TrmB, a tRNA m7G46 methyltransferase, plays a role in hydrogen peroxide resistance and positively modulates the translation of katA and katB mRNAs in Pseudomonas aeruginosa

Abstract

Cellular response to oxidative stress is a crucial mechanism that promotes the survival of Pseudomonas aeruginosa during infection. However, the translational regulation of oxidative stress response remains largely unknown. Here, we reveal a tRNA modification-mediated translational response to H2O2 in P. aeruginosa. We demonstrated that the P. aeruginosa trmB gene encodes a tRNA guanine (46)-N7-methyltransferase that catalyzes the formation of m7G46 in the tRNA variable loop. Twenty-three tRNA substrates of TrmB with a guanosine residue at position 46 were identified, including 11 novel tRNA substrates. We showed that loss of trmB had a strong negative effect on the translation of Phe- and Asp-enriched mRNAs. The trmB-mediated m7G modification modulated the expression of the catalase genes katA and katB, which are enriched with Phe/Asp codons at the translational level. In response to H2O2 exposure, the level of m7G modification increased, consistent with the increased translation efficiency of Phe- and Asp-enriched mRNAs. Inactivation of trmB led to decreased KatA and KatB protein abundance and decreased catalase activity, resulting in H2O2-sensitive phenotype. Taken together, our observations reveal a novel role of m7G46 tRNA modification in oxidative stress response through translational regulation of Phe- and Asp-enriched genes, such as katA and katB.

Pseudouridines of tRNA Anticodon Stem-Loop Have Unexpected Role in Mutagenesis in Pseudomonas sp.

“…The most common exogenous and endogenous stressors are reactive oxygen species (ROS). It has been shown that some tRNA modifications (e.g., methylation and thiolation) can modulate oxidative stress response in bacteria [ 8 , 9 , 86 ]. Adding ROS scavenging agents to the growth medium of bacteria could indicate whether the elevated mutation frequency originates from reduced tolerance to intracellular ROS levels [ 87 ].…”

“…For example, in yeast there are Ψ38 or Ψ39 in at least 19 tRNAs, but the temperature-sensitive phenotype of the Pus3p mutant is mainly due to a defect in tRNA gln(UUG) , showing that Ψs can have distinct effects on different tRNAs [ 101 ]. In addition, although in P. aeruginosa TrmB methylates many tRNAs, the expression of KatA and KatB is selectively upregulated at the translation level, since both, katA and katB gene, are enriched in Phe and Asp codons [ 9 ].…”

“…In addition to the four standard nucleotides, tRNA molecules acquire numerous post-transcriptional modifications, thus representing the most abundantly modified molecules in cell. Although some modifications have been proven to fulfil a role in tRNA structure formation and stabilization [ 1 ], translation decoding [ 2 , 3 , 4 , 5 ], maintenance of translation accuracy and processivity [ 6 ], as well as regulation of stress responses [ 7 , 8 , 9 ], the physiological role of several tRNA modifications is still enigmatic.…”

RNA Modifications in Pathogenic Bacteria: Impact on Host Adaptation and Virulence

“…For example, m 7 G46 catalyzed by tRNA guanine-N7-methyltransferase (trmB) is important for decoding efficiency of tRNA Asp GUC and tRNA Phe GAA . In P. aeruginosa, loss of trmB has a strong negative effect on the translation of Phe-and Asp-enriched mRNAs, including those coding the major peroxide detoxifying enzymes, the catalases KatA and KatB, resulting in oxidative stress-sensitive phenotype [173]. Using tRNAseq and mass spectrometry performed on Vibrio cholera revealed specific modifications in various tRNAs that were not described in E. coli tRNAs [174].…”

Balanced Input from the tRNA Prenyltransferase MiaA Controls the Stress Resistance and Virulence Potential of Extraintestinal PathogenicEscherichia coli

“…In Escherichia coli and other bacteria, the hypomodification of tRNAs can result in decreased growth rates, altered metabolic requirements, and reduced stress resistance [5][6][7][8]. Loss of tRNA modifications can also impact the fitness and virulence potential of many important bacterial pathogens, including Streptomyces pyogenes, Pseudomonas spp., Shigella flexneri, Agrobacterium tumefaciens, Mycobacterium tuberculosis, Aeromonas hydrophila, Streptococcus spp., and Salmonella enterica serotype Typhimurium [6,[9][10][11][12][13][14][15][16][17][18][19][20][21]. Together, these findings suggest that tRNA modification serves as a regulatory nexus that can control a wide array of bacterial activities.…”