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Abstract
The study of eukaryotic tRNA processing has given rise to an explosion of new information and insights in the last several years. We now have unprecedented knowledge of each step in the tRNA processing pathway, revealing unexpected twists in biochemical pathways, multiple new connections with regulatory pathways, and numerous biological effects of defects in processing steps that have profound consequences throughout eukaryotes, leading to growth phenotypes in the yeast Saccharomyces cerevisiae and to neurological and other disorders in humans. This review highlights seminal new results within the pathways that comprise the life of a tRNA, from its birth after transcription until its death by decay. We focus on new findings and revelations in each step of the pathway including the end-processing and splicing steps, many of the numerous modifications throughout the main body and anticodon loop of tRNA that are so crucial for tRNA function, the intricate tRNA trafficking pathways, and the quality control decay pathways, as well as the biogenesis and biology of tRNA-derived fragments. We also describe the many interactions of these pathways with signaling and other pathways in the cell.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, Ohio 43235, USA
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2
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Schultz SK, Meadows K, Kothe U. Molecular mechanism of tRNA binding by the Escherichia coli N7 guanosine methyltransferase TrmB. J Biol Chem 2023; 299:104612. [PMID: 36933808 PMCID: PMC10130221 DOI: 10.1016/j.jbc.2023.104612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 03/11/2023] [Accepted: 03/12/2023] [Indexed: 03/18/2023] Open
Abstract
Among the large and diverse collection of tRNA modifications, 7-methylguanosine (m7G) is frequently found in the tRNA variable loop at position 46. This modification is introduced by the TrmB enzyme, which is conserved in bacteria and eukaryotes. However, the molecular determinants and the mechanism for tRNA recognition by TrmB are not well understood. Complementing the report of various phenotypes for different organisms lacking TrmB homologs, we report here hydrogen peroxide sensitivity for the Escherichia coli ΔtrmB knockout strain. To gain insight into the molecular mechanism of tRNA binding by E. coli TrmB in real-time, we developed a new assay based on introducing a 4-thiouridine modification at position 8 of in vitro transcribed tRNAPhe enabling us to fluorescently label this unmodified tRNA. Using rapid kinetic stopped-flow measurements with this fluorescent tRNA, we examined the interaction of wildtype and single substitution variants of TrmB with tRNA. Our results reveal the role of SAM for rapid and stable tRNA binding, the rate-limiting nature of m7G46 catalysis for tRNA release, and the importance of residues R26, T127 and R155 across the entire surface of TrmB for tRNA binding.
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Affiliation(s)
- Sarah K Schultz
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kieran Meadows
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Ute Kothe
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada.
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3
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Hori H. Transfer RNA Modification Enzymes with a Thiouridine Synthetase, Methyltransferase and Pseudouridine Synthase (THUMP) Domain and the Nucleosides They Produce in tRNA. Genes (Basel) 2023; 14:genes14020382. [PMID: 36833309 PMCID: PMC9957541 DOI: 10.3390/genes14020382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
The existence of the thiouridine synthetase, methyltransferase and pseudouridine synthase (THUMP) domain was originally predicted by a bioinformatic study. Since the prediction of the THUMP domain more than two decades ago, many tRNA modification enzymes containing the THUMP domain have been identified. According to their enzymatic activity, THUMP-related tRNA modification enzymes can be classified into five types, namely 4-thiouridine synthetase, deaminase, methyltransferase, a partner protein of acetyltransferase and pseudouridine synthase. In this review, I focus on the functions and structures of these tRNA modification enzymes and the modified nucleosides they produce. Biochemical, biophysical and structural studies of tRNA 4-thiouridine synthetase, tRNA methyltransferases and tRNA deaminase have established the concept that the THUMP domain captures the 3'-end of RNA (in the case of tRNA, the CCA-terminus). However, in some cases, this concept is not simply applicable given the modification patterns observed in tRNA. Furthermore, THUMP-related proteins are involved in the maturation of other RNAs as well as tRNA. Moreover, the modified nucleosides, which are produced by the THUMP-related tRNA modification enzymes, are involved in numerous biological phenomena, and the defects of genes for human THUMP-related proteins are implicated in genetic diseases. In this review, these biological phenomena are also introduced.
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Affiliation(s)
- Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan
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4
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Xia X, Wang Y, Zheng JC. Internal m7G methylation: A novel epitranscriptomic contributor in brain development and diseases. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:295-308. [PMID: 36726408 PMCID: PMC9883147 DOI: 10.1016/j.omtn.2023.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In recent years, N7-methylguanosine (m7G) methylation, originally considered as messenger RNA (mRNA) 5' caps modifications, has been identified at defined internal positions within multiple types of RNAs, including transfer RNAs, ribosomal RNAs, miRNA, and mRNAs. Scientists have put substantial efforts to discover m7G methyltransferases and methylated sites in RNAs to unveil the essential roles of m7G modifications in the regulation of gene expression and determine the association of m7G dysregulation in various diseases, including neurological disorders. Here, we review recent findings regarding the distribution, abundance, biogenesis, modifiers, and functions of m7G modifications. We also provide an up-to-date summary of m7G detection and profile mapping techniques, databases for validated and predicted m7G RNA sites, and web servers for m7G methylation prediction. Furthermore, we discuss the pathological roles of METTL1/WDR-driven m7G methylation in neurological disorders. Last, we outline a roadmap for future directions and trends of m7G modification research, particularly in the central nervous system.
