CELL JUNCTIONS AND CELL MEMBRANES IN THE LENS

我们建议将细胞连接和细胞膜的研究扩展到 脊椎动物的眼晶状体。为了维持无血管晶状体 作为一种正常和透明的状态，缝隙连接被认为发挥了 在调节离子和代谢通讯方面起着至关重要的作用 上皮细胞、纤维细胞之间以及上皮细胞和纤维细胞之间 晶状体中的细胞。最近的研究表明，晶状体缝隙连接 由多种连接蛋白和结构类型组成。的重要意义。 晶状体中存在多种缝隙连接蛋白和结构 仍有待确定。我们计划更详细地调查 备受争议的镜片的独特结构特征和功能 缝隙连接。此外，它还会与细胞结合在一起 黏附分子(钙粘附素)和肌动蛋白束被认为在 在管理镜片发展方面发挥着重要作用。我们计划研究 钙粘附素在出生前后晶状体中的差异表达 发展。此外，我们将扩展我们的研究目标，以获得一些 深入了解细胞膜在受体介导中的作用 细胞增多症。这一新发现的机制可能与隔离有关 以及运送正常晶状体所需的重要小分子 成长。最后，我们将研究分子马达、动蛋白及其 需要与基于微管的细胞器转运机制相关联 用于形成透明透镜。 我们将为这些项目应用几种新的方式和方法。 这些技术包括扫描隧道显微镜、快速冷冻、冷冻- 冰冻切片深冷冻蚀刻电子显微镜替换 免疫荧光标记、激光共聚焦扫描显微镜、 使用冷冻替代制剂的免疫细胞化学，薄片 使用一种改进的固定剂的电子显微镜 实验室、示踪剂和细胞化学技术、器官培养、凝胶 电泳法和免疫印迹法。 此应用程序的长期目标是获得更好的 对细胞连接和功能的结构和作用的理解 晶状体中的细胞膜。

We propose to extend the studies of cell junctions and cell membranes in the ocular lens of vertebrates. In order to maintain an avascular lens in a normal and transparent state, gap junctions are believed to play a crucial role in regulating ionic and metabolic communications between epithelial cells, between fiber cells, and between epithelial and fiber cells in the lens. Recent progress suggests that lens gap junctions consist of multiple connexins and structural types. The significance of the existence of multiple gap junction proteins and structures in the lens remains to be determined. We plan to investigate in greater detail the unique structural characteristics and functions of the controversial lens gap junctions. In addition, adherens junctions along with their cell adhesion molecules (cadherins) and actin bundles are thought to play an important role in governing lens development. We plan to study the differential expressions of cadherins during prenatal and postnatal lens development. Moreover, we will extend our research goals to gain some insights into the roles of cell membranes involved in receptor-mediated potocytosis. This newly-found mechanism may be involved in sequestering and transporting important small molecules necessary for normal lens growth. Finally, we will study the molecular motor, kinesin, and its association with microtubule-based organelle transport mechanisms required for the formation of a transparent lens. We will apply several new approaches and methodologies for these projects. These include scanning tunneling microscopy, rapid-freezing, freeze- substitution, deep freeze-etch electron microscopy, frozen-section immunofluorescence labeling, confocal laser scanning microscopy, immunocytochemistry using freeze-substitution preparations, thin-section electron microscopy using an improved fixative developed in our laboratory, tracer and cytochemical techniques, organ cultures, gel electrophoresis, and immunoblotting. The long-term objectives of this application are to gain a better understanding of the structure and functional role of cell junctions and cell membranes in the lens.