Specialized ribosomes in control of gene expression and embryonic development

描述(由申请人提供) 摘要：生物学中的一个主要挑战是了解基因表达是如何在每一分钟的基础上调节的，从而产生在胚胎发育过程中形成的各种细胞类型。几十年的研究已经证明，在转录和转录后水平上，基因表达的调控有很多层面，这一过程是协调这一过程的。核糖体是一种分子机器，它执行将基因组表达的所有mRNAs翻译成功能蛋白质的艰巨任务。值得注意的是，流行的教条是，核糖体--尽管是一台极其复杂和令人惊叹的机器--在翻译mRNA时具有结构性功能，而不是调节功能。我们的发现出人意料地揭示了基因调控和哺乳动物身体计划形成的基本方面，相反，由专门的核糖体功能控制，该功能指导特定蛋白质产品的制造地点和时间。在这里，我们建议全面和系统地测试这一假设，即“核糖体蛋白密码”在基因表达中给予一个新的水平的调节。为了实现这一点，我们开发了新的遗传和分子工具来研究脊椎动物胚胎发育中的翻译控制。我们的研究将描绘出与核糖体RNA相关的79种不同的核糖体蛋白(RP)是如何为基于RNA的翻译机制赋予更高的特异性，作为一种指导转录特异性翻译控制的机制。此外，我们将识别上游的、发育调节的信号通路，这些信号通路聚集在对RP表达和活性的控制上，指示核糖体在翻译控制中执行更多的调节功能。总之，这些研究将描绘出体内核糖体的一种新的调节功能，这是基因表达和哺乳动物发育的基本方面所必需的。 与公共卫生的相关性：在人类中，越来越多的证据表明，许多核糖体蛋白(RP)的突变与人类疾病有关，例如钻石黑扇贫血，其特点是特定组织和细胞类型的独特病理特征以及癌症的易感性。这项建议将调查这些鲜为人知的RP在基因表达控制中的功能，这对理解这组人类疾病的病因具有重要意义，并可能有助于指导合理治疗的设计。

DESCRIPTION (Provided by the applicant) Abstract: A major challenge in biology is to understand how gene expression is regulated on a minute-by-minute basis to give rise to the remarkable diversity of cell types that are formed during embryonic development. Decades of research have demonstrated numerous layers in regulation of gene expression, at both the transcription and post-transcription level, which orchestrates this process. Ribosomes are molecular machines that carry out the daunting task of translating all the mRNAs expressed by the genome into functional proteins. Notably, the prevailing dogma has been that the ribosome--although an immensely complex and amazing machine--possesses a constitutive rather than regulatory function in translating mRNAs. Our findings unexpectedly reveal that fundamental aspects of gene regulation and formation of the mammalian body plan are instead controlled by specialized ribosome function that directs where and when specific protein products are made. Here we propose to comprehensively and systematically test the hypothesis that a ""ribosome protein code"" imparts a new level of regulation in gene expression. To accomplish this, we have developed novel genetic and molecular tools to study translational control directly within the developing vertebrate embryo. Our studies will delineate how the 79 distinct ribosomal proteins (RPs) that associate with ribosomal RNA confer greater specificity to the RNA-based translational machinery as a mechanism to direct transcript-specific translational control. In addition, we will identify the upstream, developmentally regulated signaling pathways that converge on control of RP expression and activity, which instruct ribosomes to carry out more regulated functions in translational control. Together, these studies will delineate a novel regulatory function of the ribosome in-vivo that is critically required for fundamental aspects of gene expression and mammalian development. Public Health Relevance: In humans, accumulating evidence links mutations in a number of ribosomal proteins (RPs) to human disease, such as Diamond Blackfan anemia, that is characterized by distinct pathological features in specific tissues and cell types as well as predisposition to cancer. This proposal will investigate the poorly understood functions of these RPs in control of gene expression that has important implications for understanding the etiology of this group of human disorders and may help lead the design of rational therapies.