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Iñigo S, Durand AN, Ritter A, Le Gall S, Termathe M, Klassen R, Tohge T, De Coninck B, Van Leene J, De Clercq R, Cammue BPA, Fernie AR, Gevaert K, De Jaeger G, Leidel SA, Schaffrath R, Van Lijsebettens M, Pauwels L, Goossens A. Glutaredoxin GRXS17 Associates with the Cytosolic Iron-Sulfur Cluster Assembly Pathway. PLANT PHYSIOLOGY 2016; 172:858-873. [PMID: 27503603 PMCID: PMC5047072 DOI: 10.1104/pp.16.00261] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/03/2016] [Indexed: 05/12/2023]
Abstract
Cytosolic monothiol glutaredoxins (GRXs) are required in iron-sulfur (Fe-S) cluster delivery and iron sensing in yeast and mammals. In plants, it is unclear whether they have similar functions. Arabidopsis (Arabidopsis thaliana) has a sole class II cytosolic monothiol GRX encoded by GRXS17 Here, we used tandem affinity purification to establish that Arabidopsis GRXS17 associates with most known cytosolic Fe-S assembly (CIA) components. Similar to mutant plants with defective CIA components, grxs17 loss-of-function mutants showed some degree of hypersensitivity to DNA damage and elevated expression of DNA damage marker genes. We also found that several putative Fe-S client proteins directly bind to GRXS17, such as XANTHINE DEHYDROGENASE1 (XDH1), involved in the purine salvage pathway, and CYTOSOLIC THIOURIDYLASE SUBUNIT1 and CYTOSOLIC THIOURIDYLASE SUBUNIT2, both essential for the 2-thiolation step of 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) modification of tRNAs. Correspondingly, profiling of the grxs17-1 mutant pointed to a perturbed flux through the purine degradation pathway and revealed that it phenocopied mutants in the elongator subunit ELO3, essential for the mcm5 tRNA modification step, although we did not find XDH1 activity or tRNA thiolation to be markedly reduced in the grxs17-1 mutant. Taken together, our data suggest that plant cytosolic monothiol GRXs associate with the CIA complex, as in other eukaryotes, and contribute to, but are not essential for, the correct functioning of client Fe-S proteins in unchallenged conditions.
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Affiliation(s)
- Sabrina Iñigo
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Astrid Nagels Durand
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Andrés Ritter
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Sabine Le Gall
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Martin Termathe
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Roland Klassen
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Takayuki Tohge
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Barbara De Coninck
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Jelle Van Leene
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Rebecca De Clercq
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Bruno P A Cammue
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Alisdair R Fernie
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Kris Gevaert
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Geert De Jaeger
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Sebastian A Leidel
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Raffael Schaffrath
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Mieke Van Lijsebettens
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Laurens Pauwels
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
| | - Alain Goossens
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., B.D.C., J.V.L., R.D.C., B.P.A.C., G.D.J., M.V.L., L.P., A.G.);Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium (S.I., A.N.D., A.R., S.L.G., J.V.L., R.D.C., G.D.J., M.V.L., L.P., A.G.);Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany (M.T., S.A.L.);Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, D-34132 Kassel, Germany (R.K., R.S.);Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany (T.T., A.R.F.);Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium (B.D.C., B.P.A.C.);Cells-in-Motion Cluster of Excellence (M.T., S.A.L.) and Faculty of Medicine (S.A.L.), University of Muenster, 48149 Muenster, Germany;Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium (K.G.); andDepartment of Biochemistry, Ghent University, B-9000 Ghent, Belgium (K.G.)
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Deng W, Babu IR, Su D, Yin S, Begley TJ, Dedon PC. Trm9-Catalyzed tRNA Modifications Regulate Global Protein Expression by Codon-Biased Translation. PLoS Genet 2015; 11:e1005706. [PMID: 26670883 PMCID: PMC4689569 DOI: 10.1371/journal.pgen.1005706] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/06/2015] [Indexed: 12/30/2022] Open
Abstract
Post-transcriptional modifications of transfer RNAs (tRNAs) have long been recognized to play crucial roles in regulating the rate and fidelity of translation. However, the extent to which they determine global protein production remains poorly understood. Here we use quantitative proteomics to show a direct link between wobble uridine 5-methoxycarbonylmethyl (mcm5) and 5-methoxy-carbonyl-methyl-2-thio (mcm5s2) modifications catalyzed by tRNA methyltransferase 9 (Trm9) in tRNAArg(UCU) and tRNAGlu(UUC) and selective translation of proteins from genes enriched with their cognate codons. Controlling for bias in protein expression and alternations in mRNA expression, we find that loss of Trm9 selectively impairs expression of proteins from genes enriched with AGA and GAA codons under both normal and stress conditions. Moreover, we show that AGA and GAA codons occur with high frequency in clusters along the transcripts, which may play a role in modulating translation. Consistent with these results, proteins subject to enhanced ribosome pausing in yeast lacking mcm5U and mcm5s2U are more likely to be down-regulated and contain a larger number of AGA/GAA clusters. Together, these results suggest that Trm9-catalyzed tRNA modifications play a significant role in regulating protein expression within the cell. Here we present evidence for a more complicated role for transfer RNAs (tRNAs) than as mere adapters that link the genetic code in messenger RNA (mRNA) to the amino acid sequence of a protein during translation. tRNAs have long been known to be modified with dozens of different chemical structures other than the 4 canonical ribonucleosides, though the role of these modifications in controlling translation is poorly understood. By quantifying the expression of thousands of proteins in the yeast S. cerevisiae, we identified a mechanistic link between modified ribonucleosides located at the wobble position of two tRNAs, tRNAArg(UCU) and tRNAGlu(UUC), and the translation of proteins derived from genes enriched with codons read by these tRNAs: AGA and GAA. In cells lacking the enzyme that inserts these modifications, tRNA methyltransferase 9 (Trm9), we found a significant reduction in proteins from genes enriched with AGA and GAA codons and with runs of these codons. Also, mRNAs enriched with runs of AGA and GAA codons are subject to stalled translation on ribosomes in yeast lacking mcm5U and mcm5s2U. Together, these results reveal a distinct role for Trm9-catalyzed tRNA modifications in selectively regulating the expression of proteins enriched with AGA and GAA codons.
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Affiliation(s)
- Wenjun Deng
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - I. Ramesh Babu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Dan Su
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Shanye Yin
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thomas J. Begley
- SUNY College of Nanoscale Science and Engineering, Albany, New York, United States of America
- RNA Institute and Cancer Research Center, University at Albany, State University of New York, Albany, New York, United States of America
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Singapore-MIT Alliance for Research and Technology, Singapore
- * E-mail:
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53
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Endres L, Dedon PC, Begley TJ. Codon-biased translation can be regulated by wobble-base tRNA modification systems during cellular stress responses. RNA Biol 2015; 12:603-14. [PMID: 25892531 DOI: 10.1080/15476286.2015.1031947] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
tRNA (tRNA) is a key molecule used for protein synthesis, with multiple points of stress-induced regulation that can include transcription, transcript processing, localization and ribonucleoside base modification. Enzyme-catalyzed modification of tRNA occurs at a number of base and sugar positions and has the potential to influence specific anticodon-codon interactions and regulate translation. Notably, altered tRNA modification has been linked to mitochondrial diseases and cancer progression. In this review, specific to Eukaryotic systems, we discuss how recent systems-level analyses using a bioanalytical platform have revealed that there is extensive reprogramming of tRNA modifications in response to cellular stress and during cell cycle progression. Combined with genome-wide codon bias analytics and gene expression studies, a model emerges in which stress-induced reprogramming of tRNA drives the translational regulation of critical response proteins whose transcripts display a distinct codon bias. Termed Modification Tunable Transcripts (MoTTs), (1) we define them as (1) transcripts that use specific degenerate codons and codon biases to encode critical stress response proteins, and (2) transcripts whose translation is influenced by changes in wobble base tRNA modification. In this review we note that the MoTTs translational model is also applicable to the process of stop-codon recoding for selenocysteine incorporation, as stop-codon recoding involves a selective codon bias and modified tRNA to decode selenocysteine during the translation of a key subset of oxidative stress response proteins. Further, we discuss how in addition to RNA modification analytics, the comprehensive characterization of translational regulation of specific transcripts requires a variety of tools, including high coverage codon-reporters, ribosome profiling and linked genomic and proteomic approaches. Together these tools will yield important new insights into the role of translational elongation in cell stress response.
