1
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Schultz SK, Katanski CD, Halucha M, Peña N, Fahlman RP, Pan T, Kothe U. Modifications in the T arm of tRNA globally determine tRNA maturation, function, and cellular fitness. Proc Natl Acad Sci U S A 2024; 121:e2401154121. [PMID: 38889150 DOI: 10.1073/pnas.2401154121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 05/22/2024] [Indexed: 06/20/2024] Open
Abstract
Almost all elongator tRNAs (Transfer RNAs) harbor 5-methyluridine 54 and pseudouridine 55 in the T arm, generated by the enzymes TrmA and TruB, respectively, in Escherichia coli. TrmA and TruB both act as tRNA chaperones, and strains lacking trmA or truB are outcompeted by wild type. Here, we investigate how TrmA and TruB contribute to cellular fitness. Deletion of trmA and truB in E. coli causes a global decrease in aminoacylation and alters other tRNA modifications such as acp3U47. While overall protein synthesis is not affected in ΔtrmA and ΔtruB strains, the translation of a subset of codons is significantly impaired. As a consequence, we observe translationally reduced expression of many specific proteins, that are either encoded with a high frequency of these codons or that are large proteins. The resulting proteome changes are not related to a specific growth phenotype, but overall cellular fitness is impaired upon deleting trmA and truB in accordance with a general protein synthesis impact. In conclusion, we demonstrate that universal modifications of the tRNA T arm are critical for global tRNA function by enhancing tRNA maturation, tRNA aminoacylation, and translation, thereby improving cellular fitness irrespective of the growth conditions which explains the conservation of trmA and truB.
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Affiliation(s)
- Sarah K Schultz
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Christopher D Katanski
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Mateusz Halucha
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Noah Peña
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Tao Pan
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Ute Kothe
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
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2
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Schultz SK, Kothe U. RNA modifying enzymes shape tRNA biogenesis and function. J Biol Chem 2024:107488. [PMID: 38908752 DOI: 10.1016/j.jbc.2024.107488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/24/2024] Open
Abstract
Transfer RNAs (tRNAs) are the most highly modified cellular RNAs, both with respect to the proportion of nucleotides that are modified within the tRNA sequence and with respect to the extraordinary diversity in tRNA modification chemistry. However, the functions of many different tRNA modifications are only beginning to emerge. tRNAs have two general clusters of modifications. The first cluster is within the anticodon stem-loop including several modifications essential for protein translation. The second cluster of modifications is within the tRNA elbow, and roles for these modifications are less clear. In general, tRNA elbow modifications are typically not essential for cell growth, but nonetheless several tRNA elbow modifications have been highly conserved throughout all domains of life. In addition to forming modifications, many tRNA modifying enzymes have been demonstrated or hypothesized to additionally play an important role in folding tRNA acting as tRNA chaperones. In this review, we summarize the known functions of tRNA modifying enzymes throughout the lifecycle of a tRNA molecule, from transcription to degradation. Thereby, we describe how tRNA modification and folding by tRNA modifying enzymes enhance tRNA maturation, tRNA aminoacylation, and tRNA function during protein synthesis, ultimately impacting cellular phenotypes and disease.
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Affiliation(s)
- Sarah K Schultz
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada.
| | - Ute Kothe
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada.
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3
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Yared MJ, Marcelot A, Barraud P. Beyond the Anticodon: tRNA Core Modifications and Their Impact on Structure, Translation and Stress Adaptation. Genes (Basel) 2024; 15:374. [PMID: 38540433 PMCID: PMC10969862 DOI: 10.3390/genes15030374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 06/14/2024] Open
Abstract
Transfer RNAs (tRNAs) are heavily decorated with post-transcriptional chemical modifications. Approximately 100 different modifications have been identified in tRNAs, and each tRNA typically contains 5-15 modifications that are incorporated at specific sites along the tRNA sequence. These modifications may be classified into two groups according to their position in the three-dimensional tRNA structure, i.e., modifications in the tRNA core and modifications in the anticodon-loop (ACL) region. Since many modified nucleotides in the tRNA core are involved in the formation of tertiary interactions implicated in tRNA folding, these modifications are key to tRNA stability and resistance to RNA decay pathways. In comparison to the extensively studied ACL modifications, tRNA core modifications have generally received less attention, although they have been shown to play important roles beyond tRNA stability. Here, we review and place in perspective selected data on tRNA core modifications. We present their impact on tRNA structure and stability and report how these changes manifest themselves at the functional level in translation, fitness and stress adaptation.
