Cadherin-independent epithelial formation

描述（由申请人提供）：本拨款提案的目标是启动一个新的研究领域，研究上皮形成的新途径。上皮在保持组织、器官和细胞在不同的拓扑区室中发挥重要作用。例如，上皮层系器官，上皮管在全身运输液体和气体。经典实验建立了粘附蛋白E-cadherin及其伙伴1-catenin和2-catenin在上皮形成过程中启动极性的范式。最近使用3D培养系统的研究表明，整合素和磷酸肌苷是产生上皮细胞的极化线索。这些研究依赖于可以在体外诱导形成上皮结构的组织培养模型或遗传生物，主要是果蝇。我们的目标是用一个新的上皮发育遗传系统来补充经典的方法。秀丽隐杆线虫的拱廊细胞经历间充质向上皮细胞的转变，由此产生的上皮管将肠道与外表皮连接起来。我们新项目的动力是观察到秀丽隐杆线虫产生这种上皮（及其其他上皮）独立于已知的上皮调节剂，包括钙粘蛋白，连环蛋白或整合素。我们假设秀丽隐杆线虫的拱廊细胞依赖于另一种途径来构建上皮，一种适合遗传分析和体内成像的途径。我们将分析MKLP激酶zen-4在上皮形成过程中的作用。我们之前的研究表明，zen-4的失活阻断了拱廊细胞的上皮形成，这是线虫中迄今为止观察到的最强的上皮缺陷。我们将分析ZEN-4及其在上皮中的作用，作为理解非典型上皮形成的切入点。这些实验将建立秀丽隐杆线虫拱廊细胞作为上皮形成的模型，并将为理解非典型上皮形成奠定基础。

DESCRIPTION (provided by applicant): The goal of this grant proposal is to initiate a new area of research that will investigate novel pathways of epithelium formation. Epithelia perform a vital function to keep tissues, organs and cells in distinct topological compartments. For example, sheets of epithelia line organs, epithelial tubes transport liquids and gases throughout the body. Classic experiments established the paradigm that the adhesion protein E-cadherin and its partners 1-catenin and 2-catenin initiate polarity during epithelium formation. More recent work using 3D culture systems has implicated integrins and phosphoinositides as polarizing cues to create epithelia. These studies relied on tissue culture models that can be induced to form epithelial structures in vitro or on genetic organisms, predominantly Drosophila. Our aim is to complement the classical approaches with a new genetic system for epithelium development. The C. elegans arcade cells undergo a mesenchymal to epithelial transition, and the resulting epithelial tube links the gut to the exterior epidermis. The impetus for our new project is the observation that C. elegans generates this epithelium (and its other epithelia) independent of known epithelial regulators including cadherins, catenins or integrins. We hypothesize that the C. elegans arcade cells rely on an alternative pathway to build epithelia, one that is amenable to genetic analyses and in vivo imaging. We will analyze the MKLP kinesin zen-4 during epithelium formation. We previously showed that inactivation of zen-4 blocks epithelium formation of the arcade cells, the strongest epithelial defect yet observed in C. elegans. We will analyze ZEN-4 and its role in epithelia, as an entry point towards understanding non-canonical epithelium formation. These experiments will establish the C. elegans arcade cells as a model for epithelium formation, and will set the stage for understanding non-canonical epithelium formation. PUBLIC HEALTH RELEVANCE: Epithelia are composed of highly polarized, adherent cells with an asymmetric distribution of proteins, lipids and organelles within the cytoplasm and at the cell surface. Epithelia perform a vital function to keep tissues, organs and cells in distinct topological compartments. This proposal seeks to establish a new model system to study epithelium formation, one that will uncover non-classical pathways for polarity and epithelialization. )