Translational Control by Human Pumilio Proteins

项目摘要 人类RNA结合蛋白PUM1和PUM2对哺乳动物的发育和它们的 功能障碍与多种人类疾病有关，包括发育缺陷、神经障碍、 不孕不育、癌症和线粒体功能障碍。这些重要职能迫使我们的总体目标 了解PUM1&2如何控制从基因到mRNA再到蛋白质的遗传信息流，并识别 它们所调控的全部基因。PUM1&2通过识别与人类细胞中的数千个mRNA结合 一种名为Pumilio Response Element(Pre)的RNA序列。先前的研究表明，PUM1&2 通过招募RNA衰变酶来促进数百个这些预先包含的mRNAs的降解。现在是时候了 然而，很明显，这一机制只代表了PUM介导的一种监管结果。数千人 的mRNAs与PUM1&2结合，但不被降解。因此，现在有必要确定如何 PUM1&2控制所有靶向mRNAs的命运。由此产生的数据将提供对其 在生物学和发病机制中的调节作用。 我们认为人类PUM1&2通过抑制翻译过程而抑制了许多靶mRNAs。 多个由PUM1&2在蛋白质水平上抑制的基因的例子支持了这一假设 在没有mRNA降解的情况下丰度。这种翻译抑制的机制和普遍存在 是未知的。此外，我们的数据表明，对于某些基因，pum介导的翻译抑制可以 与RNA降解协同作用，在更大程度上调节基因表达，而不是单独进行这两个过程。 RNA分子形成的结构会影响它们的功能和命运。而生化证据 提示RNA结构可以调节PUM-Pre相互作用，其在体内的作用尚不清楚。事实上, 在人类细胞中，普遍缺乏mRNAs的rna结构信息，这限制了我们对 这种结构如何影响像PUM1&2这样的RNA结合蛋白的基因调控。 这项拟议的研究试图确定PUM1&2是如何抑制翻译的，并确定 PUM1&2活性所必需的翻译调节因子。人类mRNAs的结构将是 并分析其对PUM-mRNA相互作用和调控网络的影响。通过集成 利用现有的PUM1&2结合和降解哪些mRNA的现有知识，我们将开发一种 全面了解这一关键的基因调控网络。发现完整的监管网络 PUM1&2将为它们如何控制基因表达以调节正常的生物过程提供新的见解。 此外，这一知识将有助于阐明它们的功能障碍是如何导致神经退化等疾病的 和癌症。

Project Summary The human RNA-binding proteins, PUM1 and PUM2, are essential for mammalian development and their dysfunction is linked to multiple human diseases including developmental defects, neurological disorders, infertility, cancers, and mitochondrial dysfunction. These important functions compel our overall objective to discover how PUM1&2 control the flow of genetic information from gene to mRNA to protein and to identify the full repertoire of genes that they regulate. PUM1&2 bind to thousands of mRNAs in human cells by recognizing an RNA sequence called the Pumilio Response Element (PRE). Previous research showed that PUM1&2 promote degradation of hundreds of these PRE-containing mRNAs by recruiting RNA decay enzymes. It is now clear, however, that this mechanism represents only one type of PUM-mediated regulatory outcome. Thousands of mRNAs are bound by PUM1&2 but are not degraded. Therefore, it is now necessary to determine how PUM1&2 control the fate of all target mRNAs. The resulting data will provide a comprehensive view of their regulatory roles in biology and pathogenesis. We propose that human PUM1&2 repress many target mRNAs by inhibiting the process of translation. This hypothesis is supported by multiple examples of genes that are repressed by PUM1&2 at the level of protein abundance in the absence of mRNA degradation. The mechanism and prevalence of this translational inhibition is unknown. In addition, our data indicate that for some genes PUM-mediated translational inhibition can synergize with RNA degradation to regulate gene expression to a larger extent than either process alone. RNA molecules form structures that influence their function and fate. While biochemical evidence indicates that RNA structure can modulate PUM-PRE interactions, its effect in vivo remains unknown. In fact, there is an overall lack of RNA structural information of mRNAs in human cells that limits our understanding of how that structure influences gene regulation by RNA-binding proteins like PUM1&2. The proposed research seeks to determine how PUM1&2 inhibit translation and to identify the translational regulatory factors that are necessary for PUM1&2 activity. The structure of human mRNAs will be determined and its effect on PUM-mRNA interactions and regulatory network will be analyzed. By integrating this new data with existing knowledge of which mRNAs are bound and degraded by PUM1&2, we will develop a comprehensive understanding of this key genetic regulatory network. Discovery of the full regulatory network of PUM1&2 will provide new insights into how they control gene expression to regulate normal biological processes. Moreover, this knowledge will help elucidate how their dysfunction leads to diseases such as neurodegeneration and cancer.