Studies of Translation Initiation in Bacteria

基因表达的最后一步是翻译，即从信使RNA(信使RNA)的信息内容合成蛋白质。翻译发生在核糖体中，核糖体是由核糖体RNA(RRNA)和蛋白质组成的亚细胞机器。近年来，X射线结晶学和冷冻电子显微镜揭示了核糖体的结构及其与各种底物和翻译因子的相互作用。尽管有如此丰富的结构信息，关于核糖体如何在翻译过程中促进特定事件的问题仍然不清楚。这个项目的目标是更好地理解翻译的初始阶段。起始是一个复杂的过程，需要从其他种类的tRNA中选择启动子tRNA，并从mRNA中其他相似或相同的三联体序列中选择起始密码子。在细菌中，这一过程受启动因子IF1、IF2和IF3的动力学控制。在其他生物中，启动从根本上说是相似的，但更复杂，除了普遍保守的IF2(EIF5B)和IF1(EIF1A)外，还涉及10个或更多因素。弗雷德里克实验室已经确定了小亚基rRNA中的一些突变，这些突变导致了起始密码子选择的缺陷。这个项目的中心是对这些突变的分析，这将有助于阐明rRNA和因子IF1和IF3在启动过程中的作用。该项目的更广泛影响在于其强烈的教育重点。该项目不仅将为本科生和研究生提供研究培训，还将为中学教育工作者提供研究机会。每年夏天，该实验室将接待一名来自哥伦布公立学校的高中理科教师。在为实验室的研究工作做出贡献的同时，这些教师将获得现代分子生物学的经验，以加强他们的课程。

The final step of gene expression is translation, the synthesis of protein from the information content of messenger RNA (mRNA). Translation occurs in ribosomes, subcellular machines composed of both ribosomal RNA (rRNA) and protein. In recent years, x-ray crystallography and cryo-electron microscopy have revealed the structure of the ribosome and its interactions with a variety of substrates and translation factors. Despite this wealth of structural information, questions of how the ribosome facilitates specific events during translation remain unclear. The goal of this project is to better understand the initiation phase of translation. Initiation is a complex process that requires selection of the initiator tRNA from other species of tRNA and selection of the start codon from other similar or identical triplet sequences in the mRNA. In bacteria, the process is kinetically controlled by initiation factors IF1, IF2 and IF3. In other organisms, initiation is fundamentally similar but more elaborate, involving 10 or more factors in addition to universally conserved IF2 (eIF5B) and IF1 (eIF1A). The Fredrick lab has identified a number of mutations in the rRNA of the small subunit that cause defects in start codon selection. This project is centered on the analysis of these mutations, which will help elucidate the role of rRNA and factors IF1 and IF3 in the initiation process.The broader impact of this project lies in its strong educational emphasis. This project will not only provide research training for both undergraduate and graduate students but will also give research opportunities for secondary educators. Each summer, the laboratory will host a high school science teacher from one of the Columbus Public Schools. While contributing to the research efforts of the laboratory, these teachers will gain experience with modern molecular biology to strengthen their curriculum.