Regulation of cell fates by the Bicaudal-C translational repressor

翻译后摘要：在一个动物的一生中，细胞命运的决定不断作出，允许 正常的发育和生长以及成年机体的健康。细胞命运的决定需要 精确控制特定蛋白质的时空表达。在脊椎动物的早期发育中， 某些成年细胞类型，如神经系统的细胞，这种受调节的蛋白质表达严重依赖于 转录后机制，特别是翻译控制。该建议侧重于一个保守的 一种名为Bicaudal-C（Bicc 1）的RNA结合蛋白，在翻译调节中起作用，是 正常的脊椎动物发育。虽然已经确定Bicc 1是一种RNA结合蛋白， Bicc 1基因在脊椎动物的正常发育和健康中的细胞和分子机制 执行这些角色在很大程度上是未知的，因此代表了知识的重大差距。另外由于 几个相关的Bicc 1靶mRNA只是最近才被鉴定出来，它们在脊椎动物发育中的作用 也是未知的，限制了将Bicc 1的分子功能与特定细胞命运决定联系起来的能力。的 长期的研究目标是确定发育重要的RNA 结合蛋白选择它们的靶mRNA并控制mRNA表达以影响特定的细胞命运决定， 并了解这些过程中的缺陷如何导致细胞功能障碍和有机体疾病。的 中心假设是Bicc 1通过一个复杂的RNA结合结构域选择特定的靶mRNA， 多个独立的RNA结合表面，并通过其他不同的区域调节翻译， 定义了这一假设是基于实验室的广泛研究，重点是定义Bicc 1如何指导 模式生物非洲爪蟾脊椎动物发育的最早的母性阶段。这项工作 建立了Bicc 1作为理解RNA结合蛋白如何控制mRNA翻译的范例， 直接决定复杂的细胞命运在过去广泛的概念和技术进步的基础上再接再厉 十年来，具体目标将解决中心假设：1。定义Bicc 1目标中的元素 Bicc 1结合和翻译调控所需的mRNA; 2.确定Bicc 1的区域， 选择性地结合和接触mRNA并在翻译调节中起作用是必要的和足够的。 这些区域在胚胎发生中的作用也将被检查;和3。确定Bicc 1 mRNA靶点的作用 在脊椎动物发育过程中的细胞命运决定。该研究采用了严格的多学科 结合RNA-蛋白质生物化学、独特的抑制-报告基因测定、基因组激活 方法，反向分子遗传学和胚胎学，以确定分子机制， 保守的和疾病相关的RNA结合蛋白Bicc 1指导最早的细胞命运决定， 脊椎动物发育

Abstract: Over the course of an animal’s lifetime, cell-fate decisions are continually being made that allow for normal development and growth as well as the health of the adult organism. Cell-fate decisions require precisely controlled temporal and spatial expression of particular proteins. In early vertebrate development and certain adult cell types, such as those of the nervous system, this regulated protein expression relies heavily on post-transcriptional mechanisms, particularly translational control. This proposal focuses on a conserved RNA binding protein named Bicaudal-C (Bicc1) that functions in translational regulation and is essential for normal vertebrate development. While it is established that Bicc1 is an RNA binding protein required for the normal development and health of vertebrates, the cellular and molecular mechanisms by which Bicc1 performs these roles are largely unknown and thus represent a major gap in knowledge. In addition, because several relevant Bicc1 target mRNAs have only recently been identified, their roles in vertebrate development are also unknown, limiting the ability to connect Bicc1’s molecular functions to specific cell-fate decisions. The long-term research goal is to define the molecular mechanisms by which developmentally important RNA binding proteins select their target mRNAs and control mRNA expression to effect specific cell-fate decisions, and to understand how defects in these processes contribute to cell dysfunction and organismal disease. The central hypothesis is that Bicc1 selects particular target mRNAs through a complex RNA binding domain with multiple independent RNA binding surfaces, and regulates translation via additional distinct regions yet to be defined. This hypothesis is based on extensive research from the lab focused on defining how Bicc1 directs the earliest, maternal stages of vertebrate development in the model organism Xenopus laevis. This work has established Bicc1 as a paradigm for understanding how RNA binding proteins control mRNA translation to direct complex cell-fate decisions. Building on extensive conceptual and technical progress over the past decade, the Specific Aims will address the central hypothesis by: 1. Defining elements within Bicc1 target mRNAs required for Bicc1 binding and translational regulation; 2. Determining the regions of Bicc1 that are necessary and sufficient to selectively bind and contact mRNAs and to function in translational regulation. These regions’ roles in embryogenesis will also be examined; and 3. Defining the roles of Bicc1 mRNA targets in cell-fate decisions during vertebrate development. The research employs a rigorous and multidisciplinary strategy incorporating RNA-protein biochemistry, unique translation-reporter assays, genome-enabled approaches, reverse molecular genetics and embryology to define the molecular mechanisms by which the conserved and disease-relevant RNA binding protein Bicc1 directs the earliest cell-fate decisions essential for vertebrate development.