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是简单上皮的屏障功能的原因，但是TJ并未被认为在包括表皮在内的哺乳动物分层上皮的屏障功能中起重要作用。在这项研究中，我们产生了Claudin-1缺陷小鼠，发现这些动物在出生后的一天内死亡，皮肤包裹着。脱水测定法以及跨表皮水分流失测量结果表明，在这些小鼠中，表皮屏障受到严重影响，尽管角质形成细胞的分层组织似乎是正常的。这些意外的发现促使我们在野生型小鼠表皮中重新检查TJ。通过抗蛋白蛋白mAb（TJSpefific标记）在颗粒颗粒中鉴定出连续的TJ，在其中浓缩了claudin-1和-4。 Claudin-1缺陷小鼠，Claudin-1似乎只是从这些TJ中删除了，留下了occl…更多的din（以及Claudin-4）阳性TJ。有趣的是，在野生型表皮中，这些咬合阳性的TJ有效地阻止了皮下注射的示踪剂（约600道尔顿）向皮肤表面的扩散，而在Claudin-1缺陷率表面上，示踪剂似乎通过这些TJ。这些发现提供了第一个证据，表明在表皮中出现连续的基于克劳丁的TJ，并且这些TJ是哺乳动物皮肤的屏障功能的裂痕。（2）紧密连接（TJ）支架是线性聚合物，是典型的蛋白质聚合物，是蛋白质聚合物在等质膜内的蛋白质聚合物，其物理性质，其物理性质仍然存在。最近，Claudins被确定为TJ链的主要成分，当在小鼠L成纤维细胞中外源表达时，它们被证明可以在细胞细胞边界重建TJ链。在这项研究中，我们表明，具有claudin-1的GFP（绿色荧光蛋白）融合蛋白还可以在L成纤维细胞中重新构建TJ链，从而使我们能够直接观察活细胞中的单个TJ链。较少的