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Affiliation(s)
| | | | - Pierre Barraud
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique, F-75005 Paris, France; (M.-J.Y.); (A.M.)
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4
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Jones JD, Franco MK, Tardu M, Smith TJ, Snyder LR, Eyler DE, Polikanov Y, Kennedy RT, Niederer RO, Koutmou KS. Conserved 5-methyluridine tRNA modification modulates ribosome translocation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.12.566704. [PMID: 37986750 PMCID: PMC10659410 DOI: 10.1101/2023.11.12.566704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
While the centrality of post-transcriptional modifications to RNA biology has long been acknowledged, the function of the vast majority of modified sites remains to be discovered. Illustrative of this, there is not yet a discrete biological role assigned for one the most highly conserved modifications, 5-methyluridine at position 54 in tRNAs (m 5 U54). Here, we uncover contributions of m 5 U54 to both tRNA maturation and protein synthesis. Our mass spectrometry analyses demonstrate that cells lacking the enzyme that installs m 5 U in the T-loop (TrmA in E. coli , Trm2 in S. cerevisiae ) exhibit altered tRNA modifications patterns. Furthermore, m 5 U54 deficient tRNAs are desensitized to small molecules that prevent translocation in vitro. This finding is consistent with our observations that, relative to wild-type cells, trm2 Δ cell growth and transcriptome-wide gene expression are less perturbed by translocation inhibitors. Together our data suggest a model in which m 5 U54 acts as an important modulator of tRNA maturation and translocation of the ribosome during protein synthesis.
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5
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Porat J, Vakiloroayaei A, Remnant BM, Talebi M, Cargill T, Bayfield MA. Crosstalk between the tRNA methyltransferase Trm1 and RNA chaperone La influences eukaryotic tRNA maturation. J Biol Chem 2023; 299:105326. [PMID: 37805140 PMCID: PMC10652106 DOI: 10.1016/j.jbc.2023.105326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/17/2023] [Accepted: 09/20/2023] [Indexed: 10/09/2023] Open
Abstract
tRNAs undergo an extensive maturation process involving posttranscriptional modifications often associated with tRNA structural stability and promoting the native fold. Impaired posttranscriptional modification has been linked to human disease, likely through defects in translation, mitochondrial function, and increased susceptibility to degradation by various tRNA decay pathways. More recently, evidence has emerged that bacterial tRNA modification enzymes can act as tRNA chaperones to guide tRNA folding in a manner independent from catalytic activity. Here, we provide evidence that the fission yeast tRNA methyltransferase Trm1, which dimethylates nuclear- and mitochondrial-encoded tRNAs at G26, can also promote tRNA functionality in the absence of catalysis. We show that WT and catalytic-dead Trm1 are active in an in vivo tRNA-mediated suppression assay and possess RNA strand annealing and dissociation activity in vitro, similar to previously characterized RNA chaperones. Trm1 and the RNA chaperone La have previously been proposed to function synergistically in promoting tRNA maturation, yet we surprisingly demonstrate that La binding to nascent pre-tRNAs decreases Trm1 tRNA dimethylation in vivo and in vitro. Collectively, these results support the hypothesis for tRNA modification enzymes that combine catalytic and noncatalytic activities to promote tRNA maturation, as well as expand our understanding of how La function can influence tRNA modification.
