The Role of Eukaryotic Initiation Factor (eIF) 4G in Initiation of Translation

真核起始因子 (eIF) 4G 在翻译起始中的作用

• 批准号: 9726958
• 负责人: Christopher Hellen
• 金额: $ 24万
• 依托单位: SUNY Health Science Center at Brooklyn
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9726958&HistoricalAwards=false
• 关键词: Role; Eukaryotic; Initiation; Factor; eIF

Hellen MCB 9726958 1. Technical Eukaryotic initiation factor (eIF) 4G coordinates the rate-limiting step in protein synthesis by interacting with other factors in the recruitment of mRNA to ribosomes. eIF4G associates with the cap-binding protein eIF4E and the ATPase/RNA helicase eIF4A to form the eIF4F complex. eIF4G also binds to eIF3, a component of the 43S ribosomal preinitiation complex. This study applies biochemical and molecular genetic approaches to characterize the role of eIF4G' in initiation of translation. This is achieved through reconstitution experiments in vitro using purified components, which include recombinant eIFs 4A, 4B, 4E and 4G, on a variety of clone mRNAs. Sensitive toe-printing and footprinting methods to map the position of ribosomal and preinitiation complexes on mRNAs are developed for this purpose. The significance of this study lies in its advancing our knowledge of protein synthesis at the molecular level. 2. Non Technical This study is to elucidate fundamental aspects of the mechanism and regulation of protein synthesis, particularly the role of the initiation factor, 4G (eIF4G), in coordinating the activities of various cellular components that together recruit individual mRNAs for the onset of translation. Experimentally, purified components on different mRNAs are reconstituted in vitro at the beginning stage of translation. Various protein or mRNA components are systematically substituted with a series of variants, and their effects compared under specific conditions such as growth arrest and mitosis. The importance of determinants in eIF4G that enable it to bind to all mRNAs nonspecifically, and to a few with high specificity, are identified and characterized. Viral and cellular mRNAs that bind eIF4G with high affinity are chosen in this study, since they may be models for translation when eIF4E is inactive. Also being studied are determinants of eIF4A's which interact with eIF4G, another initiation factor. This interaction directs the unwinding of eIF4A to a specific site on the mRNA to permit the attachment of ribosomes, the anchorage machinery for protein synthesis.

1. casino技术 真核起始因子（eIF）4G协调细胞内的限速步骤， 在mRNA向核糖体的募集过程中，通过与其他因子相互作用来合成蛋白质。eIF4G与帽结合蛋白eIF4E和ATP酶/RNA解旋酶eIF4A结合形成eIF4F复合物。 eIF4G还结合eIF3，eIF3是43S核糖体前起始复合物的一种组分。本研究应用生物化学和分子遗传学方法来表征eIF4G '在翻译起始中的作用。 这是通过使用纯化组分（包括重组eIF 4A、4 B、4 E和4G）对各种克隆mRNA进行体外重建实验来实现的。 灵敏的脚趾印和足迹法映射的核糖体和preinitiation复合物的mRNA的位置是为此目的而开发的。这项研究的意义在于它在分子水平上推进了我们对蛋白质合成的认识。 2.非技术性本研究旨在阐明蛋白质合成的机制和调控的基本方面，特别是起始因子4G（eIF4G）在协调各种细胞组分的活动中的作用，这些组分共同招募单个mRNA进行翻译。在实验上，不同mRNA上的纯化组分在翻译的开始阶段在体外重构。各种蛋白质或mRNA组分被一系列变体系统地取代，并在特定条件下（如生长停滞和有丝分裂）比较它们的作用。eIF4G中的决定簇的重要性，使其能够结合到所有的mRNA非特异性，并以高特异性的几个，被确定和表征。在本研究中选择了以高亲和力结合eIF4G的病毒和细胞mRNA，因为它们可能是eIF4E失活时的翻译模型。 也正在研究的是与eIF4G（另一种起始因子）相互作用的eIF4A的决定因素。这种相互作用指导eIF4A解旋到mRNA上的特定位点，以允许核糖体的附着，核糖体是蛋白质合成的锚定机制。