1
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van Breugel ME, Gerber A, van Leeuwen F. The choreography of chromatin in RNA polymerase III regulation. Biochem Soc Trans 2024; 52:1173-1189. [PMID: 38666598 DOI: 10.1042/bst20230770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 06/27/2024]
Abstract
Regulation of eukaryotic gene expression involves a dynamic interplay between the core transcriptional machinery, transcription factors, and chromatin organization and modification. While this applies to transcription by all RNA polymerase complexes, RNA polymerase III (RNAPIII) seems to be atypical with respect to its mechanisms of regulation. One distinctive feature of most RNAPIII transcribed genes is that they are devoid of nucleosomes, which relates to the high levels of transcription. Moreover, most of the regulatory sequences are not outside but within the transcribed open chromatin regions. Yet, several lines of evidence suggest that chromatin factors affect RNAPIII dynamics and activity and that gene sequence alone does not explain the observed regulation of RNAPIII. Here we discuss the role of chromatin modification and organization of RNAPIII transcribed genes and how they interact with the core transcriptional RNAPIII machinery and regulatory DNA elements in and around the transcribed genes.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
| | - Alan Gerber
- Department of Neurosurgery, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam 1081HV, The Netherlands
- Cancer Center Amsterdam, Cancer Biology, Amsterdam 1081HV, The Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
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2
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Weiss JL, Decker JC, Bolano A, Krahn N. Tuning tRNAs for improved translation. Front Genet 2024; 15:1436860. [PMID: 38983271 PMCID: PMC11231383 DOI: 10.3389/fgene.2024.1436860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 06/06/2024] [Indexed: 07/11/2024] Open
Abstract
Transfer RNAs have been extensively explored as the molecules that translate the genetic code into proteins. At this interface of genetics and biochemistry, tRNAs direct the efficiency of every major step of translation by interacting with a multitude of binding partners. However, due to the variability of tRNA sequences and the abundance of diverse post-transcriptional modifications, a guidebook linking tRNA sequences to specific translational outcomes has yet to be elucidated. Here, we review substantial efforts that have collectively uncovered tRNA engineering principles that can be used as a guide for the tuning of translation fidelity. These principles have allowed for the development of basic research, expansion of the genetic code with non-canonical amino acids, and tRNA therapeutics.
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Affiliation(s)
- Joshua L Weiss
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - J C Decker
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Ariadna Bolano
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Natalie Krahn
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
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3
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Kapur M, Molumby MJ, Guzman C, Heinz S, Ackerman SL. Cell-type-specific expression of tRNAs in the brain regulates cellular homeostasis. Neuron 2024; 112:1397-1415.e6. [PMID: 38377989 PMCID: PMC11065635 DOI: 10.1016/j.neuron.2024.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/23/2023] [Accepted: 01/29/2024] [Indexed: 02/22/2024]
Abstract
Defects in tRNA biogenesis are associated with multiple neurological disorders, yet our understanding of these diseases has been hampered by an inability to determine tRNA expression in individual cell types within a complex tissue. Here, we developed a mouse model in which RNA polymerase III is conditionally epitope tagged in a Cre-dependent manner, allowing us to accurately profile tRNA expression in any cell type in vivo. We investigated tRNA expression in diverse nervous system cell types, revealing dramatic heterogeneity in the expression of tRNA genes between populations. We found that while maintenance of levels of tRNA isoacceptor families is critical for cellular homeostasis, neurons are differentially vulnerable to insults to distinct tRNA isoacceptor families. Cell-type-specific translatome analysis suggests that the balance between tRNA availability and codon demand may underlie such differential resilience. Our work provides a platform for investigating the complexities of mRNA translation and tRNA biology in the brain.
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Affiliation(s)
- Mridu Kapur
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute
| | - Michael J Molumby
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute
| | - Carlos Guzman
- Department of Medicine, Division of Endocrinology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, Bioinformatics & Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sven Heinz
- Department of Medicine, Division of Endocrinology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, Bioinformatics & Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute; Department of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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4
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Čáp M, Palková Z. Non-Coding RNAs: Regulators of Stress, Ageing, and Developmental Decisions in Yeast? Cells 2024; 13:599. [PMID: 38607038 PMCID: PMC11012152 DOI: 10.3390/cells13070599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/19/2024] [Accepted: 03/27/2024] [Indexed: 04/13/2024] Open
Abstract
Cells must change their properties in order to adapt to a constantly changing environment. Most of the cellular sensing and regulatory mechanisms described so far are based on proteins that serve as sensors, signal transducers, and effectors of signalling pathways, resulting in altered cell physiology. In recent years, however, remarkable examples of the critical role of non-coding RNAs in some of these regulatory pathways have been described in various organisms. In this review, we focus on all classes of non-coding RNAs that play regulatory roles during stress response, starvation, and ageing in different yeast species as well as in structured yeast populations. Such regulation can occur, for example, by modulating the amount and functional state of tRNAs, rRNAs, or snRNAs that are directly involved in the processes of translation and splicing. In addition, long non-coding RNAs and microRNA-like molecules are bona fide regulators of the expression of their target genes. Non-coding RNAs thus represent an additional level of cellular regulation that is gradually being uncovered.
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Affiliation(s)
- Michal Čáp
- Department of Genetics and Microbiology, Faculty of Science, Charles University, BIOCEV, 128 00 Prague, Czech Republic
| | - Zdena Palková
- Department of Genetics and Microbiology, Faculty of Science, Charles University, BIOCEV, 128 00 Prague, Czech Republic
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5
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van Breugel ME, van Kruijsbergen I, Mittal C, Lieftink C, Brouwer I, van den Brand T, Kluin RJC, Hoekman L, Menezes RX, van Welsem T, Del Cortona A, Malik M, Beijersbergen RL, Lenstra TL, Verstrepen KJ, Pugh BF, van Leeuwen F. Locus-specific proteome decoding reveals Fpt1 as a chromatin-associated negative regulator of RNA polymerase III assembly. Mol Cell 2023; 83:4205-4221.e9. [PMID: 37995691 PMCID: PMC11289708 DOI: 10.1016/j.molcel.2023.10.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023]
Abstract
Transcription of tRNA genes by RNA polymerase III (RNAPIII) is tuned by signaling cascades. The emerging notion of differential tRNA gene regulation implies the existence of additional regulatory mechanisms. However, tRNA gene-specific regulators have not been described. Decoding the local chromatin proteome of a native tRNA gene in yeast revealed reprogramming of the RNAPIII transcription machinery upon nutrient perturbation. Among the dynamic proteins, we identified Fpt1, a protein of unknown function that uniquely occupied RNAPIII-regulated genes. Fpt1 binding at tRNA genes correlated with the efficiency of RNAPIII eviction upon nutrient perturbation and required the transcription factors TFIIIB and TFIIIC but not RNAPIII. In the absence of Fpt1, eviction of RNAPIII was reduced, and the shutdown of ribosome biogenesis genes was impaired upon nutrient perturbation. Our findings provide support for a chromatin-associated mechanism required for RNAPIII eviction from tRNA genes and tuning the physiological response to changing metabolic demands.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Ila van Kruijsbergen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Chitvan Mittal
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
| | - Cor Lieftink
- Division of Molecular Carcinogenesis and Robotics and Screening Center, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Ineke Brouwer
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066 CX, the Netherlands
| | - Teun van den Brand
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Roelof J C Kluin
- Genomics Core Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Liesbeth Hoekman
- Proteomics Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Renée X Menezes
- Biostatistics Centre and Division of Psychosocial Research and Epidemiology, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Tibor van Welsem
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Andrea Del Cortona
- VIB-KU Leuven Center for Microbiology, KU Leuven, 3001 Heverlee-Leuven, Belgium
| | - Muddassir Malik
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis and Robotics and Screening Center, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Genomics Core Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066 CX, the Netherlands
| | - Kevin J Verstrepen
- VIB-KU Leuven Center for Microbiology, KU Leuven, 3001 Heverlee-Leuven, Belgium
| | - B Franklin Pugh
- Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands.
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6
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Foo JL, Kitano S, Susanto AV, Jin Z, Lin Y, Luo Z, Huang L, Liang Z, Mitchell LA, Yang K, Wong A, Cai Y, Cai J, Stracquadanio G, Bader JS, Boeke JD, Dai J, Chang MW. Establishing chromosomal design-build-test-learn through a synthetic chromosome and its combinatorial reconfiguration. CELL GENOMICS 2023; 3:100435. [PMID: 38020970 PMCID: PMC10667554 DOI: 10.1016/j.xgen.2023.100435] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/19/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023]
Abstract
Chromosome-level design-build-test-learn cycles (chrDBTLs) allow systematic combinatorial reconfiguration of chromosomes with ease. Here, we established chrDBTL with a redesigned synthetic Saccharomyces cerevisiae chromosome XV, synXV. We designed and built synXV to harbor strategically inserted features, modified elements, and synonymously recoded genes throughout the chromosome. Based on the recoded chromosome, we developed a method to enable chrDBTL: CRISPR-Cas9-mediated mitotic recombination with endoreduplication (CRIMiRE). CRIMiRE allowed the creation of customized wild-type/synthetic combinations, accelerating genotype-phenotype mapping and synthetic chromosome redesign. We also leveraged synXV as a "build-to-learn" model organism for translation studies by ribosome profiling. We conducted a locus-to-locus comparison of ribosome occupancy between synXV and the wild-type chromosome, providing insight into the effects of codon changes and redesigned features on translation dynamics in vivo. Overall, we established synXV as a versatile reconfigurable system that advances chrDBTL for understanding biological mechanisms and engineering strains.
