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Wu Z, Zhou R, Li B, Cao M, Wang W, Li X. Methylation modifications in tRNA and associated disorders: Current research and potential therapeutic targets. Cell Prolif 2024:e13692. [PMID: 38943267 DOI: 10.1111/cpr.13692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 05/14/2024] [Accepted: 06/03/2024] [Indexed: 07/01/2024] Open
Abstract
High-throughput sequencing has sparked increased research interest in RNA modifications, particularly tRNA methylation, and its connection to various diseases. However, the precise mechanisms underpinning the development of these diseases remain largely elusive. This review sheds light on the roles of several tRNA methylations (m1A, m3C, m5C, m1G, m2G, m7G, m5U, and Nm) in diverse biological functions, including metabolic processing, stability, protein interactions, and mitochondrial activities. It further outlines diseases linked to aberrant tRNA modifications, related enzymes, and potential underlying mechanisms. Moreover, disruptions in tRNA regulation and abnormalities in tRNA-derived small RNAs (tsRNAs) contribute to disease pathogenesis, highlighting their potential as biomarkers for disease diagnosis. The review also delves into the exploration of drugs development targeting tRNA methylation enzymes, emphasizing the therapeutic prospects of modulating these processes. Continued research is imperative for a comprehensive comprehension and integration of these molecular mechanisms in disease diagnosis and treatment.
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Affiliation(s)
- Zhijing Wu
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ruixin Zhou
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Baizao Li
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingyu Cao
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wenlong Wang
- Department of Breast Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Clinical Research Center for Breast Cancer in Hunan Province, Changsha, Hunan, China
| | - Xinying Li
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
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2
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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 PMCID: PMC11214086 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, MBR3T 2N2, Canada
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, ABT1K 3M4, Canada
| | | | - Mateusz Halucha
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL60637
| | - Noah Peña
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL60637
| | - Richard P. Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, ABT6G 2H7, Canada
| | - Tao Pan
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL60637
| | - Ute Kothe
- Department of Chemistry, University of Manitoba, Winnipeg, MBR3T 2N2, Canada
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, ABT1K 3M4, Canada
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3
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Schultz SK, Kothe U. RNA modifying enzymes shape tRNA biogenesis and function. J Biol Chem 2024; 300:107488. [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 also 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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4
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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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Wang Z, Xu X, Li X, Fang J, Huang Z, Zhang M, Liu J, Qiu X. Investigations of Single-Subunit tRNA Methyltransferases from Yeast. J Fungi (Basel) 2023; 9:1030. [PMID: 37888286 PMCID: PMC10608323 DOI: 10.3390/jof9101030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/13/2023] [Accepted: 10/13/2023] [Indexed: 10/28/2023] Open
Abstract
tRNA methylations, including base modification and 2'-O-methylation of ribose moiety, play critical roles in the structural stabilization of tRNAs and the fidelity and efficiency of protein translation. These modifications are catalyzed by tRNA methyltransferases (TRMs). Some of the TRMs from yeast can fully function only by a single subunit. In this study, after performing the primary bioinformatic analyses, the progress of the studies of yeast single-subunit TRMs, as well as the studies of their homologues from yeast and other types of eukaryotes and the corresponding TRMs from other types of organisms was systematically reviewed, which will facilitate the understanding of the evolutionary origin of functional diversity of eukaryotic single-subunit TRM.
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Affiliation(s)
- Zhongyuan Wang
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Xiangbin Xu
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Xinhai Li
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Jiaqi Fang
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Zhenkuai Huang
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Mengli Zhang
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Jiameng Liu
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
| | - Xiaoting Qiu
- Ministry of Education Key Laboratory of Applied Marine Biotechnology, Ningbo University, Ningbo 315800, China; (Z.W.); (X.L.); (J.F.); (Z.H.); (M.Z.); (J.L.)
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315800, China;
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Centre, Ningbo University, Ningbo 315800, China
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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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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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8
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Boughanem H, Böttcher Y, Tomé-Carneiro J, López de Las Hazas MC, Dávalos A, Cayir A, Macias-González M. The emergent role of mitochondrial RNA modifications in metabolic alterations. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1753. [PMID: 35872632 DOI: 10.1002/wrna.1753] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/14/2022] [Accepted: 06/27/2022] [Indexed: 11/11/2022]
Abstract
Mitochondrial epitranscriptomics refers to the modifications occurring in all the different RNA types of mitochondria. Although the number of mitochondrial RNA modifications is less than those in cytoplasm, substantial evidence indicates that they play a critical role in accurate protein synthesis. Recent evidence supported those modifications in mitochondrial RNAs also have crucial implications in mitochondrial-related diseases. In the light of current knowledge about the involvement, the association between mitochondrial RNA modifications and diseases arises from studies focusing on mutations in both mitochondrial and nuclear DNA genes encoding enzymes involved in such modifications. Here, we review the current evidence available for mitochondrial RNA modifications and their role in metabolic disorders, and we also explore the possibility of using them as promising targets for prevention and early detection. Finally, we discuss future directions of mitochondrial epitranscriptomics in these metabolic alterations, and how these RNA modifications may offer a new diagnostic and theragnostic avenue for preventive purposes. This article is categorized under: RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Hatim Boughanem
- Instituto de Investigación Biomédica de Málaga (IBIMA), Unidad de Gestión Clínica de Endocrinología y Nutrición del Hospital Virgen de la Victoria and University of Málaga, Spain.,Instituto de Salud Carlos III (ISCIII), Consorcio CIBER, M.P. Fisiopatología de la Obesidad y Nutrición (CIBERObn), Madrid, Spain
| | - Yvonne Böttcher
- Institute of Clinical Medicine, Department of Clinical Molecular Biology, University of Oslo, Oslo, Norway.,Akershus Universitetssykehus, Medical Department, Lørenskog, Norway
| | - João Tomé-Carneiro
- Laboratory of Functional Foods, Madrid Institute for Advanced Studies (IMDEA)-Food, CEI UAM + CSIC, Madrid, Spain
| | - María-Carmen López de Las Hazas
- Laboratory of Epigenetics of Lipid Metabolism, Madrid Institute for Advanced Studies (IMDEA)-Food, CEI UAM + CSIC, Madrid, Spain
| | - Alberto Dávalos
- Laboratory of Epigenetics of Lipid Metabolism, Madrid Institute for Advanced Studies (IMDEA)-Food, CEI UAM + CSIC, Madrid, Spain
| | - Akin Cayir
- Vocational Health College, Canakkale Onsekiz Mart University, Canakkale, Turkey.,Clinical Molecular Biology (EpiGen), Division of Medicine, Akershus Universitetssykehus, Lørenskog, Norway
| | - Manuel Macias-González
- Instituto de Investigación Biomédica de Málaga (IBIMA), Unidad de Gestión Clínica de Endocrinología y Nutrición del Hospital Virgen de la Victoria and University of Málaga, Spain.,Instituto de Salud Carlos III (ISCIII), Consorcio CIBER, M.P. Fisiopatología de la Obesidad y Nutrición (CIBERObn), Madrid, Spain
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9
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Nishida Y, Ohmori S, Kakizono R, Kawai K, Namba M, Okada K, Yamagami R, Hirata A, Hori H. Required Elements in tRNA for Methylation by the Eukaryotic tRNA (Guanine- N2-) Methyltransferase (Trm11-Trm112 Complex). Int J Mol Sci 2022; 23:ijms23074046. [PMID: 35409407 PMCID: PMC8999500 DOI: 10.3390/ijms23074046] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 12/10/2022] Open
Abstract
The Saccharomyces cerevisiae Trm11 and Trm112 complex (Trm11-Trm112) methylates the 2-amino group of guanosine at position 10 in tRNA and forms N2-methylguanosine. To determine the elements required in tRNA for methylation by Trm11-Trm112, we prepared 60 tRNA transcript variants and tested them for methylation by Trm11-Trm112. The results show that the precursor tRNA is not a substrate for Trm11-Trm112. Furthermore, the CCA terminus is essential for methylation by Trm11-Trm112, and Trm11-Trm112 also only methylates tRNAs with a regular-size variable region. In addition, the G10-C25 base pair is required for methylation by Trm11-Trm112. The data also demonstrated that Trm11-Trm112 recognizes the anticodon-loop and that U38 in tRNAAla acts negatively in terms of methylation. Likewise, the U32-A38 base pair in tRNACys negatively affects methylation. The only exception in our in vitro study was tRNAValAAC1. Our experiments showed that the tRNAValAAC1 transcript was slowly methylated by Trm11-Trm112. However, position 10 in this tRNA was reported to be unmodified G. We purified tRNAValAAC1 from wild-type and trm11 gene deletion strains and confirmed that a portion of tRNAValAAC1 is methylated by Trm11-Trm112 in S. cerevisiae. Thus, our study explains the m2G10 modification pattern of all S. cerevisiae class I tRNAs and elucidates the Trm11-Trm112 binding sites.
