Cadherin-independent epithelial formation

描述(由申请者提供)：这项拨款提案的目标是启动一个新的研究领域，研究新的上皮形成途径。上皮起着重要的作用，使组织、器官和细胞保持在不同的拓扑室中。例如，上皮片排列在器官上，上皮管将液体和气体输送到全身。经典实验确立了黏附蛋白E-钙粘蛋白及其伴侣1-连环蛋白和2-连环蛋白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，整合素和磷脂酰肌醇是产生上皮细胞的极化信号。这些研究依赖于组织培养模型，这些模型可以在体外诱导形成上皮结构，或者依赖于遗传生物，主要是果蝇。我们的目标是用一种新的上皮发育遗传系统来补充经典的方法。线虫的拱廊细胞经历了从间充质到上皮的转变，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线虫产生这种上皮(和它的其他上皮)不依赖于已知的上皮调节因子，包括钙粘附素、连环素或整合素。我们假设线虫拱廊细胞依赖于另一种建立上皮的途径，一种服从遗传分析和体内成像的途径。我们将分析MKLP Kinesin Zen-4在上皮形成过程中的作用。我们之前的研究表明，ZEN-4的失活阻止了拱廊细胞上皮的形成，这是迄今在线虫中观察到的最强烈的上皮缺陷。我们将分析ZEN-4及其在上皮细胞中的作用，作为了解非规范上皮形成的切入点。这些实验将建立线虫拱廊细胞作为上皮形成的模型，并将为理解非规范上皮形成奠定基础。

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.