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6
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Witzenberger M, Burczyk S, Settele D, Mayer W, Welp L, Heiss M, Wagner M, Monecke T, Janowski R, Carell T, Urlaub H, Hauck S, Voigt A, Niessing D. Human TRMT2A methylates tRNA and contributes to translation fidelity. Nucleic Acids Res 2023; 51:8691-8710. [PMID: 37395448 PMCID: PMC10484741 DOI: 10.1093/nar/gkad565] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 06/13/2023] [Accepted: 06/21/2023] [Indexed: 07/04/2023] Open
Abstract
5-Methyluridine (m5U) is one of the most abundant RNA modifications found in cytosolic tRNA. tRNA methyltransferase 2 homolog A (hTRMT2A) is the dedicated mammalian enzyme for m5U formation at tRNA position 54. However, its RNA binding specificity and functional role in the cell are not well understood. Here we dissected structural and sequence requirements for binding and methylation of its RNA targets. Specificity of tRNA modification by hTRMT2A is achieved by a combination of modest binding preference and presence of a uridine in position 54 of tRNAs. Mutational analysis together with cross-linking experiments identified a large hTRMT2A-tRNA binding surface. Furthermore, complementing hTRMT2A interactome studies revealed that hTRMT2A interacts with proteins involved in RNA biogenesis. Finally, we addressed the question of the importance of hTRMT2A function by showing that its knockdown reduces translation fidelity. These findings extend the role of hTRMT2A beyond tRNA modification towards a role in translation.
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Affiliation(s)
- Monika Witzenberger
- Institute of Structural Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Sandra Burczyk
- Institute of Pharmaceutical Biotechnology, Ulm University, Ulm, Germany
| | - David Settele
- Institute of Structural Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Wieland Mayer
- Institute of Pharmaceutical Biotechnology, Ulm University, Ulm, Germany
| | - Luisa M Welp
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Matthias Heiss
- Department of Chemistry and Biochemistry, Ludwig-Maximilians University Munich, München, Germany
| | - Mirko Wagner
- Department of Chemistry and Biochemistry, Ludwig-Maximilians University Munich, München, Germany
| | - Thomas Monecke
- Institute of Pharmaceutical Biotechnology, Ulm University, Ulm, Germany
| | - Robert Janowski
- Institute of Structural Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Thomas Carell
- Department of Chemistry and Biochemistry, Ludwig-Maximilians University Munich, München, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Research Unit Protein Science, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Aaron Voigt
- Department of Neurology, Faculty of Medicine, RWTH Aachen, Aachen, Germany
| | - Dierk Niessing
- Institute of Structural Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Pharmaceutical Biotechnology, Ulm University, Ulm, Germany
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7
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Tomoda E, Nagao A, Shirai Y, Asano K, Suzuki T, Battersby B, Suzuki T. Restoration of mitochondrial function through activation of hypomodified tRNAs with pathogenic mutations associated with mitochondrial diseases. Nucleic Acids Res 2023; 51:7563-7579. [PMID: 36928678 PMCID: PMC10415153 DOI: 10.1093/nar/gkad139] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/14/2023] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
Mutations in mitochondrial (mt-)tRNAs frequently cause mitochondrial dysfunction. Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and myoclonus epilepsy associated with ragged red fibers (MERRF) are major clinical subgroups of mitochondrial diseases caused by pathogenic point mutations in tRNA genes encoded in mtDNA. We previously reported a severe reduction in the frequency of 5-taurinomethyluridine (τm5U) and its 2-thiouridine derivative (τm5s2U) in the anticodons of mutant mt-tRNAs isolated from the cells of patients with MELAS and MERRF, respectively. The hypomodified tRNAs fail to decode cognate codons efficiently, resulting in defective translation of respiratory chain proteins in mitochondria. To restore the mitochondrial activity of MELAS patient cells, we overexpressed MTO1, a τm5U-modifying enzyme, in patient-derived myoblasts. We used a newly developed primer extension method and showed that MTO1 overexpression almost completely restored the τm5U modification of the MELAS mutant mt-tRNALeu(UUR). An increase in mitochondrial protein synthesis and oxygen consumption rate suggested that the mitochondrial function of MELAS patient cells can be activated by restoring the τm5U of the mutant tRNA. In addition, we confirmed that MTO1 expression restored the τm5s2U of the mutant mt-tRNALys in MERRF patient cells. These findings pave the way for epitranscriptomic therapies for mitochondrial diseases.