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10
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Centeno-Leija S, Espinosa-Barrera L, Velazquez-Cruz B, Cárdenas-Conejo Y, Virgen-Ortíz R, Valencia-Cruz G, Saenz RA, Marín-Tovar Y, Gómez-Manzo S, Hernández-Ochoa B, Rocha-Ramirez LM, Zataraín-Palacios R, Osuna-Castro JA, López-Munguía A, Serrano-Posada H. Mining for novel cyclomaltodextrin glucanotransferases unravels the carbohydrate metabolism pathway via cyclodextrins in Thermoanaerobacterales. Sci Rep 2022; 12:730. [PMID: 35031648 PMCID: PMC8760340 DOI: 10.1038/s41598-021-04569-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/20/2021] [Indexed: 11/21/2022] Open
Abstract
Carbohydrate metabolism via cyclodextrins (CM-CD) is an uncommon starch-converting pathway that thoroughly depends on extracellular cyclomaltodextrin glucanotransferases (CGTases) to transform the surrounding starch substrate to α-(1,4)-linked oligosaccharides and cyclodextrins (CDs). The CM-CD pathway has emerged as a convenient microbial adaptation to thrive under extreme temperatures, as CDs are functional amphipathic toroids with higher heat-resistant values than linear dextrins. Nevertheless, although the CM-CD pathway has been described in a few mesophilic bacteria and archaea, it remains obscure in extremely thermophilic prokaryotes (Topt ≥ 70 °C). Here, a new monophyletic group of CGTases with an exceptional three-domain ABC architecture was detected by (meta)genome mining of extremely thermophilic Thermoanaerobacterales living in a wide variety of hot starch-poor environments on Earth. Functional studies of a representative member, CldA, showed a maximum activity in a thermoacidophilic range (pH 4.0 and 80 °C) with remarkable product diversification that yielded a mixture of α:β:γ-CDs (34:62:4) from soluble starch, as well as G3-G7 linear dextrins and fermentable sugars as the primary products. Together, comparative genomics and predictive functional analysis, combined with data of the functionally characterized key proteins of the gene clusters encoding CGTases, revealed the CM-CD pathway in Thermoanaerobacterales and showed that it is involved in the synthesis, transportation, degradation, and metabolic assimilation of CDs.
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Affiliation(s)
- Sara Centeno-Leija
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico.
| | - Laura Espinosa-Barrera
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Beatriz Velazquez-Cruz
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Yair Cárdenas-Conejo
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Raúl Virgen-Ortíz
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Georgina Valencia-Cruz
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Avenida 25 de julio 965, Colonia Villa de San Sebastián, 28045, Colima, Colima, Mexico
| | - Roberto A Saenz
- Facultad de Ciencias, Universidad de Colima, Bernal Díaz del Castillo 340, 28045, Colima, Colima, Mexico
| | - Yerli Marín-Tovar
- Laboratorio de Bioquímica Estructural, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Mexico
| | - Saúl Gómez-Manzo
- Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, Secretaría de Salud, 04530, Mexico City, Mexico
| | - Beatriz Hernández-Ochoa
- Laboratorio de Inmunoquímica y Biología Celular, Hospital Infantil de México Federico Gómez, Secretaría de Salud, 06720, Mexico City, Mexico
| | - Luz María Rocha-Ramirez
- Unidad de Investigación en Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Dr. Márquez No. 162, Colonia Doctores, 06720, Delegación Cuauhtémoc, Mexico
| | - Rocío Zataraín-Palacios
- Escuela de Medicina General, Universidad José Martí, Bosques del Decán 351, 28089, Colima, Colima, México
| | - Juan A Osuna-Castro
- Facultad de Ciencias Biológicas y Agropecuarias, Universidad de Colima, Autopista Colima-Manzanillo, 28100, Tecomán, Colima, Mexico
| | - Agustín López-Munguía
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Morelos, Mexico
| | - Hugo Serrano-Posada
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico.
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11
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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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12
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Cherkasova V, Iben JR, Pridham KJ, Kessler AC, Maraia RJ. The leucine-NH4+ uptake regulator Any1 limits growth as part of a general amino acid control response to loss of La protein by fission yeast. PLoS One 2021; 16:e0253494. [PMID: 34153074 PMCID: PMC8216550 DOI: 10.1371/journal.pone.0253494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/04/2021] [Indexed: 11/19/2022] Open
Abstract
The sla1+ gene of Schizosachharoymces pombe encodes La protein which promotes proper processing of precursor-tRNAs. Deletion of sla1 (sla1Δ) leads to disrupted tRNA processing and sensitivity to target of rapamycin (TOR) inhibition. Consistent with this, media containing NH4+ inhibits leucine uptake and growth of sla1Δ cells. Here, transcriptome analysis reveals that genes upregulated in sla1Δ cells exhibit highly significant overalp with general amino acid control (GAAC) genes in relevant transcriptomes from other studies. Growth in NH4+ media leads to additional induced genes that are part of a core environmental stress response (CESR). The sla1Δ GAAC response adds to evidence linking tRNA homeostasis and broad signaling in S. pombe. We provide evidence that deletion of the Rrp6 subunit of the nuclear exosome selectively dampens a subset of GAAC genes in sla1Δ cells suggesting that nuclear surveillance-mediated signaling occurs in S. pombe. To study the NH4+-effects, we isolated sla1Δ spontaneous revertants (SSR) of the slow growth phenotype and found that GAAC gene expression and rapamycin hypersensitivity were also reversed. Genome sequencing identified a F32V substitution in Any1, a known negative regulator of NH4+-sensitive leucine uptake linked to TOR. We show that 3H-leucine uptake by SSR-any1-F32V cells in NH4+-media is more robust than by sla1Δ cells. Moreover, F32V may alter any1+ function in sla1Δ vs. sla1+ cells in a distinctive way. Thus deletion of La, a tRNA processing factor leads to a GAAC response involving reprogramming of amino acid metabolism, and isolation of the any1-F32V rescuing mutant provides an additional specific link.
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Affiliation(s)
- Vera Cherkasova
- Kelly@DeWitt, Inc, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States of America
| | - James R. Iben
- Molecular Genomics Core, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Kevin J. Pridham
- Fralin Biomedical Research Institute at Virginia Tech, Roanoke, VA, United States of America
| | - Alan C. Kessler
- Section on Molecular and Cell Biology, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD United States of America
| | - Richard J. Maraia
- Section on Molecular and Cell Biology, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD United States of America
- * E-mail:
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13
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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: 15] [Impact Index Per Article: 5.0] [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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14
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Bayfield MA, Vinayak J, Kerkhofs K, Mansouri-Noori F. La proteins couple use of sequence-specific and non-specific binding modes to engage RNA substrates. RNA Biol 2021; 18:168-177. [PMID: 30777481 PMCID: PMC7928037 DOI: 10.1080/15476286.2019.1582955] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/05/2019] [Accepted: 02/05/2019] [Indexed: 12/31/2022] Open
Abstract
La shuttles between the nucleus and cytoplasm where it binds nascent RNA polymerase III (pol III) transcripts and mRNAs, respectively. La protects the 3' end of pol III transcribed RNA precursors, such as pre-tRNAs, through the use of a well-characterized UUU-3'OH binding mode. La proteins are also RNA chaperones, and La-dependent RNA chaperone activity is hypothesized to promote pre-tRNA maturation and translation at cellular and viral internal ribosome entry sites via binding sites distinct from those used for UUU-3'OH recognition. Since the publication of La-UUU-3'OH co-crystal structures, biochemical and genetic experiments have expanded our understanding of how La proteins use UUU-3'OH-independent binding modes to make sequence-independent contacts that can increase affinity for ligands and promote RNA remodeling. Other recent work has also expanded our understanding of how La binds mRNAs through contacts to the poly(A) tail. In this review, we focus on advances in the study of La protein-RNA complex surfaces beyond the description of the La-UUU-3'OH binding mode. We highlight recent advances in the functions of expected canonical nucleic acid interaction surfaces, a heightened appreciation of disordered C-terminal regions, and the nature of sequence-independent RNA determinants in La-RNA target binding. We further discuss how these RNA binding modes may have relevance to the function of the La-related proteins.
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Affiliation(s)
- Mark A. Bayfield
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Jyotsna Vinayak
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Kyra Kerkhofs
- Department of Biology, York University, Toronto, Ontario, Canada
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15
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Chujo T, Tomizawa K. Human transfer RNA modopathies: diseases caused by aberrations in transfer RNA modifications. FEBS J 2021; 288:7096-7122. [PMID: 33513290 PMCID: PMC9255597 DOI: 10.1111/febs.15736] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/13/2020] [Accepted: 01/27/2021] [Indexed: 12/14/2022]
Abstract
tRNA molecules are post-transcriptionally modified by tRNA modification enzymes. Although composed of different chemistries, more than 40 types of human tRNA modifications play pivotal roles in protein synthesis by regulating tRNA structure and stability as well as decoding genetic information on mRNA. Many tRNA modifications are conserved among all three kingdoms of life, and aberrations in various human tRNA modification enzymes cause life-threatening diseases. Here, we describe the class of diseases and disorders caused by aberrations in tRNA modifications as 'tRNA modopathies'. Aberrations in over 50 tRNA modification enzymes are associated with tRNA modopathies, which most frequently manifest as dysfunctions of the brain and/or kidney, mitochondrial diseases, and cancer. However, the molecular mechanisms that link aberrant tRNA modifications to human diseases are largely unknown. In this review, we provide a comprehensive compilation of human tRNA modification functions, tRNA modification enzyme genes, and tRNA modopathies, and we summarize the elucidated pathogenic mechanisms underlying several tRNA modopathies. We will also discuss important questions that need to be addressed in order to understand the molecular pathogenesis of tRNA modopathies.