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Affiliation(s)
- Xiaohuan Xia
- Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai 200331, China,Corresponding author: Xiaohuan Xia, Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai 200065, China.
| | - Yi Wang
- Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai 200331, China,Translational Research Center, Shanghai Yangzhi Rehabilitation Hospital affiliated to Tongji University School of Medicine, Shanghai 201613, China
| | - Jialin C. Zheng
- Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai 200331, China,Corresponding author: Jialin C. Zheng, Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai 200065, China.
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5
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Ruiz-Arroyo VM, Raj R, Babu K, Onolbaatar O, Roberts PH, Nam Y. Structures and mechanisms of tRNA methylation by METTL1-WDR4. Nature 2023; 613:383-390. [PMID: 36599982 PMCID: PMC9930641 DOI: 10.1038/s41586-022-05565-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/16/2022] [Indexed: 01/06/2023]
Abstract
Specific, regulated modification of RNAs is important for proper gene expression1,2. tRNAs are rich with various chemical modifications that affect their stability and function3,4. 7-Methylguanosine (m7G) at tRNA position 46 is a conserved modification that modulates steady-state tRNA levels to affect cell growth5,6. The METTL1-WDR4 complex generates m7G46 in humans, and dysregulation of METTL1-WDR4 has been linked to brain malformation and multiple cancers7-22. Here we show how METTL1 and WDR4 cooperate to recognize RNA substrates and catalyse methylation. A crystal structure of METTL1-WDR4 and cryo-electron microscopy structures of METTL1-WDR4-tRNA show that the composite protein surface recognizes the tRNA elbow through shape complementarity. The cryo-electron microscopy structures of METTL1-WDR4-tRNA with S-adenosylmethionine or S-adenosylhomocysteine along with METTL1 crystal structures provide additional insights into the catalytic mechanism by revealing the active site in multiple states. The METTL1 N terminus couples cofactor binding with conformational changes in the tRNA, the catalytic loop and the WDR4 C terminus, acting as the switch to activate m7G methylation. Thus, our structural models explain how post-translational modifications of the METTL1 N terminus can regulate methylation. Together, our work elucidates the core and regulatory mechanisms underlying m7G modification by METTL1, providing the framework to understand its contribution to biology and disease.
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Affiliation(s)
- Victor M Ruiz-Arroyo
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rishi Raj
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kesavan Babu
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Otgonbileg Onolbaatar
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Paul H Roberts
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yunsun Nam
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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6
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Li J, Wang L, Hahn Q, Nowak RP, Viennet T, Orellana EA, Roy Burman SS, Yue H, Hunkeler M, Fontana P, Wu H, Arthanari H, Fischer ES, Gregory RI. Structural basis of regulated m 7G tRNA modification by METTL1-WDR4. Nature 2023; 613:391-397. [PMID: 36599985 PMCID: PMC11179147 DOI: 10.1038/s41586-022-05566-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 11/16/2022] [Indexed: 01/05/2023]
Abstract
Chemical modifications of RNA have key roles in many biological processes1-3. N7-methylguanosine (m7G) is required for integrity and stability of a large subset of tRNAs4-7. The methyltransferase 1-WD repeat-containing protein 4 (METTL1-WDR4) complex is the methyltransferase that modifies G46 in the variable loop of certain tRNAs, and its dysregulation drives tumorigenesis in numerous cancer types8-14. Mutations in WDR4 cause human developmental phenotypes including microcephaly15-17. How METTL1-WDR4 modifies tRNA substrates and is regulated remains elusive18. Here we show, through structural, biochemical and cellular studies of human METTL1-WDR4, that WDR4 serves as a scaffold for METTL1 and the tRNA T-arm. Upon tRNA binding, the αC region of METTL1 transforms into a helix, which together with the α6 helix secures both ends of the tRNA variable loop. Unexpectedly, we find that the predicted disordered N-terminal region of METTL1 is part of the catalytic pocket and essential for methyltransferase activity. Furthermore, we reveal that S27 phosphorylation in the METTL1 N-terminal region inhibits methyltransferase activity by locally disrupting the catalytic centre. Our results provide a molecular understanding of tRNA substrate recognition and phosphorylation-mediated regulation of METTL1-WDR4, and reveal the presumed disordered N-terminal region of METTL1 as a nexus of methyltransferase activity.
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Affiliation(s)
- Jiazhi Li
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Longfei Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Quentin Hahn
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Radosław P Nowak
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Thibault Viennet
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Esteban A Orellana
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Shourya S Roy Burman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Hong Yue
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Moritz Hunkeler
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Pietro Fontana
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Eric S Fischer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Cambridge, MA, USA.
- Harvard Initiative for RNA Medicine, Boston, MA, USA.
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7
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Multiple Gene Expression in Cell-Free Protein Synthesis Systems for Reconstructing Bacteriophages and Metabolic Pathways. Microorganisms 2022; 10:microorganisms10122477. [PMID: 36557730 PMCID: PMC9786908 DOI: 10.3390/microorganisms10122477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/10/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
As a fast and reliable technology with applications in diverse biological studies, cell-free protein synthesis has become popular in recent decades. The cell-free protein synthesis system can be considered a complex chemical reaction system that is also open to exogenous manipulation, including that which could otherwise potentially harm the cell's viability. On the other hand, since the technology depends on the cell lysates by which genetic information is transformed into active proteins, the whole system resembles the cell to some extent. These features make cell-free protein synthesis a valuable addition to synthetic biology technologies, expediting the design-build-test-learn cycle of synthetic biology routines. While the system has traditionally been used to synthesize one protein product from one gene addition, recent studies have employed multiple gene products in order to, for example, develop novel bacteriophages, viral particles, or synthetic metabolisms. Thus, we would like to review recent advancements in applying cell-free protein synthesis technology to synthetic biology, with an emphasis on multiple gene expressions.