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Affiliation(s)
- Ena Tomoda
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Asuteka Nagao
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yuki Shirai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kana Asano
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takeo Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | | | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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8
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Schultz SK, Kothe U. Fluorescent labeling of tRNA for rapid kinetic interaction studies with tRNA-binding proteins. Methods Enzymol 2023; 692:103-126. [PMID: 37925176 DOI: 10.1016/bs.mie.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2023]
Abstract
Transfer RNA (tRNA) plays a critical role during translation and interacts with numerous proteins during its biogenesis, functional cycle and degradation. In particular, tRNA is extensively post-transcriptionally modified by various tRNA modifying enzymes which each target a specific nucleotide at different positions within tRNAs to introduce different chemical modifications. Fluorescent assays can be used to study the interaction between a protein and tRNA. Moreover, rapid mixing fluorescence stopped-flow assays provide insights into the kinetics of the tRNA-protein interaction in order to elucidate the tRNA binding mechanism for the given protein. A prerequisite for these studies is a fluorescently labeled molecule, such as fluorescent tRNA, wherein a change in fluorescence occurs upon protein binding. In this chapter, we discuss the utilization of tRNA modifications in order to introduce fluorophores at particular positions within tRNAs. Particularly, we focus on in vitro thiolation of a uridine at position 8 within tRNAs using the tRNA modification enzyme ThiI, followed by labeling of the thiol group with fluorescein. As such, this fluorescently labeled tRNA is primarily unmodified, with the exception of the thiolation modification to which the fluorophore is attached, and can be used as a substrate to study the binding of different tRNA-interacting factors. Herein, we discuss the example of studying the tRNA binding mechanism of the tRNA modifying enzymes TrmB and DusA using internally fluorescein-labeled tRNA.
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Affiliation(s)
- Sarah K Schultz
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada; Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
| | - Ute Kothe
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada; Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada.
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9
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Yu L, Zhang Y, Xue L, Liu F, Jing R, Luo J. Evaluation and development of deep neural networks for RNA 5-Methyluridine classifications using autoBioSeqpy. Front Microbiol 2023; 14:1175925. [PMID: 37275146 PMCID: PMC10232852 DOI: 10.3389/fmicb.2023.1175925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/27/2023] [Indexed: 06/07/2023] Open
Abstract
Post-transcriptionally RNA modifications, also known as the epitranscriptome, play crucial roles in the regulation of gene expression during development. Recently, deep learning (DL) has been employed for RNA modification site prediction and has shown promising results. However, due to the lack of relevant studies, it is unclear which DL architecture is best suited for some pyrimidine modifications, such as 5-methyluridine (m5U). To fill this knowledge gap, we first performed a comparative evaluation of various commonly used DL models for epigenetic studies with the help of autoBioSeqpy. We identified optimal architectural variations for m5U site classification, optimizing the layer depth and neuron width. Second, we used this knowledge to develop Deepm5U, an improved convolutional-recurrent neural network that accurately predicts m5U sites from RNA sequences. We successfully applied Deepm5U to transcriptomewide m5U profiling data across different sequencing technologies and cell types. Third, we showed that the techniques for interpreting deep neural networks, including LayerUMAP and DeepSHAP, can provide important insights into the internal operation and behavior of models. Overall, we offered practical guidance for the development, benchmark, and analysis of deep learning models when designing new algorithms for RNA modifications.