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Affiliation(s)
- Takeshi Chujo
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Japan
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16
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Keffer-Wilkes LC, Soon EF, Kothe U. The methyltransferase TrmA facilitates tRNA folding through interaction with its RNA-binding domain. Nucleic Acids Res 2020; 48:7981-7990. [PMID: 32597953 PMCID: PMC7641329 DOI: 10.1093/nar/gkaa548] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 05/29/2020] [Accepted: 06/17/2020] [Indexed: 11/12/2022] Open
Abstract
tRNAs are the most highly modified RNAs in all cells, and formation of 5-methyluridine (m5U) at position 54 in the T arm is a common RNA modification found in all tRNAs. The m5U modification is generated by the methyltransferase TrmA. Here, we test and prove the hypothesis that Escherichia coli TrmA has dual functions, acting both as a methyltransferase and as a tRNA chaperone. We identify two conserved residues, F106 and H125, in the RNA-binding domain of TrmA, which interact with the tRNA elbow and are critical for tRNA binding. Co-culture competition assays reveal that the catalytic activity of TrmA is important for cellular fitness, and that substitutions of F106 or H125 impair cellular fitness. We directly show that TrmA enhances tRNA folding in vitro independent of its catalytic activity. In conclusion, our study suggests that F106 and H125 in the RNA-binding domain of TrmA act as a wedge disrupting tertiary interactions between tRNA’s D arm and T arm; this tRNA unfolding is the mechanistic basis for TrmA’s tRNA chaperone activity. TrmA is the second tRNA modifying enzyme next to the pseudouridine synthase TruB shown to act as a tRNA chaperone supporting a functional link between RNA modification and folding.
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Affiliation(s)
- Laura Carole Keffer-Wilkes
- University of Lethbridge, Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, Lethbridge, AB T1K 3M4, Canada
| | - Emily F Soon
- University of Lethbridge, Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, Lethbridge, AB T1K 3M4, Canada
| | - Ute Kothe
- University of Lethbridge, Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, Lethbridge, AB T1K 3M4, Canada
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17
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Abstract
RNA species play host to a plethora of post-transcriptional modifications which together make up the epitranscriptome. 5-methyluridine (m5U) is one of the most common modifications made to cellular RNA, where it is found almost ubiquitously in bacterial and eukaryotic cytosolic tRNAs at position 54. Here, we demonstrate that m5U54 in human mitochondrial tRNAs is catalysed by the nuclear-encoded enzyme TRMT2B, and that its repertoire of substrates is expanded to ribosomal RNAs, catalysing m5U429 in 12S rRNA. We show that TRMT2B is not essential for viability in human cells and that knocking-out the gene shows no obvious phenotype with regards to RNA stability, mitochondrial translation, or cellular growth.
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Affiliation(s)
- Christopher A Powell
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Michal Minczuk
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
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18
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Laptev I, Shvetsova E, Levitskii S, Serebryakova M, Rubtsova M, Bogdanov A, Kamenski P, Sergiev P, Dontsova O. Mouse Trmt2B protein is a dual specific mitochondrial metyltransferase responsible for m 5U formation in both tRNA and rRNA. RNA Biol 2019; 17:441-450. [PMID: 31736397 DOI: 10.1080/15476286.2019.1694733] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
RNA molecules of all species contain modified nucleotides and particularly m5U residues. The vertebrate mitochondrial small subunit rRNA contains m5U nucleotide in a unique site. In this work we found an enzyme, TRMT2B, responsible for the formation of this nucleotide and m5U residues in a number of mitochondrial tRNA species. Inactivation of the Trmt2B gene leads to a reduction of the activity of respiratory chain complexes I, III and IV, containing the subunits synthesized by the mitochondrial protein synthesis apparatus. Comparative sequence analysis of m5U-specific RNA methyltransferases revealed an unusual evolutionary pathway of TRMT2B formation which includes consecutive substrate specificity switches from the large subunit rRNA to tRNA and then to the small subunit rRNA.
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Affiliation(s)
- Ivan Laptev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Ekaterina Shvetsova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Sergey Levitskii
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Marina Serebryakova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow Region, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Maria Rubtsova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Alexey Bogdanov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Piotr Kamenski
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Petr Sergiev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, Russia
| | - Olga Dontsova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Department of Functioning of Living Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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19
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González-Velasco Ó, De Las Rivas J, Lacal J. Proteomic and Transcriptomic Profiling Identifies Early Developmentally Regulated Proteins in Dictyostelium Discoideum. Cells 2019; 8:cells8101187. [PMID: 31581556 PMCID: PMC6830349 DOI: 10.3390/cells8101187] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 09/26/2019] [Indexed: 02/06/2023] Open
Abstract
Cyclic AMP acts as a secondary messenger involving different cellular functions in eukaryotes. Here, proteomic and transcriptomic profiling has been combined to identify novel early developmentally regulated proteins in eukaryote cells. These proteomic and transcriptomic experiments were performed in Dictyostelium discoideum given the unique advantages that this organism offers as a eukaryotic model for cell motility and as a nonmammalian model of human disease. By comparing whole-cell proteome analysis of developed (cAMP-pulsed) wild-type AX2 cells and an independent transcriptomic analysis of developed wild-type AX4 cells, our results show that up to 70% of the identified proteins overlap in the two independent studies. Among them, we have found 26 proteins previously related to cAMP signaling and identified 110 novel proteins involved in calcium signaling, adhesion, actin cytoskeleton, the ubiquitin-proteasome pathway, metabolism, and proteins that previously lacked any annotation. Our study validates previous findings, mostly for the canonical cAMP-pathway, and also generates further insight into the complexity of the transcriptomic changes during early development. This article also compares proteomic data between parental and cells lacking glkA, a GSK-3 kinase implicated in substrate adhesion and chemotaxis in Dictyostelium. This analysis reveals a set of proteins that show differences in expression in the two strains as well as overlapping protein level changes independent of GlkA.
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Affiliation(s)
- Óscar González-Velasco
- Bioinformatics and Functional Genomics Research Group. Cancer Research Center (CIC-IBMCC, CSIC/USAL/IBSAL), 37007 Salamanca, Spain.
| | - Javier De Las Rivas
- Bioinformatics and Functional Genomics Research Group. Cancer Research Center (CIC-IBMCC, CSIC/USAL/IBSAL), 37007 Salamanca, Spain.
| | - Jesus Lacal
- Department of Microbiology and Genetics, Faculty of Biology, University of Salamanca, 37007 Salamanca, Spain.
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20
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Abstract
A wide variety of factors are required for the conversion of pre-tRNA molecules into the mature tRNAs that function in translation. To identify factors influencing tRNA biogenesis, we previously performed a screen for strains carrying mutations that induce lethality when combined with a sup61-T47:2C allele, encoding a mutant form of [Formula: see text]. Analyzes of two complementation groups led to the identification of Tan1 as a protein involved in formation of the modified nucleoside N4-acetylcytidine (ac4C) in tRNA and Bud13 as a factor controlling the levels of ac4C by promoting TAN1 pre-mRNA splicing. Here, we describe the remaining complementation groups and show that they include strains with mutations in genes for known tRNA biogenesis factors that modify (DUS2, MOD5 and TRM1), transport (LOS1), or aminoacylate (SES1) [Formula: see text]. Other strains carried mutations in genes for factors involved in rRNA/mRNA synthesis (RPA49, RRN3 and MOT1) or magnesium uptake (ALR1). We show that mutations in not only DUS2, LOS1 and SES1 but also in RPA49, RRN3 and MOT1 cause a reduction in the levels of the altered [Formula: see text]. These results indicate that Rpa49, Rrn3 and Mot1 directly or indirectly influence [Formula: see text] biogenesis.
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Affiliation(s)
- Fu Xu
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
| | - Yang Zhou
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
| | - Anders S Byström
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
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21
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Vakiloroayaei A, Shah NS, Oeffinger M, Bayfield MA. The RNA chaperone La promotes pre-tRNA maturation via indiscriminate binding of both native and misfolded targets. Nucleic Acids Res 2017; 45:11341-11355. [PMID: 28977649 PMCID: PMC5737608 DOI: 10.1093/nar/gkx764] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/17/2017] [Indexed: 12/14/2022] Open
Abstract
Non-coding RNAs have critical roles in biological processes, and RNA chaperones can promote their folding into the native shape required for their function. La proteins are a class of highly abundant RNA chaperones that contact pre-tRNAs and other RNA polymerase III transcripts via their common UUU-3′OH ends, as well as through less specific contacts associated with RNA chaperone activity. However, whether La proteins preferentially bind misfolded pre-tRNAs or instead engage all pre-tRNA substrates irrespective of their folding status is not known. La deletion in yeast is synthetically lethal when combined with the loss of tRNA modifications predicted to contribute to the native pre-tRNA fold, such as the N2, N2-dimethylation of G26 by the methyltransferase Trm1p. In this work, we identify G26 containing pre-tRNAs that misfold in the absence of Trm1p and/or La (Sla1p) in Schizosaccharomyces pombe cells, then test whether La preferentially associates with such tRNAs in vitro and in vivo. Our data suggest that La does not discriminate a native from misfolded RNA target, and highlights the potential challenges faced by RNA chaperones in preferentially binding defective substrates.