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8
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Abstract
As one of the prevalent posttranscriptional modifications of RNA, N7-methylguanosine (m7G) plays essential roles in RNA processing, metabolism, and function, mainly regulated by the methyltransferase-like 1 (METTL1) and WD repeat domain 4 (WDR4) complex. Emerging evidence suggests that the METTL1/WDR4 complex promoted or inhibited the processes of many tumors, including head and neck, lung, liver, colon, bladder cancer, and teratoma, dependent on close m7G methylation modification of tRNA or microRNA (miRNA). Therefore, METTL1 and m7G modification can be used as biomarkers or potential intervention targets, providing new possibilities for early diagnosis and treatment of tumors. This review will mainly focus on the mechanisms of METTL1/WDR4 via m7G in tumorigenesis and the corresponding detection methods.
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Affiliation(s)
- Wenli Cheng
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Aili Gao
- Guangzhou Institution of Dermatology, Guangzhou, Guangdong 510095, P.R. China
| | - Hui Lin
- Department of Radiation Oncology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P. R. China
| | - Wenjuan Zhang
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong 510632, P.R. China
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9
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Blersch KF, Burchert JP, August SC, Welp L, Neumann P, Köster S, Urlaub H, Ficner R. Structural model of the M7G46 Methyltransferase TrmB in complex with tRNA. RNA Biol 2021; 18:2466-2479. [PMID: 34006170 DOI: 10.1080/15476286.2021.1925477] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TrmB belongs to the class I S-adenosylmethionine (SAM)-dependent methyltransferases (MTases) and introduces a methyl group to guanine at position 7 (m7G) in tRNA. In tRNAs m7G is most frequently found at position 46 in the variable loop and forms a tertiary base pair with C13 and U22, introducing a positive charge at G46. The TrmB/Trm8 enzyme family is structurally diverse, as TrmB proteins exist in a monomeric, homodimeric, and heterodimeric form. So far, the exact enzymatic mechanism, as well as the tRNA-TrmB crystal structure is not known. Here we present the first crystal structures of B. subtilis TrmB in complex with SAM and SAH. The crystal structures of TrmB apo and in complex with SAM and SAH have been determined by X-ray crystallography to 1.9 Å (apo), 2.5 Å (SAM), and 3.1 Å (SAH). The obtained crystal structures revealed Tyr193 to be important during SAM binding and MTase activity. Applying fluorescence polarization, the dissociation constant Kd of TrmB and tRNAPhe was determined to be 0.12 µM ± 0.002 µM. Luminescence-based methyltransferase activity assays revealed cooperative effects during TrmB catalysis with half-of-the-site reactivity at physiological SAM concentrations. Structural data retrieved from small-angle x-ray scattering (SAXS), mass-spectrometry of cross-linked complexes, and molecular docking experiments led to the determination of the TrmB-tRNAPhe complex structure.
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Affiliation(s)
- Katharina F Blersch
- Department of Molecular Structural Biology, Institute of Microbiology and Genetics, GZMB, Georg August University Göttingen, Göttingen, Germany
| | - Jan-Philipp Burchert
- Institute for X-Ray Physics, Georg August University Göttingen, Göttingen, Germany
| | | | - Luisa Welp
- Bioanalytical Mass Spectrometry Research Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Piotr Neumann
- Department of Molecular Structural Biology, Institute of Microbiology and Genetics, GZMB, Georg August University Göttingen, Göttingen, Germany
| | - Sarah Köster
- Institute for X-Ray Physics, Georg August University Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Research Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute of Microbiology and Genetics, GZMB, Georg August University Göttingen, Göttingen, Germany
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10
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ENDO Y. Development of a cell-free protein synthesis system for practical use. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:261-276. [PMID: 33980755 PMCID: PMC8141837 DOI: 10.2183/pjab.97.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Conventional cell-free protein synthesis systems had been the major platform to study the mechanism behind translating genetic information into proteins, as proven in the central dogma of molecular biology. Albeit being powerful research tools, most of the in vitro methods at the time failed to produce enough protein for practical use. Tremendous efforts were being made to overcome the limitations of in vitro translation systems, though mostly with limited success. While great knowledge was accumulated on the translation mechanism and ribosome structure, researchers rationalized that it may be impossible to fully reconstitute such a complex molecular process in a test tube. This review will examine how we have solved the difficulties holding back progress. Our newly developed cell-free protein synthesis system is based on wheat embryos and has many excellent characteristics, in addition to its high translation activity and robustness. Combined with other novel elementary technologies, we have established cell-free protein synthesis systems for practical use in research and applied sciences.