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Affiliation(s)
- Lauren Endres
- a College of Nanoscale Science and Engineering; State University of New York ; Albany , NY USA
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54
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Ramírez V, Gonzalez B, López A, Castelló MJ, Gil MJ, Zheng B, Chen P, Vera P. Loss of a Conserved tRNA Anticodon Modification Perturbs Plant Immunity. PLoS Genet 2015; 11:e1005586. [PMID: 26492405 PMCID: PMC4619653 DOI: 10.1371/journal.pgen.1005586] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 09/16/2015] [Indexed: 12/20/2022] Open
Abstract
tRNA is the most highly modified class of RNA species, and modifications are found in tRNAs from all organisms that have been examined. Despite their vastly different chemical structures and their presence in different tRNAs, occurring in different locations in tRNA, the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent discoveries have revealed unprecedented complexity in the modification patterns of tRNA, their regulation and function, suggesting that each modified nucleoside in tRNA may have its own specific function. However, in plants, our knowledge on the role of individual tRNA modifications and how they are regulated is very limited. In a genetic screen designed to identify factors regulating disease resistance and activation of defenses in Arabidopsis, we identified SUPPRESSOR OF CSB3 9 (SCS9). Our results reveal SCS9 encodes a tRNA methyltransferase that mediates the 2´-O-ribose methylation of selected tRNA species in the anticodon loop. These SCS9-mediated tRNA modifications enhance during the course of infection with the bacterial pathogen Pseudomonas syringae DC3000, and lack of such tRNA modification, as observed in scs9 mutants, severely compromise plant immunity against the same pathogen without affecting the salicylic acid (SA) signaling pathway which regulates plant immune responses. Our results support a model that gives importance to the control of certain tRNA modifications for mounting an effective immune response in Arabidopsis, and therefore expands the repertoire of molecular components essential for an efficient disease resistance response. Numerous studies revealed the existence of nearly 110 ribonucleoside structures incorporated as post-transcriptional modifications in tRNA, with 25–30 modifications present in any one organism. Emerging evidence points to the critical role of tRNA modifications in various cellular responses to stimuli, including transcription of stress response genes and control of cell viability and growth. The primary function of tRNA modifications, and in particular tRNA methylations, are linked to different steps in protein synthesis including stabilization of tRNA structures, reinforcement of the codon-anticodon interaction, regulation of wobble base pairing, and prevention of frameshift errors. Furthermore, tRNA methylations are involved in the RNA quality control system and regulation of tRNA localization in the cell, all of which affect translation rate, but modifications in the anti-codon, which exhibit important roles in decoding mRNA are particularly important. We identified that the SCS9 gene from Arabidopsis encodes a tRNA 2´-O-ribose methyltransferase homologous to the TRM7 methyltransferase from yeast. We identify that SCS9 is crucial for the 2´-O-ribose methylation of nucleotides 32 and 34 of the tRNAs anticodon loop of certain tRNA molecules. We show that SCS9 is required for effectiveness of plant immunity and suggest the importance of precise tRNA modifications in this process.
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Affiliation(s)
- Vicente Ramírez
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain
| | - Beatriz Gonzalez
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain
| | - Ana López
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain
| | - María José Castelló
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain
| | - María José Gil
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain
| | - Bo Zheng
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Peng Chen
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, HuaZhong Agricultural University, Wuhan, China
| | - Pablo Vera
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C, Ciudad Politécnica de la Innovación, Valencia, Spain
- * E-mail:
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55
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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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56
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Karlsborn T, Tükenmez H, Mahmud AKMF, Xu F, Xu H, Byström AS. Elongator, a conserved complex required for wobble uridine modifications in eukaryotes. RNA Biol 2015; 11:1519-28. [PMID: 25607684 DOI: 10.4161/15476286.2014.992276] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Elongator is a 6 subunit protein complex highly conserved in eukaryotes. The role of this complex has been controversial as the pleiotropic phenotypes of Elongator mutants have implicated the complex in several cellular processes. However, in yeast there is convincing evidence that the primary and probably only role of this complex is in formation of the 5-methoxycarbonylmethyl (mcm(5)) and 5-carbamoylmethyl (ncm(5)) side chains on uridines at wobble position in tRNA. In this review we summarize the cellular processes that have been linked to the Elongator complex and discuss its role in tRNA modification and regulation of translation. We also describe additional gene products essential for formation of ncm(5) and mcm(5) side chains at U34 and their influence on Elongator activity.
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Affiliation(s)
- Tony Karlsborn
- a Department of Molecular Biology ; Umeå University; Umeå , Sweden
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57
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Létoquart J, van Tran N, Caroline V, Aleksandrov A, Lazar N, van Tilbeurgh H, Liger D, Graille M. Insights into molecular plasticity in protein complexes from Trm9-Trm112 tRNA modifying enzyme crystal structure. Nucleic Acids Res 2015; 43:10989-1002. [PMID: 26438534 PMCID: PMC4678810 DOI: 10.1093/nar/gkv1009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 09/24/2015] [Indexed: 11/15/2022] Open
Abstract
Most of the factors involved in translation (tRNA, rRNA and proteins) are subject to post-transcriptional and post-translational modifications, which participate in the fine-tuning and tight control of ribosome and protein synthesis processes. In eukaryotes, Trm112 acts as an obligate activating platform for at least four methyltransferases (MTase) involved in the modification of 18S rRNA (Bud23), tRNA (Trm9 and Trm11) and translation termination factor eRF1 (Mtq2). Trm112 is then at a nexus between ribosome synthesis and function. Here, we present a structure-function analysis of the Trm9-Trm112 complex, which is involved in the 5-methoxycarbonylmethyluridine (mcm5U) modification of the tRNA anticodon wobble position and hence promotes translational fidelity. We also compare the known crystal structures of various Trm112-MTase complexes, highlighting the structural plasticity allowing Trm112 to interact through a very similar mode with its MTase partners, although those share less than 20% sequence identity.
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Affiliation(s)
- Juliette Létoquart
- Laboratoire de Biochimie, CNRS, UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France Fonction et Architecture des Assemblages Macromoléculaires, Département B3S, Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, UMR 9198, CEA, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Nhan van Tran
- Laboratoire de Biochimie, CNRS, UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France
| | - Vonny Caroline
- Laboratoire de Biochimie, CNRS, UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France
| | - Alexey Aleksandrov
- Laboratoire de Biochimie, CNRS, UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France
| | - Noureddine Lazar
- Fonction et Architecture des Assemblages Macromoléculaires, Département B3S, Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, UMR 9198, CEA, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Herman van Tilbeurgh
- Fonction et Architecture des Assemblages Macromoléculaires, Département B3S, Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, UMR 9198, CEA, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Dominique Liger
- Fonction et Architecture des Assemblages Macromoléculaires, Département B3S, Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, UMR 9198, CEA, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Marc Graille
- Laboratoire de Biochimie, CNRS, UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France Fonction et Architecture des Assemblages Macromoléculaires, Département B3S, Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, UMR 9198, CEA, Université Paris Sud, F-91405 Orsay Cedex, France
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58
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Wemhoff S, Klassen R, Meinhardt F. DNA damage induced by the anticodon nuclease from a Pichia acaciae killer strain is linked to ribonucleotide reductase depletion. Cell Microbiol 2015; 18:211-22. [PMID: 26247322 DOI: 10.1111/cmi.12496] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/24/2015] [Accepted: 07/26/2015] [Indexed: 11/30/2022]
Abstract
Virus like element (VLE) encoded killer toxins of Pichia acaciae and Kluyveromyces lactis kill target cells through anticodon nuclease (ACNase) activity directed against tRNA(Gln) and tRNA(Glu) respectively. Not only does tRNA cleavage disable translation, it also affects DNA integrity as well. Consistent with DNA damage, which is involved in toxicity, target cells' mutation frequencies are elevated upon ACNase exposure, suggesting a link between translational integrity and genome surveillance. Here, we analysed whether ACNase action impedes the periodically and highly expressed S-phase specific ribonucleotide reductase (RNR) and proved that RNR expression is severely affected by PaT. Because RNR catalyses the rate-limiting step in dNTP synthesis, mutants affected in dNTP synthesis were scrutinized with respect to ACNase action. Mutations elevating cellular dNTPs antagonized the action of both the above ACNases, whereas mutations lowering dNTPs aggravated toxicity. Consistently, prevention of tRNA cleavage in elp3 or trm9 mutants, which both affect the wobble uridine modification of the target tRNA, suppressed the toxin hypersensitivity of a dNTP synthesis mutant. Moreover, dNTP synthesis defects exacerbated the PaT ACNase sensitivity of cells defective in homologous recombination, proving that dNTP depletion is responsible for subsequent DNA damage.
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Affiliation(s)
- Sabrina Wemhoff
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| | - Roland Klassen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| | - Friedhelm Meinhardt
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
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59
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Tükenmez H, Xu H, Esberg A, Byström AS. The role of wobble uridine modifications in +1 translational frameshifting in eukaryotes. Nucleic Acids Res 2015; 43:9489-99. [PMID: 26283182 PMCID: PMC4627075 DOI: 10.1093/nar/gkv832] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 08/06/2015] [Indexed: 12/31/2022] Open
Abstract
In Saccharomyces cerevisiae, 11 out of 42 tRNA species contain 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U), 5-methoxycarbonylmethyluridine (mcm(5)U), 5-carbamoylmethyluridine (ncm(5)U) or 5-carbamoylmethyl-2'-O-methyluridine (ncm(5)Um) nucleosides in the anticodon at the wobble position (U34). Earlier we showed that mutants unable to form the side chain at position 5 (ncm(5) or mcm(5)) or lacking sulphur at position 2 (s(2)) of U34 result in pleiotropic phenotypes, which are all suppressed by overexpression of hypomodified tRNAs. This observation suggests that the observed phenotypes are due to inefficient reading of cognate codons or an increased frameshifting. The latter may be caused by a ternary complex (aminoacyl-tRNA*eEF1A*GTP) with a modification deficient tRNA inefficiently being accepted to the ribosomal A-site and thereby allowing an increased peptidyl-tRNA slippage and thus a frameshift error. In this study, we have investigated the role of wobble uridine modifications in reading frame maintenance, using either the Renilla/Firefly luciferase bicistronic reporter system or a modified Ty1 frameshifting site in a HIS4A::lacZ reporter system. We here show that the presence of mcm(5) and s(2) side groups at wobble uridines are important for reading frame maintenance and thus the aforementioned mutant phenotypes might partly be due to frameshift errors.