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Affiliation(s)
- Ana Vakiloroayaei
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
| | - Neha S Shah
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
| | - Marlene Oeffinger
- Institut de Recherches Cliniques de Montréal (IRCM), 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada.,Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec H3A 1A3, Canada.,Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Mark A Bayfield
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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22
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Maraia RJ, Mattijssen S, Cruz-Gallardo I, Conte MR. The La and related RNA-binding proteins (LARPs): structures, functions, and evolving perspectives. WILEY INTERDISCIPLINARY REVIEWS. RNA 2017; 8:10.1002/wrna.1430. [PMID: 28782243 PMCID: PMC5647580 DOI: 10.1002/wrna.1430] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 01/02/2023]
Abstract
La was first identified as a polypeptide component of ribonucleic protein complexes targeted by antibodies in autoimmune patients and is now known to be a eukaryote cell-ubiquitous protein. Structure and function studies have shown that La binds to a common terminal motif, UUU-3'-OH, of nascent RNA polymerase III (RNAP III) transcripts and protects them from exonucleolytic decay. For precursor-tRNAs, the most diverse and abundant of these transcripts, La also functions as an RNA chaperone that helps to prevent their misfolding. Related to this, we review evidence that suggests that La and its link to RNAP III were significant in the great expansions of the tRNAomes that occurred in eukaryotes. Four families of La-related proteins (LARPs) emerged during eukaryotic evolution with specialized functions. We provide an overview of the high-resolution structural biology of La and LARPs. LARP7 family members most closely resemble La but function with a single RNAP III nuclear transcript, 7SK, or telomerase RNA. A cytoplasmic isoform of La protein as well as LARPs 6, 4, and 1 function in mRNA metabolism and translation in distinct but similar ways, sometimes with the poly(A)-binding protein, and in some cases by direct binding to poly(A)-RNA. New structures of LARP domains, some complexed with RNA, provide novel insights into the functional versatility of these proteins. We also consider LARPs in relation to ancestral La protein and potential retention of links to specific RNA-related pathways. One such link may be tRNA surveillance and codon usage by LARP-associated mRNAs. WIREs RNA 2017, 8:e1430. doi: 10.1002/wrna.1430 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Richard J. Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
- Commissioned Corps, U.S. Public Health Service, Rockville, MD USA
| | - Sandy Mattijssen
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Isabel Cruz-Gallardo
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
| | - Maria R. Conte
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
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23
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Maraia RJ, Arimbasseri AG. Factors That Shape Eukaryotic tRNAomes: Processing, Modification and Anticodon-Codon Use. Biomolecules 2017; 7:biom7010026. [PMID: 28282871 PMCID: PMC5372738 DOI: 10.3390/biom7010026] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/24/2017] [Indexed: 01/24/2023] Open
Abstract
Transfer RNAs (tRNAs) contain sequence diversity beyond their anticodons and the large variety of nucleotide modifications found in all kingdoms of life. Some modifications stabilize structure and fit in the ribosome whereas those to the anticodon loop modulate messenger RNA (mRNA) decoding activity more directly. The identities of tRNAs with some universal anticodon loop modifications vary among distant and parallel species, likely to accommodate fine tuning for their translation systems. This plasticity in positions 34 (wobble) and 37 is reflected in codon use bias. Here, we review convergent evidence that suggest that expansion of the eukaryotic tRNAome was supported by its dedicated RNA polymerase III transcription system and coupling to the precursor-tRNA chaperone, La protein. We also review aspects of eukaryotic tRNAome evolution involving G34/A34 anticodon-sparing, relation to A34 modification to inosine, biased codon use and regulatory information in the redundancy (synonymous) component of the genetic code. We then review interdependent anticodon loop modifications involving position 37 in eukaryotes. This includes the eukaryote-specific tRNA modification, 3-methylcytidine-32 (m3C32) and the responsible gene, TRM140 and homologs which were duplicated and subspecialized for isoacceptor-specific substrates and dependence on i6A37 or t6A37. The genetics of tRNA function is relevant to health directly and as disease modifiers.
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Affiliation(s)
- Richard J Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
- Commissioned Corps, U.S. Public Health Service, Rockville, MD, 20016, USA.
| | - Aneeshkumar G Arimbasseri
- Molecular Genetics Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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24
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Two for the price of one: RNA modification enzymes as chaperones. Proc Natl Acad Sci U S A 2016; 113:14176-14178. [PMID: 27911836 DOI: 10.1073/pnas.1617402113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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25
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Abstract
Cellular RNAs are chemically modified by many RNA modification enzymes; however, often the functions of modifications remain unclear, such as for pseudouridine formation in the tRNA TΨC arm by the bacterial tRNA pseudouridine synthase TruB. Here we test the hypothesis that RNA modification enzymes also act as RNA chaperones. Using TruB as a model, we demonstrate that TruB folds tRNA independent of its catalytic activity, thus increasing the fraction of tRNA that can be aminoacylated. By rapid kinetic stopped-flow analysis, we identified the molecular mechanism of TruB's RNA chaperone activity: TruB binds and unfolds both misfolded and folded tRNAs thereby providing misfolded tRNAs a second chance at folding. Previously, it has been shown that a catalytically inactive TruB variant has no phenotype when expressed in an Escherichia coli truB KO strain [Gutgsell N, et al. (2000) RNA 6(12):1870-1881]. However, here we uncover that E. coli strains expressing a TruB variant impaired in tRNA binding and in in vitro tRNA folding cannot compete with WT E. coli. Consequently, the tRNA chaperone activity of TruB is critical for bacterial fitness. In conclusion, we prove the tRNA chaperone activity of the pseudouridine synthase TruB, reveal its molecular mechanism, and demonstrate its importance for cellular fitness. We discuss the likelihood that other RNA modification enzymes are also RNA chaperones.
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26
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Yamagami R, Tomikawa C, Shigi N, Kazayama A, Asai SI, Takuma H, Hirata A, Fourmy D, Asahara H, Watanabe K, Yoshizawa S, Hori H. Folate-/FAD-dependent tRNA methyltransferase from Thermus thermophilus regulates other modifications in tRNA at low temperatures. Genes Cells 2016; 21:740-54. [PMID: 27238446 DOI: 10.1111/gtc.12376] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/19/2016] [Indexed: 11/29/2022]
Abstract
TrmFO is a N(5) , N(10) -methylenetetrahydrofolate (CH2 THF)-/FAD-dependent tRNA methyltransferase, which synthesizes 5-methyluridine at position 54 (m(5) U54) in tRNA. Thermus thermophilus is an extreme-thermophilic eubacterium, which grows in a wide range of temperatures (50-83 °C). In T. thermophilus, modified nucleosides in tRNA and modification enzymes form a network, in which one modification regulates the degrees of other modifications and controls the flexibility of tRNA. To clarify the role of m(5) U54 and TrmFO in the network, we constructed the trmFO gene disruptant (∆trmFO) strain of T. thermophilus. Although this strain did not show any growth retardation at 70 °C, it showed a slow-growth phenotype at 50 °C. Nucleoside analysis showed increase in 2'-O-methylguanosine at position 18 and decrease in N(1) -methyladenosine at position 58 in the tRNA mixture from the ∆trmFO strain at 50 °C. These in vivo results were reproduced by in vitro experiments with purified enzymes. Thus, we concluded that the m(5) U54 modification have effects on the other modifications in tRNA through the network at 50 °C. (35) S incorporations into proteins showed that the protein synthesis activity of ∆trmFO strain was inferior to the wild-type strain at 50 °C, suggesting that the growth delay at 50 °C was caused by the inferior protein synthesis activity.
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Affiliation(s)
- Ryota Yamagami
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Chie Tomikawa
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Naoki Shigi
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Ai Kazayama
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Shin-Ichi Asai
- Japan Biological Information Research Center (JBIRC), Japan Biological Informatics Consortium (JBIC), Tokyo, 135-0064, Japan
| | - Hiroyuki Takuma
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Dominique Fourmy
- Institute for Integrative Biology of the Cell (I2BC), UMR9198, CEA, CNRS, Université Paris-Sud, 1 Avenue de la Terrasse, Gif-sur-Yvette, Cedex, 91198, France
| | - Haruichi Asahara
- New England Biolabs, Inc, 240 County Road, Ipswich, MA, 01938, USA
| | - Kimitsuna Watanabe
- Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Satoko Yoshizawa
- Institute for Integrative Biology of the Cell (I2BC), UMR9198, CEA, CNRS, Université Paris-Sud, 1 Avenue de la Terrasse, Gif-sur-Yvette, Cedex, 91198, France
| | - Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
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27
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Huang HY, Hopper AK. Multiple Layers of Stress-Induced Regulation in tRNA Biology. Life (Basel) 2016; 6:life6020016. [PMID: 27023616 PMCID: PMC4931453 DOI: 10.3390/life6020016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/14/2016] [Accepted: 03/17/2016] [Indexed: 01/28/2023] Open
Abstract
tRNAs are the fundamental components of the translation machinery as they deliver amino acids to the ribosomes during protein synthesis. Beyond their essential function in translation, tRNAs also function in regulating gene expression, modulating apoptosis and several other biological processes. There are multiple layers of regulatory mechanisms in each step of tRNA biogenesis. For example, tRNA 3′ trailer processing is altered upon nutrient stress; tRNA modification is reprogrammed under various stresses; nuclear accumulation of tRNAs occurs upon nutrient deprivation; tRNA halves accumulate upon oxidative stress. Here we address how environmental stresses can affect nearly every step of tRNA biology and we describe the possible regulatory mechanisms that influence the function or expression of tRNAs under stress conditions.
