Loss of -methylation of G37 in TRNA Induces Ribosome Stalling and Reprograms Gene Expression

-methylation of G37 is required for a subset of tRNAs to maintain the translational reading-frame. While loss of mG37 increases ribosomal +1 frameshifting, whether it incurs additional translational defects is unknown. Here, we address this question by applying ribosome profiling to gain a genome-wide view of the effects of mG37 deficiency on protein synthesis. Using as a model, we show that mG37 deficiency induces ribosome stalling at codons that are normally translated by mG37-containing tRNAs. Stalling occurs during decoding of affected codons at the ribosomal A site, indicating a distinct mechanism than that of +1 frameshifting, which occurs after the affected codons leave the A site. Enzyme- and cell-based assays show that mG37 deficiency reduces tRNA aminoacylation and in some cases peptide-bond formation. We observe changes of gene expression in mG37 deficiency similar to those in the stringent response that is typically induced by deficiency of amino acids. This work demonstrates a previously unrecognized function of mG37 that emphasizes its role throughout the entire elongation cycle of protein synthesis, providing new insight into its essentiality for bacterial growth and survival.