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Affiliation(s)
- Hasan Tükenmez
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Hao Xu
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Anders Esberg
- Department of Odontology/Cariology, Umeå University, Umeå, 901 87, Sweden
| | - Anders S Byström
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
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60
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Endres L, Begley U, Clark R, Gu C, Dziergowska A, Małkiewicz A, Melendez JA, Dedon PC, Begley TJ. Alkbh8 Regulates Selenocysteine-Protein Expression to Protect against Reactive Oxygen Species Damage. PLoS One 2015; 10:e0131335. [PMID: 26147969 PMCID: PMC4492958 DOI: 10.1371/journal.pone.0131335] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 06/01/2015] [Indexed: 01/12/2023] Open
Abstract
Environmental and metabolic sources of reactive oxygen species (ROS) can damage DNA, proteins and lipids to promote disease. Regulation of gene expression can prevent this damage and can include increased transcription, translation and post translational modification. Cellular responses to ROS play important roles in disease prevention, with deficiencies linked to cancer, neurodegeneration and ageing. Here we detail basal and damage-induced translational regulation of a group of oxidative-stress response enzymes by the tRNA methyltransferase Alkbh8. Using a new gene targeted knockout mouse cell system, we show that Alkbh8-/- embryonic fibroblasts (MEFs) display elevated ROS levels, increased DNA and lipid damage and hallmarks of cellular stress. We demonstrate that Alkbh8 is induced in response to ROS and is required for the efficient expression of selenocysteine-containing ROS detoxification enzymes belonging to the glutathione peroxidase (Gpx1, Gpx3, Gpx6 and likely Gpx4) and thioredoxin reductase (TrxR1) families. We also show that, in response to oxidative stress, the tRNA modification 5-methoxycarbonylmethyl-2′-O-methyluridine (mcm5Um) increases in normal MEFs to drive the expression of ROS detoxification enzymes, with this damage-induced reprogramming of tRNA and stop-codon recoding corrupted in Alkbh8-/- MEFS. These studies define Alkbh8 and tRNA modifications as central regulators of cellular oxidative stress responses in mammalian systems. In addition they highlight a new animal model for use in environmental and cancer studies and link translational regulation to the prevention of DNA and lipid damage.
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Affiliation(s)
- Lauren Endres
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America
- RNA Institute and Cancer Research Center, University at Albany, State University of New York, Albany, New York 12222, United States of America
| | - Ulrike Begley
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America
| | - Ryan Clark
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America
| | - Chen Gu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States of America
| | | | - Andrzej Małkiewicz
- Institute of Organic Chemistry, Lodz University of Technology, Lodz, Poland
| | - J. Andres Melendez
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States of America
- Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States of America
| | - Thomas J. Begley
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America
- RNA Institute and Cancer Research Center, University at Albany, State University of New York, Albany, New York 12222, United States of America
- * E-mail:
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61
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Klassen R, Grunewald P, Thüring KL, Eichler C, Helm M, Schaffrath R. Loss of anticodon wobble uridine modifications affects tRNA(Lys) function and protein levels in Saccharomyces cerevisiae. PLoS One 2015; 10:e0119261. [PMID: 25747122 PMCID: PMC4352028 DOI: 10.1371/journal.pone.0119261] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 01/22/2015] [Indexed: 11/22/2022] Open
Abstract
In eukaryotes, wobble uridines in the anticodons of tRNALysUUU, tRNAGluUUC and tRNAGlnUUG are modified to 5-methoxy-carbonyl-methyl-2-thio-uridine (mcm5s2U). While mutations in subunits of the Elongator complex (Elp1-Elp6), which disable mcm5 side chain formation, or removal of components of the thiolation pathway (Ncs2/Ncs6, Urm1, Uba4) are individually tolerated, the combination of both modification defects has been reported to have lethal effects on Saccharomyces cerevisiae. Contrary to such absolute requirement of mcm5s2U for viability, we demonstrate here that in the S. cerevisiae S288C-derived background, both pathways can be simultaneously inactivated, resulting in combined loss of tRNA anticodon modifications (mcm5U and s2U) without a lethal effect. However, an elp3 disruption strain displays synthetic sick interaction and synergistic temperature sensitivity when combined with either uba4 or urm1 mutations, suggesting major translational defects in the absence of mcm5s2U modifications. Consistent with this notion, we find cellular protein levels drastically decreased in an elp3uba4 double mutant and show that this effect as well as growth phenotypes can be partially rescued by excess of tRNALysUUU. These results may indicate a global translational or protein homeostasis defect in cells simultaneously lacking mcm5 and s2 wobble uridine modification that could account for growth impairment and mainly originates from tRNALysUUU hypomodification and malfunction.
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Affiliation(s)
- Roland Klassen
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Kassel, Germany
- * E-mail: (RK); (RS)
| | - Pia Grunewald
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Kassel, Germany
| | - Kathrin L. Thüring
- Institut für Pharmazie und Biochemie, Johannes Gutenberg Universität Mainz, Mainz, Germany
| | - Christian Eichler
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Kassel, Germany
| | - Mark Helm
- Institut für Pharmazie und Biochemie, Johannes Gutenberg Universität Mainz, Mainz, Germany
| | - Raffael Schaffrath
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Kassel, Germany
- * E-mail: (RK); (RS)
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62
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Kazayama A, Yamagami R, Yokogawa T, Hori H. Improved solid-phase DNA probe method for tRNA purification: large-scale preparation and alteration of DNA fixation. J Biochem 2015; 157:411-8. [DOI: 10.1093/jb/mvu089] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/02/2014] [Indexed: 11/12/2022] Open
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63
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Guy MP, Phizicky EM. Conservation of an intricate circuit for crucial modifications of the tRNAPhe anticodon loop in eukaryotes. RNA (NEW YORK, N.Y.) 2015; 21:61-74. [PMID: 25404562 PMCID: PMC4274638 DOI: 10.1261/rna.047639.114] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Post-transcriptional tRNA modifications are critical for efficient and accurate translation, and have multiple different roles. Lack of modifications often leads to different biological consequences in different organisms, and in humans is frequently associated with neurological disorders. We investigate here the conservation of a unique circuitry for anticodon loop modification required for healthy growth in the yeast Saccharomyces cerevisiae. S. cerevisiae Trm7 interacts separately with Trm732 and Trm734 to 2'-O-methylate three substrate tRNAs at anticodon loop residues C₃₂ and N₃₄, and these modifications are required for efficient wybutosine formation at m(1)G₃₇ of tRNA(Phe). Moreover, trm7Δ and trm732Δ trm734Δ mutants grow poorly due to lack of functional tRNA(Phe). It is unknown if this circuitry is conserved and important for tRNA(Phe) modification in other eukaryotes, but a likely human TRM7 ortholog is implicated in nonsyndromic X-linked intellectual disability. We find that the distantly related yeast Schizosaccharomyces pombe has retained this circuitry for anticodon loop modification, that S. pombe trm7Δ and trm734Δ mutants have more severe phenotypes than the S. cerevisiae mutants, and that tRNA(Phe) is the major biological target. Furthermore, we provide evidence that Trm7 and Trm732 function is widely conserved throughout eukaryotes, since human FTSJ1 and THADA, respectively, complement growth defects of S. cerevisiae trm7Δ and trm732Δ trm734Δ mutants by modifying C₃₂ of tRNA(Phe), each working with the corresponding S. cerevisiae partner protein. These results suggest widespread importance of 2'-O-methylation of the tRNA anticodon loop, implicate tRNA(Phe) as the crucial substrate, and suggest that this modification circuitry is important for human neuronal development.
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Affiliation(s)
- Michael P Guy
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Eric M Phizicky
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
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64
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Iron-sulfur proteins responsible for RNA modifications. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1272-83. [PMID: 25533083 DOI: 10.1016/j.bbamcr.2014.12.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/08/2014] [Accepted: 12/09/2014] [Indexed: 12/22/2022]
Abstract
RNA molecules are decorated with various chemical modifications, which are introduced post-transcriptionally by RNA-modifying enzymes. These modifications are required for proper RNA function. Among more than 100 known species of RNA modifications, several modified bases in tRNAs and rRNAs are introduced by RNA-modifying enzymes containing iron-sulfur (Fe/S) clusters. Most Fe/S-containing RNA-modifying enzymes contain radical SAM domains that catalyze a variety of chemical reactions, including methylation, methylthiolation, carboxymethylation, tricyclic purine formation, and deazaguanine formation. Lack of these modifications can cause pathological consequences. Here, we review recent studies on the biogenesis and function of RNA modifications mediated by Fe/S proteins. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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65
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Damon JR, Pincus D, Ploegh HL. tRNA thiolation links translation to stress responses in Saccharomyces cerevisiae. Mol Biol Cell 2014; 26:270-82. [PMID: 25392298 PMCID: PMC4294674 DOI: 10.1091/mbc.e14-06-1145] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The URM1 pathway functions in a tRNA thiolation reaction that is required for synthesis of the mcm5s2U34 nucleoside found in tRNAs. Growth of Saccharomyces cerevisiae cells at an elevated temperature results in altered levels of modification enzymes, and this leads to decreased levels of tRNA thiolation. tRNA thiolation is tied to cellular stress responses. Although tRNA modifications have been well catalogued, the precise functions of many modifications and their roles in mediating gene expression are still being elucidated. Whereas tRNA modifications were long assumed to be constitutive, it is now apparent that the modification status of tRNAs changes in response to different environmental conditions. The URM1 pathway is required for thiolation of the cytoplasmic tRNAs tGluUUC, tGlnUUG, and tLysUUU in Saccharomyces cerevisiae. We demonstrate that URM1 pathway mutants have impaired translation, which results in increased basal activation of the Hsf1-mediated heat shock response; we also find that tRNA thiolation levels in wild-type cells decrease when cells are grown at elevated temperature. We show that defects in tRNA thiolation can be conditionally advantageous, conferring resistance to endoplasmic reticulum stress. URM1 pathway proteins are unstable and hence are more sensitive to changes in the translational capacity of cells, which is decreased in cells experiencing stresses. We propose a model in which a stress-induced decrease in translation results in decreased levels of URM1 pathway components, which results in decreased tRNA thiolation levels, which further serves to decrease translation. This mechanism ensures that tRNA thiolation and translation are tightly coupled and coregulated according to need.