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Affiliation(s)
- Hsiao-Yun Huang
- Department of Biology, Indiana University, 915 E third St., Myers 300, Bloomington, IN 47405, USA.
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
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28
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Manzanares-Miralles L, Sarikaya-Bayram Ö, Smith EB, Dolan SK, Bayram Ö, Jones GW, Doyle S. Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger. J Proteomics 2016; 131:149-162. [DOI: 10.1016/j.jprot.2015.10.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/14/2015] [Accepted: 10/18/2015] [Indexed: 12/25/2022]
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29
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Hori H. Methylated nucleosides in tRNA and tRNA methyltransferases. Front Genet 2014; 5:144. [PMID: 24904644 PMCID: PMC4033218 DOI: 10.3389/fgene.2014.00144] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/04/2014] [Indexed: 12/26/2022] Open
Abstract
To date, more than 90 modified nucleosides have been found in tRNA and the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent studies of the biosynthetic pathways have demonstrated that the availability of methyl group donors for the methylation in tRNA is important for correct and efficient protein synthesis. In this review, I focus on the methylated nucleosides and tRNA methyltransferases. The primary functions of tRNA methylations are linked to the different steps of protein synthesis, such as the stabilization of tRNA structure, reinforcement of the codon-anticodon interaction, regulation of wobble base pairing, and prevention of frameshift errors. However, beyond these basic functions, recent studies have demonstrated that tRNA methylations are also involved in the RNA quality control system and regulation of tRNA localization in the cell. In a thermophilic eubacterium, tRNA modifications and the modification enzymes form a network that responses to temperature changes. Furthermore, several modifications are involved in genetic diseases, infections, and the immune response. Moreover, structural, biochemical, and bioinformatics studies of tRNA methyltransferases have been clarifying the details of tRNA methyltransferases and have enabled these enzymes to be classified. In the final section, the evolution of modification enzymes is discussed.
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Affiliation(s)
- Hiroyuki Hori
- Department of Materials Science and Biotechnology, Applied Chemistry, Graduate School of Science and Engineering, Ehime University Matsuyama, Japan
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30
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Mojardín L, Botet J, Quintales L, Moreno S, Salas M. New insights into the RNA-based mechanism of action of the anticancer drug 5'-fluorouracil in eukaryotic cells. PLoS One 2013; 8:e78172. [PMID: 24223771 PMCID: PMC3815194 DOI: 10.1371/journal.pone.0078172] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 09/18/2013] [Indexed: 01/23/2023] Open
Abstract
5-Fluorouracil (5FU) is a chemotherapeutic drug widely used in treating a range of advanced, solid tumours and, in particular, colorectal cancer. Here, we used high-density tiling DNA microarray technology to obtain the specific transcriptome-wide response induced by 5FU in the eukaryotic model Schizosaccharomyces pombe. This approach combined with real-time quantitative PCR analysis allowed us to detect splicing defects of a significant number of intron-containing mRNA, in addition to identify some rRNA and tRNA processing defects after 5FU treatment. Interestingly, our studies also revealed that 5FU specifically induced the expression of certain genes implicated in the processing of mRNA, tRNA and rRNA precursors, and in the post-transcriptional modification of uracil residues in RNA. The transcription of several tRNA genes was also significantly induced after drug exposure. These transcriptional changes might represent a cellular response mechanism to counteract 5FU damage since deletion strains for some of these up-regulated genes were hypersensitive to 5FU. Moreover, most of these RNA processing genes have human orthologs that participate in conserved pathways, suggesting that they could be novel targets to improve the efficacy of 5FU-based treatments.
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Affiliation(s)
- Laura Mojardín
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
- * E-mail: (LM); (MS)
| | - Javier Botet
- Instituto de Biología Funcional y Genómica (CSIC/Universidad de Salamanca), Salamanca, Spain
| | - Luis Quintales
- Instituto de Biología Funcional y Genómica (CSIC/Universidad de Salamanca), Salamanca, Spain
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica (CSIC/Universidad de Salamanca), Salamanca, Spain
| | - Margarita Salas
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
- * E-mail: (LM); (MS)
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31
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Zhou Y, Chen C, Johansson MJO. The pre-mRNA retention and splicing complex controls tRNA maturation by promoting TAN1 expression. Nucleic Acids Res 2013; 41:5669-78. [PMID: 23605039 PMCID: PMC3675484 DOI: 10.1093/nar/gkt269] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The conserved pre-mRNA retention and splicing (RES) complex, which in yeast consists of Bud13p, Snu17p and Pml1p, is thought to promote nuclear retention of unspliced pre-mRNAs and enhance splicing of a subset of transcripts. Here, we find that the absence of Bud13p or Snu17p causes greatly reduced levels of the modified nucleoside N4-acetylcytidine (ac4C) in tRNA and that a lack of Pml1p reduces ac4C levels at elevated temperatures. The ac4C nucleoside is normally found at position 12 in the tRNA species specific for serine and leucine. We show that the tRNA modification defect in RES-deficient cells is attributable to inefficient splicing of TAN1 pre-mRNA and the effects of reduced Tan1p levels on formation of ac4C. Analyses of cis-acting elements in TAN1 pre-mRNA showed that the intron sequence between the 5′ splice site and branchpoint is necessary and sufficient to mediate RES dependency. We also show that in RES-deficient cells, the TAN1 pre-mRNA is targeted for degradation by the cytoplasmic nonsense-mediated mRNA decay pathway, indicating that poor nuclear retention may contribute to the tRNA modification defect. Our results demonstrate that TAN1 pre-mRNA processing has an unprecedented requirement for RES factors and that the complex controls the formation of ac4C in tRNA.
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Affiliation(s)
- Yang Zhou
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
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32
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Yamagami R, Yamashita K, Nishimasu H, Tomikawa C, Ochi A, Iwashita C, Hirata A, Ishitani R, Nureki O, Hori H. The tRNA recognition mechanism of folate/FAD-dependent tRNA methyltransferase (TrmFO). J Biol Chem 2012; 287:42480-94. [PMID: 23095745 DOI: 10.1074/jbc.m112.390112] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conserved U54 in tRNA is often modified to 5-methyluridine (m(5)U) and forms a reverse Hoogsteen base pair with A58 that stabilizes the L-shaped tRNA structure. In Gram-positive and some Gram-negative eubacteria, m(5)U54 is produced by folate/FAD-dependent tRNA (m(5)U54) methyltransferase (TrmFO). TrmFO utilizes N(5),N(10)-methylenetetrahydrofolate (CH(2)THF) as a methyl donor. We previously reported an in vitro TrmFO assay system, in which unstable [(14)C]CH(2)THF was supplied from [(14)C]serine and tetrahydrofolate by serine hydroxymethyltransferase. In the current study, we have improved the TrmFO assay system by optimization of enzyme and substrate concentrations and introduction of a filter assay system. Using this assay, we have focused on the tRNA recognition mechanism of TrmFO. 42 tRNA mutant variants were prepared, and experiments with truncated tRNA and microhelix RNAs revealed that the minimum requirement of TrmFO exists in the T-arm structure. The positive determinants for TrmFO were found to be the U54U55C56 sequence and G53-C61 base pair. The gel mobility shift assay and fluorescence quenching showed that the affinity of TrmFO for tRNA in the initial binding process is weak. The inhibition experiments showed that the methylated tRNA is released before the structural change process. Furthermore, we found that A38 prevents incorrect methylation of U32 in the anticodon loop. Moreover, the m(1)A58 modification clearly accelerates the TrmFO reaction, suggesting a synergistic effect of the m(5)U54, m(1)A58, and s(2)U54 modifications on m(5)s(2)U54 formation in Thermus thermophilus cells. The docking model of TrmFO and the T-arm showed that the G53-C61 base pair is not able to directly contact the enzyme.
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Affiliation(s)
- Ryota Yamagami
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo, Matsuyama, Ehime 790-8577, Japan
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33
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Towns WL, Begley TJ. Transfer RNA methytransferases and their corresponding modifications in budding yeast and humans: activities, predications, and potential roles in human health. DNA Cell Biol 2012; 31:434-54. [PMID: 22191691 PMCID: PMC3322404 DOI: 10.1089/dna.2011.1437] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/07/2011] [Accepted: 11/11/2011] [Indexed: 12/13/2022] Open
Abstract
Throughout the kingdoms of life, transfer RNA (tRNA) undergoes over 100 enzyme-catalyzed, methyl-based modifications. Although a majority of the methylations are conserved from bacteria to mammals, the functions of a number of these modifications are unknown. Many of the proteins responsible for tRNA methylation, named tRNA methyltransferases (Trms), have been characterized in Saccharomyces cerevisiae. In contrast, only a few human Trms have been characterized. A BLAST search for human homologs of each S. cerevisiae Trm revealed a total of 34 human proteins matching our search criteria for an S. cerevisiae Trm homolog candidate. We have compiled a database cataloging basic information about each human and yeast Trm. Every S. cerevisiae Trm has at least one human homolog, while several Trms have multiple candidates. A search of cancer cell versus normal cell mRNA expression studies submitted to Oncomine found that 30 of the homolog genes display a significant change in mRNA expression levels in at least one data set. While 6 of the 34 human homolog candidates have confirmed tRNA methylation activity, the other candidates remain uncharacterized. We believe that our database will serve as a resource for investigating the role of human Trms in cellular stress signaling.