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Affiliation(s)
- Jee Loon Foo
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
- Wilmar-NUS Corporate Laboratory (WIL@NUS), National University of Singapore, Singapore 117599, Singapore
| | - Shohei Kitano
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
- Wilmar-NUS Corporate Laboratory (WIL@NUS), National University of Singapore, Singapore 117599, Singapore
| | - Adelia Vicanatalita Susanto
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
- Wilmar-NUS Corporate Laboratory (WIL@NUS), National University of Singapore, Singapore 117599, Singapore
| | - Zhu Jin
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
- Wilmar-NUS Corporate Laboratory (WIL@NUS), National University of Singapore, Singapore 117599, Singapore
| | - Yicong Lin
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Zhouqing Luo
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Linsen Huang
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Zhenzhen Liang
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Leslie A. Mitchell
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA
| | - Kun Yang
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Adison Wong
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
- Singapore Institute of Technology, 10 Dover Drive, Singapore 138683, Singapore
| | - Yizhi Cai
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Jitong Cai
- High-Throughput Biological Center and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Giovanni Stracquadanio
- High-Throughput Biological Center and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Joel S. Bader
- High-Throughput Biological Center and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jef D. Boeke
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Junbiao Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Matthew Wook Chang
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
- Wilmar-NUS Corporate Laboratory (WIL@NUS), National University of Singapore, Singapore 117599, Singapore
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7
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Davyt M, Bharti N, Ignatova Z. Effect of mRNA/tRNA mutations on translation speed: Implications for human diseases. J Biol Chem 2023; 299:105089. [PMID: 37495112 PMCID: PMC10470029 DOI: 10.1016/j.jbc.2023.105089] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 07/28/2023] Open
Abstract
Recent discoveries establish tRNAs as central regulators of mRNA translation dynamics, and therefore cotranslational folding and function of the encoded protein. The tRNA pool, whose composition and abundance change in a cell- and tissue-dependent manner, is the main factor which determines mRNA translation velocity. In this review, we discuss a group of pathogenic mutations, in the coding sequences of either protein-coding genes or in tRNA genes, that alter mRNA translation dynamics. We also summarize advances in tRNA biology that have uncovered how variations in tRNA levels on account of genetic mutations affect protein folding and function, and thereby contribute to phenotypic diversity in clinical manifestations.
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Affiliation(s)
- Marcos Davyt
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Nikhil Bharti
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
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8
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Hughes LA, Rudler DL, Siira SJ, McCubbin T, Raven SA, Browne JM, Ermer JA, Rientjes J, Rodger J, Marcellin E, Rackham O, Filipovska A. Copy number variation in tRNA isodecoder genes impairs mammalian development and balanced translation. Nat Commun 2023; 14:2210. [PMID: 37072429 PMCID: PMC10113395 DOI: 10.1038/s41467-023-37843-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/29/2023] [Indexed: 04/20/2023] Open
Abstract
The number of tRNA isodecoders has increased dramatically in mammals, but the specific molecular and physiological reasons for this expansion remain elusive. To address this fundamental question we used CRISPR editing to knockout the seven-membered phenylalanine tRNA gene family in mice, both individually and combinatorially. Using ATAC-Seq, RNA-seq, ribo-profiling and proteomics we observed distinct molecular consequences of single tRNA deletions. We show that tRNA-Phe-1-1 is required for neuronal function and its loss is partially compensated by increased expression of other tRNAs but results in mistranslation. In contrast, the other tRNA-Phe isodecoder genes buffer the loss of each of the remaining six tRNA-Phe genes. In the tRNA-Phe gene family, the expression of at least six tRNA-Phe alleles is required for embryonic viability and tRNA-Phe-1-1 is most important for development and survival. Our results reveal that the multi-copy configuration of tRNA genes is required to buffer translation and viability in mammals.
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Affiliation(s)
- Laetitia A Hughes
- Harry Perkins Institute of Medical Research, Perth, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Danielle L Rudler
- Harry Perkins Institute of Medical Research, Perth, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research, Perth, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Tim McCubbin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Samuel A Raven
- Harry Perkins Institute of Medical Research, Perth, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Jasmin M Browne
- Harry Perkins Institute of Medical Research, Perth, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Judith A Ermer
- Harry Perkins Institute of Medical Research, Perth, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Jeanette Rientjes
- Monash Genome Modification Platform, Monash University, 35 Rainforest Walk, Clayton, VIC, 3800, Australia
| | - Jennifer Rodger
- School of Biological Sciences (Physiology), The University of Western Australia, Crawley, WA, 6009, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA, 6009, Australia
| | - Esteban Marcellin
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, 4072, QLD, Australia
- Queensland Metabolomics and Proteomics (Q-MAP), The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, Perth, WA, Australia.
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia.
- Curtin Medical School, Curtin University, Bentley, WA, 6102, Australia.
- Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, 6102, Australia.
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia.
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, Perth, WA, Australia.
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA, 6009, Australia.
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA, 6009, Australia.
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia.
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9
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Raval PK, Ngan WY, Gallie J, Agashe D. The layered costs and benefits of translational redundancy. eLife 2023; 12:81005. [PMID: 36862572 PMCID: PMC9981150 DOI: 10.7554/elife.81005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 01/25/2023] [Indexed: 03/03/2023] Open
Abstract
The rate and accuracy of translation hinges upon multiple components - including transfer RNA (tRNA) pools, tRNA modifying enzymes, and rRNA molecules - many of which are redundant in terms of gene copy number or function. It has been hypothesized that the redundancy evolves under selection, driven by its impacts on growth rate. However, we lack empirical measurements of the fitness costs and benefits of redundancy, and we have poor a understanding of how this redundancy is organized across components. We manipulated redundancy in multiple translation components of Escherichia coli by deleting 28 tRNA genes, 3 tRNA modifying systems, and 4 rRNA operons in various combinations. We find that redundancy in tRNA pools is beneficial when nutrients are plentiful and costly under nutrient limitation. This nutrient-dependent cost of redundant tRNA genes stems from upper limits to translation capacity and growth rate, and therefore varies as a function of the maximum growth rate attainable in a given nutrient niche. The loss of redundancy in rRNA genes and tRNA modifying enzymes had similar nutrient-dependent fitness consequences. Importantly, these effects are also contingent upon interactions across translation components, indicating a layered hierarchy from copy number of tRNA and rRNA genes to their expression and downstream processing. Overall, our results indicate both positive and negative selection on redundancy in translation components, depending on a species' evolutionary history with feasts and famines.
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Affiliation(s)
- Parth K Raval
- National Centre for Biological Sciences (NCBS-TIFR)BengaluruIndia
| | - Wing Yui Ngan
- Max Plank Institute for Evolutionary BiologyPlönGermany
| | - Jenna Gallie
- Max Plank Institute for Evolutionary BiologyPlönGermany
| | - Deepa Agashe
- National Centre for Biological Sciences (NCBS-TIFR)BengaluruIndia
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10
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Cozma E, Rao M, Dusick M, Genereaux J, Rodriguez-Mias RA, Villén J, Brandl CJ, Berg MD. Anticodon sequence determines the impact of mistranslating tRNA Ala variants. RNA Biol 2023; 20:791-804. [PMID: 37776539 PMCID: PMC10543346 DOI: 10.1080/15476286.2023.2257471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2023] [Indexed: 10/02/2023] Open
Abstract
Transfer RNAs (tRNAs) maintain translation fidelity through accurate charging by their cognate aminoacyl-tRNA synthetase and codon:anticodon base pairing with the mRNA at the ribosome. Mistranslation occurs when an amino acid not specified by the genetic message is incorporated into proteins and has applications in biotechnology, therapeutics and is relevant to disease. Since the alanyl-tRNA synthetase uniquely recognizes a G3:U70 base pair in tRNAAla and the anticodon plays no role in charging, tRNAAla variants with anticodon mutations have the potential to mis-incorporate alanine. Here, we characterize the impact of the 60 non-alanine tRNAAla anticodon variants on the growth of Saccharomyces cerevisiae. Overall, 36 tRNAAla anticodon variants decreased growth in single- or multi-copy. Mass spectrometry analysis of the cellular proteome revealed that 52 of 57 anticodon variants, not decoding alanine or stop codons, induced mistranslation when on single-copy plasmids. Variants with G/C-rich anticodons resulted in larger growth deficits than A/U-rich variants. In most instances, synonymous anticodon variants impact growth differently, with anticodons containing U at base 34 being the least impactful. For anticodons generating the same amino acid substitution, reduced growth generally correlated with the abundance of detected mistranslation events. Differences in decoding specificity, even between synonymous anticodons, resulted in each tRNAAla variant mistranslating unique sets of peptides and proteins. We suggest that these differences in decoding specificity are also important in determining the impact of tRNAAla anticodon variants.
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Affiliation(s)
- Ecaterina Cozma
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Megha Rao
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Madison Dusick
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Julie Genereaux
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | | | - Judit Villén
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Christopher J. Brandl
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Matthew D. Berg
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
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11
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Disproportionate investment in Spiralin B production limits in-host growth and favors the vertical transmission of Spiroplasma insect endosymbionts. Proc Natl Acad Sci U S A 2022; 119:e2208461119. [PMID: 35858432 PMCID: PMC9335233 DOI: 10.1073/pnas.2208461119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Insects frequently harbor endosymbionts, which are bacteria housed within host tissues. These associations are stably maintained over evolutionary timescales through vertical transmission of endosymbionts from host mothers to their offspring. Some endosymbionts manipulate host reproduction to facilitate spread within natural populations. Consequently, such infections have major impacts on insect physiology and evolution. However, technical hurdles have limited our understanding of the molecular mechanisms underlying such insect-endosymbiont interactions. Here, we investigate the nutritional interactions between endosymbiotic partners using the tractable insect Drosophila melanogaster and its natural endosymbiont Spiroplasma poulsonii. Using a combination of functional assays, metabolomics, and proteomics, we show that the abundance and amino acid composition of a single Spiroplasma membrane lectin, Spiralin B (SpiB), dictates the amino acid requirements of the endosymbiont and determines its proliferation within host tissues. Ectopically increasing SpiB levels in host tissues disrupts localization of endosymbionts in the fly egg chambers and decreases vertical transmission. We find that SpiB is likely to be required by the endosymbiont to enter host oocytes, which may explain the massive investment of S. poulsonii in SpiB synthesis. SpiB both permits vertical transmission of the symbiont and limits its growth in nutrient-limiting conditions for the host; therefore, a single protein plays a pivotal role in ensuring durability of the interaction in a variable environment.
