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

 Abstract

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 (mcm5U) and 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U), classified as key determinants of translational fidelity. We also show that in the absence of mcm5U and mcm5s2U, 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.

Full Text Options
Article
Metrics
 Share
 Supplemental Material
 Info
Pages
990 - 1001
doi
10.4161/rna.20531
Type
Research Paper
 Metrics
 Cite This Article
 Permissions
 Permissions
 Reprints
Translational infidelity-induced protein stress results from a deficiency in Trm9-catalyzed tRNA modifications