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Affiliation(s)
- Lezheng Yu
- School of Chemistry and Materials Science, Guizhou Education University, Guiyang, China
| | - Yonglin Zhang
- Department of Pharmacy, Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Li Xue
- School of Public Health, Southwest Medical University, Luzhou, China
| | - Fengjuan Liu
- School of Geography and Resources, Guizhou Education University, Guiyang, China
| | - Runyu Jing
- School of Cyber Science and Engineering, Sichuan University, Chengdu, China
| | - Jiesi Luo
- Basic Medical College, Southwest Medical University, Luzhou, China
- Sichuan Key Medical Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Activity Screening and Druggability Evaluation for Chinese Materia Medica, Southwest Medical University, Luzhou, China
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10
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Leiva LE, Zegarra V, Bange G, Ibba M. At the Crossroad of Nucleotide Dynamics and Protein Synthesis in Bacteria. Microbiol Mol Biol Rev 2023; 87:e0004422. [PMID: 36853029 PMCID: PMC10029340 DOI: 10.1128/mmbr.00044-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Nucleotides are at the heart of the most essential biological processes in the cell, be it as key protagonists in the dogma of molecular biology or by regulating multiple metabolic pathways. The dynamic nature of nucleotides, the cross talk between them, and their constant feedback to and from the cell's metabolic state position them as a hallmark of adaption toward environmental and growth challenges. It has become increasingly clear how the activity of RNA polymerase, the synthesis and maintenance of tRNAs, mRNA translation at all stages, and the biogenesis and assembly of ribosomes are fine-tuned by the pools of intracellular nucleotides. With all aspects composing protein synthesis involved, the ribosome emerges as the molecular hub in which many of these nucleotides encounter each other and regulate the state of the cell. In this review, we aim to highlight intracellular nucleotides in bacteria as dynamic characters permanently cross talking with each other and ultimately regulating protein synthesis at various stages in which the ribosome is mainly the principal character.
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Affiliation(s)
- Lorenzo Eugenio Leiva
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Victor Zegarra
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Michael Ibba
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
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11
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Schultz SK, Meadows K, Kothe U. Molecular mechanism of tRNA binding by the Escherichia coli N7 guanosine methyltransferase TrmB. J Biol Chem 2023; 299:104612. [PMID: 36933808 PMCID: PMC10130221 DOI: 10.1016/j.jbc.2023.104612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 03/11/2023] [Accepted: 03/12/2023] [Indexed: 03/18/2023] Open
Abstract
Among the large and diverse collection of tRNA modifications, 7-methylguanosine (m7G) is frequently found in the tRNA variable loop at position 46. This modification is introduced by the TrmB enzyme, which is conserved in bacteria and eukaryotes. However, the molecular determinants and the mechanism for tRNA recognition by TrmB are not well understood. Complementing the report of various phenotypes for different organisms lacking TrmB homologs, we report here hydrogen peroxide sensitivity for the Escherichia coli ΔtrmB knockout strain. To gain insight into the molecular mechanism of tRNA binding by E. coli TrmB in real-time, we developed a new assay based on introducing a 4-thiouridine modification at position 8 of in vitro transcribed tRNAPhe enabling us to fluorescently label this unmodified tRNA. Using rapid kinetic stopped-flow measurements with this fluorescent tRNA, we examined the interaction of wildtype and single substitution variants of TrmB with tRNA. Our results reveal the role of SAM for rapid and stable tRNA binding, the rate-limiting nature of m7G46 catalysis for tRNA release, and the importance of residues R26, T127 and R155 across the entire surface of TrmB for tRNA binding.
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Affiliation(s)
- Sarah K Schultz
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kieran Meadows
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Ute Kothe
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada.
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12
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Wang L, Lin S. Emerging functions of tRNA modifications in mRNA translation and diseases. J Genet Genomics 2022; 50:223-232. [PMID: 36309201 DOI: 10.1016/j.jgg.2022.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 10/17/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
tRNAs are essential modulators that recognize mRNA codons and bridge amino acids for mRNA translation. The tRNAs are heavily modified, which is essential for forming a complex secondary structure that facilitates codon recognition and mRNA translation. In recent years, studies have identified the regulatory roles of tRNA modifications in mRNA translation networks. Misregulation of tRNA modifications is closely related to the progression of developmental diseases and cancers. In this review, we summarize the tRNA biogenesis process and then discuss the effects and mechanisms of tRNA modifications on tRNA processing and mRNA translation. Finally, we provide a comprehensive overview of tRNA modifications' physiological and pathological functions, focusing on diseases including cancers.