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Affiliation(s)
- William L. Towns
- College of Nanoscale Science and Engineering, University at Albany, Albany, New York
| | - Thomas J. Begley
- College of Nanoscale Science and Engineering, University at Albany, Albany, New York
- RNA Institute, University at Albany, Rensselaer, New York
- Cancer Research Center, University at Albany, Rensselaer, New York
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34
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Naeeni AR, Conte MR, Bayfield MA. RNA chaperone activity of human La protein is mediated by variant RNA recognition motif. J Biol Chem 2012; 287:5472-82. [PMID: 22203678 PMCID: PMC3285324 DOI: 10.1074/jbc.m111.276071] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 12/23/2011] [Indexed: 02/05/2023] Open
Abstract
La proteins are conserved factors in eukaryotes that bind and protect the 3' trailers of pre-tRNAs from exonuclease digestion via sequence-specific recognition of UUU-3'OH. La has also been hypothesized to assist pre-tRNAs in attaining their native fold through RNA chaperone activity. In addition to binding polymerase III transcripts, human La has also been shown to enhance the translation of several internal ribosome entry sites and upstream ORF-containing mRNA targets, also potentially through RNA chaperone activity. Using in vitro FRET-based assays, we show that human and Schizosaccharomyces pombe La proteins harbor RNA chaperone activity by enhancing RNA strand annealing and strand dissociation. We use various RNA substrates and La mutants to show that UUU-3'OH-dependent La-RNA binding is not required for this function, and we map RNA chaperone activity to its RRM1 motif including a noncanonical α3-helix. We validate the importance of this α3-helix by appending it to the RRM of the unrelated U1A protein and show that this fusion protein acquires significant strand annealing activity. Finally, we show that residues required for La-mediated RNA chaperone activity in vitro are required for La-dependent rescue of tRNA-mediated suppression via a mutated suppressor tRNA in vivo. This work delineates the structural elements required for La-mediated RNA chaperone activity and provides a basis for understanding how La can enhance the folding of its various RNA targets.
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Affiliation(s)
- Amir R. Naeeni
- From the Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada and
| | - Maria R. Conte
- the Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
| | - Mark A. Bayfield
- From the Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada and
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35
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Abstract
Post-transcriptional ribonucleotide modification is a phenomenon best studied in tRNA, where it occurs most frequently and in great chemical diversity. This paper reviews the intrinsic network of modifications in the structural core of the tRNA, which governs structural flexibility and rigidity to fine-tune the molecule to peak performance and to regulate its steady-state level. Structural effects of RNA modifications range from nanometer-scale rearrangements to subtle restrictions of conformational space on the angstrom scale. Structural stabilization resulting from nucleotide modification results in increased thermal stability and translates into protection against unspecific degradation by bases and nucleases. Several mechanisms of specific degradation of hypomodified tRNA, which were only recently discovered, provide a link between structural and metabolic stability.
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Affiliation(s)
- Yuri Motorin
- Laboratoire ARN-RNP Maturation-Structure-Fonction, Enzymologie Moléculaire et Structurale (AREMS), UMR 7214 CNRS-UHP Faculté des Sciences et Techniques, Université Henri Poincaré, Nancy 1, Bld des Aiguillettes, BP 70239, 54506 Vandoeuvre-les-Nancy, France
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36
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Bayfield MA, Yang R, Maraia RJ. Conserved and divergent features of the structure and function of La and La-related proteins (LARPs). BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1799:365-78. [PMID: 20138158 PMCID: PMC2860065 DOI: 10.1016/j.bbagrm.2010.01.011] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 01/08/2010] [Accepted: 01/27/2010] [Indexed: 12/19/2022]
Abstract
Genuine La proteins contain two RNA binding motifs, a La motif (LAM) followed by a RNA recognition motif (RRM), arranged in a unique way to bind RNA. These proteins interact with an extensive variety of cellular RNAs and exhibit activities in two broad categories: i) to promote the metabolism of nascent pol III transcripts, including precursor-tRNAs, by binding to their common, UUU-3'OH containing ends, and ii) to modulate the translation of certain mRNAs involving an unknown binding mechanism. Characterization of several La-RNA crystal structures as well as biochemical studies reveal insight into their unique two-motif domain architecture and how the LAM recognizes UUU-3'OH while the RRM binds other parts of a pre-tRNA. Recent studies of members of distinct families of conserved La-related proteins (LARPs) indicate that some of these harbor activity related to genuine La proteins, suggesting that their UUU-3'OH binding mode has been appropriated for the assembly and regulation of a specific snRNP (e.g., 7SK snRNP assembly by hLARP7/PIP7S). Analyses of other LARP family members suggest more diverged RNA binding modes and specialization for cytoplasmic mRNA-related functions. Thus it appears that while genuine La proteins exhibit broad general involvement in both snRNA-related and mRNA-related functions, different LARP families may have evolved specialized activities in either snRNA or mRNA-related functions. In this review, we summarize recent progress that has led to greater understanding of the structure and function of La proteins and their roles in tRNA processing and RNP assembly dynamics, as well as progress on the different LARPs.
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Affiliation(s)
- Mark A Bayfield
- Department of Biology, York University, Toronto, ON, Canada.
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37
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Tovy A, Siman Tov R, Gaentzsch R, Helm M, Ankri S. A new nuclear function of the Entamoeba histolytica glycolytic enzyme enolase: the metabolic regulation of cytosine-5 methyltransferase 2 (Dnmt2) activity. PLoS Pathog 2010; 6:e1000775. [PMID: 20174608 PMCID: PMC2824750 DOI: 10.1371/journal.ppat.1000775] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 01/18/2010] [Indexed: 12/27/2022] Open
Abstract
Cytosine-5 methyltransferases of the Dnmt2 family function as DNA and tRNA methyltransferases. Insight into the role and biological significance of Dnmt2 is greatly hampered by a lack of knowledge about its protein interactions. In this report, we address the subject of protein interaction by identifying enolase through a yeast two-hybrid screen as a Dnmt2-binding protein. Enolase, which is known to catalyze the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), was shown to have both a cytoplasmatic and a nuclear localization in the parasite Entamoeba histolytica. We discovered that enolase acts as a Dnmt2 inhibitor. This unexpected inhibitory activity was antagonized by 2-PG, which suggests that glucose metabolism controls the non-glycolytic function of enolase. Interestingly, glucose starvation drives enolase to accumulate within the nucleus, which in turn leads to the formation of additional enolase-E.histolytica DNMT2 homolog (Ehmeth) complex, and to a significant reduction of the tRNA(Asp) methylation in the parasite. The crucial role of enolase as a Dnmt2 inhibitor was also demonstrated in E.histolytica expressing a nuclear localization signal (NLS)-fused-enolase. These results establish enolase as the first Dnmt2 interacting protein, and highlight an unexpected role of a glycolytic enzyme in the modulation of Dnmt2 activity.
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Affiliation(s)
- Ayala Tovy
- Department of Molecular Microbiology, The Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Rama Siman Tov
- Department of Molecular Microbiology, The Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Ricarda Gaentzsch
- Department of Chemistry, The Pharmacy and Molecular Biotechnology Institute, Ruprecht-Karls University of Heidelberg, Heidelberg, Germany
| | - Mark Helm
- Department of Chemistry, The Pharmacy and Molecular Biotechnology Institute, Ruprecht-Karls University of Heidelberg, Heidelberg, Germany
- The Pharmacy and Biochemistry Institute, Johannes Gutenberg University, Mainz, Germany
| | - Serge Ankri
- Department of Molecular Microbiology, The Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
- * E-mail:
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38
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Functional conservation of tRNase ZL among Saccharomyces cerevisiae, Schizosaccharomyces pombe and humans. Biochem J 2009; 422:483-92. [PMID: 19555350 DOI: 10.1042/bj20090743] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although tRNase Z from various organisms was shown to process nuclear tRNA 3' ends in vitro, only a very limited number of studies have reported its in vivo biological functions. tRNase Z is present in a short form, tRNase Z(S), and a long form, tRNase Z(L). Unlike Saccharomyces cerevisiae, which contains one tRNase Z(L) gene (scTRZ1) and humans, which contain one tRNase Z(L) encoded by the prostate-cancer susceptibility gene ELAC2 and one tRNase Z(S), Schizosaccharomyces pombe contains two tRNase Z(L) genes, designated sptrz1(+) and sptrz2(+). We report that both sptrz1(+) and sptrz2(+) are essential for growth. Moreover, sptrz1(+) is required for cell viability in the absence of Sla1p, which is thought to be required for endonuclease-mediated maturation of pre-tRNA 3' ends in yeast. Both scTRZ1 and ELAC2 can complement a temperature-sensitive allele of sptrz1(+), sptrz1-1, but not the sptrz1 null mutant, indicating that despite exhibiting species specificity, tRNase Z(L)s are functionally conserved among S. cerevisiae, S. pombe and humans. Overexpression of sptrz1(+), scTRZ1 and ELAC2 can increase suppression of the UGA nonsense mutation ade6-704 through facilitating 3' end processing of the defective suppressor tRNA that mediates suppression. Our findings reveal that 3' end processing is a limiting step for defective tRNA maturation and demonstrate that overexpression of sptrz1(+), scTRZ1 and ELAC2 can promote defective tRNA 3' processing in vivo. Our results also support the notion that yeast tRNase Z(L) is absolutely required for 3' end processing of at least a few pre-tRNAs even in the absence of Sla1p.