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Affiliation(s)
- Yaeta ENDO
- Ehime Prefectural University of Health Sciences, Tobe-cho, Iyo-gun, Ehime, Japan
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11
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De Zoysa T, Phizicky EM. Hypomodified tRNA in evolutionarily distant yeasts can trigger rapid tRNA decay to activate the general amino acid control response, but with different consequences. PLoS Genet 2020; 16:e1008893. [PMID: 32841241 PMCID: PMC7473580 DOI: 10.1371/journal.pgen.1008893] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/04/2020] [Accepted: 07/22/2020] [Indexed: 12/14/2022] Open
Abstract
All tRNAs are extensively modified, and modification deficiency often results in growth defects in the budding yeast Saccharomyces cerevisiae and neurological or other disorders in humans. In S. cerevisiae, lack of any of several tRNA body modifications results in rapid tRNA decay (RTD) of certain mature tRNAs by the 5'-3' exonucleases Rat1 and Xrn1. As tRNA quality control decay mechanisms are not extensively studied in other eukaryotes, we studied trm8Δ mutants in the evolutionarily distant fission yeast Schizosaccharomyces pombe, which lack 7-methylguanosine at G46 (m7G46) of their tRNAs. We report here that S. pombe trm8Δ mutants are temperature sensitive primarily due to decay of tRNATyr(GUA) and that spontaneous mutations in the RAT1 ortholog dhp1+ restored temperature resistance and prevented tRNA decay, demonstrating conservation of the RTD pathway. We also report for the first time evidence linking the RTD and the general amino acid control (GAAC) pathways, which we show in both S. pombe and S. cerevisiae. In S. pombe trm8Δ mutants, spontaneous GAAC mutations restored temperature resistance and tRNA levels, and the trm8Δ temperature sensitivity was precisely linked to GAAC activation due to tRNATyr(GUA) decay. Similarly, in the well-studied S. cerevisiae trm8Δ trm4Δ RTD mutant, temperature sensitivity was closely linked to GAAC activation due to tRNAVal(AAC) decay; however, in S. cerevisiae, GAAC mutations increased tRNA loss and exacerbated temperature sensitivity. A similar exacerbated growth defect occurred upon GAAC mutation in S. cerevisiae trm8Δ and other single modification mutants that triggered RTD. Thus, these results demonstrate a conserved GAAC activation coincident with RTD in S. pombe and S. cerevisiae, but an opposite impact of the GAAC response in the two organisms. We speculate that the RTD pathway and its regulation of the GAAC pathway is widely conserved in eukaryotes, extending to other mutants affecting tRNA body modifications.
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Affiliation(s)
- Thareendra De Zoysa
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY, United States of America
| | - Eric M. Phizicky
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY, United States of America
- * E-mail:
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12
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Hirata A, Okada K, Yoshii K, Shiraishi H, Saijo S, Yonezawa K, Shimizu N, Hori H. Structure of tRNA methyltransferase complex of Trm7 and Trm734 reveals a novel binding interface for tRNA recognition. Nucleic Acids Res 2020; 47:10942-10955. [PMID: 31586407 PMCID: PMC6847430 DOI: 10.1093/nar/gkz856] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/20/2019] [Accepted: 10/02/2019] [Indexed: 12/18/2022] Open
Abstract
The complex between Trm7 and Trm734 (Trm7–Trm734) from Saccharomyces cerevisiae catalyzes 2′-O-methylation at position 34 in tRNA. We report biochemical and structural studies of the Trm7–Trm734 complex. Purified recombinant Trm7–Trm734 preferentially methylates tRNAPhe transcript variants possessing two of three factors (Cm32, m1G37 and pyrimidine34). Therefore, tRNAPhe, tRNATrp and tRNALeu are specifically methylated by Trm7–Trm734. We have solved the crystal structures of the apo and S-adenosyl-L-methionine bound forms of Trm7–Trm734. Small angle X-ray scattering reveals that Trm7–Trm734 exists as a hetero-dimer in solution. Trm7 possesses a Rossmann-fold catalytic domain, while Trm734 consists of three WD40 β-propeller domains (termed BPA, BPB and BPC). BPA and BPC form a unique V-shaped cleft, which docks to Trm7. The C-terminal region of Trm7 is required for binding to Trm734. The D-arm of substrate tRNA is required for methylation by Trm7–Trm734. If the D-arm in tRNAPhe is docked onto the positively charged area of BPB in Trm734, the anticodon-loop is located near the catalytic pocket of Trm7. This model suggests that Trm734 is required for correct positioning of tRNA for methylation. Additionally, a point-mutation in Trm7, which is observed in FTSJ1 (human Trm7 ortholog) of nosyndromic X-linked intellectual disability patients, decreases the methylation activity.
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Affiliation(s)
- Akira Hirata
- Department of Materials Science and Biotechnology, Graduate school of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Keisuke Okada
- Department of Materials Science and Biotechnology, Graduate school of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Kazuaki Yoshii
- Department of Materials Science and Biotechnology, Graduate school of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Hiroyuki Shiraishi
- Department of Materials Science and Biotechnology, Graduate school of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Shinya Saijo
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Kento Yonezawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Nobutaka Shimizu
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate school of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
- To whom correspondence should be addressed. Tel: +81 89 927 8548; Fax: +81 89 927 9941;
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Enroth C, Poulsen LD, Iversen S, Kirpekar F, Albrechtsen A, Vinther J. Detection of internal N7-methylguanosine (m7G) RNA modifications by mutational profiling sequencing. Nucleic Acids Res 2020; 47:e126. [PMID: 31504776 PMCID: PMC6847341 DOI: 10.1093/nar/gkz736] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 08/06/2019] [Accepted: 08/16/2019] [Indexed: 01/05/2023] Open
Abstract
Methylation of guanosine on position N7 (m7G) on internal RNA positions has been found in all domains of life and have been implicated in human disease. Here, we present m7G Mutational Profiling sequencing (m7G-MaP-seq), which allows high throughput detection of m7G modifications at nucleotide resolution. In our method, m7G modified positions are converted to abasic sites by reduction with sodium borohydride, directly recorded as cDNA mutations through reverse transcription and sequenced. We detect positions with increased mutation rates in the reduced and control samples taking the possibility of sequencing/alignment error into account and use replicates to calculate statistical significance based on log likelihood ratio tests. We show that m7G-MaP-seq efficiently detects known m7G modifications in rRNA with mutational rates up to 25% and we map a previously uncharacterised evolutionarily conserved rRNA modification at position 1581 in Arabidopsis thaliana SSU rRNA. Furthermore, we identify m7G modifications in budding yeast, human and arabidopsis tRNAs and demonstrate that m7G modification occurs before tRNA splicing. We do not find any evidence for internal m7G modifications being present in other small RNA, such as miRNA, snoRNA and sRNA, including human Let-7e. Likewise, high sequencing depth m7G-MaP-seq analysis of mRNA from E. coli or yeast cells did not identify any internal m7G modifications.
