The final step of gene expression is translation, the synthesis of protein based on the sequence of messenger RNA (mRNA). Translation is performed by ribosomes, sub-cellular 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 characterized a number of mutations in the rRNA of the small (30S) subunit that cause defects in initiation. This project will investigate the role of the large (50S) subunit and factors IF1, IF3, and S1, providing further insight into the molecular mechanisms that govern the initiation process.
BROADER IMPACT: The broader impact of this project lies in its strong educational emphasis. This project will provide (1) research training for undergraduate and graduate students, (2) summer research opportunities for local high school students (Columbus Public Schools), and (3) laboratory internships for students of the Ohio STEM (Science, Technology, Engineering, and Mathematics) Talent Expansion Program, which aims to boost the success rate of STEM majors. In addition, genetic experiments (relevant to the project) will be incorporated into the curriculum of the advanced laboratory course in Microbiology. By conducting actual experiments rather than lab exercises, these students will be given the opportunity for discovery as they gain technical skills.