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Affiliation(s)
- Jadyn R Damon
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - David Pincus
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Hidde L Ploegh
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
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Karlsborn T, Tükenmez H, Chen C, Byström AS. Familial dysautonomia (FD) patients have reduced levels of the modified wobble nucleoside mcm5s2U in tRNA. Biochem Biophys Res Commun 2014; 454:441-5. [DOI: 10.1016/j.bbrc.2014.10.116] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 10/21/2014] [Indexed: 12/30/2022]
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67
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Zdżalik D, Vågbø CB, Kirpekar F, Davydova E, Puścian A, Maciejewska AM, Krokan HE, Klungland A, Tudek B, van den Born E, Falnes PØ. Protozoan ALKBH8 oxygenases display both DNA repair and tRNA modification activities. PLoS One 2014; 9:e98729. [PMID: 24914785 PMCID: PMC4051686 DOI: 10.1371/journal.pone.0098729] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/07/2014] [Indexed: 11/29/2022] Open
Abstract
The ALKBH family of Fe(II) and 2-oxoglutarate dependent oxygenases comprises enzymes that display sequence homology to AlkB from E. coli, a DNA repair enzyme that uses an oxidative mechanism to dealkylate methyl and etheno adducts on the nucleobases. Humans have nine different ALKBH proteins, ALKBH1–8 and FTO. Mammalian and plant ALKBH8 are tRNA hydroxylases targeting 5-methoxycarbonylmethyl-modified uridine (mcm5U) at the wobble position of tRNAGly(UCC). In contrast, the genomes of some bacteria encode a protein with strong sequence homology to ALKBH8, and robust DNA repair activity was previously demonstrated for one such protein. To further explore this apparent functional duality of the ALKBH8 proteins, we have here enzymatically characterized a panel of such proteins, originating from bacteria, protozoa and mimivirus. All the enzymes showed DNA repair activity in vitro, but, interestingly, two protozoan ALKBH8s also catalyzed wobble uridine modification of tRNA, thus displaying a dual in vitro activity. Also, we found the modification status of tRNAGly(UCC) to be unaltered in an ALKBH8 deficient mutant of Agrobacterium tumefaciens, indicating that bacterial ALKBH8s have a function different from that of their eukaryotic counterparts. The present study provides new insights on the function and evolution of the ALKBH8 family of proteins.
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Affiliation(s)
- Daria Zdżalik
- Department of Biosciences, University of Oslo, Oslo, Norway
- Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Cathrine B. Vågbø
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Finn Kirpekar
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Erna Davydova
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Alicja Puścian
- Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
- Department of Neurophysiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | | | - Hans E. Krokan
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Arne Klungland
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Barbara Tudek
- Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | | | - Pål Ø. Falnes
- Department of Biosciences, University of Oslo, Oslo, Norway
- * E-mail:
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68
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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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69
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Immunity factors for two related tRNAGln targeting killer toxins distinguish cognate and non-cognate toxic subunits. Curr Genet 2014; 60:213-22. [DOI: 10.1007/s00294-014-0426-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 10/25/2022]
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Abstract
SIGNIFICANCE The well-studied sequences in the human genome are those of protein-coding genes, which account for only 1%-2% of the total genome. However, with the advent of high-throughput transcriptome sequencing technology, we now know that about 90% of our genome is extensively transcribed and that the vast majority of them are transcribed into noncoding RNAs (ncRNAs). It is of great interest and importance to decipher the functions of these ncRNAs in humans. RECENT ADVANCES In the last decade, it has become apparent that ncRNAs play a crucial role in regulating gene expression in normal development, in stress responses to internal and environmental stimuli, and in human diseases. CRITICAL ISSUES In addition to those constitutively expressed structural RNA, such as ribosomal and transfer RNAs, regulatory ncRNAs can be classified as microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs), small interfering RNAs (siRNAs), small nucleolar RNAs (snoRNAs), and long noncoding RNAs (lncRNAs). However, little is known about the biological features and functional roles of these ncRNAs in DNA repair and genome instability, although a number of miRNAs and lncRNAs are regulated in the DNA damage response. FUTURE DIRECTIONS A major goal of modern biology is to identify and characterize the full profile of ncRNAs with regard to normal physiological functions and roles in human disorders. Clinically relevant ncRNAs will also be evaluated and targeted in therapeutic applications.
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Affiliation(s)
- Guohui Wan
- 1 Department of Cancer Biology, The University of Texas MD Anderson Cancer Center , Houston, Texas
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71
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A comprehensive tRNA deletion library unravels the genetic architecture of the tRNA pool. PLoS Genet 2014; 10:e1004084. [PMID: 24453985 PMCID: PMC3894157 DOI: 10.1371/journal.pgen.1004084] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 11/19/2013] [Indexed: 12/19/2022] Open
Abstract
Deciphering the architecture of the tRNA pool is a prime challenge in translation research, as tRNAs govern the efficiency and accuracy of the process. Towards this challenge, we created a systematic tRNA deletion library in Saccharomyces cerevisiae, aimed at dissecting the specific contribution of each tRNA gene to the tRNA pool and to the cell's fitness. By harnessing this resource, we observed that the majority of tRNA deletions show no appreciable phenotype in rich medium, yet under more challenging conditions, additional phenotypes were observed. Robustness to tRNA gene deletion was often facilitated through extensive backup compensation within and between tRNA families. Interestingly, we found that within tRNA families, genes carrying identical anti-codons can contribute differently to the cellular fitness, suggesting the importance of the genomic surrounding to tRNA expression. Characterization of the transcriptome response to deletions of tRNA genes exposed two disparate patterns: in single-copy families, deletions elicited a stress response; in deletions of genes from multi-copy families, expression of the translation machinery increased. Our results uncover the complex architecture of the tRNA pool and pave the way towards complete understanding of their role in cell physiology.
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72
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Transfer RNA post-transcriptional processing, turnover, and subcellular dynamics in the yeast Saccharomyces cerevisiae. Genetics 2013; 194:43-67. [PMID: 23633143 DOI: 10.1534/genetics.112.147470] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transfer RNAs (tRNAs) are essential for protein synthesis. In eukaryotes, tRNA biosynthesis employs a specialized RNA polymerase that generates initial transcripts that must be subsequently altered via a multitude of post-transcriptional steps before the tRNAs beome mature molecules that function in protein synthesis. Genetic, genomic, biochemical, and cell biological approaches possible in the powerful Saccharomyces cerevisiae system have led to exciting advances in our understandings of tRNA post-transcriptional processing as well as to novel insights into tRNA turnover and tRNA subcellular dynamics. tRNA processing steps include removal of transcribed leader and trailer sequences, addition of CCA to the 3' mature sequence and, for tRNA(His), addition of a 5' G. About 20% of yeast tRNAs are encoded by intron-containing genes. The three-step splicing process to remove the introns surprisingly occurs in the cytoplasm in yeast and each of the splicing enzymes appears to moonlight in functions in addition to tRNA splicing. There are 25 different nucleoside modifications that are added post-transcriptionally, creating tRNAs in which ∼15% of the residues are nucleosides other than A, G, U, or C. These modified nucleosides serve numerous important functions including tRNA discrimination, translation fidelity, and tRNA quality control. Mature tRNAs are very stable, but nevertheless yeast cells possess multiple pathways to degrade inappropriately processed or folded tRNAs. Mature tRNAs are also dynamic in cells, moving from the cytoplasm to the nucleus and back again to the cytoplasm; the mechanism and function of this retrograde process is poorly understood. Here, the state of knowledge for tRNA post-transcriptional processing, turnover, and subcellular dynamics is addressed, highlighting the questions that remain.
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73
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Laxman S, Sutter BM, Wu X, Kumar S, Guo X, Trudgian DC, Mirzaei H, Tu BP. Sulfur amino acids regulate translational capacity and metabolic homeostasis through modulation of tRNA thiolation. Cell 2013; 154:416-29. [PMID: 23870129 PMCID: PMC3757545 DOI: 10.1016/j.cell.2013.06.043] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 03/15/2013] [Accepted: 06/25/2013] [Indexed: 02/06/2023]
Abstract
Protein translation is an energetically demanding process that must be regulated in response to changes in nutrient availability. Herein, we report that intracellular methionine and cysteine availability directly controls the thiolation status of wobble-uridine (U34) nucleotides present on lysine, glutamine, or glutamate tRNAs to regulate cellular translational capacity and metabolic homeostasis. tRNA thiolation is important for growth under nutritionally challenging environments and required for efficient translation of genes enriched in lysine, glutamine, and glutamate codons, which are enriched in proteins important for translation and growth-specific processes. tRNA thiolation is downregulated during sulfur starvation in order to decrease sulfur consumption and growth, and its absence leads to a compensatory increase in enzymes involved in methionine, cysteine, and lysine biosynthesis. Thus, tRNA thiolation enables cells to modulate translational capacity according to the availability of sulfur amino acids, establishing a functional significance for this conserved tRNA nucleotide modification in cell growth control.