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Affiliation(s)
- Christel Enroth
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Line Dahl Poulsen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Søren Iversen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Finn Kirpekar
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Anders Albrechtsen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Jeppe Vinther
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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14
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Barraud P, Tisné C. To be or not to be modified: Miscellaneous aspects influencing nucleotide modifications in tRNAs. IUBMB Life 2019; 71:1126-1140. [PMID: 30932315 PMCID: PMC6850298 DOI: 10.1002/iub.2041] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/10/2019] [Indexed: 12/12/2022]
Abstract
Transfer RNAs (tRNAs) are essential components of the cellular protein synthesis machineries, but are also implicated in many roles outside translation. To become functional, tRNAs, initially transcribed as longer precursor tRNAs, undergo a tightly controlled biogenesis process comprising the maturation of their extremities, removal of intronic sequences if present, addition of the 3'-CCA amino-acid accepting sequence, and aminoacylation. In addition, the most impressive feature of tRNA biogenesis consists in the incorporation of a large number of posttranscriptional chemical modifications along its sequence. The chemical nature of these modifications is highly diverse, with more than hundred different modifications identified in tRNAs to date. All functions of tRNAs in cells are controlled and modulated by modifications, making the understanding of the mechanisms that determine and influence nucleotide modifications in tRNAs an essential point in tRNA biology. This review describes the different aspects that determine whether a certain position in a tRNA molecule is modified or not. We describe how sequence and structural determinants, as well as the presence of prior modifications control modification processes. We also describe how environmental factors and cellular stresses influence the level and/or the nature of certain modifications introduced in tRNAs, and report situations where these dynamic modulations of tRNA modification levels are regulated by active demodification processes. © 2019 IUBMB Life, 71(8):1126-1140, 2019.
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Affiliation(s)
- Pierre Barraud
- Expression génétique microbienneInstitut de biologie physico‐chimique (IBPC), UMR 8261, CNRS, Université Paris DiderotParisFrance
| | - Carine Tisné
- Expression génétique microbienneInstitut de biologie physico‐chimique (IBPC), UMR 8261, CNRS, Université Paris DiderotParisFrance
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15
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Dixit S, Henderson JC, Alfonzo JD. Multi-Substrate Specificity and the Evolutionary Basis for Interdependence in tRNA Editing and Methylation Enzymes. Front Genet 2019; 10:104. [PMID: 30838029 PMCID: PMC6382703 DOI: 10.3389/fgene.2019.00104] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/30/2019] [Indexed: 12/12/2022] Open
Abstract
Among tRNA modification enzymes there is a correlation between specificity for multiple tRNA substrates and heteromultimerization. In general, enzymes that modify a conserved residue in different tRNA sequences adopt a heterodimeric structure. Presumably, such changes in the oligomeric state of enzymes, to gain multi-substrate recognition, are driven by the need to accommodate and catalyze a particular reaction in different substrates while maintaining high specificity. This review focuses on two classes of enzymes where the case for multimerization as a way to diversify molecular recognition can be made. We will highlight several new themes with tRNA methyltransferases and will also discuss recent findings with tRNA editing deaminases. These topics will be discussed in the context of several mechanisms by which heterodimerization may have been achieved during evolution and how these mechanisms might impact modifications in different systems.
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Affiliation(s)
| | | | - Juan D. Alfonzo
- Department of Microbiology, The Ohio State Biochemistry Program, The Center for RNA Biology, The Ohio State University, Columbus, OH, United States
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16
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7-Methylguanosine Modifications in Transfer RNA (tRNA). Int J Mol Sci 2018; 19:ijms19124080. [PMID: 30562954 PMCID: PMC6320965 DOI: 10.3390/ijms19124080] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/05/2018] [Accepted: 12/13/2018] [Indexed: 01/15/2023] Open
Abstract
More than 90 different modified nucleosides have been identified in tRNA. Among the tRNA modifications, the 7-methylguanosine (m7G) modification is found widely in eubacteria, eukaryotes, and a few archaea. In most cases, the m7G modification occurs at position 46 in the variable region and is a product of tRNA (m7G46) methyltransferase. The m7G46 modification forms a tertiary base pair with C13-G22, and stabilizes the tRNA structure. A reaction mechanism for eubacterial tRNA m7G methyltransferase has been proposed based on the results of biochemical, bioinformatic, and structural studies. However, an experimentally determined mechanism of methyl-transfer remains to be ascertained. The physiological functions of m7G46 in tRNA have started to be determined over the past decade. For example, tRNA m7G46 or tRNA (m7G46) methyltransferase controls the amount of other tRNA modifications in thermophilic bacteria, contributes to the pathogenic infectivity, and is also associated with several diseases. In this review, information of tRNA m7G modifications and tRNA m7G methyltransferases is summarized and the differences in reaction mechanism between tRNA m7G methyltransferase and rRNA or mRNA m7G methylation enzyme are discussed.
