Poster abstracts
Poster number 19 submitted by Michelle Gibbs
Conserved GTPase LepA (Elongation Factor 4) functions in biogenesis of the 30S subunit of the 70S ribosome
Michelle R. Gibbs (Department of Microbiology, Center for RNA Biology, The Ohio State University ), Kyung-Mee Moon (Department of Biochemistry and Molecular Biology, University of British Columbia), Menglin Chen (Department of Microbiology, Center for RNA Biology, Ohio State Biochemistry Program, The Ohio State University ), Rohan Balakrishnan (Department of Microbiology, Center for RNA Biology, Ohio State Biochemistry Program, The Ohio State University ), Leonard J. Foster (Department of Biochemistry and Molecular Biology, University of British Columbia), Kurt Fredrick (Department of Microbiology, Center for RNA Biology, Ohio State Biochemistry Program, The Ohio State University )
Abstract:
The physiological role of LepA, a paralog of EF-G found in all bacteria, has been a mystery for decades. Here, we show that LepA functions in ribosome biogenesis. In cells lacking LepA, immature 30S particles accumulate. Four proteins are specifically underrepresented in these particles—S3, S10, S14, and S21—all of which bind late in the assembly process and contribute to the folding of the 3’ domain of 16S rRNA. Processing of 16S rRNA is also delayed in the mutant strain, as indicated by increased levels of precursor 17S rRNA in assembly intermediates. Mutation ΔlepA confers a synthetic phenotype in absence of RsgA, another GTPase, well known to act in 30S subunit assembly. Analysis of the ΔrsgA strain reveals accumulation of intermediates that resemble those seen in the absence of LepA. These data suggest that RsgA and LepA play partially redundant roles to ensure efficient 30S assembly.
Keywords: protein synthesis, translation, RsgA