Mechanisms of eIF3-mediated translation regulation

项目摘要 对细胞中表达的蛋白质进行精确的空间和时间控制对于正确的蛋白质表达至关重要。 分化和细胞生长的决定。尽管mRNA翻译是基因表达的核心步骤， 监管仍然知之甚少。在我们对特化的分子基础的理解上， 翻译的特定转录本，以及这种调控对细胞反应的整体功能意义 到信号提示在这里，我们建议研究mRNA翻译调节的动态贡献， 细胞生理学基础的基因表达程序。我们将关注的系统是13亚基eIF 3 翻译起始因子复合物，其在一般翻译期间充当支架以组织相互作用 小核糖体蛋白和其他起始因子之间的联系。我们最近发现eIF 3也可以 通过新的RNA结合和帽结合活性控制选择的细胞转录物的翻译。这些 研究结果表明，经典翻译启动因素在一般翻译之外发挥作用， 来驱动不同基因程序的表达。尽管有这些有趣的发现，eIF 3是最大的 除了核糖体之外，翻译机器的组成部分，将功能归于大多数亚基， 一直在挑战。标准的遗传技术不能应用于eIF 3; eIF 3亚基是必需的， 多亚基eIF 3复合物的组装受到亚基水平改变的阻碍。这些 方法也不能将一般翻译活动与专门翻译活动分开。我们将开发一种创新的 一组高通量方法来解决这些困难，并全面发现eIF 3 在细胞分化和细胞对外部信号的反应过程中控制动态基因程序。通过 结合这些广泛的方法与详细的生物化学和细胞为基础的方法，我们将提供 翻译调节网络的分子理解，协调所需的精确控制 纠正细胞功能和信号传导。这项研究将为基因工程的基本原理提供新的见解。 调控由于eIF 3和其他起始因子在遗传上与癌症、衰老、先天性疾病、 这项工作也将指导非传统的方法来靶向疾病中的翻译调节。

Project Summary Exquisite spatial and temporal control of the proteins that are expressed in a cell is essential for correct differentiation and cell growth decisions. Despite being a central step in gene expression, how mRNA translation is regulated remains poorly understood. There is a gap in our understanding of the molecular basis of specialized translation of specific transcripts, and of the overall functional significance of this regulation on cellular responses to signaling cues. Here we propose to investigate the contribution of mRNA translation regulation to the dynamic gene expression programs that underlie cell physiology. The system we will focus on is the 13-subunit eIF3 translation initiation factor complex, which acts as a scaffold during general translation to organize interactions between the small ribosomal proteins and other initiation factors. We recently discovered that eIF3 can also control the translation of select cellular transcripts through novel RNA-binding and cap-binding activities. These findings demonstrate that canonical translation initiation factors moonlight in roles outside of general translation to drive expression of distinct gene programs. Despite these intriguing findings, and eIF3 being the largest component of the translation machinery besides the ribosome, ascribing functions to the majority of subunits has been challenging. Standard genetic techniques cannot be applied to eIF3; eIF3 subunits are essential for viability, and the assembly of the multi-subunit eIF3 complex is hindered by alterations to subunit levels. These methods also cannot segregate activities in general versus specialized translation. We will develop an innovative set of high-throughput methodologies to address these difficulties and comprehensively discover how eIF3 controls the dynamic gene programs during cell differentiation and cellular response to extrinsic signals. By combining these broad approaches with detailed biochemical and cell-based approaches, we will provide molecular understanding of the translation regulation networks that coordinate the precise control required for correct cellular function and signaling. This research will create new insights into fundamental principles of gene regulation. As eIF3 and other initiation factors are genetically associated with cancer, aging, congenital disorders, this work will also guide unconventional approaches to target translation regulation in disease.