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17
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McKenney KM, Rubio MAT, Alfonzo JD. Binding synergy as an essential step for tRNA editing and modification enzyme codependence in Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2018; 24:56-66. [PMID: 29042505 PMCID: PMC5733570 DOI: 10.1261/rna.062893.117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/02/2017] [Indexed: 05/10/2023]
Abstract
Transfer RNAs acquire a variety of naturally occurring chemical modifications during their maturation; these fine-tune their structure and decoding properties in a manner critical for protein synthesis. We recently reported that in the eukaryotic parasite, Trypanosoma brucei, a methylation and deamination event are unexpectedly interconnected, whereby the tRNA adenosine deaminase (TbADAT2/3) and the 3-methylcytosine methyltransferase (TbTrm140) strictly rely on each other for activity, leading to formation of m3C and m3U at position 32 in several tRNAs. Still however, it is not clear why these two enzymes, which work independently in other systems, are strictly codependent in T. brucei Here, we show that these enzymes exhibit binding synergism, or a mutual increase in binding affinity, that is more than the sum of the parts, when added together in a reaction. Although these enzymes interact directly with each other, tRNA binding assays using enzyme variants mutated in critical binding and catalytic sites indicate that the observed binding synergy stems from contributions from tRNA-binding domains distal to their active sites. These results provide a rationale for the known interactions of these proteins, while also speaking to the modulation of substrate specificity between seemingly unrelated enzymes. This information should be of value in furthering our understanding of how tRNA modification enzymes act together to regulate gene expression at the post-transcriptional level and provide a basis for the interdependence of such activities.
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Affiliation(s)
- Katherine M McKenney
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
| | - Mary Anne T Rubio
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Juan D Alfonzo
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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18
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Tomikawa C, Takai K, Hori H. Kinetic characterization of substrate-binding sites of thermostable tRNA methyltransferase (TrmB). J Biochem 2017; 163:133-142. [DOI: 10.1093/jb/mvx068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/01/2017] [Indexed: 11/13/2022] Open
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19
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Abstract
tRNA molecules undergo extensive post-transcriptional processing to generate the mature functional tRNA species that are essential for translation in all organisms. These processing steps include the introduction of numerous specific chemical modifications to nucleotide bases and sugars; among these modifications, methylation reactions are by far the most abundant. The tRNA methyltransferases comprise a diverse enzyme superfamily, including members of multiple structural classes that appear to have arisen independently during evolution. Even among closely related family members, examples of unusual substrate specificity and chemistry have been observed. Here we review recent advances in tRNA methyltransferase mechanism and function with a particular emphasis on discoveries of alternative substrate specificities and chemistry associated with some methyltransferases. Although the molecular function for a specific tRNA methylation may not always be clear, mutations in tRNA methyltransferases have been increasingly associated with human disease. The impact of tRNA methylation on human biology is also discussed.
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Affiliation(s)
- William E Swinehart
- a Center for RNA Biology and Department of Chemistry and Biochemistry ; Ohio State University ; Columbus , OH USA
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20
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Abstract
tRNA modifications are crucial for efficient and accurate protein translation, with defects often linked to disease. There are 7 cytoplasmic tRNA modifications in the yeast Saccharomyces cerevisiae that are formed by an enzyme consisting of a catalytic subunit and an auxiliary protein, 5 of which require only a single subunit in bacteria, and 2 of which are not found in bacteria. These enzymes include the deaminase Tad2-Tad3, and the methyltransferases Trm6-Trm61, Trm8-Trm82, Trm7-Trm732, and Trm7-Trm734, Trm9-Trm112, and Trm11-Trm112. We describe the occurrence and biological role of each modification, evidence for a required partner protein in S. cerevisiae and other eukaryotes, evidence for a single subunit in bacteria, and evidence for the role of the non-catalytic binding partner. Although it is unclear why these eukaryotic enzymes require partner proteins, studies of some 2-subunit modification enzymes suggest that the partner proteins help expand substrate range or allow integration of cellular activities.
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Affiliation(s)
- Michael P Guy
- a Department of Biochemistry and Biophysics; Center for RNA Biology ; University of Rochester School of Medicine ; Rochester , NY USA
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21
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Takuma H, Ushio N, Minoji M, Kazayama A, Shigi N, Hirata A, Tomikawa C, Ochi A, Hori H. Substrate tRNA recognition mechanism of eubacterial tRNA (m1A58) methyltransferase (TrmI). J Biol Chem 2015; 290:5912-25. [PMID: 25593312 DOI: 10.1074/jbc.m114.606038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TrmI generates N(1)-methyladenosine at position 58 (m(1)A58) in tRNA. The Thermus thermophilus tRNA(Phe) transcript was methylated efficiently by T. thermophilus TrmI, whereas the yeast tRNA(Phe) transcript was poorly methylated. Fourteen chimeric tRNA transcripts derived from these two tRNAs revealed that TrmI recognized the combination of aminoacyl stem, variable region, and T-loop. This was confirmed by 10 deletion tRNA variants: TrmI methylated transcripts containing the aminoacyl stem, variable region, and T-arm. The requirement for the T-stem itself was confirmed by disrupting the T-stem. Disrupting the interaction between T- and D-arms accelerated the methylation, suggesting that this disruption is included in part of the reaction. Experiments with 17 point mutant transcripts elucidated the positive sequence determinants C56, purine 57, A58, and U60. Replacing A58 with inosine and 2-aminopurine completely abrogated methylation, demonstrating that the 6-amino group in A58 is recognized by TrmI. T. thermophilus tRNAGGU(Thr)GGU(Thr) contains C60 instead of U60. The tRNAGGU(Thr) transcript was poorly methylated by TrmI, and replacing C60 with U increased the methylation, consistent with the point mutation experiments. A gel shift assay revealed that tRNAGGU(Thr) had a low affinity for TrmI than tRNA(Phe). Furthermore, analysis of tRNAGGU(Thr) purified from the trmI gene disruptant strain revealed that the other modifications in tRNA accelerated the formation of m(1)A58 by TrmI. Moreover, nucleoside analysis of tRNAGGU(Thr) from the wild-type strain indicated that less than 50% of tRNAGG(Thr) contained m(1)A58. Thus, the results from the in vitro experiments were confirmed by the in vivo methylation patterns.
