Translational infidelity-induced protein stress results from a deficiency in Trm9-catalyzed tRNA modifications

RNA Biol. 2012 Jul;9(7):990-1001. doi: 10.4161/rna.20531. Epub 2012 Jul 1.


Correct codon-anticodon pairing promotes translational fidelity, with these interactions greatly facilitated by modified nucleosides found in tRNA. We hypothesized that wobble uridine modifications catalyzed by tRNA methyltransferase 9 (Trm9) are essential for translational fidelity. In support, we have used phenotypic, reporter and protein-based assays to demonstrate increased translational infidelity in trm9Δ Saccharomyces cerevisiae cells. Codon reengineering studies suggest that Trm9-catalyzed tRNA modifications promote fidelity during the translation of specific genes, those rich in arginine and glutamic acid codons from mixed boxes. Using quantitative tRNA modification analysis, we determined that trm9Δ cells are only deficient in 2 of 23 tRNA modifications, with those 2, 5-methoxycarbonylmethyluridine (mcm ( 5) U) and 5-methoxycarbonylmethyl-2-thiouridine (mcm ( 5) s ( 2) U), classified as key determinants of translational fidelity. We also show that in the absence of mcm ( 5) U and mcm ( 5) s ( 2) U, the resulting translational infidelity promotes protein errors and activation of unfolded protein and heat shock responses. These data support a model in which Trm9-catalyzed tRNA modifications promote fidelity during the translation of specific transcripts, with decreased wobble base modification leading to translational infidelity, protein errors and activation of protein stress response pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Pairing
  • Base Sequence
  • Codon
  • Gene Knockout Techniques
  • Gentamicins / pharmacology
  • Peptide Elongation Factors / genetics
  • Peptide Elongation Factors / metabolism
  • Protein Biosynthesis*
  • Protein Synthesis Inhibitors / pharmacology
  • RNA Processing, Post-Transcriptional*
  • RNA, Transfer / metabolism*
  • Ribonucleotide Reductases / genetics
  • Ribonucleotide Reductases / metabolism
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / physiology
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Stress, Physiological
  • Unfolded Protein Response
  • tRNA Methyltransferases / deficiency*
  • tRNA Methyltransferases / genetics


  • Codon
  • Gentamicins
  • Peptide Elongation Factors
  • Protein Synthesis Inhibitors
  • Saccharomyces cerevisiae Proteins
  • YEF3 protein, S cerevisiae
  • RNA, Transfer
  • antibiotic G 418
  • Ribonucleotide Reductases
  • Rnr1 protein, S cerevisiae
  • TRM9 protein, S cerevisiae
  • tRNA Methyltransferases