Loss of N1-methylation of G37 in tRNA induces ribosome stalling and reprograms gene expression [article]

Isao Masuda, Jae-Yeon Hwang, Thomas Christian, Sunita Maharjan, Fuad Mohammad, Howard Gamper, Allen Buskirk, Ya-MIng Hou
2021 bioRxiv   pre-print
N1-methylation of G37 is required for a subset of tRNAs to maintain the translational reading frame. While loss of m1G37 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 m1G37 deficiency on protein synthesis. Using E. coli as a model, we show that m1G37 deficiency induces ribosome stalling at codons that are normally translated by
more » ... taining 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 A site. Enzyme and cell-based assays show that m1G37 deficiency reduces tRNA aminoacylation and in some cases peptide-bond formation. We observe changes of gene expression in m1G37 deficiency similar to those in the starvation-induced stringent response, consistent with the notion that loss of tRNA aminoacylation activates the response. This work demonstrates a previously unrecognized function of m1G37 that emphasizes its role throughout the entire elongation cycle of protein synthesis, providing new insight into its essentiality for bacterial growth and survival.
doi:10.1101/2021.05.27.446073 fatcat:lvthlgt5cbe2df5msieia3u3ym