RRC ID 35318
Author Chadani Y, Ono K, Ozawa S, Takahashi Y, Takai K, Nanamiya H, Tozawa Y, Kutsukake K, Abo T.
Title Ribosome rescue by Escherichia coli ArfA (YhdL) in the absence of trans-translation system.
Journal Mol Microbiol
Abstract Although SsrA(tmRNA)-mediated trans-translation is thought to maintain the translation capacity of bacterial cells by rescuing ribosomes stalled on messenger RNA lacking an in-frame stop codon, single disruption of ssrA does not crucially hamper growth of Escherichia coli. Here, we identified YhdL (renamed ArfA for alternative ribosome-rescue factor) as a factor essential for the viability of E. coli in the absence of SsrA. The ssrA-arfA synthetic lethality was alleviated by SsrA(DD) , an SsrA variant that adds a proteolysis-refractory tag through trans-translation, indicating that ArfA-deficient cells require continued translation, rather than subsequent proteolysis of the truncated polypeptide. In accordance with this notion, depletion of SsrA in the ΔarfA background led to reduced translation of a model protein without affecting transcription, and puromycin, a codon-independent mimic of aminoacyl-tRNA, rescued the bacterial growth under such conditions. That ArfA takes over the role of SsrA was suggested by the observation that its overexpression enabled detection of the polypeptide encoded by a model non-stop mRNA, which was otherwise SsrA-tagged and degraded. In vitro, purified ArfA acted on a ribosome-nascent chain complex to resolve the peptidyl-tRNA. These results indicate that ArfA rescues the ribosome stalled at the 3' end of a non-stop mRNA without involving trans-translation.
Volume 78(4)
Pages 796-808
Published 2010-11
DOI 10.1111/j.1365-2958.2010.07375.x
PMID 21062370
MeSH Escherichia coli / metabolism* Escherichia coli Proteins / genetics Escherichia coli Proteins / metabolism* Gene Deletion Genes, Bacterial Genes, Essential Protein Biosynthesis* RNA, Bacterial / metabolism* RNA-Binding Proteins / genetics RNA-Binding Proteins / metabolism* Ribosomes / metabolism*
IF 3.649
Times Cited 85
Prokaryotes E. coli JW3253-KC