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Affiliation(s)
- Lu Wang
- Department of Medical Laboratory, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, Guangdong 510515, China; Center for Translational Medicine, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Shuibin Lin
- Center for Translational Medicine, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510080, China.
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13
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Tyagi W, Pandey V, Pokharel YR. Membrane linked RNA glycosylation as new trend to envision epi-transcriptome epoch. Cancer Gene Ther 2022; 30:641-646. [PMID: 35136215 DOI: 10.1038/s41417-022-00430-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/21/2021] [Accepted: 01/25/2022] [Indexed: 11/09/2022]
Abstract
RNAs play several prominent roles in the cellular environment ranging from structural, messengers, translators, and effector molecules. RNA molecules while performing these roles are associated with several chemical modifications occurring post-transcriptionally, responsible for these supporting vital functions. The recent documentation of surface RNA modification with sialic acid residues has sparked advancement to the framework of RNA modifications. Glycan modification of surface RNA which was previously known to modify only proteins and lipids has opened new vistas to explore how these surface RNA modifications affect the cellular responses and phenotype. This paradigm shift in RNA biology with a vision of "glycans being all over the cells" has posed the field with a repertoire of questions and has given headway to the RNA world hypothesis. The review provides a comprehensive overview of glycoRNA discovery with a conceptual understanding of its previous underlying discoveries and their biological consequences with possible insights into the dynamic influence of this modification on their molecular versatility deciding cancer-immunology fate with potential implications of these glycosylation in cellular interaction, signaling, immune regulation, cancer evasion and proliferation.
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Affiliation(s)
- Witty Tyagi
- Molecular Oncology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Vivek Pandey
- Faculty of Life Science and Biotechnology, South Asian University, Akbar Bhawan, Chanakyapuri, New Delhi, India
| | - Yuba Raj Pokharel
- Faculty of Life Science and Biotechnology, South Asian University, Akbar Bhawan, Chanakyapuri, New Delhi, India.
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14
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Purchal MK, Eyler DE, Tardu M, Franco MK, Korn MM, Khan T, McNassor R, Giles R, Lev K, Sharma H, Monroe J, Mallik L, Koutmos M, Koutmou KS. Pseudouridine synthase 7 is an opportunistic enzyme that binds and modifies substrates with diverse sequences and structures. Proc Natl Acad Sci U S A 2022; 119:e2109708119. [PMID: 35058356 PMCID: PMC8794802 DOI: 10.1073/pnas.2109708119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 11/17/2021] [Indexed: 12/13/2022] Open
Abstract
Pseudouridine (Ψ) is a ubiquitous RNA modification incorporated by pseudouridine synthase (Pus) enzymes into hundreds of noncoding and protein-coding RNA substrates. Here, we determined the contributions of substrate structure and protein sequence to binding and catalysis by pseudouridine synthase 7 (Pus7), one of the principal messenger RNA (mRNA) modifying enzymes. Pus7 is distinct among the eukaryotic Pus proteins because it modifies a wider variety of substrates and shares limited homology with other Pus family members. We solved the crystal structure of Saccharomyces cerevisiae Pus7, detailing the architecture of the eukaryotic-specific insertions thought to be responsible for the expanded substrate scope of Pus7. Additionally, we identified an insertion domain in the protein that fine-tunes Pus7 activity both in vitro and in cells. These data demonstrate that Pus7 preferentially binds substrates possessing the previously identified UGUAR (R = purine) consensus sequence and that RNA secondary structure is not a strong requirement for Pus7-binding. In contrast, the rate constants and extent of Ψ incorporation are more influenced by RNA structure, with Pus7 modifying UGUAR sequences in less-structured contexts more efficiently both in vitro and in cells. Although less-structured substrates were preferred, Pus7 fully modified every transfer RNA, mRNA, and nonnatural RNA containing the consensus recognition sequence that we tested. Our findings suggest that Pus7 is a promiscuous enzyme and lead us to propose that factors beyond inherent enzyme properties (e.g., enzyme localization, RNA structure, and competition with other RNA-binding proteins) largely dictate Pus7 substrate selection.
