V.cholerae DusB analysis in oxidative stress

RNA modifications play a fundamental role in regulating essential cellular processes, including RNA folding, stability, gene expression, and the accuracy and efficiency of decoding. These modifications are installed post-transcriptionally by specialized enzymes, yet their broader roles beyond RNA modification remain poorly understood. In this study, we uncover a novel function for Vibrio cholerae tRNA dihydrouridine synthase B (VcDusB) in bacterial adaptation to oxidative stress. VcDusB is traditionally recognized for catalyzing the reduction of uridine to dihydrouridine in tRNA, and our findings reveal that its deletion severely compromises V. cholerae survival under hydrogen peroxide-induced oxidative stress. Unexpectedly, VcDusB not only modulates decoding efficiency at its target tRNAs but also influences global translation, including codons unrelated to its canonical substrates—a phenomenon particularly pronounced under oxidative stress. Proteomic analysis of the ?dusB strain exposed a substantial reduction in protein synthesis, highlighting widespread translational defects in response to stress. Strikingly, point mutations in dusB demonstrated that its protective role during stress is independent of its tRNA modification activity. Instead, its NADPH oxidase activity are crucial for survival. We propose role for DusB in cell metabolism. These findings unveil a previously unrecognized, non-canonical function of DusB in oxidative stress defense, expanding our understanding of RNA-modifying enzymes. More broadly, this work paves the way for exploring the multifaceted roles of these enzymes in cellular metabolism and stress responses, far beyond their well-established functions in RNA modification.