GENESIS OF CELL MEMBRANE POLARITY IN CORNEAL EPITHELIUM

角膜上皮是一种极化的多层组织， 具有高效、多项生理和保护作用 这对角膜健康至关重要，同时进行快速细胞更换。 到 提高对参与的生理活动的理解， 保存正常上皮，这项为期5年的研究检查了一些 a）表面细胞替换的基础事件 和B）细胞膜极性的成熟 在它们通过上皮层迁移的过程中 对这些至关重要 研究是最近开发的一种方法，以诱导剥落的 一层一层的上皮细胞。 该方法允许解剖 将上皮细胞分成5个可区分的层， 研究细胞生长过程中一些性质或功能的变化 沿着基底到地表的分层轴。 细胞紧密连接（t.j.）成熟表面细胞之间 将通过电子显微镜测定。 然后，在诱导剥落后， 在这些细胞中，t.j.组装的结构动力学在新的细胞之间， 将表征表面的细胞。 的蛋白质组成 T.J.的和细节的细胞内动员的具体蛋白质 将使用a）产生的单克隆抗体来研究t.j.组装 必需的t.j.组分卵球蛋白，和B）放射性标记新生 蛋白质在蛋白质合成（翻译）依赖性阶段的紧密 结的形成 对t.j.来说关键的平移步骤的位置。 大会已经成立，研究，以确定一个 进行转录（mRNA合成）步骤。 电生理 方法将用于确定分层期间的哪个点 Cl-通道插入顶膜。 扫描电子 显微镜和荧光凝集素电池将被用来研究 根尖膜成熟的显微解剖和表面表达 糖。 将评估基底外侧活动的伴随变化 通过测定β-肾上腺素能受体Na ++ K + ATP酶的变化。 不利的环境条件对表面细胞的影响 更换过程也将被审查，以及某些影响， 细胞膜极性成熟的生物学变量 培养体系

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 Cl-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.