Molecular mechanisms underlying the establishment of cell polarity.

项目摘要（家长资助）：R35 GM 145340 真核生物的一个基本特征是细胞的建立和维持。 极性分子马达通过转运mRNA、蛋白质、囊泡， 和细胞器到细胞内的特定部位。各种各样的生物， 酵母对人类使用mRNA定位与翻译调控相结合的方式， 不对称地分选蛋白质。这一现象的普遍性最能说明问题的是 发育中的胚胎、神经元和上皮细胞，其中成千上万的mRNA在空间上被 本地化。当这个过程受到损害时，它可能会导致发育和神经系统疾病。 紊乱尽管这一主题很重要，而且这一现象很普遍，但我们缺乏 对mRNA定位的机械理解。我们理解的一个关键差距是 确定定位的mRNA是如何被细胞识别并与非定位mRNA区分开来的。 定位mRNA。除了存在于定位mRNA中的序列外， 结合这些mRNA是它们细胞命运的关键。这种蛋白质复合体负责 将定位mRNA与分子马达连接并调节其翻译。然而，在这方面， 鉴定这些关键蛋白质已被证明是极具挑战性的。就其性质而言， mRNA定位过程是高度动态的。因此，蛋白质和蛋白质- 组装定位信使核糖核蛋白（mRNP）所需的RNA相互作用 粒子是弱的和瞬态的。这使得他们的鉴定使用经典的生物化学 这几乎是不可能的;复合物福尔斯在纯化步骤中分解。在这 应用，我们提出了新的战略，以解决这一关键的知识差距。模型我们 我建议用于这些研究的是已充分表征的黑腹果蝇卵 室。在本申请的目的1中，我们提出使用邻近生物素连接来定义 运输粒子的核心组成部分，并检查这些因素的守恒 苍蝇和哺乳动物之间的区别在目标2中，我们提出测试假设，颗粒 称为P体的结构协调mRNA的定位及其翻译， 调控

Project Summary (parent grant): R35GM145340 A fundamental feature of eukaryotic life is the establishment and maintenance of cellular polarity. Molecular motors help to establish polarity by transporting mRNAs, proteins, vesicles, and organelles to specific sites within the cell. A variety of organisms from the single-celled yeast to humans use mRNA localization coupled with translational regulation as a way to asymmetrically sort proteins. The prevalence of this phenomenon is best illustrated in developing embryos, neurons and epithelial, in which thousands of mRNAs are spatially localized. When this process is compromised, it can result in developmental and neurological disorders. Despite the importance of this topic and the prevalence of this phenomenon, we lack a mechanistic understanding of mRNA localization. A critical gap in our understanding pertains to how mRNAs destined for localization are recognized by the cell and distinguished from non- localizing mRNAs. In addition to sequences present within localizing mRNAs, the proteins that bind these mRNAs are key to their cellular fate. This complex of proteins is responsible for linking localizing mRNAs with molecular motors and for regulating their translation. However, identifying these critical proteins has proven to be extremely challenging. By its very nature, the process of mRNA localization is highly dynamic. Consequently, the protein-protein and protein- RNA interactions required for assembling localizing messenger ribonucleoprotein (mRNP) particles are weak and transient. This has made their identification using classical biochemical approaches almost impossible; the complex falls apart during the purification step. In this application, we propose novel strategies to address this critical knowledge gap. The model we propose to use for these studies is the well characterized Drosophila melanogaster egg chamber. In Objective 1 of this application, we propose to use proximity biotin ligation to define the core components of transport particles and to examine the conservation of these factors between flies and mammals. In Objective 2, we propose to test the hypothesis that granular structures referred to as P bodies coordinate the localization of mRNAs with their translational regulation.