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12
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Reprogramming mRNA Expression in Response to Defect in RNA Polymerase III Assembly in the Yeast Saccharomyces cerevisiae. Int J Mol Sci 2021; 22:ijms22147298. [PMID: 34298922 PMCID: PMC8306304 DOI: 10.3390/ijms22147298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/25/2021] [Accepted: 07/03/2021] [Indexed: 12/18/2022] Open
Abstract
The coordinated transcription of the genome is the fundamental mechanism in molecular biology. Transcription in eukaryotes is carried out by three main RNA polymerases: Pol I, II, and III. One basic problem is how a decrease in tRNA levels, by downregulating Pol III efficiency, influences the expression pattern of protein-coding genes. The purpose of this study was to determine the mRNA levels in the yeast mutant rpc128-1007 and its overdose suppressors, RBS1 and PRT1. The rpc128-1007 mutant prevents assembly of the Pol III complex and functionally mimics similar mutations in human Pol III, which cause hypomyelinating leukodystrophies. We applied RNAseq followed by the hierarchical clustering of our complete RNA-seq transcriptome and functional analysis of genes from the clusters. mRNA upregulation in rpc128-1007 cells was generally stronger than downregulation. The observed induction of mRNA expression was mostly indirect and resulted from the derepression of general transcription factor Gcn4, differently modulated by suppressor genes. rpc128-1007 mutation, regardless of the presence of suppressors, also resulted in a weak increase in the expression of ribosome biogenesis genes. mRNA genes that were downregulated by the reduction of Pol III assembly comprise the proteasome complex. In summary, our results provide the regulatory links affected by Pol III assembly that contribute differently to cellular fitness.
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13
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Genome-Wide Essentiality Analysis of Mycobacterium abscessus by Saturated Transposon Mutagenesis and Deep Sequencing. mBio 2021; 12:e0104921. [PMID: 34126767 PMCID: PMC8262987 DOI: 10.1128/mbio.01049-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium abscessus is an emerging opportunistic human pathogen that naturally resists most major classes of antibiotics, making infections difficult to treat. Thus far, little is known about M. abscessus physiology, pathogenesis, and drug resistance. Genome-wide analyses have comprehensively catalogued genes with essential functions in Mycobacterium tuberculosis and Mycobacterium avium subsp. hominissuis (here, M. avium) but not in M. abscessus. By optimizing transduction conditions, we achieved full saturation of TA insertion sites with Himar1 transposon mutagenesis in the M. abscessus ATCC 19977T genome, as confirmed by deep sequencing prior to essentiality analyses of annotated genes and other genomic features. The overall densities of inserted TA sites (85.7%), unoccupied TA sites (14.3%), and nonpermissive TA sites (8.1%) were similar to results in M. tuberculosis and M. avium. Of the 4,920 annotated genes, 326 were identified as essential, 269 (83%) of which have mutual homology with essential M. tuberculosis genes, while 39 (12%) are homologous to genes that are not essential in M. tuberculosis and M. avium, and 11 (3.4%) only have homologs in M. avium. Interestingly, 7 (2.1%) essential M. abscessus genes have no homologs in either M. tuberculosis or M. avium, two of which were found in phage-like elements. Most essential genes are involved in DNA replication, RNA transcription and translation, and posttranslational events to synthesize important macromolecules. Some essential genes may be involved in M. abscessus pathogenesis and antibiotics response, including certain essential tRNAs and new short open reading frames. Our findings will help to pave the way for better understanding of M. abscessus and benefit development of novel bactericidal drugs against M. abscessus. IMPORTANCE Limited knowledge regarding Mycobacterium abscessus pathogenesis and intrinsic resistance to most classes of antibiotics is a major obstacle to developing more effective strategies to prevent and mitigate disease. Using optimized procedures for Himar1 transposon mutagenesis and deep sequencing, we performed a comprehensive analysis to identify M. abscessus genetic elements essential for in vitro growth and compare them to similar data sets for M. tuberculosis and M. avium subsp. hominissuis. Most essential M. abscessus genes have mutual homology with essential M. tuberculosis genes, providing a foundation for leveraging available knowledge from M. tuberculosis to develop more effective drugs and other interventions against M. abscessus. A small number of essential genes unique to M. abscessus deserve further attention to gain insights into what makes M. abscessus different from other mycobacteria. The essential genes and other genomic features such as short open reading frames and noncoding RNA identified here will provide useful information for future study of M. abscessus pathogenicity and new drug development.
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14
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Guimarães AR, Correia I, Sousa I, Oliveira C, Moura G, Bezerra AR, Santos MAS. tRNAs as a Driving Force of Genome Evolution in Yeast. Front Microbiol 2021; 12:634004. [PMID: 33776966 PMCID: PMC7990762 DOI: 10.3389/fmicb.2021.634004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
Transfer RNAs (tRNAs) are widely known for their roles in the decoding of the linear mRNA information into amino acid sequences of proteins. They are also multifunctional platforms in the translation process and have other roles beyond translation, including sensing amino acid abundance, interacting with the general stress response machinery, and modulating cellular adaptation, survival, and death. In this mini-review, we focus on the emerging role of tRNA genes in the organization and modification of the genomic architecture of yeast and the role of tRNA misexpression and decoding infidelity in genome stability, evolution, and adaption. We discuss published work showing how quickly tRNA genes can mutate to meet novel translational demands, how tRNAs speed up genome evolution, and how tRNA genes can be sites of genomic instability. We highlight recent works showing that loss of tRNA decoding fidelity and small alterations in tRNA expression have unexpected and profound impacts on genome stability. By dissecting these recent evidence, we hope to lay the groundwork that prompts future investigations on the mechanistic interplay between tRNAs and genome modification that likely triggers genome evolution.
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Affiliation(s)
- Ana Rita Guimarães
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Inês Correia
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Inês Sousa
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Carla Oliveira
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Gabriela Moura
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ana Rita Bezerra
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Manuel A S Santos
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
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15
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Deparis Q, Duitama J, Foulquié-Moreno MR, Thevelein JM. Whole-Genome Transformation Promotes tRNA Anticodon Suppressor Mutations under Stress. mBio 2021; 12:e03649-20. [PMID: 33758086 PMCID: PMC8092322 DOI: 10.1128/mbio.03649-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/16/2021] [Indexed: 11/20/2022] Open
Abstract
tRNAs are encoded by a large gene family, usually with several isogenic tRNAs interacting with the same codon. Mutations in the anticodon region of other tRNAs can overcome specific tRNA deficiencies. Phylogenetic analysis suggests that such mutations have occurred in evolution, but the driving force is unclear. We show that in yeast suppressor mutations in other tRNAs are able to overcome deficiency of the essential TRT2-encoded tRNAThrCGU at high temperature (40°C). Surprisingly, these tRNA suppressor mutations were obtained after whole-genome transformation with DNA from thermotolerant Kluyveromyces marxianus or Ogataea polymorpha strains but from which the mutations did apparently not originate. We suggest that transient presence of donor DNA in the host facilitates proliferation at high temperature and thus increases the chances for occurrence of spontaneous mutations suppressing defective growth at high temperature. Whole-genome sequence analysis of three transformants revealed only four to five nonsynonymous mutations of which one causing TRT2 anticodon stem stabilization and two anticodon mutations in non-threonyl-tRNAs, tRNALysCUU and tRNAeMetCAU, were causative. Both anticodon mutations suppressed lethality of TRT2 deletion and apparently caused the respective tRNAs to become novel substrates for threonyl-tRNA synthetase. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) data could not detect any significant mistranslation, and reverse transcription-quantitative PCR results contradicted induction of the unfolded protein response. We suggest that stress conditions have been a driving force in evolution for the selection of anticodon-switching mutations in tRNAs as revealed by phylogenetic analysis.IMPORTANCE In this work, we have identified for the first time the causative elements in a eukaryotic organism introduced by applying whole-genome transformation and responsible for the selectable trait of interest, i.e., high temperature tolerance. Surprisingly, the whole-genome transformants contained just a few single nucleotide polymorphisms (SNPs), which were unrelated to the sequence of the donor DNA. In each of three independent transformants, we have identified a SNP in a tRNA, either stabilizing the essential tRNAThrCGU at high temperature or switching the anticodon of tRNALysCUU or tRNAeMetCAU into CGU, which is apparently enough for in vivo recognition by threonyl-tRNA synthetase. LC-MS/MS analysis indeed indicated absence of significant mistranslation. Phylogenetic analysis showed that similar mutations have occurred throughout evolution and we suggest that stress conditions may have been a driving force for their selection. The low number of SNPs introduced by whole-genome transformation may favor its application for improvement of industrial yeast strains.
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Affiliation(s)
- Quinten Deparis
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Flanders, Belgium
| | - Jorge Duitama
- Systems and Computing Engineering Department, Universidad de los Andes, Bogotá, Colombia
| | - Maria R Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Flanders, Belgium
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Flanders, Belgium
- NovelYeast bv, Open Bio-Incubator, Erasmus High School, Brussels (Jette), Belgium
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16
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Buyel JF, Stöger E, Bortesi L. Targeted genome editing of plants and plant cells for biomanufacturing. Transgenic Res 2021; 30:401-426. [PMID: 33646510 PMCID: PMC8316201 DOI: 10.1007/s11248-021-00236-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/03/2021] [Indexed: 02/07/2023]
Abstract
Plants have provided humans with useful products since antiquity, but in the last 30 years they have also been developed as production platforms for small molecules and recombinant proteins. This initially niche area has blossomed with the growth of the global bioeconomy, and now includes chemical building blocks, polymers and renewable energy. All these applications can be described as “plant molecular farming” (PMF). Despite its potential to increase the sustainability of biologics manufacturing, PMF has yet to be embraced broadly by industry. This reflects a combination of regulatory uncertainty, limited information on process cost structures, and the absence of trained staff and suitable manufacturing capacity. However, the limited adaptation of plants and plant cells to the requirements of industry-scale manufacturing is an equally important hurdle. For example, the targeted genetic manipulation of yeast has been common practice since the 1980s, whereas reliable site-directed mutagenesis in most plants has only become available with the advent of CRISPR/Cas9 and similar genome editing technologies since around 2010. Here we summarize the applications of new genetic engineering technologies to improve plants as biomanufacturing platforms. We start by identifying current bottlenecks in manufacturing, then illustrate the progress that has already been made and discuss the potential for improvement at the molecular, cellular and organism levels. We discuss the effects of metabolic optimization, adaptation of the endomembrane system, modified glycosylation profiles, programmable growth and senescence, protease inactivation, and the expression of enzymes that promote biodegradation. We outline strategies to achieve these modifications by targeted gene modification, considering case-by-case examples of individual improvements and the combined modifications needed to generate a new general-purpose “chassis” for PMF.