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Affiliation(s)
- Sunil Laxman
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
| | - Benjamin M. Sutter
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
| | - Xi Wu
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
| | - Sujai Kumar
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, EH9 3JT UK
| | - Xiaofeng Guo
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
| | - David C. Trudgian
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
| | - Hamid Mirzaei
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
| | - Benjamin P. Tu
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
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74
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Begley U, Sosa MS, Avivar-Valderas A, Patil A, Endres L, Estrada Y, Chan CTY, Su D, Dedon PC, Aguirre-Ghiso JA, Begley T. A human tRNA methyltransferase 9-like protein prevents tumour growth by regulating LIN9 and HIF1-α. EMBO Mol Med 2013; 5:366-83. [PMID: 23381944 PMCID: PMC3598078 DOI: 10.1002/emmm.201201161] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 12/05/2012] [Accepted: 12/07/2012] [Indexed: 12/31/2022] Open
Abstract
Emerging evidence points to aberrant regulation of translation as a driver of cell transformation in cancer. Given the direct control of translation by tRNA modifications, tRNA modifying enzymes may function as regulators of cancer progression. Here, we show that a tRNA methyltransferase 9-like (hTRM9L/KIAA1456) mRNA is down-regulated in breast, bladder, colorectal, cervix and testicular carcinomas. In the aggressive SW620 and HCT116 colon carcinoma cell lines, hTRM9L is silenced and its re-expression and methyltransferase activity dramatically suppressed tumour growth in vivo. This growth inhibition was linked to decreased proliferation, senescence-like G0/G1-arrest and up-regulation of the RB interacting protein LIN9. Additionally, SW620 cells re-expressing hTRM9L did not respond to hypoxia via HIF1-α-dependent induction of GLUT1. Importantly, hTRM9L-negative tumours were highly sensitive to aminoglycoside antibiotics and this was associated with altered tRNA modification levels compared to antibiotic resistant hTRM9L-expressing SW620 cells. Our study links hTRM9L and tRNA modifications to inhibition of tumour growth via LIN9 and HIF1-α-dependent mechanisms. It also suggests that aminoglycoside antibiotics may be useful to treat hTRM9L-deficient tumours.
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Affiliation(s)
- Ulrike Begley
- College of Nanoscale Science and Engineering, University at Albany, State University of New York, Albany, NY, USA
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75
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Meineke B, Kast A, Schwer B, Meinhardt F, Shuman S, Klassen R. A fungal anticodon nuclease ribotoxin exploits a secondary cleavage site to evade tRNA repair. RNA (NEW YORK, N.Y.) 2012; 18:1716-1724. [PMID: 22836353 PMCID: PMC3425785 DOI: 10.1261/rna.034132.112] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 06/14/2012] [Indexed: 06/01/2023]
Abstract
PaOrf2 and γ-toxin subunits of Pichia acaciae toxin (PaT) and Kluyveromyces lactis zymocin are tRNA anticodon nucleases. These secreted ribotoxins are assimilated by Saccharomyces cerevisiae, wherein they arrest growth by depleting specific tRNAs. Toxicity can be recapitulated by induced intracellular expression of PaOrf2 or γ-toxin in S. cerevisiae. Mutational analysis of γ-toxin has identified amino acids required for ribotoxicity in vivo and RNA transesterification in vitro. Here, we report that PaOrf2 residues Glu9 and His287 (putative counterparts of γ-toxin Glu9 and His209) are essential for toxicity. Our results suggest a similar basis for RNA transesterification by PaOrf2 and γ-toxin, despite their dissimilar primary structures and distinctive tRNA target specificities. PaOrf2 makes two sequential incisions in tRNA, the first of which occurs 3' from the mcm(5)s(2)U wobble nucleoside and depends on mcm(5). A second incision two nucleotides upstream results in the net excision of a di-nucleotide. Expression of phage and plant tRNA repair systems can relieve PaOrf2 toxicity when tRNA cleavage is restricted to the secondary site in elp3 cells that lack the mcm(5) wobble U modification. Whereas the endogenous yeast tRNA ligase Trl1 can heal tRNA halves produced by PaOrf2 cleavage in elp3 cells, its RNA sealing activity is inadequate to complete the repair. Compatible sealing activity can be provided in trans by plant tRNA ligase. The damage-rescuing ability of tRNA repair systems is lost when PaOrf2 can break tRNA at both sites. These results highlight the logic of a two-incision mechanism of tRNA anticodon damage that evades productive repair by tRNA ligases.
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Affiliation(s)
- Birthe Meineke
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Alene Kast
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Beate Schwer
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
| | - Friedhelm Meinhardt
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Roland Klassen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
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76
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The potential of 2-oxoglutarate oxygenases acting on nucleic acids as therapeutic targets. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.ddstr.2012.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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77
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Patil A, Dyavaiah M, Joseph F, Rooney JP, Chan CTY, Dedon PC, Begley TJ. Increased tRNA modification and gene-specific codon usage regulate cell cycle progression during the DNA damage response. Cell Cycle 2012; 11:3656-65. [PMID: 22935709 DOI: 10.4161/cc.21919] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
S-phase and DNA damage promote increased ribonucleotide reductase (RNR) activity. Translation of RNR1 has been linked to the wobble uridine modifying enzyme tRNA methyltransferase 9 (Trm9). We predicted that changes in tRNA modification would translationally regulate RNR1 after DNA damage to promote cell cycle progression. In support, we demonstrate that the Trm9-dependent tRNA modification 5-methoxycarbonylmethyluridine (mcm(5)U) is increased in hydroxyurea (HU)-induced S-phase cells, relative to G(1) and G(2), and that mcm(5)U is one of 16 tRNA modifications whose levels oscillate during the cell cycle. Codon-reporter data matches the mcm(5)U increase to Trm9 and the efficient translation of AGA codons and RNR1. Further, we show that in trm9Δ cells reduced Rnr1 protein levels cause delayed transition into S-phase after damage. Codon re-engineering of RNR1 increased the number of trm9Δ cells that have transitioned into S-phase 1 h after DNA damage and that have increased Rnr1 protein levels, similar to that of wild-type cells expressing native RNR1. Our data supports a model in which codon usage and tRNA modification are regulatory components of the DNA damage response, with both playing vital roles in cell cycle progression.
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Affiliation(s)
- Ashish Patil
- College of Nanoscale Science and Engineering, University at Albany, State University of New York, Albany, NY, USA
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78
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Satwika D, Klassen R, Meinhardt F. Anticodon nuclease encoding virus-like elements in yeast. Appl Microbiol Biotechnol 2012; 96:345-56. [PMID: 22899498 DOI: 10.1007/s00253-012-4349-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/31/2012] [Accepted: 08/01/2012] [Indexed: 11/29/2022]
Abstract
A variety of yeast species are known to host systems of cytoplasmic linear dsDNA molecules that establish replication and transcription independent of the nucleus via self-encoded enzymes that are phylogenetically related to those encoded by true infective viruses. Such yeast virus-like elements (VLE) fall into two categories: autonomous VLEs encode all the essential functions for their inheritance, and additional, dependent VLEs, which may encode a toxin-antitoxin system, generally referred to as killer toxin and immunity. In the two cases studied in depth, killer toxin action relies on chitin binding and hydrophobic domains, together allowing a separate toxic subunit to sneak into the target cell. Mechanistically, the latter sabotages codon-anticodon interaction by endonucleolytic cleavage of specific tRNAs 3' of the wobble nucleotide. This primary action provokes a number of downstream effects, including DNA damage accumulation, which contribute to the cell-killing efficiency and highlight the importance of proper transcript decoding capacity for other cellular processes than translation itself. Since wobble uridine modifications are crucial for efficient anticodon nuclease (ACNase) action of yeast killer toxins, the latter are valuable tools for the characterization of a surprisingly complex network regulating the addition of wobble base modifications in tRNA.
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Affiliation(s)
- Dhira Satwika
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstr. 3, 48149, Münster, Germany
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79
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Chan CTY, Pang YLJ, Deng W, Babu IR, Dyavaiah M, Begley TJ, Dedon PC. Reprogramming of tRNA modifications controls the oxidative stress response by codon-biased translation of proteins. Nat Commun 2012; 3:937. [PMID: 22760636 PMCID: PMC3535174 DOI: 10.1038/ncomms1938] [Citation(s) in RCA: 322] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 05/31/2012] [Indexed: 11/09/2022] Open
Abstract
Selective translation of survival proteins is an important facet of the cellular stress response. We recently demonstrated that this translational control involves a stress-specific reprogramming of modified ribonucleosides in tRNA. Here we report the discovery of a step-wise translational control mechanism responsible for survival following oxidative stress. In yeast exposed to hydrogen peroxide, there is a Trm4 methyltransferase-dependent increase in the proportion of tRNALEU(CAA) containing m5C at the wobble position, which causes selective translation of mRNA from genes enriched in the TTG codon. Of these genes, oxidative stress increases protein expression from the TTG-enriched ribosomal protein gene RPL22A, but not its unenriched paralog. Loss of either TRM4 or RPL22A confers hypersensitivity to oxidative stress. Proteomic analysis reveals that oxidative stress causes a significant translational bias toward proteins coded by TTG-enriched genes. These results point to stress-induced reprogramming of tRNA modifications and consequential reprogramming of ribosomes in translational control of cell survival.
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Affiliation(s)
- Clement T Y Chan
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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80
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Patil A, Chan CTY, Dyavaiah M, Rooney JP, Dedon PC, Begley TJ. Translational infidelity-induced protein stress results from a deficiency in Trm9-catalyzed tRNA modifications. RNA Biol 2012; 9:990-1001. [PMID: 22832247 DOI: 10.4161/rna.20531] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Correct codon-anticodon pairing promotes translational fidelity, with these interactions greatly facilitated by modified nucleosides found in tRNA. We hypothesized that wobble uridine modifications catalyzed by tRNA methyltransferase 9 (Trm9) are essential for translational fidelity. In support, we have used phenotypic, reporter and protein-based assays to demonstrate increased translational infidelity in trm9Δ Saccharomyces cerevisiae cells. Codon reengineering studies suggest that Trm9-catalyzed tRNA modifications promote fidelity during the translation of specific genes, those rich in arginine and glutamic acid codons from mixed boxes. Using quantitative tRNA modification analysis, we determined that trm9Δ cells are only deficient in 2 of 23 tRNA modifications, with those 2, 5-methoxycarbonylmethyluridine (mcm ( 5) U) and 5-methoxycarbonylmethyl-2-thiouridine (mcm ( 5) s ( 2) U), classified as key determinants of translational fidelity. We also show that in the absence of mcm ( 5) U and mcm ( 5) s ( 2) U, the resulting translational infidelity promotes protein errors and activation of unfolded protein and heat shock responses. These data support a model in which Trm9-catalyzed tRNA modifications promote fidelity during the translation of specific transcripts, with decreased wobble base modification leading to translational infidelity, protein errors and activation of protein stress response pathways.