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Affiliation(s)
- Hiroyuki Takuma
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Natsumi Ushio
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Masayuki Minoji
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Ai Kazayama
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Naoki Shigi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Akira Hirata
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Chie Tomikawa
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Anna Ochi
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
| | - Hiroyuki Hori
- From the Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan and
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22
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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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23
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Collinet B, Friberg A, Brooks MA, van den Elzen T, Henriot V, Dziembowski A, Graille M, Durand D, Leulliot N, Saint André C, Lazar N, Sattler M, Séraphin B, van Tilbeurgh H. Strategies for the structural analysis of multi-protein complexes: lessons from the 3D-Repertoire project. J Struct Biol 2011; 175:147-58. [PMID: 21463689 DOI: 10.1016/j.jsb.2011.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/18/2011] [Accepted: 03/19/2011] [Indexed: 11/25/2022]
Abstract
Structural studies of multi-protein complexes, whether by X-ray diffraction, scattering, NMR spectroscopy or electron microscopy, require stringent quality control of the component samples. The inability to produce 'keystone' subunits in a soluble and correctly folded form is a serious impediment to the reconstitution of the complexes. Co-expression of the components offers a valuable alternative to the expression of single proteins as a route to obtain sufficient amounts of the sample of interest. Even in cases where milligram-scale quantities of purified complex of interest become available, there is still no guarantee that good quality crystals can be obtained. At this step, protein engineering of one or more components of the complex is frequently required to improve solubility, yield or the ability to crystallize the sample. Subsequent characterization of these constructs may be performed by solution techniques such as Small Angle X-ray Scattering and Nuclear Magnetic Resonance to identify 'well behaved' complexes. Herein, we recount our experiences gained at protein production and complex assembly during the European 3D Repertoire project (3DR). The goal of this consortium was to obtain structural information on multi-protein complexes from yeast by combining crystallography, electron microscopy, NMR and in silico modeling methods. We present here representative set case studies of complexes that were produced and analyzed within the 3DR project. Our experience provides useful insight into strategies that are more generally applicable for structural analysis of protein complexes.
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Affiliation(s)
- B Collinet
- IBBMC-CNRS UMR8619, IFR 115, Bât. 430, Université Paris-Sud, 91405 Orsay, France
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24
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Tomikawa C, Yokogawa T, Kanai T, Hori H. N7-Methylguanine at position 46 (m7G46) in tRNA from Thermus thermophilus is required for cell viability at high temperatures through a tRNA modification network. Nucleic Acids Res 2010; 38:942-57. [PMID: 19934251 PMCID: PMC2817472 DOI: 10.1093/nar/gkp1059] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/24/2009] [Accepted: 10/26/2009] [Indexed: 02/06/2023] Open
Abstract
N(7)-methylguanine at position 46 (m(7)G46) in tRNA is produced by tRNA (m(7)G46) methyltransferase (TrmB). To clarify the role of this modification, we made a trmB gene disruptant (DeltatrmB) of Thermus thermophilus, an extreme thermophilic eubacterium. The absence of TrmB activity in cell extract from the DeltatrmB strain and the lack of the m(7)G46 modification in tRNA(Phe) were confirmed by enzyme assay, nucleoside analysis and RNA sequencing. When the DeltatrmB strain was cultured at high temperatures, several modified nucleotides in tRNA were hypo-modified in addition to the lack of the m(7)G46 modification. Assays with tRNA modification enzymes revealed hypo-modifications of Gm18 and m(1)G37, suggesting that the m(7)G46 positively affects their formations. Although the lack of the m(7)G46 modification and the hypo-modifications do not affect the Phe charging activity of tRNA(Phe), they cause a decrease in melting temperature of class I tRNA and degradation of tRNA(Phe) and tRNA(Ile). (35)S-Met incorporation into proteins revealed that protein synthesis in DeltatrmB cells is depressed above 70 degrees C. At 80 degrees C, the DeltatrmB strain exhibits a severe growth defect. Thus, the m(7)G46 modification is required for cell viability at high temperatures via a tRNA modification network, in which the m(7)G46 modification supports introduction of other modifications.