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Affiliation(s)
- J F Buyel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074, Aachen, Germany. .,Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
| | - E Stöger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - L Bortesi
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD, Geleen, The Netherlands
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17
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Berg MD, Brandl CJ. Transfer RNAs: diversity in form and function. RNA Biol 2021; 18:316-339. [PMID: 32900285 PMCID: PMC7954030 DOI: 10.1080/15476286.2020.1809197] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/31/2020] [Accepted: 08/08/2020] [Indexed: 12/11/2022] Open
Abstract
As the adaptor that decodes mRNA sequence into protein, the basic aspects of tRNA structure and function are central to all studies of biology. Yet the complexities of their properties and cellular roles go beyond the view of tRNAs as static participants in protein synthesis. Detailed analyses through more than 60 years of study have revealed tRNAs to be a fascinatingly diverse group of molecules in form and function, impacting cell biology, physiology, disease and synthetic biology. This review analyzes tRNA structure, biosynthesis and function, and includes topics that demonstrate their diversity and growing importance.
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Affiliation(s)
- Matthew D. Berg
- Department of Biochemistry, The University of Western Ontario, London, Canada
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18
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Swamy KBS, Schuyler SC, Leu JY. Protein Complexes Form a Basis for Complex Hybrid Incompatibility. Front Genet 2021; 12:609766. [PMID: 33633780 PMCID: PMC7900514 DOI: 10.3389/fgene.2021.609766] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/20/2021] [Indexed: 12/20/2022] Open
Abstract
Proteins are the workhorses of the cell and execute many of their functions by interacting with other proteins forming protein complexes. Multi-protein complexes are an admixture of subunits, change their interaction partners, and modulate their functions and cellular physiology in response to environmental changes. When two species mate, the hybrid offspring are usually inviable or sterile because of large-scale differences in the genetic makeup between the two parents causing incompatible genetic interactions. Such reciprocal-sign epistasis between inter-specific alleles is not limited to incompatible interactions between just one gene pair; and, usually involves multiple genes. Many of these multi-locus incompatibilities show visible defects, only in the presence of all the interactions, making it hard to characterize. Understanding the dynamics of protein-protein interactions (PPIs) leading to multi-protein complexes is better suited to characterize multi-locus incompatibilities, compared to studying them with traditional approaches of genetics and molecular biology. The advances in omics technologies, which includes genomics, transcriptomics, and proteomics can help achieve this end. This is especially relevant when studying non-model organisms. Here, we discuss the recent progress in the understanding of hybrid genetic incompatibility; omics technologies, and how together they have helped in characterizing protein complexes and in turn multi-locus incompatibilities. We also review advances in bioinformatic techniques suitable for this purpose and propose directions for leveraging the knowledge gained from model-organisms to identify genetic incompatibilities in non-model organisms.
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Affiliation(s)
- Krishna B. S. Swamy
- Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Ahmedabad, India
| | - Scott C. Schuyler
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Division of Head and Neck Surgery, Department of Otolaryngology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jun-Yi Leu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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19
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Pavlova NN, King B, Josselsohn RH, Violante S, Macera VL, Vardhana SA, Cross JR, Thompson CB. Translation in amino-acid-poor environments is limited by tRNA Gln charging. eLife 2020; 9:62307. [PMID: 33289483 PMCID: PMC7744096 DOI: 10.7554/elife.62307] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
An inadequate supply of amino acids leads to accumulation of uncharged tRNAs, which can bind and activate GCN2 kinase to reduce translation. Here, we show that glutamine-specific tRNAs selectively become uncharged when extracellular amino acid availability is compromised. In contrast, all other tRNAs retain charging of their cognate amino acids in a manner that is dependent upon intact lysosomal function. In addition to GCN2 activation and reduced total translation, the reduced charging of tRNAGln in amino-acid-deprived cells also leads to specific depletion of proteins containing polyglutamine tracts including core-binding factor α1, mediator subunit 12, transcriptional coactivator CBP and TATA-box binding protein. Treating amino-acid-deprived cells with exogenous glutamine or glutaminase inhibitors restores tRNAGln charging and the levels of polyglutamine-containing proteins. Together, these results demonstrate that the activation of GCN2 and the translation of polyglutamine-encoding transcripts serve as key sensors of glutamine availability in mammalian cells.
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Affiliation(s)
- Natalya N Pavlova
- Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Bryan King
- Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Rachel H Josselsohn
- Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Sara Violante
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Victoria L Macera
- Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Santosha A Vardhana
- Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Justin R Cross
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Craig B Thompson
- Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, United States
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20
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Shukla A, Bhalla P, Potdar PK, Jampala P, Bhargava P. Transcription-dependent enrichment of the yeast FACT complex influences nucleosome dynamics on the RNA polymerase III-transcribed genes. RNA (NEW YORK, N.Y.) 2020; 27:rna.077974.120. [PMID: 33277439 PMCID: PMC7901838 DOI: 10.1261/rna.077974.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 11/30/2020] [Indexed: 05/04/2023]
Abstract
The FACT (FAcilitates Chromatin Transactions) complex influences transcription initiation and enables passage of RNA polymerase (pol) II through gene body nucleosomes during elongation. In the budding yeast, ~280 non-coding RNA genes highly transcribed in vivo by pol III are found in the nucleosome-free regions bordered by positioned nucleosomes. The downstream nucleosome dynamics was found to regulate transcription via controlling the gene terminator accessibility and hence, terminator-dependent pol III recycling. As opposed to the enrichment at the 5'-ends of pol II-transcribed genes, our genome-wide mapping found transcription-dependent enrichment of the FACT subunit Spt16 near the 3'-end of all pol III-transcribed genes. Spt16 physically associates with the pol III transcription complex and shows gene-specific occupancy levels on the individual genes. On the non-tRNA pol III-transcribed genes, Spt16 facilitates transcription by reducing the nucleosome occupany on the gene body. On the tRNA genes, it maintains the position of the nucleosome at the 3' gene-end and affects transcription in gene-specific manner. Under nutritional stress, Spt16 enrichment is abolished in the gene downstream region of all pol III-transcribed genes and reciprocally changed on the induced or repressed pol II-transcribed ESR genes. Under the heat and replicative stress, its occupancy on the pol III-transcribed genes increases significantly. Our results show that Spt16 elicits a differential, gene-specific and stress-responsive dynamics, which provides a novel stress-sensor mechanism of regulating transcription against external stress. By primarily influencing the nucleosomal organization, FACT links the downstream nucleosome dynamics to transcription and environmental stress on the pol III-transcribed genes.
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21
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Kim M, van Hoof A. Suppressors of mRNA Decapping Defects Restore Growth Without Major Effects on mRNA Decay Rates or Abundance. Genetics 2020; 216:1051-1069. [PMID: 32998951 PMCID: PMC7768250 DOI: 10.1534/genetics.120.303641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/28/2020] [Indexed: 01/09/2023] Open
Abstract
Faithful degradation of mRNAs is a critical step in gene expression, and eukaryotes share a major conserved mRNA decay pathway. In this major pathway, the two rate-determining steps in mRNA degradation are the initial gradual removal of the poly(A) tail, followed by removal of the cap structure. Removal of the cap structure is carried out by the decapping enzyme, containing the Dcp2 catalytic subunit. Although the mechanism and regulation of mRNA decay is well understood, the consequences of defects in mRNA degradation are less clear. Dcp2 has been reported as either essential or nonessential. Here, we clarify that Dcp2 is not absolutely required for spore germination and extremely slow growth, but in practical terms it is impossible to continuously culture dcp2∆ under laboratory conditions without suppressors arising. We show that null mutations in at least three different genes are each sufficient to restore growth to a dcp2∆, of which kap123∆ and tl(gag)g∆ appear the most specific. We show that kap123∆ and tl(gag)g∆ suppress dcp2 by mechanisms that are different from each other and from previously isolated dcp2 suppressors. The suppression mechanism for tL(GAG)G is determined by the unique GAG anticodon of this tRNA, and thus likely by translation of some CUC or CUU codons. Unlike previously reported suppressors of decapping defects, these suppressors do not detectably restore decapping or mRNA decay to normal rates, but instead allow survival while only modestly affecting RNA homeostasis. These results provide important new insight into the importance of decapping, resolve previously conflicting publications about the essentiality of DCP2, provide the first phenotype for a tl(gag)g mutant, and show that multiple distinct mechanisms can bypass Dcp2 requirement.
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Affiliation(s)
- Minseon Kim
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ambro van Hoof
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
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22
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Construction of anti-codon table of the plant kingdom and evolution of tRNA selenocysteine (tRNA Sec). BMC Genomics 2020; 21:804. [PMID: 33213362 PMCID: PMC7678280 DOI: 10.1186/s12864-020-07216-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/08/2020] [Indexed: 12/26/2022] Open
Abstract
Background The tRNAs act as a bridge between the coding mRNA and incoming amino acids during protein translation. The anti-codon of tRNA recognizes the codon of the mRNA and deliver the amino acid into the protein translation chain. However, we did not know about the exact abundance of anti-codons in the genome and whether the frequency of abundance remains same across the plant lineage or not. Results Therefore, we analysed the tRNAnome of 128 plant species and reported an anti-codon table of the plant kingdom. We found that CAU anti-codon of tRNAMet has highest (5.039%) whereas GCG anti-codon of tRNAArg has lowest (0.004%) abundance. However, when we compared the anti-codon frequencies according to the tRNA isotypes, we found tRNALeu (7.808%) has highest abundance followed by tRNASer (7.668%) and tRNAGly (7.523%). Similarly, suppressor tRNA (0.036%) has lowest abundance followed by tRNASec (0.066%) and tRNAHis (2.109). The genome of Ipomoea nil, Papaver somniferum, and Zea mays encoded the highest number of anti-codons (isoacceptor) at 59 each whereas the genome of Ostreococcus tauri was found to encode only 18 isoacceptors. The tRNASec genes undergone losses more frequently than duplication and we found that tRNASec showed anti-codon switch during the course of evolution. Conclusion The anti-codon table of the plant tRNA will enable us to understand the synonymous codon usage of the plant kingdom and can be very helpful to understand which codon is preferred over other during the translation. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-020-07216-3.
