Segbert Christoph, Johnson Kevin, Theres Carin, van Fürden Daniela, Bossinger Olaf
Institut für Genetik, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany.
Dev Biol. 2004 Feb 1;266(1):17-26. doi: 10.1016/j.ydbio.2003.10.019.
The Caenorhabditis elegans intestine is a simple and accessible model system to analyze the mechanism of junction assembly. In comparison to Drosophila and vertebrates, the C. elegans apical junction is remarkable because a single electron-dense structure is implicated in complex processes such as epithelial tightness, vectorial transport and cell adhesion. Here we present evidence in support of a heterogeneous molecular assembly of junctional proteins found in Drosophila and vertebrate epithelia associated with different junctions or regions of the plasma membrane. In addition, we show that molecularly diverse complexes participate in different aspects of epithelial maturation in the C. elegans intestine. DLG-1 (Discs large) acts synergistically with the catenin-cadherin complex (HMP-1-HMP-2-HMR-1) and the Ezrin-Radixin-Moesin homolog (ERM-1) to ensure tissue integrity of the intestinal tube. The correct localization of DLG-1 itself depends on AJM-1, a coiled-coil protein. Double depletion of HMP-1 (alpha-catenin) and LET-413 (C. elegans homolog of Drosophila Scribble) suggests that the catenin-cadherin complex is epistatic to LET-413, while additional depletion of subapically expressed CRB-1 (Crumbs) emphasizes a role of CRB-1 concerning apical junction formation in the C. elegans intestine.
秀丽隐杆线虫的肠道是一个简单且易于研究的模型系统，用于分析连接组装的机制。与果蝇和脊椎动物相比，秀丽隐杆线虫的顶端连接很显著，因为单个电子致密结构参与了诸如上皮紧密性、向量运输和细胞黏附等复杂过程。在这里，我们提供证据支持在果蝇和脊椎动物上皮中发现的与不同连接或质膜区域相关的连接蛋白的异质分子组装。此外，我们表明分子组成多样的复合物参与了秀丽隐杆线虫肠道上皮成熟的不同方面。DLG-1（盘状大蛋白）与连环蛋白-钙黏蛋白复合物（HMP-1-HMP-2-HMR-1）和埃兹蛋白-根蛋白-莫伊塞林同源物（ERM-1）协同作用，以确保肠管的组织完整性。DLG-1自身的正确定位取决于AJM-1，一种卷曲螺旋蛋白。HMP-1（α-连环蛋白）和LET-413（果蝇Scribble的秀丽隐杆线虫同源物）的双重缺失表明连环蛋白-钙黏蛋白复合物对LET-413是上位性的，而顶端表达的CRB-1（crumbs）的额外缺失强调了CRB-1在秀丽隐杆线虫肠道顶端连接形成中的作用。
