We used ribosome profiling to characterize the biological role of ribosome recycling factor (RRF) in E. coli. As expected, RRF depletion leads to enrichment of post-termination 70S complexes in 3'-UTRs. We also observe that elongating ribosomes are unable to complete translation because they are blocked by non-recycled ribosomes at stop codons. Previous studies have suggested a role for recycling in translational coupling within operons; if a ribosome remains bound to an mRNA after termination, it may re-initiate downstream. We found, however, that RRF depletion did not significantly affect coupling efficiency in reporter assays or in ribosome density genome-wide. These findings argue that re-initiation is not a major mechanism of translational coupling in E. coli. Finally, RRF depletion has dramatic effects on the activity of ribosome rescue factors tmRNA and ArfA. Our results provide a global view of the effects of the loss of ribosome recycling on protein synthesis in E. coli.
Sequencing data have been deposited in GEO under accession codes GSE151688.
RRF plays critical roles in ribosome homeostasis in E. coli but has little effect on translational couplingNCBI Gene Expression Omnibus, GSE151688.
- Allen R Buskirk
- Rachel Green
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Joseph T Wade, Wadsworth Center, New York State Department of Health, United States
© 2020, Saito et al.
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