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23
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Schäck MA, Jablonski KP, Gräf S, Klassen R, Schaffrath R, Kellner S, Hammann C. Eukaryotic life without tQCUG: the role of Elongator-dependent tRNA modifications in Dictyostelium discoideum. Nucleic Acids Res 2020; 48:7899-7913. [PMID: 32609816 PMCID: PMC7430636 DOI: 10.1093/nar/gkaa560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/16/2020] [Accepted: 06/18/2020] [Indexed: 12/23/2022] Open
Abstract
In the Elongator-dependent modification pathway, chemical modifications are introduced at the wobble uridines at position 34 in transfer RNAs (tRNAs), which serve to optimize codon translation rates. Here, we show that this three-step modification pathway exists in Dictyostelium discoideum, model of the evolutionary superfamily Amoebozoa. Not only are previously established modifications observable by mass spectrometry in strains with the most conserved genes of each step deleted, but also additional modifications are detected, indicating a certain plasticity of the pathway in the amoeba. Unlike described for yeast, D. discoideum allows for an unconditional deletion of the single tQCUG gene, as long as the Elongator-dependent modification pathway is intact. In gene deletion strains of the modification pathway, protein amounts are significantly reduced as shown by flow cytometry and Western blotting, using strains expressing different glutamine leader constructs fused to GFP. Most dramatic are these effects, when the tQCUG gene is deleted, or Elp3, the catalytic component of the Elongator complex is missing. In addition, Elp3 is the most strongly conserved protein of the modification pathway, as our phylogenetic analysis reveals. The implications of this observation are discussed with respect to the evolutionary age of the components acting in the Elongator-dependent modification pathway.
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Affiliation(s)
- Manfred A Schäck
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, DE 28759 Bremen, Germany
| | - Kim Philipp Jablonski
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, DE 28759 Bremen, Germany
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Roland Klassen
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Raffael Schaffrath
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Stefanie Kellner
- Department of Chemistry and Pharmacy, Ludwig-Maximilians University Munich, Butenandtstr. 5-13, 81377 Munich, Germany
| | - Christian Hammann
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, DE 28759 Bremen, Germany
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24
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Kapur M, Ganguly A, Nagy G, Adamson SI, Chuang JH, Frankel WN, Ackerman SL. Expression of the Neuronal tRNA n-Tr20 Regulates Synaptic Transmission and Seizure Susceptibility. Neuron 2020; 108:193-208.e9. [PMID: 32853550 DOI: 10.1016/j.neuron.2020.07.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/07/2020] [Accepted: 07/19/2020] [Indexed: 12/31/2022]
Abstract
The mammalian genome has hundreds of nuclear-encoded tRNAs, but the contribution of individual tRNA genes to cellular and organismal function remains unknown. Here, we demonstrate that mutations in a neuronally enriched arginine tRNA, n-Tr20, increased seizure threshold and altered synaptic transmission. n-Tr20 expression also modulated seizures caused by an epilepsy-linked mutation in Gabrg2, a gene encoding a GABAA receptor subunit. Loss of n-Tr20 altered translation initiation by activating the integrated stress response and suppressing mTOR signaling, the latter of which may contribute to altered neurotransmission in mutant mice. Deletion of a highly expressed isoleucine tRNA similarly altered these signaling pathways in the brain, suggesting that regulation of translation initiation is a conserved response to tRNA loss. Our data indicate that loss of a single member of a tRNA family results in multiple cellular phenotypes, highlighting the disease-causing potential of tRNA mutations.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Archan Ganguly
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gabor Nagy
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Scott I Adamson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA; Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT 06030, USA
| | - Jeffrey H Chuang
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Wayne N Frankel
- Institute for Genomic Medicine, Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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25
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Luo Z, Hoffmann SA, Jiang S, Cai Y, Dai J. Probing eukaryotic genome functions with synthetic chromosomes. Exp Cell Res 2020; 390:111936. [PMID: 32165165 DOI: 10.1016/j.yexcr.2020.111936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/25/2020] [Accepted: 02/29/2020] [Indexed: 02/07/2023]
Abstract
The ability to redesign and reconstruct a cell at whole-genome level provides new platforms for biological study. The international synthetic yeast genome project-Sc2.0, designed by interrogating knowledge amassed by the yeast community to date, exemplifies how a classical synthetic biology "design-build-test-learn" engineering cycle can effectively test hypotheses about various genome fundamentals. The genome reshuffling SCRaMbLE system implemented in synthetic yeast strains also provides unprecedented diversified resources for genotype-phenotype study and yeast metabolic engineering. Further development of genome synthesis technology will shed new lights on complex biological processes in higher eukaryotes.
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Affiliation(s)
- Zhouqing Luo
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Stefan A Hoffmann
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, M1 7DN, Manchester, UK
| | - Shuangying Jiang
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Yizhi Cai
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, M1 7DN, Manchester, UK.
| | - Junbiao Dai
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518055, China.
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26
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Calles J, Justice I, Brinkley D, Garcia A, Endy D. Fail-safe genetic codes designed to intrinsically contain engineered organisms. Nucleic Acids Res 2019; 47:10439-10451. [PMID: 31511890 PMCID: PMC6821295 DOI: 10.1093/nar/gkz745] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/13/2019] [Accepted: 08/19/2019] [Indexed: 11/24/2022] Open
Abstract
One challenge in engineering organisms is taking responsibility for their behavior over many generations. Spontaneous mutations arising before or during use can impact heterologous genetic functions, disrupt system integration, or change organism phenotype. Here, we propose restructuring the genetic code itself such that point mutations in protein-coding sequences are selected against. Synthetic genetic systems so-encoded should fail more safely in response to most spontaneous mutations. We designed fail-safe codes and simulated their expected effects on the evolution of so-encoded proteins. We predict fail-safe codes supporting expression of 20 or 15 amino acids could slow protein evolution to ∼30% or 0% the rate of standard-encoded proteins, respectively. We also designed quadruplet-codon codes that should ensure all single point mutations in protein-coding sequences are selected against while maintaining expression of 20 or more amino acids. We demonstrate experimentally that a reduced set of 21 tRNAs is capable of expressing a protein encoded by only 20 sense codons, whereas a standard 64-codon encoding is not expressed. Our work suggests that biological systems using rationally depleted but otherwise natural translation systems should evolve more slowly and that such hypoevolvable organisms may be less likely to invade new niches or outcompete native populations.
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Affiliation(s)
- Jonathan Calles
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
| | - Isaac Justice
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
| | - Detravious Brinkley
- Department of Mathematics and Computer Science, Claflin University, Orangeburg, SC 29115, USA
| | - Alexa Garcia
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
| | - Drew Endy
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
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27
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Liko D, Mitchell L, Campbell KJ, Ridgway RA, Jones C, Dudek K, King A, Bryson S, Stevenson D, Blyth K, Strathdee D, Morton JP, Bird TG, Knight JRP, Willis AE, Sansom OJ. Brf1 loss and not overexpression disrupts tissues homeostasis in the intestine, liver and pancreas. Cell Death Differ 2019; 26:2535-2550. [PMID: 30858608 PMCID: PMC6861133 DOI: 10.1038/s41418-019-0316-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 01/18/2019] [Accepted: 02/13/2019] [Indexed: 12/22/2022] Open
Abstract
RNA polymerase III (Pol-III) transcribes tRNAs and other small RNAs essential for protein synthesis and cell growth. Pol-III is deregulated during carcinogenesis; however, its role in vivo has not been studied. To address this issue, we manipulated levels of Brf1, a Pol-III transcription factor that is essential for recruitment of Pol-III holoenzyme at tRNA genes in vivo. Knockout of Brf1 led to embryonic lethality at blastocyst stage. In contrast, heterozygous Brf1 mice were viable, fertile and of a normal size. Conditional deletion of Brf1 in gastrointestinal epithelial tissues, intestine, liver and pancreas, was incompatible with organ homeostasis. Deletion of Brf1 in adult intestine and liver induced apoptosis. However, Brf1 heterozygosity neither had gross effects in these epithelia nor did it modify tumorigenesis in the intestine or pancreas. Overexpression of BRF1 rescued the phenotypes of Brf1 deletion in intestine and liver but was unable to initiate tumorigenesis. Thus, Brf1 and Pol-III activity are absolutely essential for normal homeostasis during development and in adult epithelia. However, Brf1 overexpression or heterozygosity are unable to modify tumorigenesis, suggesting a permissive, but not driving role for Brf1 in the development of epithelial cancers of the pancreas and gut.
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Affiliation(s)
- Dritan Liko
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Louise Mitchell
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Kirsteen J Campbell
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Rachel A Ridgway
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Carolyn Jones
- MRC Toxicology Unit, Hodgkin Building Lancaster Road, Leicester, LE1 9HN, UK
| | - Kate Dudek
- MRC Toxicology Unit, Hodgkin Building Lancaster Road, Leicester, LE1 9HN, UK
| | - Ayala King
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Sheila Bryson
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - David Stevenson
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Karen Blyth
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1BD, UK
| | - Douglas Strathdee
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Jennifer P Morton
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1BD, UK
| | - Thomas G Bird
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - John R P Knight
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
| | - Anne E Willis
- MRC Toxicology Unit, Hodgkin Building Lancaster Road, Leicester, LE1 9HN, UK
| | - Owen J Sansom
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1BD, UK.
