RRC ID 35207
Author Singh NS, Ahmad R, Sangeetha R, Varshney U.
Title Recycling of ribosomal complexes stalled at the step of elongation in Escherichia coli.
Journal J. Mol. Biol.
Abstract Translating ribosomes often stall during elongation. The stalled ribosomes are known to be recycled by tmRNA (SsrA)-mediated trans-translation. Another process that recycles the stalled ribosomes is characterized by peptidyl-tRNA release. However, the mechanism of peptidyl-tRNA release from the stalled ribosomes is not well understood. We used a defined system of an AGA-minigene containing a small open reading frame (ATG AGA AGA). Translation of the AGA-minigene mRNA is toxic to Escherichia coli because it stalls ribosomes during elongation and sequesters tRNA(Arg4) as a short-chain peptidyl-tRNA(Arg4) in the ribosomal P-site. We show that a ribosome recycling factor (RRF)-mediated process rescues the host from the AGA-minigene toxicity by releasing the peptidyl-tRNA(Arg4) from the ribosomes. The growth phenotypes of E. coli strains harboring mutant alleles of RRF and initiation factor 3 (IF3) genes and their consequences on lambdaimmP22 phage replication upon AGA-minigene expression reveal that IF3 facilitates the RRF-mediated processing of the stalled ribosomes. Additionally, we have designed a uracil DNA glycosylase gene construct, ung-stopless, whose expression is toxic to E. coli. We show that the RRF-mediated process also alleviates the ung-stopless construct-mediated toxicity to the host by releasing the ung mRNA from the ribosomes harboring long-chain peptidyl-tRNAs.
Volume 380(3)
Pages 451-64
Published 2008-7-11
DOI 10.1016/j.jmb.2008.05.033
PII S0022-2836(08)00599-8
PMID 18565340
MeSH Alleles Escherichia coli / genetics* Escherichia coli / growth & development Escherichia coli / metabolism* Plasmids Prokaryotic Initiation Factor-3 / genetics Prokaryotic Initiation Factor-3 / physiology RNA, Bacterial / metabolism RNA, Transfer, Amino Acyl / secretion Ribosomal Proteins / genetics Ribosomal Proteins / metabolism Ribosomes / genetics* Ribosomes / metabolism*
IF 4.894
Times Cited 26
Prokaryotes E. coli ?