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39
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Wohlgamuth-Benedum JM, Rubio MAT, Paris Z, Long S, Poliak P, Lukes J, Alfonzo JD. Thiolation controls cytoplasmic tRNA stability and acts as a negative determinant for tRNA editing in mitochondria. J Biol Chem 2009; 284:23947-53. [PMID: 19574216 DOI: 10.1074/jbc.m109.029421] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kinetoplastids encode a single nuclear tryptophanyl tRNA that contains a CCA anticodon able to decode the UGG codons used in cytoplasmic protein synthesis but cannot decode the mitochondrial UGA codons. Following mitochondrial import, this problem is circumvented in Trypanosoma brucei by specifically editing the tRNA(Trp) anticodon to UCA, which can now decode the predominant mitochondrial UGA tryptophan codons. This tRNA also undergoes an unusual thiolation at position 33 of the anticodon loop, the only known modification at U33 in any tRNA. In other organisms, tRNA thiolation is mediated by the cysteine desulfurase, Nfs1 (IscS). However, T. brucei encodes two Nfs homologues, one cytoplasmic and the other mitochondrial. We show by a combination of RNA interference and Northern and Western analyses that the mitochondria-targeted TbNfs, and not TbNfs-like protein, is essential for thiolation of both cytosolic and mitochondrial tRNAs. Given the exclusive mitochondrial localization of TbNfs, how it mediates thiolation in the cytoplasm remains unclear. Furthermore, thiolation specifically affects thiolated tRNA stability in the cytoplasm but more surprisingly acts as a negative determinant for the essential C to U editing in T. brucei. This provides a first line of evidence for mitochondrial C to U editing regulation in this system.
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Affiliation(s)
- Jessica M Wohlgamuth-Benedum
- Department of Microbiology and The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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Bayfield MA, Maraia RJ. Precursor-product discrimination by La protein during tRNA metabolism. Nat Struct Mol Biol 2009; 16:430-7. [PMID: 19287396 PMCID: PMC2666094 DOI: 10.1038/nsmb.1573] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 02/09/2009] [Indexed: 11/09/2022]
Abstract
La proteins bind pre-tRNAs at their UUU-3'OH ends, facilitating their maturation. Although the mechanism by which La binds pre-tRNA 3' trailers is known, the function of the RNA binding beta-sheet surface of the RNA-recognition motif (RRM1) is unknown. How La dissociates from UUU-3'OH-containing trailers after 3' processing is also unknown. Here we show that La preferentially binds pre-tRNAs over processed tRNAs or 3' trailer products through coupled use of two sites: one on the La motif and another on the RRM1 beta-surface that binds elsewhere on tRNA. Two sites provide stable pre-tRNA binding, whereas the processed tRNA and 3' trailer are released from their single sites relatively fast. RRM1 loop-3 mutations decrease affinity for pre-tRNA and tRNA, but not for the UUU-3'OH trailer, and impair tRNA maturation in vivo. We propose that RRM1 functions in activities that are more complex than UUU-3'OH binding. Accordingly, the RRM1 mutations also impair an RNA chaperone activity of La. The results suggest how La distinguishes precursor from product RNAs, allowing it to recycle onto a new pre-tRNA.
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Affiliation(s)
| | - Richard J. Maraia
- To whom correspondence should be directed at: 31 Center Drive, Building 31, Room 2A25, Bethesda, MD 20892-2426, Phone: 301-402-3567, Fax: 301-480-6863, E-mail:
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41
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Chernyakov I, Whipple JM, Kotelawala L, Grayhack EJ, Phizicky EM. Degradation of several hypomodified mature tRNA species in Saccharomyces cerevisiae is mediated by Met22 and the 5'-3' exonucleases Rat1 and Xrn1. Genes Dev 2008; 22:1369-80. [PMID: 18443146 DOI: 10.1101/gad.1654308] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mature tRNA is normally extensively modified and extremely stable. Recent evidence suggests that hypomodified mature tRNA in yeast can undergo a quality control check by a rapid tRNA decay (RTD) pathway, since mature tRNA(Val(AAC)) lacking 7-methylguanosine and 5-methylcytidine is rapidly degraded and deacylated at 37 degrees C in a trm8-Delta trm4-Delta strain, resulting in temperature-sensitive growth. We show here that components of this RTD pathway include the 5'-3' exonucleases Rat1 and Xrn1, and Met22, which likely acts indirectly through Rat1 and Xrn1. Since deletion of MET22 or mutation of RAT1 and XRN1 prevent both degradation and deacylation of mature tRNA(Val(AAC)) in a trm8-Delta trm4-Delta strain and result in healthy growth at 37 degrees C, hypomodified tRNA(Val(AAC)) is at least partially functional and structurally intact under these conditions. The integrity of multiple mature tRNA species is subject to surveillance by the RTD pathway, since mutations in this pathway also prevent degradation of at least three other mature tRNAs lacking other combinations of modifications. The RTD pathway is the first to be implicated in the turnover of mature RNA species from the class of stable RNAs. These results and the results of others demonstrate that tRNA, like mRNA, is subject to multiple quality control steps.
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Affiliation(s)
- Irina Chernyakov
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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42
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The conserved Wobble uridine tRNA thiolase Ctu1-Ctu2 is required to maintain genome integrity. Proc Natl Acad Sci U S A 2008; 105:5459-64. [PMID: 18391219 DOI: 10.1073/pnas.0709404105] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Modified nucleosides close to the anticodon are important for the proper decoding of mRNA by the ribosome. Particularly, the uridine at the first anticodon position (U34) of glutamate, lysine, and glutamine tRNAs is universally thiolated (S(2)U34), which is proposed to be crucial for both restriction of wobble in the corresponding split codon box and efficient codon-anticodon interaction. Here we show that the highly conserved complex Ctu1-Ctu2 (cytosolic thiouridylase) is responsible for the 2-thiolation of cytosolic tRNAs in the nematode and fission yeast. In both species, inactivation of the complex leads to loss of thiolation on tRNAs and to a thermosensitive decrease of viability associated with marked ploidy abnormalities and aberrant development. Increased level of the corresponding tRNAs suppresses the fission yeast defects, and our data suggest that these defects could result from both misreading and frame shifting during translation. Thus, a translation defect due to unmodified tRNAs results in severe genome instability.
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43
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Eukaryotic wobble uridine modifications promote a functionally redundant decoding system. Mol Cell Biol 2008; 28:3301-12. [PMID: 18332122 DOI: 10.1128/mcb.01542-07] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The translational decoding properties of tRNAs are modulated by naturally occurring modifications of their nucleosides. Uridines located at the wobble position (nucleoside 34 [U(34)]) in eukaryotic cytoplasmic tRNAs often harbor a 5-methoxycarbonylmethyl (mcm(5)) or a 5-carbamoylmethyl (ncm(5)) side chain and sometimes an additional 2-thio (s(2)) or 2'-O-methyl group. Although a variety of models explaining the role of these modifications have been put forth, their in vivo functions have not been defined. In this study, we utilized recently characterized modification-deficient Saccharomyces cerevisiae cells to test the wobble rules in vivo. We show that mcm(5) and ncm(5) side chains promote decoding of G-ending codons and that concurrent mcm(5) and s(2) groups improve reading of both A- and G-ending codons. Moreover, the observation that the mcm(5)U(34)- and some ncm(5)U(34)-containing tRNAs efficiently read G-ending codons challenges the notion that eukaryotes do not use U-G wobbling.
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44
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Chernyakov I, Baker MA, Grayhack EJ, Phizicky EM. Chapter 11. Identification and analysis of tRNAs that are degraded in Saccharomyces cerevisiae due to lack of modifications. Methods Enzymol 2008; 449:221-37. [PMID: 19215761 PMCID: PMC2788775 DOI: 10.1016/s0076-6879(08)02411-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Mounting evidence shows that tRNA modifications play crucial roles in the maintenance of wild-type levels of several tRNA species. This chapter describes a generalized framework in which to study tRNA turnover in the yeast Saccharomyces cerevisiae as a consequence of a defect in tRNA modification status. It describes several approaches for the identification of tRNA species that are reduced as a consequence of a modification defect, methods for analysis of the rate of tRNA loss and analysis of its aminoacylation, and methods for initial characterization of tRNA turnover. These approaches have been used successfully for several modification defects that result in tRNA turnover.