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28
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Cameron A, Zaheer R, McAllister TA. Emerging Variants of the Integrative and Conjugant Element ICE Mh1 in Livestock Pathogens: Structural Insights, Potential Host Range, and Implications for Bacterial Fitness and Antimicrobial Therapy. Front Microbiol 2019; 10:2608. [PMID: 31781082 PMCID: PMC6861422 DOI: 10.3389/fmicb.2019.02608] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/28/2019] [Indexed: 11/23/2022] Open
Abstract
Horizontal gene transfer of integrative and conjugative elements (ICE) in bacterial pathogens of the bovine respiratory disease (BRD) complex has emerged as a significant cause of antimicrobial resistance (AMR) and therapeutic failure and mortalities in cattle. The aim of this study was to assess an AMR ICE occurring in Pasteurella multocida from a case of BRD, designated ICEMh1PM22 for its structure and host genome insertion site, and to identify consequences for host fitness and antimicrobial therapy. The modular structure of ICEMh1-like elements found in several related livestock pathogens was compared to ICEMh1PM22, and the repertoire of cargo genes in variable ICE modules was functionally categorized. AMR genes were identified as frequent additions to the variable modules of ICEMh1-like elements. Random PCR-based mapping of ICEMh1PM22-genome junctions in transconjugants provided evidence that ICEMh1PM22 integrates into the tRNA-leu for the UUG codon, and not into tRNA-leu for other codons. This was separately confirmed in the genomes of ICEMh1-like-harboring livestock pathogens. Bacterial genera harboring receptive tRNA-leuUUG were identified to establish the potential host range of ICEMh1-like elements. ICEMh1PM22-carrying transconjugants in P. multocida and Mannheimia haemolytica were less fit than isogenic strains without the ICE when grown without antimicrobial selection. This fitness cost was abrogated in the presence of subinhibitory concentrations of antimicrobials. Despite this cost, ICEMh1PM22 was retained in transconjugants in extended culture. To identify possible therapeutic efficiencies, antimicrobial combinations were screened for synergistic interactions against AMR ICEMh1PM22-carrying transconjugants. No antimicrobial combination tested exhibited synergistic interactions against AMR P. multocida or M. haemolytica harboring ICEMh1PM22. In conclusion, this study provided information on the structural variation of ICEMh1-like elements, refined the ICE insertion site and potential host range, and demonstrated the risk and consequences for AMR following horizontal transfer of ICE into BRD pathogens.
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Affiliation(s)
- Andrew Cameron
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.,Lethbridge Research and Development Centre, Lethbridge, AB, Canada
| | - Rahat Zaheer
- Lethbridge Research and Development Centre, Lethbridge, AB, Canada
| | - Tim A McAllister
- Lethbridge Research and Development Centre, Lethbridge, AB, Canada
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29
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Berg MD, Giguere DJ, Dron JS, Lant JT, Genereaux J, Liao C, Wang J, Robinson JF, Gloor GB, Hegele RA, O'Donoghue P, Brandl CJ. Targeted sequencing reveals expanded genetic diversity of human transfer RNAs. RNA Biol 2019; 16:1574-1585. [PMID: 31407949 PMCID: PMC6779403 DOI: 10.1080/15476286.2019.1646079] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Transfer RNAs are required to translate genetic information into proteins as well as regulate other cellular processes. Nucleotide changes in tRNAs can result in loss or gain of function that impact the composition and fidelity of the proteome. Despite links between tRNA variation and disease, the importance of cytoplasmic tRNA variation has been overlooked. Using a custom capture panel, we sequenced 605 human tRNA-encoding genes from 84 individuals. We developed a bioinformatic pipeline that allows more accurate tRNA read mapping and identifies multiple polymorphisms occurring within the same variant. Our analysis identified 522 unique tRNA-encoding sequences that differed from the reference genome from 84 individuals. Each individual had ~66 tRNA variants including nine variants found in less than 5% of our sample group. Variants were identified throughout the tRNA structure with 17% predicted to enhance function. Eighteen anticodon mutants were identified including potentially mistranslating tRNAs; e.g., a tRNASer that decodes Phe codons. Similar engineered tRNA variants were previously shown to inhibit cell growth, increase apoptosis and induce the unfolded protein response in mammalian cell cultures and chick embryos. Our analysis shows that human tRNA variation has been underestimated. We conclude that the large number of tRNA genes provides a buffer enabling the emergence of variants, some of which could contribute to disease.
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Affiliation(s)
- Matthew D Berg
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada
| | - Daniel J Giguere
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada
| | - Jacqueline S Dron
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada.,Robarts Research Institute, The University of Western Ontario , London , ON , Canada
| | - Jeremy T Lant
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada
| | - Julie Genereaux
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada
| | - Calwing Liao
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada.,Robarts Research Institute, The University of Western Ontario , London , ON , Canada
| | - Jian Wang
- Robarts Research Institute, The University of Western Ontario , London , ON , Canada
| | - John F Robinson
- Robarts Research Institute, The University of Western Ontario , London , ON , Canada
| | - Gregory B Gloor
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada
| | - Robert A Hegele
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada.,Robarts Research Institute, The University of Western Ontario , London , ON , Canada.,Department of Medicine, The University of Western Ontario , London , ON , Canada
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada.,Department of Chemistry, The University of Western Ontario , London , ON , Canada
| | - Christopher J Brandl
- Department of Biochemistry, The University of Western Ontario , London , ON , Canada
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30
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Li JJ, Chew GL, Biggin MD. Quantitative principles of cis-translational control by general mRNA sequence features in eukaryotes. Genome Biol 2019; 20:162. [PMID: 31399036 PMCID: PMC6689182 DOI: 10.1186/s13059-019-1761-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/11/2019] [Indexed: 12/17/2022] Open
Abstract
Background General translational cis-elements are present in the mRNAs of all genes and affect the recruitment, assembly, and progress of preinitiation complexes and the ribosome under many physiological states. These elements include mRNA folding, upstream open reading frames, specific nucleotides flanking the initiating AUG codon, protein coding sequence length, and codon usage. The quantitative contributions of these sequence features and how and why they coordinate to control translation rates are not well understood. Results Here, we show that these sequence features specify 42–81% of the variance in translation rates in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Arabidopsis thaliana, Mus musculus, and Homo sapiens. We establish that control by RNA secondary structure is chiefly mediated by highly folded 25–60 nucleotide segments within mRNA 5′ regions, that changes in tri-nucleotide frequencies between highly and poorly translated 5′ regions are correlated between all species, and that control by distinct biochemical processes is extensively correlated as is regulation by a single process acting in different parts of the same mRNA. Conclusions Our work shows that general features control a much larger fraction of the variance in translation rates than previously realized. We provide a more detailed and accurate understanding of the aspects of RNA structure that directs translation in diverse eukaryotes. In addition, we note that the strongly correlated regulation between and within cis-control features will cause more even densities of translational complexes along each mRNA and therefore more efficient use of the translation machinery by the cell. Electronic supplementary material The online version of this article (10.1186/s13059-019-1761-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jingyi Jessica Li
- Department of Statistics, Department of Biomathematics, and Department of Human Genetics, University of California, Los Angeles, CA, 90095, USA.
| | - Guo-Liang Chew
- Computational Biology Program, Public Health Sciences and Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Mark Douglas Biggin
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94708, USA.
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31
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tRNA Genes Affect Chromosome Structure and Function via Local Effects. Mol Cell Biol 2019; 39:MCB.00432-18. [PMID: 30718362 DOI: 10.1128/mcb.00432-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 01/18/2019] [Indexed: 11/20/2022] Open
Abstract
The genome is packaged and organized in an ordered, nonrandom manner, and specific chromatin segments contact nuclear substructures to mediate this organization. tRNA genes (tDNAs) are binding sites for transcription factors and architectural proteins and are thought to play an important role in the organization of the genome. In this study, we investigate the roles of tDNAs in genomic organization and chromosome function by editing a chromosome so that it lacked any tDNAs. Surprisingly our analyses of this tDNA-less chromosome show that loss of tDNAs does not grossly affect chromatin architecture or chromosome tethering and mobility. However, loss of tDNAs affects local nucleosome positioning and the binding of SMC proteins at these loci. The absence of tDNAs also leads to changes in centromere clustering and a reduction in the frequency of long-range HML-HMR heterochromatin clustering with concomitant effects on gene silencing. We propose that the tDNAs primarily affect local chromatin structure, which results in effects on long-range chromosome architecture.
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32
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Torrent M, Chalancon G, de Groot NS, Wuster A, Madan Babu M. Cells alter their tRNA abundance to selectively regulate protein synthesis during stress conditions. Sci Signal 2018; 11:11/546/eaat6409. [PMID: 30181241 PMCID: PMC6130803 DOI: 10.1126/scisignal.aat6409] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Decoding the information in mRNA during protein synthesis relies on tRNA adaptors, the abundance of which can affect the decoding rate and translation efficiency. To determine whether cells alter tRNA abundance to selectively regulate protein expression, we quantified changes in the abundance of individual tRNAs at different time points in response to diverse stress conditions in Saccharomyces cerevisiae. We found that the tRNA pool was dynamic and rearranged in a manner that facilitated selective translation of stress-related transcripts. Through genomic analysis of multiple data sets, stochastic simulations, and experiments with designed sequences of proteins with identical amino acids but altered codon usage, we showed that changes in tRNA abundance affected protein expression independently of factors such as mRNA abundance. We suggest that cells alter their tRNA abundance to selectively affect the translation rates of specific transcripts to increase the amounts of required proteins under diverse stress conditions.
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Affiliation(s)
- Marc Torrent
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK. .,Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Guilhem Chalancon
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Natalia S de Groot
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Arthur Wuster
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - M Madan Babu
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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33
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Thornlow BP, Hough J, Roger JM, Gong H, Lowe TM, Corbett-Detig RB. Transfer RNA genes experience exceptionally elevated mutation rates. Proc Natl Acad Sci U S A 2018; 115:8996-9001. [PMID: 30127029 PMCID: PMC6130373 DOI: 10.1073/pnas.1801240115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Transfer RNAs (tRNAs) are a central component for the biological synthesis of proteins, and they are among the most highly conserved and frequently transcribed genes in all living things. Despite their clear significance for fundamental cellular processes, the forces governing tRNA evolution are poorly understood. We present evidence that transcription-associated mutagenesis and strong purifying selection are key determinants of patterns of sequence variation within and surrounding tRNA genes in humans and diverse model organisms. Remarkably, the mutation rate at broadly expressed cytosolic tRNA loci is likely between 7 and 10 times greater than the nuclear genome average. Furthermore, evolutionary analyses provide strong evidence that tRNA genes, but not their flanking sequences, experience strong purifying selection acting against this elevated mutation rate. We also find a strong correlation between tRNA expression levels and the mutation rates in their immediate flanking regions, suggesting a simple method for estimating individual tRNA gene activity. Collectively, this study illuminates the extreme competing forces in tRNA gene evolution and indicates that mutations at tRNA loci contribute disproportionately to mutational load and have unexplored fitness consequences in human populations.