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Affiliation(s)
- Ashish Patil
- Cancer Research Center, University at Albany, State University of New York, Rensselaer, NY, USA
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81
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Trm112 is required for Bud23-mediated methylation of the 18S rRNA at position G1575. Mol Cell Biol 2012; 32:2254-67. [PMID: 22493060 DOI: 10.1128/mcb.06623-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Posttranscriptional and posttranslational modification of macromolecules is known to fine-tune their functions. Trm112 is unique, acting as an activator of both tRNA and protein methyltransferases. Here we report that in Saccharomyces cerevisiae, Trm112 is required for efficient ribosome synthesis and progression through mitosis. Trm112 copurifies with pre-rRNAs and with multiple ribosome synthesis trans-acting factors, including the 18S rRNA methyltransferase Bud23. Consistent with the known mechanisms of activation of methyltransferases by Trm112, we found that Trm112 interacts directly with Bud23 in vitro and that it is required for its stability in vivo. Consequently, trm112Δ cells are deficient for Bud23-mediated 18S rRNA methylation at position G1575 and for small ribosome subunit formation. Bud23 failure to bind nascent preribosomes activates a nucleolar surveillance pathway involving the TRAMP complexes, leading to preribosome degradation. Trm112 is thus active in rRNA, tRNA, and translation factor modification, ideally placing it at the interface between ribosome synthesis and function.
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82
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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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83
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Fislage M, Roovers M, Tuszynska I, Bujnicki JM, Droogmans L, Versées W. Crystal structures of the tRNA:m2G6 methyltransferase Trm14/TrmN from two domains of life. Nucleic Acids Res 2012; 40:5149-61. [PMID: 22362751 PMCID: PMC3367198 DOI: 10.1093/nar/gks163] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Methyltransferases (MTases) form a major class of tRNA-modifying enzymes needed for the proper functioning of tRNA. Recently, RNA MTases from the TrmN/Trm14 family that are present in Archaea, Bacteria and Eukaryota have been shown to specifically modify tRNAPhe at guanosine 6 in the tRNA acceptor stem. Here, we report the first X-ray crystal structures of the tRNA m2G6 (N2-methylguanosine) MTase TTCTrmN from Thermus thermophilus and its ortholog PfTrm14 from Pyrococcus furiosus. Structures of PfTrm14 were solved in complex with the methyl donor S-adenosyl-l-methionine (SAM or AdoMet), as well as the reaction product S-adenosyl-homocysteine (SAH or AdoHcy) and the inhibitor sinefungin. TTCTrmN and PfTrm14 consist of an N-terminal THUMP domain fused to a catalytic Rossmann-fold MTase (RFM) domain. These results represent the first crystallographic structure analysis of proteins containing both THUMP and RFM domain, and hence provide further insight in the contribution of the THUMP domain in tRNA recognition and catalysis. Electrostatics and conservation calculations suggest a main tRNA binding surface in a groove between the THUMP domain and the MTase domain. This is further supported by a docking model of TrmN in complex with tRNAPhe of T. thermophilus and via site-directed mutagenesis.
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Affiliation(s)
- Marcus Fislage
- VIB Department of Structural Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
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84
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Graille M, Figaro S, Kervestin S, Buckingham RH, Liger D, Heurgué-Hamard V. Methylation of class I translation termination factors: structural and functional aspects. Biochimie 2012; 94:1533-43. [PMID: 22266024 DOI: 10.1016/j.biochi.2012.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 01/07/2012] [Indexed: 12/23/2022]
Abstract
During protein synthesis, release of polypeptide from the ribosome occurs when an in frame termination codon is encountered. Contrary to sense codons, which are decoded by tRNAs, stop codons present in the A-site are recognized by proteins named class I release factors, leading to the release of newly synthesized proteins. Structures of these factors bound to termination ribosomal complexes have recently been obtained, and lead to a better understanding of stop codon recognition and its coordination with peptidyl-tRNA hydrolysis in bacteria. Release factors contain a universally conserved GGQ motif which interacts with the peptidyl-transferase centre to allow peptide release. The Gln side chain from this motif is methylated, a feature conserved from bacteria to man, suggesting an important biological role. However, methylation is catalysed by completely unrelated enzymes. The function of this motif and its post-translational modification will be discussed in the context of recent structural and functional studies.
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Affiliation(s)
- Marc Graille
- IBBMC, Université Paris-Sud 11, CNRS UMR8619, Orsay Cedex, F-91405, France.
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85
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Identification of N6,N6-dimethyladenosine in transfer RNA from Mycobacterium bovis Bacille Calmette-Guérin. Molecules 2011; 16:5168-81. [PMID: 21694680 PMCID: PMC6264175 DOI: 10.3390/molecules16065168] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/03/2011] [Accepted: 06/10/2011] [Indexed: 11/25/2022] Open
Abstract
There are more than 100 different ribonucleoside structures incorporated as post-transcriptional modifications, mainly in tRNA and rRNA of both prokaryotes and eukaryotes, and emerging evidence suggests that these modifications function as a system in the translational control of cellular responses. However, our understanding of this system is hampered by the paucity of information about the complete set of RNA modifications present in individual organisms. To this end, we have employed a chromatography-coupled mass spectrometric approach to define the spectrum of modified ribonucleosides in microbial species, starting with Mycobacterium bovis BCG. This approach revealed a variety of ribonucleoside candidates in tRNA from BCG, of which 12 were definitively identified based on comparisons to synthetic standards and 5 were tentatively identified by exact mass comparisons to RNA modification databases. Among the ribonucleosides observed in BCG tRNA was one not previously described in tRNA, which we have now characterized as N6,N6-dimethyladenosine.
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86
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Chen C, Huang B, Anderson JT, Byström AS. Unexpected accumulation of ncm(5)U and ncm(5)S(2) (U) in a trm9 mutant suggests an additional step in the synthesis of mcm(5)U and mcm(5)S(2)U. PLoS One 2011; 6:e20783. [PMID: 21687733 PMCID: PMC3110198 DOI: 10.1371/journal.pone.0020783] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/09/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Transfer RNAs are synthesized as a primary transcript that is processed to produce a mature tRNA. As part of the maturation process, a subset of the nucleosides are modified. Modifications in the anticodon region often modulate the decoding ability of the tRNA. At position 34, the majority of yeast cytosolic tRNA species that have a uridine are modified to 5-carbamoylmethyluridine (ncm(5)U), 5-carbamoylmethyl-2'-O-methyluridine (ncm(5)Um), 5-methoxycarbonylmethyl-uridine (mcm(5)U) or 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U). The formation of mcm(5) and ncm(5) side chains involves a complex pathway, where the last step in formation of mcm(5) is a methyl esterification of cm(5) dependent on the Trm9 and Trm112 proteins. METHODOLOGY AND PRINCIPAL FINDINGS Both Trm9 and Trm112 are required for the last step in formation of mcm(5) side chains at wobble uridines. By co-expressing a histidine-tagged Trm9p together with a native Trm112p in E. coli, these two proteins purified as a complex. The presence of Trm112p dramatically improves the methyltransferase activity of Trm9p in vitro. Single tRNA species that normally contain mcm(5)U or mcm(5)s(2)U nucleosides were isolated from trm9Δ or trm112Δ mutants and the presence of modified nucleosides was analyzed by HPLC. In both mutants, mcm(5)U and mcm(5)s(2)U nucleosides are absent in tRNAs and the major intermediates accumulating were ncm(5)U and ncm(5)s(2)U, not the expected cm(5)U and cm(5)s(2)U. CONCLUSIONS Trm9p and Trm112p function together at the final step in formation of mcm(5)U in tRNA by using the intermediate cm(5)U as a substrate. In tRNA isolated from trm9Δ and trm112Δ strains, ncm(5)U and ncm(5)s(2)U nucleosides accumulate, questioning the order of nucleoside intermediate formation of the mcm(5) side chain. We propose two alternative explanations for this observation. One is that the intermediate cm(5)U is generated from ncm(5)U by a yet unknown mechanism and the other is that cm(5)U is formed before ncm(5)U and mcm(5)U.
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Affiliation(s)
- Changchun Chen
- Department of Molecular Biology, Umeå
University, Umeå, Sweden
| | - Bo Huang
- Department of Molecular Biology, Umeå
University, Umeå, Sweden
- Division of Epidemiology, Department of
Medicine and Public Health, Vanderbilt University School of Medicine, Nashville,
Tennessee, United States of America
| | - James T. Anderson
- Department of Biological Sciences, Marquette
University, Milwaukee, Wisconsin, United States of America
- * E-mail: (JTA); (ASB)
| | - Anders S. Byström
- Department of Molecular Biology, Umeå
University, Umeå, Sweden
- * E-mail: (JTA); (ASB)
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87
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Leihne V, Kirpekar F, Vågbø CB, van den Born E, Krokan HE, Grini PE, Meza TJ, Falnes PØ. Roles of Trm9- and ALKBH8-like proteins in the formation of modified wobble uridines in Arabidopsis tRNA. Nucleic Acids Res 2011; 39:7688-701. [PMID: 21653555 PMCID: PMC3177185 DOI: 10.1093/nar/gkr406] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Uridine at the wobble position of tRNA is usually modified, and modification is required for accurate and efficient protein translation. In eukaryotes, wobble uridines are modified into 5-methoxycarbonylmethyluridine (mcm5U), 5-carbamoylmethyluridine (ncm5U) or derivatives thereof. Here, we demonstrate, both by in vitro and in vivo studies, that the Arabidopsis thaliana methyltransferase AT1G31600, denoted by us AtTRM9, is responsible for the final step in mcm5U formation, thus representing a functional homologue of the Saccharomyces cerevisiae Trm9 protein. We also show that the enzymatic activity of AtTRM9 depends on either one of two closely related proteins, AtTRM112a and AtTRM112b. Moreover, we demonstrate that AT1G36310, denoted AtALKBH8, is required for hydroxylation of mcm5U to (S)-mchm5U in tRNAGlyUCC, and has a function similar to the mammalian dioxygenase ALKBH8. Interestingly, atalkbh8 mutant plants displayed strongly increased levels of mcm5U, and also of mcm5Um, its 2′-O-ribose methylated derivative. This suggests that accumulated mcm5U is prone to further ribose methylation by a non-specialized mechanism, and may challenge the notion that the existence of mcm5U- and mcm5Um-containing forms of the selenocysteine-specific tRNASec in mammals reflects an important regulatory process. The present study reveals a role in for several hitherto uncharacterized Arabidopsis proteins in the formation of modified wobble uridines.
