥离，T.J. 新细胞之间的组装将在表面进行 特色化的。T.J.‘S的蛋白质组成和蛋白质组分 T.J.细胞内特定蛋白的动员。装配将是 使用a)针对一种必需的 T.J.卵红蛋白成分，以及b)新生组织的放射性标记 蛋白质合成(翻译)依赖阶段的蛋白质 形成紧密连接。平移步骤的位置 对T.J.来说至关重要。装配已经建立，研究到 确定转录(信使核糖核酸合成)的步骤是 承担了。将使用电生理方法来 确定分层期间的哪个点上的c1-通道 插入根尖膜内。扫描电子显微镜 一组荧光凝集素将被用来研究 根尖膜的显微解剖和表面成熟 糖分的表达。基准面的伴生变化 将通过测量Na++K+的变化来评估活动 β肾上腺素能受体中的ATPase。不利的影响 表面电池更换过程中的环境条件 也将检查以及某些生物的影响 细胞培养中膜极性成熟度的变量 系统。

The corneal epithelium is a polarized, multilayered tissue that fulfills, with high efficiency, a number of physiological and protective roles essential to corneal health while undergoing rapid cell replacement. To improve understanding of the physiological activities involved in the preservation of a normal epithelium, this 5-year study examines some of the fundamental events that underlie a) the replacement of cells at the surface of the cornea, and b) the maturation of membrane polarity of the cells during their migration through the epithelial strata. Essential to these studies is the recent development of a method to induce exfoliation of the epithelial cells on a layer-by-layer fashion. The method allows dissection of the epithelium into 5 distinguishable layers thereby facilitating the study of changes in a number of properties or functions as cells progress along the basal-to- surface stratification axis. The ultrastructure of tight junctions (t.j.) between mature surface cell will be determined by electron microscopy. Then, after induced exfoliation of these cells, the structural dynamics of t.j. assembly between the new cells at the surface will be characterized. The protein composition of t.j.'s and details of the intracellular mobilization of specific proteins t.j. assembly will be studied using a) a monoclonal antibody raised against an essential t.j. component, ovomorulin, and b) radiolabelling of nascent proteins during a protein synthesis (translation) dependent-phase of tight junction formation. The location of a translational step critical for t.j. assembly had already been established, studies to determine a transcriptional (mRNA synthesis) step are undertaken. Electrophysiological methods will be used to determine at which point during stratification C1- channels are inserted in the apical membrane. Scanning electron microscopy and a battery of fluorescent lectins will be used to study the maturation of the apical membrane microanatomy and surface expression of sugars. The concomitant changes in basolateral activities will be assessed by measuring the changes in Na++K+ ATPase in beta-adrenergic receptors. The effect of unfavorable environmental conditions on the surface cell replacement process will also be examined as well as the effect of certain biological variables on the maturation of membrane polarity in a cell culture system.