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Affiliation(s)
- Bryan P Thornlow
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064
| | - Josh Hough
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064
| | - Jacquelyn M Roger
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064
| | - Henry Gong
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064
| | - Todd M Lowe
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064;
- Genomics Institute, University of California, Santa Cruz, CA 95064
| | - Russell B Corbett-Detig
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064;
- Genomics Institute, University of California, Santa Cruz, CA 95064
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34
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Abstract
The pool of transfer RNA (tRNA) molecules in cells allows the ribosome to decode genetic information. This repertoire of molecular decoders is positioned in the crossroad of the genome, the transcriptome, and the proteome. Omics and systems biology now allow scientists to explore the entire repertoire of tRNAs of many organisms, revealing basic exciting biology. The tRNA gene set of hundreds of species is now characterized, in addition to the tRNA genes of organelles and viruses. Genes encoding tRNAs for certain anticodon types appear in dozens of copies in a genome, while others are universally absent from any genome. Transcriptome measurement of tRNAs is challenging, but in recent years new technologies have allowed researchers to determine the dynamic expression patterns of tRNAs. These advances reveal that availability of ready-to-translate tRNA molecules is highly controlled by several transcriptional and posttranscriptional regulatory processes. This regulation shapes the proteome according to the cellular state. The tRNA pool profoundly impacts many aspects of cellular and organismal life, including protein expression level, translation accuracy, adequacy of folding, and even mRNA stability. As a result, the shape of the tRNA pool affects organismal health and may participate in causing conditions such as cancer and neurological conditions.
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Affiliation(s)
- Roni Rak
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| | - Orna Dahan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| | - Yitzhak Pilpel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
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35
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Wang T, Guan C, Guo J, Liu B, Wu Y, Xie Z, Zhang C, Xing XH. Pooled CRISPR interference screening enables genome-scale functional genomics study in bacteria with superior performance. Nat Commun 2018; 9:2475. [PMID: 29946130 PMCID: PMC6018678 DOI: 10.1038/s41467-018-04899-x] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/18/2018] [Indexed: 12/26/2022] Open
Abstract
To fully exploit the microbial genome resources, a high-throughput experimental platform is needed to associate genes with phenotypes at the genome level. We present here a novel method that enables investigation of the cellular consequences of repressing individual transcripts based on the CRISPR interference (CRISPRi) pooled screening in bacteria. We identify rules for guide RNA library design to handle the unique structure of prokaryotic genomes by tiling screening and construct an E. coli genome-scale guide RNA library (~60,000 members) accordingly. We show that CRISPRi outperforms transposon sequencing, the benchmark method in the microbial functional genomics field, when similar library sizes are used or gene length is short. This tool is also effective for mapping phenotypes to non-coding RNAs (ncRNAs), as elucidated by a comprehensive tRNA-fitness map constructed here. Our results establish CRISPRi pooled screening as a powerful tool for mapping complex prokaryotic genetic networks in a precise and high-throughput manner.
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Affiliation(s)
- Tianmin Wang
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Changge Guan
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Jiahui Guo
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Bing Liu
- Beijing Syngentech Co., Ltd., Beijing, 102206, China
| | - Yinan Wu
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Zhen Xie
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and System Biology, Department of Automation, Tsinghua National Lab for Information Science and Technology, Tsinghua University, Beijing, 100084, China
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Chong Zhang
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.
| | - Xin-Hui Xing
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
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36
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Kuo J, Stirling F, Lau YH, Shulgina Y, Way JC, Silver PA. Synthetic genome recoding: new genetic codes for new features. Curr Genet 2018; 64:327-333. [PMID: 28983660 PMCID: PMC5849531 DOI: 10.1007/s00294-017-0754-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/12/2017] [Accepted: 09/13/2017] [Indexed: 12/20/2022]
Abstract
Full genome recoding, or rewriting codon meaning, through chemical synthesis of entire bacterial chromosomes has become feasible in the past several years. Recoding an organism can impart new properties including non-natural amino acid incorporation, virus resistance, and biocontainment. The estimated cost of construction that includes DNA synthesis, assembly by recombination, and troubleshooting, is now comparable to costs of early stage development of drugs or other high-tech products. Here, we discuss several recently published assembly methods and provide some thoughts on the future, including how synthetic efforts might benefit from the analysis of natural recoding processes and organisms that use alternative genetic codes.
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Affiliation(s)
- James Kuo
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Finn Stirling
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Yu Heng Lau
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Yekaterina Shulgina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Jeffrey C Way
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Pamela A Silver
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA.
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.
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37
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de Freitas Nascimento J, Kelly S, Sunter J, Carrington M. Codon choice directs constitutive mRNA levels in trypanosomes. eLife 2018; 7:e32467. [PMID: 29543152 PMCID: PMC5896880 DOI: 10.7554/elife.32467] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/27/2018] [Indexed: 11/13/2022] Open
Abstract
Selective transcription of individual protein coding genes does not occur in trypanosomes and the cellular copy number of each mRNA must be determined post-transcriptionally. Here, we provide evidence that codon choice directs the levels of constitutively expressed mRNAs. First, a novel codon usage metric, the gene expression codon adaptation index (geCAI), was developed that maximised the relationship between codon choice and the measured abundance for a transcriptome. Second, geCAI predictions of mRNA levels were tested using differently coded GFP transgenes and were successful over a 25-fold range, similar to the variation in endogenous mRNAs. Third, translation was necessary for the accelerated mRNA turnover resulting from codon choice. Thus, in trypanosomes, the information determining the levels of most mRNAs resides in the open reading frame and translation is required to access this information.
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Affiliation(s)
| | - Steven Kelly
- Department of Plant SciencesUniversity of OxfordOxfordUnited Kingdom
| | - Jack Sunter
- Department of BiochemistryUniversity of CambridgeCambridgeUnited Kingdom
| | - Mark Carrington
- Department of BiochemistryUniversity of CambridgeCambridgeUnited Kingdom
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38
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Parker S, Fraczek MG, Wu J, Shamsah S, Manousaki A, Dungrattanalert K, de Almeida RA, Invernizzi E, Burgis T, Omara W, Griffiths-Jones S, Delneri D, O’Keefe RT. Large-scale profiling of noncoding RNA function in yeast. PLoS Genet 2018; 14:e1007253. [PMID: 29529031 PMCID: PMC5864082 DOI: 10.1371/journal.pgen.1007253] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/22/2018] [Accepted: 02/13/2018] [Indexed: 11/19/2022] Open
Abstract
Noncoding RNAs (ncRNAs) are emerging as key regulators of cellular function. We have exploited the recently developed barcoded ncRNA gene deletion strain collections in the yeast Saccharomyces cerevisiae to investigate the numerous ncRNAs in yeast with no known function. The ncRNA deletion collection contains deletions of tRNAs, snoRNAs, snRNAs, stable unannotated transcripts (SUTs), cryptic unstable transcripts (CUTs) and other annotated ncRNAs encompassing 532 different individual ncRNA deletions. We have profiled the fitness of the diploid heterozygous ncRNA deletion strain collection in six conditions using batch and continuous liquid culture, as well as the haploid ncRNA deletion strain collections arrayed individually onto solid rich media. These analyses revealed many novel environmental-specific haplo-insufficient and haplo-proficient phenotypes providing key information on the importance of each specific ncRNA in every condition. Co-fitness analysis using fitness data from the heterozygous ncRNA deletion strain collection identified two ncRNA groups required for growth during heat stress and nutrient deprivation. The extensive fitness data for each ncRNA deletion strain has been compiled into an easy to navigate database called Yeast ncRNA Analysis (YNCA). By expanding the original ncRNA deletion strain collection we identified four novel essential ncRNAs; SUT527, SUT075, SUT367 and SUT259/691. We defined the effects of each new essential ncRNA on adjacent gene expression in the heterozygote background identifying both repression and induction of nearby genes. Additionally, we discovered a function for SUT527 in the expression, 3' end formation and localization of SEC4, an essential protein coding mRNA. Finally, using plasmid complementation we rescued the SUT075 lethal phenotype revealing that this ncRNA acts in trans. Overall, our findings provide important new insights into the function of ncRNAs.
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Affiliation(s)
- Steven Parker
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Marcin G. Fraczek
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Jian Wu
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Sara Shamsah
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Alkisti Manousaki
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Kobchai Dungrattanalert
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Rogerio Alves de Almeida
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Edith Invernizzi
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Tim Burgis
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Walid Omara
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Sam Griffiths-Jones
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Daniela Delneri
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Raymond T. O’Keefe
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
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39
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Hockenberry AJ, Stern AJ, Amaral LAN, Jewett MC. Diversity of Translation Initiation Mechanisms across Bacterial Species Is Driven by Environmental Conditions and Growth Demands. Mol Biol Evol 2017; 35:582-592. [PMID: 29220489 PMCID: PMC5850609 DOI: 10.1093/molbev/msx310] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The Shine-Dalgarno (SD) sequence motif is frequently found upstream of protein coding genes and is thought to be the dominant mechanism of translation initiation used by bacteria. Experimental studies have shown that the SD sequence facilitates start codon recognition and enhances translation initiation by directly interacting with the highly conserved anti-SD sequence on the 30S ribosomal subunit. However, the proportion of SD-led genes within a genome varies across species and the factors governing this variation in translation initiation mechanisms remain largely unknown. Here, we conduct a phylogenetically informed analysis and find that species capable of rapid growth contain a higher proportion of SD-led genes throughout their genomes. We show that SD sequence utilization covaries with a suite of genomic features that are important for efficient translation initiation and elongation. In addition to these endogenous genomic factors, we further show that exogenous environmental factors may influence the evolution of translation initiation mechanisms by finding that thermophilic species contain significantly more SD-led genes than mesophiles. Our results demonstrate that variation in translation initiation mechanisms across bacterial species is predictable and is a consequence of differential life-history strategies related to maximum growth rate and environmental-specific constraints.