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Affiliation(s)
- Vibeke Leihne
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway
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88
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Liger D, Mora L, Lazar N, Figaro S, Henri J, Scrima N, Buckingham RH, van Tilbeurgh H, Heurgué-Hamard V, Graille M. Mechanism of activation of methyltransferases involved in translation by the Trm112 'hub' protein. Nucleic Acids Res 2011; 39:6249-59. [PMID: 21478168 PMCID: PMC3152332 DOI: 10.1093/nar/gkr176] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Methylation is a common modification encountered in DNA, RNA and proteins. It plays a central role in gene expression, protein function and mRNA translation. Prokaryotic and eukaryotic class I translation termination factors are methylated on the glutamine of the essential and universally conserved GGQ motif, in line with an important cellular role. In eukaryotes, this modification is performed by the Mtq2-Trm112 holoenzyme. Trm112 activates not only the Mtq2 catalytic subunit but also two other tRNA methyltransferases (Trm9 and Trm11). To understand the molecular mechanisms underlying methyltransferase activation by Trm112, we have determined the 3D structure of the Mtq2-Trm112 complex and mapped its active site. Using site-directed mutagenesis and in vivo functional experiments, we show that this structure can also serve as a model for the Trm9-Trm112 complex, supporting our hypothesis that Trm112 uses a common strategy to activate these three methyltransferases.
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Affiliation(s)
- Dominique Liger
- Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, Université Paris-Sud, IFR115, CNRS UMR 8619, Orsay Cedex F-91405, France
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89
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ALKBH8-mediated formation of a novel diastereomeric pair of wobble nucleosides in mammalian tRNA. Nat Commun 2011; 2:172. [PMID: 21285950 DOI: 10.1038/ncomms1173] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 12/22/2010] [Indexed: 11/08/2022] Open
Abstract
Mammals have nine different homologues (ALKBH1-9) of the Escherichia coli DNA repair demethylase AlkB. ALKBH2 is a genuine DNA repair enzyme, but the in vivo function of the other ALKBH proteins has remained elusive. It was recently shown that ALKBH8 contains an additional transfer RNA (tRNA) methyltransferase domain, which generates the wobble nucleoside 5-methoxycarbonylmethyluridine (mcm(5)U) from its precursor 5-carboxymethyluridine (cm(5)U). In this study, we report that (R)- and 5-methoxycarbonylhydroxymethyluridine (mchm(5)U), hydroxylated forms of mcm(5)U, are present in mammalian tRNA-Arg(UCG), and tRNA-Gly(UCC), respectively, representing the first example of a diastereomeric pair of modified RNA nucleosides. Through in vitro and in vivo studies, we show that both diastereomers of mchm(5)U are generated from mcm(5)U, and that the AlkB domain of ALKBH8 specifically hydroxylates mcm(5)U into (S)-mchm(5)U in tRNA-Gly(UCC). These findings expand the function of the ALKBH oxygenases beyond nucleic acid repair and increase the current knowledge on mammalian wobble uridine modifications and their biogenesis.
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90
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DNA repair defects sensitize cells to anticodon nuclease yeast killer toxins. Mol Genet Genomics 2010; 285:185-95. [PMID: 21188417 DOI: 10.1007/s00438-010-0597-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 12/11/2010] [Indexed: 12/21/2022]
Abstract
Killer toxins from Kluyveromyces lactis (zymocin) and Pichia acaciae (PaT) were found to disable translation in target cells by virtue of anticodon nuclease (ACNase) activities on tRNA(Glu) and tRNA(Gln), respectively. Surprisingly, however, ACNase exposure does not only impair translation, but also affects genome integrity and concomitantly DNA damage occurs. Previously, it was shown that homologous recombination protects cells from ACNase toxicity. Here, we have analyzed whether other DNA repair pathways are functional in conferring ACNase resistance as well. In addition to HR, base excision repair (BER) and postreplication repair (PRR) promote clear resistance to either, PaT and zymocin. Comparative toxin sensitivity analysis of BER mutants revealed that its ACNase protective function is due to the endonucleases acting on apurinic (AP) sites, whereas none of the known DNA glycosylases is involved. Because PaT and zymocin require the presence of the ELP3/TRM9-dependent wobble uridine modification 5-methoxy-carbonyl-methyl (mcm(5)) for tRNA cleavage, we analyzed toxin response in DNA repair mutants additionally lacking such tRNA modifications. ACNase resistance caused by elp3 or trm9 mutations was found to rescue hypersensitivity of DNA repair defects, consistent with DNA damage to occur as a consequence of tRNA cleavage. The obtained genetic evidence promises to reveal new aspects into the mechanism linking translational fidelity and genome surveillance.
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91
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Chan CTY, Dyavaiah M, DeMott MS, Taghizadeh K, Dedon PC, Begley TJ. A quantitative systems approach reveals dynamic control of tRNA modifications during cellular stress. PLoS Genet 2010; 6:e1001247. [PMID: 21187895 PMCID: PMC3002981 DOI: 10.1371/journal.pgen.1001247] [Citation(s) in RCA: 322] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/15/2010] [Indexed: 11/18/2022] Open
Abstract
Decades of study have revealed more than 100 ribonucleoside structures incorporated as post-transcriptional modifications mainly in tRNA and rRNA, yet the larger functional dynamics of this conserved system are unclear. To this end, we developed a highly precise mass spectrometric method to quantify tRNA modifications in Saccharomyces cerevisiae. Our approach revealed several novel biosynthetic pathways for RNA modifications and led to the discovery of signature changes in the spectrum of tRNA modifications in the damage response to mechanistically different toxicants. This is illustrated with the RNA modifications Cm, m(5)C, and m(2) (2)G, which increase following hydrogen peroxide exposure but decrease or are unaffected by exposure to methylmethane sulfonate, arsenite, and hypochlorite. Cytotoxic hypersensitivity to hydrogen peroxide is conferred by loss of enzymes catalyzing the formation of Cm, m(5)C, and m(2) (2)G, which demonstrates that tRNA modifications are critical features of the cellular stress response. The results of our study support a general model of dynamic control of tRNA modifications in cellular response pathways and add to the growing repertoire of mechanisms controlling translational responses in cells.
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Affiliation(s)
- Clement T. Y. Chan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Madhu Dyavaiah
- Department of Biomedical Sciences, Gen*NY*sis Center for Excellence in Cancer Genomics, University at Albany, State University of New York, Rensselaer, New York, United States of America
| | - Michael S. DeMott
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Koli Taghizadeh
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail: (PCD); (TJB)
| | - Thomas J. Begley
- Department of Biomedical Sciences, Gen*NY*sis Center for Excellence in Cancer Genomics, University at Albany, State University of New York, Rensselaer, New York, United States of America
- * E-mail: (PCD); (TJB)
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92
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Fu Y, Dai Q, Zhang W, Ren J, Pan T, He C. The AlkB domain of mammalian ABH8 catalyzes hydroxylation of 5-methoxycarbonylmethyluridine at the wobble position of tRNA. Angew Chem Int Ed Engl 2010; 49:8885-8. [PMID: 20583019 PMCID: PMC3134247 DOI: 10.1002/anie.201001242] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ye Fu
- Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 (USA), Fax: (+1) 773-702-0805
| | - Qing Dai
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 (USA)
| | - Wen Zhang
- Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 (USA), Fax: (+1) 773-702-0805
| | - Jin Ren
- Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 (USA), Fax: (+1) 773-702-0805
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 (USA); Institute for Biophysical Dynamics, The University of Chicago (USA)
| | - Chuan He
- Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 (USA), Fax: (+1) 773-702-0805; Institute for Biophysical Dynamics, The University of Chicago (USA)
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93
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Fu Y, Dai Q, Zhang W, Ren J, Pan T, He C. The AlkB Domain of Mammalian ABH8 Catalyzes Hydroxylation of 5-Methoxycarbonylmethyluridine at the Wobble Position of tRNA. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001242] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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94
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Abstract
tRNA biology has come of age, revealing an unprecedented level of understanding and many unexpected discoveries along the way. This review highlights new findings on the diverse pathways of tRNA maturation, and on the formation and function of a number of modifications. Topics of special focus include the regulation of tRNA biosynthesis, quality control tRNA turnover mechanisms, widespread tRNA cleavage pathways activated in response to stress and other growth conditions, emerging evidence of signaling pathways involving tRNA and cleavage fragments, and the sophisticated intracellular tRNA trafficking that occurs during and after biosynthesis.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA.