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Affiliation(s)
- Irina Chernyakov
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York, USA
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45
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Kotelawala L, Grayhack EJ, Phizicky EM. Identification of yeast tRNA Um(44) 2'-O-methyltransferase (Trm44) and demonstration of a Trm44 role in sustaining levels of specific tRNA(Ser) species. RNA (NEW YORK, N.Y.) 2008; 14:158-69. [PMID: 18025252 PMCID: PMC2151035 DOI: 10.1261/rna.811008] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Accepted: 10/07/2007] [Indexed: 05/17/2023]
Abstract
A characteristic feature of tRNAs is the numerous modifications found throughout their sequences, which are highly conserved and often have important roles. Um(44) is highly conserved among eukaryotic cytoplasmic tRNAs with a long variable loop and unique to tRNA(Ser) in yeast. We show here that the yeast ORF YPL030w (now named TRM44) encodes tRNA(Ser) Um(44) 2'-O-methyltransferase. Trm44 was identified by screening a yeast genomic library of affinity purified proteins for activity and verified by showing that a trm44-delta strain lacks 2'-O-methyltransferase activity and has undetectable levels of Um(44) in its tRNA(Ser) and by showing that Trm44 purified from Escherichia coli 2'-O-methylates U(44) of tRNA(Ser) in vitro. Trm44 is conserved among metazoans and fungi, consistent with the conservation of Um(44) in eukaryotic tRNAs, but surprisingly, Trm44 is not found in plants. Although trm44-delta mutants have no detectable growth defect, TRM44 is required for survival at 33 degrees C in a tan1-delta mutant strain, which lacks ac(4)C12 in tRNA(Ser) and tRNA(Leu). At nonpermissive temperature, a trm44-delta tan1-delta mutant strain has reduced levels of tRNA(Ser(CGA)) and tRNA(Ser(UGA)), but not other tRNA(Ser) or tRNA(Leu) species. The trm44-delta tan1-delta growth defect is suppressed by addition of multiple copies of tRNA(Ser(CGA)) and tRNA(Ser(UGA)), directly implicating these tRNA(Ser) species in this phenotype. The reduction of specific tRNA(Ser) species in a trm44-delta tan1-delta mutant underscores the importance of tRNA modifications in sustaining tRNA levels and further emphasizes that tRNAs undergo quality control.
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Affiliation(s)
- Lakmal Kotelawala
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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46
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Bujnicki JM, Droogmans L, Grosjean H, Purushothaman SK, Lapeyre B. Bioinformatics-Guided Identification and Experimental Characterization of Novel RNA Methyltransferas. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/978-3-540-74268-5_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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47
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Wolin SL, Wurtmann EJ. Molecular chaperones and quality control in noncoding RNA biogenesis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2007; 71:505-11. [PMID: 17381333 DOI: 10.1101/sqb.2006.71.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Although noncoding RNAs have critical roles in all cells, both the mechanisms by which these RNAs fold into functional structures and the quality control pathways that monitor correct folding are only beginning to be elucidated. Here, we discuss several proteins that likely function as molecular chaperones for noncoding RNAs and review the existing knowledge on noncoding RNA quality control. One protein, the La protein, binds many nascent noncoding RNAs in eukaryotes and is required for efficient folding of certain pre-tRNAs. In prokaryotes, the Sm-like protein Hfq is required for the function of many noncoding RNAs. Recent work in bacteria and yeast has revealed the existence of quality control systems involving polyadenylation of unstable noncoding RNAs followed by exonucleolytic degradation. In addition, the Ro protein, which is present in many animal cells and also certain bacteria, binds misfolded noncoding RNAs and is proposed to function in RNA quality control.
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MESH Headings
- Bacteria/genetics
- Bacteria/metabolism
- Models, Molecular
- Molecular Chaperones/genetics
- Molecular Chaperones/metabolism
- Mutation
- Nucleic Acid Conformation
- RNA, Bacterial/biosynthesis
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Fungal/biosynthesis
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Untranslated/biosynthesis
- RNA, Untranslated/chemistry
- RNA, Untranslated/genetics
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
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Affiliation(s)
- S L Wolin
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06536, USA
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Choudhury SA, Asefa B, Kauler P, Chow TYK. Synergistic effect of TRM2/RNC1 and EXO1 in DNA double-strand break repair in Saccharomyces cerevisiae. Mol Cell Biochem 2007; 304:127-34. [PMID: 17534700 DOI: 10.1007/s11010-007-9493-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 04/27/2007] [Indexed: 11/25/2022]
Abstract
In our recently published study, we provided in vitro as well as in vivo data demonstrating the involvement of TRM2/RNC1 in homologous recombination based repair (HRR) of DNA double strand breaks (DSBs), in support of such claims reported earlier. To further validate its role in DNA DSB processing, our present study revealed that the trm2 single mutant displays higher sensitivity to persistent induction of specific DSBs at the MAT locus by HO-endonuclease with higher sterility rate among the survivors compared to wild type (wt) or exo1 single mutants. Intriguingly, both sensitivity and sterility rate increased dramatically in trm2exo1 double mutants lacking both endo-exonucleases with a progressively increased sterility rate in trm2exo1 double mutants with short-induction periods, reaching a very high level of sterility with persistent DSB inductions. Mutation analysis of the mating type (MAT) locus among the sterile survivors with persistent HO-induction in trm2 and exo1 single mutants as well as in trm2exo1 double mutants revealed a similar small insertions and deletions events, characteristic of non-homologous end joining (NHEJ) that might have occurred due to the lack of proper processing function in these mutants. In addition, trm2ku80 and trm2rad52 double mutants also displayed significantly higher sterility with persistent DSB induction compared to ku80 and rad52 single mutants, respectively, exhibiting a mutation spectra that shifted from base substitution (in ku80 and rad52 single mutants) to small insertions and deletions in the double mutants (in trm2ku80 and trm2rad52 mutants). These data indicate a defective processing in absence of TRM2, with a synergistic effect of TRM2, and EXO1 in such processing.
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Affiliation(s)
- Sibgat A Choudhury
- Department of Oncology, Faculty of Medicine, McGill University, Montreal General Hospital, 1650 Ave. Cedar, Montreal, QC, Canada, H3G 1A4
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49
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Urbonavičius J, Jäger G, Björk GR. Amino acid residues of the Escherichia coli tRNA(m5U54)methyltransferase (TrmA) critical for stability, covalent binding of tRNA and enzymatic activity. Nucleic Acids Res 2007; 35:3297-305. [PMID: 17459887 PMCID: PMC1904294 DOI: 10.1093/nar/gkm205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Escherichia coli trmA gene encodes the tRNA(m5U54)methyltransferase, which catalyses the formation of m5U54 in tRNA. During the synthesis of m5U54, a covalent 62-kDa TrmA-tRNA intermediate is formed between the amino acid C324 of the enzyme and the 6-carbon of uracil. We have analysed the formation of this TrmA-tRNA intermediate and m5U54 in vivo, using mutants with altered TrmA. We show that the amino acids F188, Q190, G220, D299, R302, C324 and E358, conserved in the C-terminal catalytic domain of several RNA(m5U)methyltransferases of the COG2265 family, are important for the formation of the TrmA-tRNA intermediate and/or the enzymatic activity. These amino acids seem to have the same function as the ones present in the catalytic domain of RumA, whose structure is known, and which catalyses the formation of m5U in position 1939 of E. coli 23 S rRNA. We propose that the unusually high in vivo level of the TrmA-tRNA intermediate in wild-type cells may be due to a suboptimal cellular concentration of SAM, which is required to resolve this intermediate. Our results are consistent with the modular evolution of RNA(m5U)methyltransferases, in which the specificity of the enzymatic reaction is achieved by combining the conserved catalytic domain with different RNA-binding domains.
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Affiliation(s)
| | | | - Glenn R. Björk
- *To whom correspondence should be addressed. Tel: +46-90-7856759; Fax: +46-90-772630;
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50
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Choudhury SA, Asefa B, Webb A, Ramotar D, Chow TYK. Functional and genetic analysis of the Saccharomyces cerevisiae RNC1/TRM2: evidences for its involvement in DNA double-strand break repair. Mol Cell Biochem 2007; 300:215-26. [PMID: 17205207 DOI: 10.1007/s11010-006-9386-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
Abstract
We previously isolated the RNC1/TRM2 gene and provided evidence that it encodes a protein with a possible role in DNA double strand break repair. RNC1 was independently re-isolated as the TRM2 gene encoding a methyl transferase involved in tRNA maturation. Here we show that Trm2p purified as a fusion protein displayed 5' --> 3' exonuclease activity on double-strand (ds) DNA, and endonuclease activity on single-strand (ss) DNA, properties characteristic of previously isolated endo-exonucleases. A variant of Trm2p, Trm2p(ctDelta76aa) lacking 76 amino acids at the C-terminus retained nuclease activities but not the methyl transferase activity. Both the native and the variant exhibited sensitivity to the endo-exonuclease inhibitor pentamidine. The Saccharomyces cerevisiae trm2(Delta232-1920nt) mutant (containing only the first 231 nucleotides of the TRM2 gene) displayed low sensitivity to methyl methane sulfonate (MMS) and suppressed the MMS sensitivity of rad52 mutants in trm2(Delta232-1920nt)rad52 double mutants. The deletion of KU80, in trm2(Delta232-1920nt) mutant background displayed higher MMS sensitivity supporting the view of the possible role of Trm2p in a competing repair pathway separate from NHEJ. In addition, trm2 exo1 double mutants were synergistically more sensitive to MMS and ionizing radiation than either of the single mutant suggesting that TRM2 and EXO1 can functionally complement each other. However, the C-terminal portion, required for its methyl transferase activity was found not important for DNA repair. These results propose an important role for TRM2 in DNA repair with a potential involvement of its nuclease function in homologous recombination based repair of DNA DSBs.
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Affiliation(s)
- Sibgat A Choudhury
- Department of Oncology, Faculty of Medicine, McGill University, Montreal General Hospital, 1650 Avenue Cedar, Montreal, Quebec, Canada
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