INTERCELLULAR COMMUNICATION IN THE EYE LENS

描述(摘自申请者的摘要)：最近的一项研究表明 晶状体缝隙连接蛋白46(Cx46)缺陷的小鼠发生 白内障，表明缝隙连接介导的沟通的直接作用 在保持镜头透明度方面。缝隙连接是由 连接相邻细胞的细胞质的跨膜通道。这些 通道允许小的代谢物、离子和第二信使从 一个细胞接一个细胞。脊椎动物眼睛内部的晶状体纤维细胞 晶状体既没有血液供应，也没有细胞器。因此，晶状体的存活率和 动态平衡独特地依赖于通过GAP的细胞间通讯 晶状体表面与上皮细胞的连接。小鸡镜头是 选择作为实验系统，因为它提供了许多比较优势 和其他物种在一起。已知有三种连接蛋白参与了 晶状体缝隙连接通道的形成：晶状体上皮细胞中的Cx43 Cx45.6和Cx56主要存在于晶状体纤维中。晶状体纤维蛋白，它们存活下来 动物的整个生命周期，都容易受到翻译后 磷酸化。晶状体连接蛋白的磷酸化可能具有 在调节晶状体缝隙连接通道中的意义。此外， 来自其他物种的证据表明，连接蛋白的磷酸化是 与缝隙结通道组装和浇注有关。这其中的第一个目标是 建议确定缝隙连接蛋白磷酸化在 该镜头包括：识别磷酸化位点，研究 连接蛋白磷酸化的功能作用，并确定相关的 牵涉到了激活酶。第二个目标涉及实验，以确定 不同晶状体连接蛋白正确靶向的信号和 异构体连接蛋白的形成。最终目标涉及 晶状体连接蛋白与MIP关系的研究进展 MIP在晶状体缝隙连接中的作用拟议的实验将是 在已建立的系统中进行，包括完整的鸡胚胎晶状体， 原代晶状体培养，连接蛋白缺陷细胞系和非洲爪哇卵母细胞，在 此外，申请人新开发的一种新型逆转录病毒检测系统， 将采用将外源连接蛋白引入到 鸡胚原位晶状体以确定晶状体间隙的作用 晶状体生理学和病理学中的结合点。

DESCRIPTION (Adapted from applicant's abstract): A recent study shows that mice deficient in the lens gap junction protein connexin 46 (Cx46) develop cataracts, indicating the direct role of gap junction-mediated communication in maintaining lens transparency. Gap junctions are clusters of transmembrane channels that connect the cytoplasm of adjacent cells. These channels permit small metabolites, ions and second messengers to pass from cell to cell. Lens fiber cells within the interior of the vertebrate eye lens have nether a blood supply nor organelles. Thus, lens survival and homeostasis are uniquely dependent on intercellular communication via gap junctions with epithelial cells at the lens surface. The chick lens is chosen as an experimental system as it provides many advantages compared with other species. Three connexins are known to participate in the formation of lens gap junction channels: Cx43 in lens epithelial cells, Cx45.6 and Cx56 mainly in lens fibers. Lens fiber proteins, which survive the whole life span of animals, are susceptible to post-translational phosphorylation. Phosphorylation of lens connexins may have functional implications in the regulation of lens gap junction channels. Moreover, evidence from other species has shown that phosphorylation of connexins is related to gap junction channel assembly and gating. The first goal of this proposal is to determine the functional role of connexin phosphorylation in the lens which includes: identifying phosphorylation sites, studying functional roles of connexin phosphorylation, and determining the relevant kinases involved. The second objective involves experiments to determine the signals for the correct targeting by different lens connexins and the formation of heteromeric connexins. The final objective involves the characterization of relationships between lens connexins and MIP and the function of MIP in lens gap junctions. The proposed experiments will be performed in established systems, including intact embryonic chicken lenses, primary lens cultures, connexin-deficient cell lines and Xenopus oocytes, In addition, a novel retroviral assay system, newly developed by the applicant, will be employed in which exogenous connexins will be introduced into the embryonic chick lens in situ in order to define the roles of lens gap junctions in lens physiology and pathology.