Dynamics of Epithelial Polarity Proteins and the Control of Tissue Architecture

描述（由申请人提供）：上皮极性蛋白的动力学和组织结构的控制上皮片位于生物体及其外部环境的边界。这些根底结构域的维持对上皮的屏障功能至关重要，根底极性的丧失与许多上皮癌的转移有关。虽然上皮层曾经被认为是很大程度上的静态集合，但现在人们认识到这些是动态结构，可以经历重大的重组和更新事件。事实上，细胞邻居交换可以通过发育过程来影响组织结构的变化，细胞嵌入可以驱动上皮组织修复。在果蝇胚胎上皮中，单个细胞能够通过细胞粘附和极性蛋白的不对称定位来巩固细胞间的接触或直接进行邻居交换运动。虽然现在很明显，肌动球蛋白收缩驱动细胞-细胞界面的收缩和丧失，上皮细胞创造新的细胞接触和界面的手段是未知的。本项目解决的主要问题是确定新的细胞界面建立和维护的机制。我们假设，在驱动邻居交换的新界面的创建过程中，一个早期和重要的事件将是定向膜的添加。在组织伸长过程中，新膜添加的关键介质，囊泡复合物，在指导局部囊泡运输中的作用将被表征。我们还将通过绘制最近创建的光学荧光笔蛋白来生成新的工具，这将允许对粘附蛋白的特定亚群进行动态跟踪。这些工具和技术应该对一般果蝇社区有用。最后，遗传学方法正在进行中，以确定与建立细胞极性的独特特性有关的新成分。这些研究中使用的方法将借鉴先进的成像技术，这些技术刚刚开始应用于果蝇。该项目的资金将是新成立的实验室的第一笔主要资助，并将代表着建立一个独立研究项目的重要一步。

DESCRIPTION (provided by applicant): Dynamics of Epithelial Polarity Proteins and the Control of Tissue Architecture Epithelial sheets sit at the boundary of the organism and its external environment. The maintenance of these apical and basolateral domains is essential to the barrier function of epithelia, and the loss of apical-basal polarity is associated with the metastasis of many epithelial cancers. While epithelial sheets were once viewed as largely static assemblies, it is now appreciated that these are dynamic structures that can undergo significant reorganizing and renewal events. Indeed, cell neighbor exchange can be harnessed by developmental processes to effect changes in tissue architecture, and cell intercalation can drive epithelial tissue repair. In the Drosophila embryonic epithelium, individual cells are able to either consolidate cell-cell contacts or direct neighbor exchange movements through the asymmetric localization of cell adhesion and polarity proteins. While it is now apparent that actomyosin contraction drives the shrinking and loss of cell-cell interfaces, the means by which epithelial cells create new cell contacts and interfaces is unknown. The main question addressed in this project is the identification of the mechanism by which new cellular interfaces are established and maintained. We hypothesize that an early and essential event in the creation of the new interfaces that drive neighbor exchange will be directed membrane addition. The role of a key mediator of new membrane addition, the exocyst complex, in directing localized vesicular trafficking during tissue elongation will be characterized. We will also generate novel tools by drawing on recently created optical highlighter proteins that will allow the dynamic tracking of specific subpopulations of adhesion proteins. These tools and techniques should be useful to the general Drosophila community. Finally, genetic approaches are underway to identify new components involved in the establishment of distinct properties of cell polarity. The approaches used in these studies will draw on advanced imaging techniques that are just beginning to be applied to Drosophila. The funding of this project will be the first major grant for the newly established lab and will represent an important step towards the founding of an independent research program.