THE NOTCH SIGNALING PATHWAY: STRUCTURE AND MECHANISM

描述(申请人提供)：这个项目的长期目标是详细了解细胞间信号如何在动物发育过程中控制细胞命运。通过Notch(N)受体的细胞-细胞信号是后生动物多种发育过程中分配细胞命运的主要机制，包括神经发生。虽然N信号通路已经得到了广泛的研究，但其结构和操作的许多基本要素仍然神秘或鲜为人知。我们已经在果蝇中发现了一组新的基因，我们称之为胡须(Brd)家族，以其创始成员的名字命名。这些基因都编码带有强碱性两亲性螺旋结构域的小蛋白.BRD家族基因是果蝇N途径中不可或缺的核心成员。它们在胚胎和胚胎后发育的N信号的多个位置特异表达，并直接受N激活的转录因子抑制物无毛的调节。当它们过度表达时，它们是N信号活性的强有力的调节器。最初的功能丧失遗传学研究表明，Brd家族蛋白在神经系统和肌肉发育中都是N信号的效应者。显然，从机制上理解节肢动物的N途径功能将需要阐明Brd蛋白家族的发育作用和生化作用模式。本申请中描述的研究计划就是为实现这一目标而设计的，并有三个具体目标：(1)Brd家族基因和蛋白质功能的遗传分析。(2)Brd家族蛋白表达及定位的细胞生物学和分子生物学分析。(3)Brd家族蛋白伙伴及其相互作用的识别与分析。我们预计，我们的研究将极大地扩大我们对古老的细胞-细胞信号通路如何决定细胞命运的知识，并可能为深入了解N途径疾病综合征的发病机制，如Alagille和CADASIL。

DESCRIPTION (provided by applicant): The long-term goal of this project is a detailed understanding of how intercellular signals control cell fate during animal development. Cell-cell signaling via the Notch (N) receptor is a principal mechanism for assigning cell fates in a broad variety of developmental processes in metazoans, including neurogenesis. Though the N signaling pathway has been studied extensively, many essential elements of its structure and operation remain mysterious or poorly understood. We have identified a novel group of genes in Drosophila that we refer to as the Bearded (Brd) family, after the founding member. These genes all encode small proteins with a strongly basic amphipathic a helical domain. Brd family genes are integral, core members of the N pathway in Drosophila. They are expressed specifically at multiple sites of N signaling in both embryonic; and post-embryonic development, and are directly regulated by the N-activated transcription factor Suppressor of Hairless. When overexpressed, they are potent modulators of N signaling activity. Initial loss-of-function genetic studies indicate that Brd family proteins act as effectors of N signaling in both nervous system and muscle development. Clearly, a mechanistic understanding of N pathway function in arthropods will require elucidating the developmental role and biochemical mode of action of the Brd protein family. The research program described in this application is designed to achieve this goal, and has 3 specific aims: (1) Genetic analysis of Brd family gene and protein function. (2) Ceil biological and molecular analysis of Brd family protein expression and localization. (3) Identification and analysis of Brd family protein partners and interactions. We expect that our investigation will greatly enlarge our knowledge of how an ancient cell-ceil signaling pathway specifies cell fate, and may offer insight into the pathogenesis of N pathway disease syndromes such as Alagille and CADASIL.