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95
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Fabrizio P, Hoon S, Shamalnasab M, Galbani A, Wei M, Giaever G, Nislow C, Longo VD. Genome-wide screen in Saccharomyces cerevisiae identifies vacuolar protein sorting, autophagy, biosynthetic, and tRNA methylation genes involved in life span regulation. PLoS Genet 2010; 6:e1001024. [PMID: 20657825 PMCID: PMC2904796 DOI: 10.1371/journal.pgen.1001024] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 06/14/2010] [Indexed: 11/18/2022] Open
Abstract
The study of the chronological life span of Saccharomyces cerevisiae, which measures the survival of populations of non-dividing yeast, has resulted in the identification of homologous genes and pathways that promote aging in organisms ranging from yeast to mammals. Using a competitive genome-wide approach, we performed a screen of a complete set of approximately 4,800 viable deletion mutants to identify genes that either increase or decrease chronological life span. Half of the putative short-/long-lived mutants retested from the primary screen were confirmed, demonstrating the utility of our approach. Deletion of genes involved in vacuolar protein sorting, autophagy, and mitochondrial function shortened life span, confirming that respiration and degradation processes are essential for long-term survival. Among the genes whose deletion significantly extended life span are ACB1, CKA2, and TRM9, implicated in fatty acid transport and biosynthesis, cell signaling, and tRNA methylation, respectively. Deletion of these genes conferred heat-shock resistance, supporting the link between life span extension and cellular protection observed in several model organisms. The high degree of conservation of these novel yeast longevity determinants in other species raises the possibility that their role in senescence might be conserved.
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Affiliation(s)
- Paola Fabrizio
- Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Laboratoire de Biologie Moléculaire de la Cellule, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Université de Lyon, Lyon, France
| | - Shawn Hoon
- Department of Genetics, Stanford University, Palo Alto, California, United States of America
| | - Mehrnaz Shamalnasab
- Laboratoire de Biologie Moléculaire de la Cellule, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Université de Lyon, Lyon, France
| | - Abdulaye Galbani
- Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Min Wei
- Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Guri Giaever
- Department of Genetics, Stanford University, Palo Alto, California, United States of America
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Corey Nislow
- Department of Genetics, Stanford University, Palo Alto, California, United States of America
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail: (VDL); (CN)
| | - Valter D. Longo
- Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- * E-mail: (VDL); (CN)
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96
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Mazauric MH, Dirick L, Purushothaman SK, Björk GR, Lapeyre B. Trm112p is a 15-kDa zinc finger protein essential for the activity of two tRNA and one protein methyltransferases in yeast. J Biol Chem 2010; 285:18505-15. [PMID: 20400505 PMCID: PMC2881776 DOI: 10.1074/jbc.m110.113100] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/16/2010] [Indexed: 11/06/2022] Open
Abstract
The degenerate base at position 34 of the tRNA anticodon is the target of numerous modification enzymes. In Saccharomyces cerevisiae, five tRNAs exhibit a complex modification of uridine 34 (mcm(5)U(34) and mcm(5)s(2)U(34)), the formation of which requires at least 25 different proteins. The addition of the last methyl group is catalyzed by the methyltransferase Trm9p. Trm9p interacts with Trm112p, a 15-kDa protein with a zinc finger domain. Trm112p is essential for the activity of Trm11p, another tRNA methyltransferase, and for Mtq2p, an enzyme that methylates the translation termination factor eRF1/Sup45. Here, we report that Trm112p is required in vivo for the formation of mcm(5)U(34) and mcm(5)s(2)U(34). When produced in Escherichia coli, Trm112p forms a complex with Trm9p, which renders the latter soluble. This recombinant complex catalyzes the formation of mcm(5)U(34) on tRNA in vitro but not mcm(5)s(2)U(34). An mtq2-0 trm9-0 strain exhibits a synthetic growth defect, thus revealing the existence of an unexpected link between tRNA anticodon modification and termination of translation. Trm112p is associated with other partners involved in ribosome biogenesis and chromatin remodeling, suggesting that it has additional roles in the cell.
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Affiliation(s)
| | - Léon Dirick
- Institut de Génétique Moléculaire, University of Montpellier 1 and 2, 34293 Montpellier, France and
| | | | - Glenn R. Björk
- the
Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
| | - Bruno Lapeyre
- From the
Centre de Recherche de Biochimie Macromoléculaire and
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97
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Human AlkB homolog ABH8 Is a tRNA methyltransferase required for wobble uridine modification and DNA damage survival. Mol Cell Biol 2010; 30:2449-59. [PMID: 20308323 DOI: 10.1128/mcb.01604-09] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
tRNA nucleosides are extensively modified to ensure their proper function in translation. However, many of the enzymes responsible for tRNA modifications in mammals await identification. Here, we show that human AlkB homolog 8 (ABH8) catalyzes tRNA methylation to generate 5-methylcarboxymethyl uridine (mcm(5)U) at the wobble position of certain tRNAs, a critical anticodon loop modification linked to DNA damage survival. We find that ABH8 interacts specifically with tRNAs containing mcm(5)U and that purified ABH8 complexes methylate RNA in vitro. Significantly, ABH8 depletion in human cells reduces endogenous levels of mcm(5)U in RNA and increases cellular sensitivity to DNA-damaging agents. Moreover, DNA-damaging agents induce ABH8 expression in an ATM-dependent manner. These results expand the role of mammalian AlkB proteins beyond that of direct DNA repair and support a regulatory mechanism in the DNA damage response pathway involving modulation of tRNA modification.
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98
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Mammalian ALKBH8 possesses tRNA methyltransferase activity required for the biogenesis of multiple wobble uridine modifications implicated in translational decoding. Mol Cell Biol 2010; 30:1814-27. [PMID: 20123966 DOI: 10.1128/mcb.01602-09] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Uridines in the wobble position of tRNA are almost invariably modified. Modifications can increase the efficiency of codon reading, but they also prevent mistranslation by limiting wobbling. In mammals, several tRNAs have 5-methoxycarbonylmethyluridine (mcm5U) or derivatives thereof in the wobble position. Through analysis of tRNA from Alkbh8-/- mice, we show here that ALKBH8 is a tRNA methyltransferase required for the final step in the biogenesis of mcm5U. We also demonstrate that the interaction of ALKBH8 with a small accessory protein, TRM112, is required to form a functional tRNA methyltransferase. Furthermore, prior ALKBH8-mediated methylation is a prerequisite for the thiolation and 2'-O-ribose methylation that form 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) and 5-methoxycarbonylmethyl-2'-O-methyluridine (mcm5Um), respectively. Despite the complete loss of all of these uridine modifications, Alkbh8-/- mice appear normal. However, the selenocysteine-specific tRNA (tRNASec) is aberrantly modified in the Alkbh8-/- mice, and for the selenoprotein Gpx1, we indeed observed reduced recoding of the UGA stop codon to selenocysteine.
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99
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Petrossian TC, Clarke SG. Multiple Motif Scanning to identify methyltransferases from the yeast proteome. Mol Cell Proteomics 2009; 8:1516-26. [PMID: 19351663 DOI: 10.1074/mcp.m900025-mcp200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A new program (Multiple Motif Scanning) was developed to scan the Saccharomyces cerevisiae proteome for Class I S-adenosylmethionine-dependent methyltransferases. Conserved Motifs I, Post I, II, and III were identified and expanded in known methyltransferases by primary sequence and secondary structural analysis through hidden Markov model profiling of both a yeast reference database and a reference database of methyltransferases with solved three-dimensional structures. The roles of the conserved amino acids in the four motifs of the methyltransferase structure and function were then analyzed to expand the previously defined motifs. Fisher-based negative log statistical matrix sets were developed from the prevalence of amino acids in the motifs. Multiple Motif Scanning is able to scan the proteome and score different combinations of the top fitting sequences for each motif. In addition, the program takes into account the conserved number of amino acids between the motifs. The output of the program is a ranked list of proteins that can be used to identify new methyltransferases and to reevaluate the assignment of previously identified putative methyltransferases. The Multiple Motif Scanning program can be used to develop a putative list of enzymes for any type of protein that has one or more motifs conserved at variable spacings and is freely available (www.chem.ucla.edu/files/MotifSetup.Zip). Finally hidden Markov model profile clustering analysis was used to subgroup Class I methyltransferases into groups that reflect their methyl-accepting substrate specificity.
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Affiliation(s)
- Tanya C Petrossian
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
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100
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Noma A, Sakaguchi Y, Suzuki T. Mechanistic characterization of the sulfur-relay system for eukaryotic 2-thiouridine biogenesis at tRNA wobble positions. Nucleic Acids Res 2009; 37:1335-52. [PMID: 19151091 PMCID: PMC2651780 DOI: 10.1093/nar/gkn1023] [Citation(s) in RCA: 171] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The wobble modification in tRNAs, 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U), is required for the proper decoding of NNR codons in eukaryotes. The 2-thio group confers conformational rigidity of mcm5s2U by largely fixing the C3′-endo ribose puckering, ensuring stable and accurate codon–anticodon pairing. We have identified five genes in Saccharomyces cerevisiae, YIL008w (URM1), YHR111w (UBA4), YOR251c (TUM1), YNL119w (NCS2) and YGL211w (NCS6), that are required for 2-thiolation of mcm5s2U. An in vitro sulfur transfer experiment revealed that Tum1p stimulated the cysteine desulfurase of Nfs1p, and accepted persulfide sulfurs from Nfs1p. URM1 is a ubiquitin-related modifier, and UBA4 is an E1-like enzyme involved in protein urmylation. The carboxy-terminus of Urm1p was activated as an acyl-adenylate (-COAMP), then thiocarboxylated (-COSH) by Uba4p. The activated thiocarboxylate can be utilized in the subsequent reactions for 2-thiouridine formation, mediated by Ncs2p/Ncs6p. We could successfully reconstitute the 2-thiouridine formation in vitro using recombinant proteins. This study revealed that 2-thiouridine formation shares a pathway and chemical reactions with protein urmylation. The sulfur-flow of eukaryotic 2-thiouridine formation is distinct mechanism from the bacterial sulfur-relay system which is based on the persulfide chemistry.
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Affiliation(s)
- Akiko Noma
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bldg. 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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