A-Site mRNA Cleavage Is Not Required for tmRNA-Mediated ssrA-Peptide Tagging

• DOI: 10.1371/journal.pone.0081319
• Publication Date: 2013-11-19T22:16:18Z
• Authors: Brian D. Janssen; Fernando Garza-Sá...; Christopher S. Hayes
• Keywords: Cleavage (geology); A-site; Ribosomal binding site; Stop codon; Ribosome profiling; Shine-Dalgarno sequence

In Escherichia coli, prolonged translational arrest allows mRNA degradation into the A site of stalled ribosomes. The enzyme that cleaves A-site codon is not known, but its activity requires RNase II to degrade downstream ribosome. This cleavage process thought function in translation quality control because ribosomes are recycled from truncated transcripts by tmRNA-SmpB "ribosome rescue" system. During rescue, tmRNA-encoded ssrA peptide added nascent chain, thereby targeting tagged protein for after release Here, we examine influence upon activity. Using a model transcript undergoes stop-codon response inefficient termination, quantify ssrA-peptide tagging encoded cells contain (rnb+) or lack (Δrnb) II. reduced approximately three-fold Δrnb backgrounds, efficiency ssrA-tagging identical rnb+ cells. Additionally, pulse-chase analysis demonstrates paused recycle test at similar rates and Together, these results indicate required tmRNA-SmpB-mediated ribosome rescue suggest may play role other recycling pathways.