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Affiliation(s)
- Chie Tomikawa
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, Kyoto 615-8510, Venture Business Laboratory, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577 and RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyougo 679-5148, Japan
| | - Takashi Yokogawa
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, Kyoto 615-8510, Venture Business Laboratory, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577 and RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyougo 679-5148, Japan
| | - Tamotsu Kanai
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, Kyoto 615-8510, Venture Business Laboratory, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577 and RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyougo 679-5148, Japan
| | - Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, Kyoto 615-8510, Venture Business Laboratory, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577 and RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyougo 679-5148, Japan
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25
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Hori H. Synthesis of a hetero subunit RNA modification enzyme by the wheat germ cell-free translation system. Methods Mol Biol 2010; 607:173-185. [PMID: 20204857 DOI: 10.1007/978-1-60327-331-2_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cell-free translation systems are a powerful tool for the production of many kinds of proteins. However, there are some barriers to improve the system in order to make it a more convenient approach. These include the fact that the production of proteins made up of hetero subunits is difficult. In this chapter, we describe the synthesis of yeast tRNA (m(7)G46) methyltransferase as a model protein. This enzyme catalyzes transfer of a methyl group from S-adenosyl-L-methionine to guanine at position 46 in tRNA and generates N(7)-methylguanine. Yeast tRNA (m(7)G46) methyltransferase is composed of two protein subunits, Trm8 and Trm82. To obtain the active Trm8-Trm82 complex, co-translation of both subunits is necessary. Preparation of mRNAs, in vitro synthesis and purification of the complex are explained in this chapter.
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Affiliation(s)
- Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Sciences and Engineering, Ehime University, Ehime, Japan
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26
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Tomikawa C, Ochi A, Hori H. The C-terminal region of thermophilic tRNA (m7G46) methyltransferase (TrmB) stabilizes the dimer structure and enhances fidelity of methylation. Proteins 2008; 71:1400-8. [PMID: 18076049 DOI: 10.1002/prot.21827] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transfer RNA (m(7)G46) methyltransferase catalyzes methyl-transfer from S-adenosyl-L-methionine to N(7) atom of the semi-conserved G46 base in tRNA. Aquifex aeolicus is a hyper thermophilic eubacterium that grows at close to 95 degrees C. A. aeolicus tRNA (m(7)G46) methyltransferase [TrmB] has an elongated C-terminal region as compared with mesophilic counterparts. In this study, the authors focused on the functions of this C-terminal region. Analytic gel filtration chromatography and amino acid sequencing reveled that the start point (Glu202) of the C-terminal region is often cleaved by proteases during purification steps and the C-terminal region tightly binds to another subunit even in the presence of 6M urea. Because the C-terminal region contains abundant basic amino acid residues, the authors assumed that some of these residues might be involved in tRNA binding. To address this idea, the authors prepared eight alanine substitution mutant proteins. However, measurements of initial velocities of these mutant proteins suggested that the basic amino acid residues in the C-terminal region are not involved in tRNA binding. The authors investigated effects of the deletion of the C-terminal region. Deletion mutant protein of the C-terminal region (the core protein) was precipitated by incubation at 85 degrees C, while the wild type protein was soluble at that temperature, demonstrating that the C-terminal region contributes to the protein stability at high temperatures. The core protein had a methyl-transfer activity to yeast tRNA(Phe) transcript. Furthermore, the core protein slowly methylated tRNA transcripts, which did not contain G46 base. Moreover, the modified base was identified as m(7)G by two-dimensional thin layer chromatography. Thus, the deletion of the C-terminal region causes nonspecific methylation of N(7) atom of guanine base(s) in tRNA transcripts.
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Affiliation(s)
- Chie Tomikawa
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama 790-8577, Japan
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Structure of the Yeast tRNA m7G Methylation Complex. Structure 2008; 16:52-61. [DOI: 10.1016/j.str.2007.10.025] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2007] [Revised: 10/19/2007] [Accepted: 10/19/2007] [Indexed: 11/17/2022]
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Matsumoto K, Tomikawa C, Toyooka T, Ochi A, Takano Y, Takayanagi N, Abe M, Endo Y, Hori H. Production of yeast tRNA (m(7)G46) methyltransferase (Trm8-Trm82 complex) in a wheat germ cell-free translation system. J Biotechnol 2007; 133:453-60. [PMID: 18164779 DOI: 10.1016/j.jbiotec.2007.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/29/2007] [Accepted: 11/13/2007] [Indexed: 11/16/2022]
Abstract
Cell-free translation systems are a powerful tool for the production of many kinds of proteins. However the production of proteins made up of hetero subunits is a major problem. In this study, we selected yeast tRNA (m(7)G46) methyltransferase (Trm8-Trm82 heterodimer) as a model protein. The enzyme catalyzes a methyl-transfer from S-adenosyl-l-methionine to the N(7) atom of guanine at position 46 in tRNA. When Trm8 or Trm82 mRNA were used for cell-free translation, Trm8 and Trm82 proteins could be synthesized. Upon mixing the synthesized Trm8 and Trm82 proteins, no active Trm8-Trm82 heterodimer was produced. Active Trm8-Trm82 heterodimer was only synthesized under conditions, in which both Trm8 and Trm82 mRNAs were co-translated. These results strongly suggest that the association of the Trm8 and Trm82 subunits is translationally controlled in living cells. Kinetic parameters of purified Trm8-Trm82 heterodimer were measured and these showed that the protein has comparable activity to other tRNA methyltransferases. The production of the m(7)G base at position 46 in tRNA was confirmed by two-dimensional thin layer chromatography and aniline cleavage of the methylated tRNA.
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Affiliation(s)
- Keisuke Matsumoto
- Department of Applied Chemistry, Faculty of Engineering, Ehime University, Bunkyo 3, Matsuyama 790-8577, Japan
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