Poster abstracts
Poster number 56 submitted by Rodney Tollerson II
EF-P functions as a growth-rate dependent translation elongation factor
Rodney Tollerson II (Department of Microbiology), Anne Witzky (Department of Molecular Genetics), Michael Ibba (Department of Microbiology)
Abstract:
Elongation Factor P (EF-P) is a universally conserved translation factor that alleviates ribosome pausing at polyproline motifs by facilitating peptide bond formation. Without EF-P, translation elongation becomes the rate-limiting step of protein synthesis, leading to a wide range of phenotypes. In this study, we observe that phenotypes resulting from the loss of EF-P are dependent on growth rate in Escherichia coli. In rapid growth conditions, Δefp E. coli displays many defects, including increased doubling time, sensitivity to antimicrobial agents, and global ribosome pausing compared to the wildtype. When growth is slowed under conditions such as low temperature or nutrient deprivation, these defects are abolished. Using polyproline translation reporter assays, we observe the requirement for EF-P in translation of polyproline motifs is greatly diminished under slow growth conditions. These global changes in EF-P dependence for translation of specific motifs in slow growth conditions may be attributed to decreased ribosome queuing, similar to effects previously observed at the single transcript level. These results highlight the growth rate-dependent role for EF-P in E. coli and its role in adaptation to environmental changes.
Keywords: translation elongation, physiology