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Affiliation(s)
- Meredith K Purchal
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109
| | - Daniel E Eyler
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Mehmet Tardu
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Monika K Franco
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109
| | - Megan M Korn
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Taslima Khan
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ryan McNassor
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Rachel Giles
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Katherine Lev
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109
| | - Hari Sharma
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Jeremy Monroe
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Leena Mallik
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109
| | - Markos Koutmos
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109;
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109
| | - Kristin S Koutmou
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109;
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
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15
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Fukuda H, Chujo T, Wei FY, Shi SL, Hirayama M, Kaitsuka T, Yamamoto T, Oshiumi H, Tomizawa K. Cooperative methylation of human tRNA3Lys at positions A58 and U54 drives the early and late steps of HIV-1 replication. Nucleic Acids Res 2021; 49:11855-11867. [PMID: 34642752 PMCID: PMC8599865 DOI: 10.1093/nar/gkab879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
Retroviral infection requires reverse transcription, and the reverse transcriptase (RT) uses cellular tRNA as its primer. In humans, the TRMT6-TRMT61A methyltransferase complex incorporates N1-methyladenosine modification at tRNA position 58 (m1A58); however, the role of m1A58 as an RT-stop site during retroviral infection has remained questionable. Here, we constructed TRMT6 mutant cells to determine the roles of m1A in HIV-1 infection. We confirmed that tRNA3Lys m1A58 was required for in vitro plus-strand strong-stop by RT. Accordingly, infectivity of VSV-G pseudotyped HIV-1 decreased when the virus contained m1A58-deficient tRNA3Lys instead of m1A58-modified tRNA3Lys. In TRMT6 mutant cells, the global protein synthesis rate was equivalent to that of wild-type cells. However, unexpectedly, plasmid-derived HIV-1 expression showed that TRMT6 mutant cells decreased accumulation of HIV-1 capsid, integrase, Tat, Gag, and GagPol proteins without reduction of HIV-1 RNAs in cells, and fewer viruses were produced. Moreover, the importance of 5,2′-O-dimethyluridine at U54 of tRNA3Lys as a second RT-stop site was supported by conservation of retroviral genome-tRNALys sequence-complementarity, and TRMT6 was required for efficient 5-methylation of U54. These findings illuminate the fundamental importance of tRNA m1A58 modification in both the early and late steps of HIV-1 replication, as well as in the cellular tRNA modification network.
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Affiliation(s)
- Hiroyuki Fukuda
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
| | - Takeshi Chujo
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan.,Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan
| | - Sheng-Lan Shi
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
| | - Mayumi Hirayama
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
| | - Taku Kaitsuka
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan.,School of Pharmacy at Fukuoka, International University of Health and Welfare, Okawa, Fukuoka 831-8501, Japan
| | - Takahiro Yamamoto
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
| | - Hiroyuki Oshiumi
- Department of Immunology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto 860-8556, Japan
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16
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Partially modified tRNAs for the study of tRNA maturation and function. Methods Enzymol 2021; 658:225-250. [PMID: 34517948 DOI: 10.1016/bs.mie.2021.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transfer RNA (tRNA) is the most highly and diversely modified class of RNA in all domains of life. However, we still have only a limited understanding of the concerted action of the many enzymes that modify tRNA during tRNA maturation and the synergistic functions of tRNA modifications for protein synthesis. Here, we describe the preparation of in vitro transcribed tRNAs with a partial set of defined modifications and the use of partially modified tRNAs in biochemical assays. By comparing the affinity and activity of tRNA modification enzymes for partially modified and unmodified tRNAs, we gain insight into the preferred pathways of tRNA maturation. Additionally, partially modified tRNAs will be highly useful to investigate the importance of tRNA modifications for tRNA function during translation including the interaction with aminoacyl-tRNA synthases, translation factors and the ribosome. Thereby, the methods described here lay the foundation for understanding the mechanistic function of tRNA modifications.
