The claudin family : Its involvement in interecellular sealing and epithelial polarity

密蛋白家族：参与细胞间密封和上皮极性

基本信息

批准号：
11307002
负责人：
TSUKITA Shoichiro
金额：
$ 24.12万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

(1) The tight junction (TJ) and its adhesion molecules, claudins, are responsible for the barrier function of simple epithelia, but TJs have not been thought to play an important role in the barrier function of mammalian stratified epithelia including the epidermis. In this study, we generated claudin-1-deficient mice and found that the animals died within one day of birth with wrinkled skin. Dehydration assay as well as transepidermal water loss measurements revealed that in these mice the epidermal barrier was severely affected, although the layered organization of keratinocytes appeared to be normal. These unexpected findings prompted us to re-examine TJs in the epidermis of wild-type mice. Close inspection by immunofluorescence microscopy with an anti-occludin mAb, a Tjspecific marker, identified continuous TJs in the stratum granulosum, where claudin-1 and -4 were concentrated. In claudin-1-deficient mice, claudin-1 appeared to have simply been removed from these TJs leaving occlu … More din(and also claudin-4)-positive TJs. Interestingly, in the wild-type epidermis, these occludin-positive TJs efficiently prevented the diffusion of subcutaneously-injected tracer (〜600 dalton) toward the skin surface, whereas in the claudin-1-deficient epidermis, the tracer appeared to pass through these TJs. These findings provide the first evidence that continuous claudin-based TJs occur in the epidermis, and that these TJs are crusial for the barrier function of the mammalian skin.(2) The tight junction (TJ) stand is linear polymer, typical of proteinaceous polymers within plasma membranes, the physicochemical nature of which remains elusive. Recently, claudins were identified as major constituents of TJ strands, and they were shown to reconstitute TJ strands at cell-cell borders when exogenously expressed in mouse L fibroblasts. In this study, we show that the GFP (green fluorescent protein) fusion protein with claudin-1 can also reconstitute TJ strands in L fibroblasts, allowing us to directly observe individual TJ strands in live cells. Less

(1)紧密连接(TJ)及其粘附分子claudins负责单层上皮的屏障功能，但TJ尚未被认为在包括表皮在内的哺乳动物复层上皮的屏障功能中发挥重要作用。在这项研究中，我们培育了claudin-1缺陷小鼠，发现这些动物在出生一天内死亡，皮肤起皱。脱水测定以及经皮失水测量表明，在这些小鼠中，尽管角质形成细胞的分层组织似乎正常，但表皮屏障受到严重影响，这些意外的发现促使我们使用抗occludin mAb（一种Tj特异性）重新检查野生型小鼠表皮中的TJ。标记，识别出颗粒层中连续的 TJ，其中claudin-1和-4集中。在claudin-1缺陷的小鼠中，出现claudin-1。简单地从这些 TJ 中移除，在野生型表皮中隐含地留下 occludin（以及claudin-4）阳性 TJ，这些 occludin 阳性 TJ 有效地阻止了皮下注射示踪剂（约 600）的扩散。道尔顿）朝向皮肤表面，而在claudin-1缺陷的表皮中，示踪剂似乎穿过这些TJ。这些发现提供了连续性的第一个证据。基于密蛋白的 TJ 存在于表皮中，这些 TJ 对于哺乳动物皮肤的屏障功能至关重要。 (2) 紧密连接 (TJ) 是线性聚合物，是质膜内典型的蛋白质聚合物，其物理化学性质最近，紧密蛋白被确定为 TJ 链的主要成分，并且当在小鼠中外源表达时，它们可以在细胞-细胞边界重建 TJ 链。在这项研究中，我们发现 GFP（绿色荧光蛋白）与claudin-1 融合蛋白也可以在 L 成纤维细胞中重建 TJ 链，从而使我们能够直接观察活细胞中的单个 TJ 链。