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17
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Porat J, Kothe U, Bayfield MA. Revisiting tRNA chaperones: New players in an ancient game. RNA (NEW YORK, N.Y.) 2021; 27:rna.078428.120. [PMID: 33593999 PMCID: PMC8051267 DOI: 10.1261/rna.078428.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/10/2021] [Indexed: 05/03/2023]
Abstract
tRNAs undergo an extensive maturation process including post-transcriptional modifications that influence secondary and tertiary interactions. Precursor and mature tRNAs lacking key modifications are often recognized as aberrant and subsequently targeted for decay, illustrating the importance of modifications in promoting structural integrity. tRNAs also rely on tRNA chaperones to promote the folding of misfolded substrates into functional conformations. The best characterized tRNA chaperone is the La protein, which interacts with nascent RNA polymerase III transcripts to promote folding and offers protection from exonucleases. More recently, certain tRNA modification enzymes have also been demonstrated to possess tRNA folding activity distinct from their catalytic activity, suggesting that they may act as tRNA chaperones. In this review, we will discuss pioneering studies relating post-transcriptional modification to tRNA stability and decay pathways, present recent advances into the mechanism by which the RNA chaperone La assists pre-tRNA maturation, and summarize emerging research directions aimed at characterizing modification enzymes as tRNA chaperones. Together, these findings shed light on the importance of tRNA folding and how tRNA chaperones, in particular, increase the fraction of nascent pre-tRNAs that adopt a folded, functional conformation.
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18
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Post-Transcriptional Modifications of Conserved Nucleotides in the T-Loop of tRNA: A Tale of Functional Convergent Evolution. Genes (Basel) 2021; 12:genes12020140. [PMID: 33499018 PMCID: PMC7912444 DOI: 10.3390/genes12020140] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/30/2022] Open
Abstract
The high conservation of nucleotides of the T-loop, including their chemical identity, are hallmarks of tRNAs from organisms belonging to the three Domains of Life. These structural characteristics allow the T-loop to adopt a peculiar intraloop conformation able to interact specifically with other conserved residues of the D-loop, which ultimately folds the mature tRNA in a unique functional canonical L-shaped architecture. Paradoxically, despite the high conservation of modified nucleotides in the T-loop, enzymes catalyzing their formation depend mostly on the considered organism, attesting for an independent but convergent evolution of the post-transcriptional modification processes. The driving force behind this is the preservation of a native conformation of the tRNA elbow that underlies the various interactions of tRNA molecules with different cellular components.
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19
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Abstract
Following its transcription, RNA can be modified by >170 chemically distinct types of modifications - the epitranscriptome. In recent years, there have been substantial efforts to uncover and characterize the modifications present on mRNA, motivated by the potential of such modifications to regulate mRNA fate and by discoveries and advances in our understanding of N 6-methyladenosine (m6A). Here, we review our knowledge regarding the detection, distribution, abundance, biogenesis, functions and possible mechanisms of action of six of these modifications - pseudouridine (Ψ), 5-methylcytidine (m5C), N 1-methyladenosine (m1A), N 4-acetylcytidine (ac4C), ribose methylations (Nm) and N 7-methylguanosine (m7G). We discuss the technical and analytical aspects that have led to inconsistent conclusions and controversies regarding the abundance and distribution of some of these modifications. We further highlight shared commonalities and important ways in which these modifications differ with respect to m6A, based on which we speculate on their origin and their ability to acquire functions over evolutionary timescales.
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