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Affiliation(s)
- Adam J Hockenberry
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
- Interdisciplinary Program in Biological Sciences, Northwestern University, Evanston, IL, USA
| | - Aaron J Stern
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
| | - Luís A N Amaral
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
- Northwestern Institute for Complex Systems, Northwestern University, Evanston, IL, USA
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, USA
- Corresponding authors: E-mails: ;
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
- Northwestern Institute for Complex Systems, Northwestern University, Evanston, IL, USA
- Center for Synthetic Biology, Northwestern University, Evanston, IL, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL, USA
- Corresponding authors: E-mails: ;
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40
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Generation of an arginine-tRNA-adapted Saccharomyces cerevisiae strain for effective heterologous protein expression. Curr Genet 2017; 64:589-598. [PMID: 29098364 DOI: 10.1007/s00294-017-0774-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/30/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
Abstract
The tRNA population reflects the codon bias of the organism and affects the translation of heterologous target mRNA molecules. In this study, Saccharomyces cerevisiae strains with modified levels of rare tRNA were engineered, that allowed efficient generation of recombinant proteins with unfavorable codon usage. We established a novel synthetic tRNA expression cassette and verified functional nonsense suppressor tRNAGlnSCUA generation in a stop codon read-through assay with a modified β-galactosidase reporter gene. Correlation between altered tRNA and protein level was shown by survival of copper sensitive S. cerevisiae cells in the presence of copper ions by an increased transcription of tRNAArgCCG molecules, recognizing rare codons in a modified CUP1 gene. Genome integration of tRNA expression cassette led to the generation of arginine-tRNA-adapted S. cerevisiae strains, which showed elevated tRNA levels (tRNAArgCCG, tRNAArgGCG and tRNAArgUCG) pairing to rare codons. The modified strain MNY3 revealed a considerably improved monitoring of protein-protein interaction from Aspergillus fumigatus bait and prey sequences in yeast two-hybrid experiments. In future, this principle to overcome limited recombinant protein expression by tRNA adaption of expression strains instead of codon adaption might provide new designer yeast cells for an efficient protein production and for improved genome-wide protein-protein interaction analyses.
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41
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Parker S, Fraczek MG, Wu J, Shamsah S, Manousaki A, Dungrattanalert K, de Almeida RA, Estrada-Rivadeneyra D, Omara W, Delneri D, O'Keefe RT. A resource for functional profiling of noncoding RNA in the yeast Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2017; 23:1166-1171. [PMID: 28468764 PMCID: PMC5513061 DOI: 10.1261/rna.061564.117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/01/2017] [Indexed: 06/07/2023]
Abstract
Eukaryotic genomes are extensively transcribed, generating many different RNAs with no known function. We have constructed 1502 molecular barcoded ncRNA gene deletion strains encompassing 443 ncRNAs in the yeast Saccharomyces cerevisiae as tools for ncRNA functional analysis. This resource includes deletions of small nuclear RNAs (snRNAs), transfer RNAs (tRNAs), small nucleolar RNAs (snoRNAs), and other annotated ncRNAs as well as the more recently identified stable unannotated transcripts (SUTs) and cryptic unstable transcripts (CUTs) whose functions are largely unknown. Specifically, deletions have been constructed for ncRNAs found in the intergenic regions, not overlapping genes or their promoters (i.e., at least 200 bp minimum distance from the closest gene start codon). The deletion strains carry molecular barcodes designed to be complementary with the protein gene deletion collection enabling parallel analysis experiments. These strains will be useful for the numerous genomic and molecular techniques that utilize deletion strains, including genome-wide phenotypic screens under different growth conditions, pooled chemogenomic screens with drugs or chemicals, synthetic genetic array analysis to uncover novel genetic interactions, and synthetic dosage lethality screens to analyze gene dosage. Overall, we created a valuable resource for the RNA community and for future ncRNA research.
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Affiliation(s)
| | | | - Jian Wu
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Sara Shamsah
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | | | | | - Rogerio Alves de Almeida
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Diego Estrada-Rivadeneyra
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Walid Omara
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minya 11432, Egypt
| | | | - Raymond T O'Keefe
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United Kingdom
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42
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Transcription by RNA polymerase III: insights into mechanism and regulation. Biochem Soc Trans 2017; 44:1367-1375. [PMID: 27911719 PMCID: PMC5095917 DOI: 10.1042/bst20160062] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 07/07/2016] [Accepted: 07/13/2016] [Indexed: 12/13/2022]
Abstract
The highly abundant, small stable RNAs that are synthesized by RNA polymerase III (RNAPIII) have key functional roles, particularly in the protein synthesis apparatus. Their expression is metabolically demanding, and is therefore coupled to changing demands for protein synthesis during cell growth and division. Here, we review the regulatory mechanisms that control the levels of RNAPIII transcripts and discuss their potential physiological relevance. Recent analyses have revealed differential regulation of tRNA expression at all steps on its biogenesis, with significant deregulation of mature tRNAs in cancer cells.
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43
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Shen Y, Wang Y, Chen T, Gao F, Gong J, Abramczyk D, Walker R, Zhao H, Chen S, Liu W, Luo Y, Müller CA, Paul-Dubois-Taine A, Alver B, Stracquadanio G, Mitchell LA, Luo Z, Fan Y, Zhou B, Wen B, Tan F, Wang Y, Zi J, Xie Z, Li B, Yang K, Richardson SM, Jiang H, French CE, Nieduszynski CA, Koszul R, Marston AL, Yuan Y, Wang J, Bader JS, Dai J, Boeke JD, Xu X, Cai Y, Yang H. Deep functional analysis of synII, a 770-kilobase synthetic yeast chromosome. Science 2017; 355:eaaf4791. [PMID: 28280153 PMCID: PMC5390853 DOI: 10.1126/science.aaf4791] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 02/01/2017] [Indexed: 12/15/2022]
Abstract
Here, we report the successful design, construction, and characterization of a 770-kilobase synthetic yeast chromosome II (synII). Our study incorporates characterization at multiple levels-including phenomics, transcriptomics, proteomics, chromosome segregation, and replication analysis-to provide a thorough and comprehensive analysis of a synthetic chromosome. Our Trans-Omics analyses reveal a modest but potentially relevant pervasive up-regulation of translational machinery observed in synII, mainly caused by the deletion of 13 transfer RNAs. By both complementation assays and SCRaMbLE (synthetic chromosome rearrangement and modification by loxP-mediated evolution), we targeted and debugged the origin of a growth defect at 37°C in glycerol medium, which is related to misregulation of the high-osmolarity glycerol response. Despite the subtle differences, the synII strain shows highly consistent biological processes comparable to the native strain.
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Affiliation(s)
- Yue Shen
- BGI-Shenzhen, Shenzhen 518083, China
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
- James D. Watson Institute of Genome Sciences, Hangzhou 310058, China
- BGI-Qingdao, Qingdao 266555, China
| | - Yun Wang
- BGI-Shenzhen, Shenzhen 518083, China
- BGI-Qingdao, Qingdao 266555, China
| | - Tai Chen
- BGI-Shenzhen, Shenzhen 518083, China
- BGI-Qingdao, Qingdao 266555, China
| | - Feng Gao
- BGI-Shenzhen, Shenzhen 518083, China
| | | | - Dariusz Abramczyk
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Roy Walker
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | | | | | - Wei Liu
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Yisha Luo
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Carolin A. Müller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | | | - Bonnie Alver
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Giovanni Stracquadanio
- High-Throughput Biology Center, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205 USA
- Department of Biomedical Engineering, School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218 USA
| | - Leslie A. Mitchell
- Institute for Systems Genetics, NYU Langone Medical Center, ACLSW Room 503, 430 East 29th Street, New York, NY 10016
| | - Zhouqing Luo
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | | | | | - Bo Wen
- BGI-Shenzhen, Shenzhen 518083, China
| | | | | | - Jin Zi
- BGI-Shenzhen, Shenzhen 518083, China
| | - Zexiong Xie
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
| | - Bingzhi Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
| | - Kun Yang
- High-Throughput Biology Center, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205 USA
| | - Sarah M. Richardson
- High-Throughput Biology Center, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205 USA
- Department of Biomedical Engineering, School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218 USA
| | - Hui Jiang
- BGI-Shenzhen, Shenzhen 518083, China
| | | | | | - Romain Koszul
- Department of Genomes and Genetics, Institut Pasteur / CNRS UMR3525, 25-28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Adele L. Marston
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Yingjin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
| | - Jian Wang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Joel S. Bader
- Department of Biomedical Engineering, School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218 USA
- Institute for Systems Genetics, NYU Langone Medical Center, ACLSW Room 503, 430 East 29th Street, New York, NY 10016
| | - Junbiao Dai
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jef D. Boeke
- Institute for Systems Genetics, NYU Langone Medical Center, ACLSW Room 503, 430 East 29th Street, New York, NY 10016
| | - Xun Xu
- BGI-Shenzhen, Shenzhen 518083, China
- BGI-Qingdao, Qingdao 266555, China
| | - Yizhi Cai
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Huanming Yang
- BGI-Shenzhen, Shenzhen 518083, China
- James D. Watson Institute of Genome Sciences, Hangzhou 310058, China
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44
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Maraia RJ, Arimbasseri AG. Factors That Shape Eukaryotic tRNAomes: Processing, Modification and Anticodon-Codon Use. Biomolecules 2017; 7:biom7010026. [PMID: 28282871 PMCID: PMC5372738 DOI: 10.3390/biom7010026] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/24/2017] [Indexed: 01/24/2023] Open
Abstract
Transfer RNAs (tRNAs) contain sequence diversity beyond their anticodons and the large variety of nucleotide modifications found in all kingdoms of life. Some modifications stabilize structure and fit in the ribosome whereas those to the anticodon loop modulate messenger RNA (mRNA) decoding activity more directly. The identities of tRNAs with some universal anticodon loop modifications vary among distant and parallel species, likely to accommodate fine tuning for their translation systems. This plasticity in positions 34 (wobble) and 37 is reflected in codon use bias. Here, we review convergent evidence that suggest that expansion of the eukaryotic tRNAome was supported by its dedicated RNA polymerase III transcription system and coupling to the precursor-tRNA chaperone, La protein. We also review aspects of eukaryotic tRNAome evolution involving G34/A34 anticodon-sparing, relation to A34 modification to inosine, biased codon use and regulatory information in the redundancy (synonymous) component of the genetic code. We then review interdependent anticodon loop modifications involving position 37 in eukaryotes. This includes the eukaryote-specific tRNA modification, 3-methylcytidine-32 (m3C32) and the responsible gene, TRM140 and homologs which were duplicated and subspecialized for isoacceptor-specific substrates and dependence on i6A37 or t6A37. The genetics of tRNA function is relevant to health directly and as disease modifiers.
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Affiliation(s)
- Richard J Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
- Commissioned Corps, U.S. Public Health Service, Rockville, MD, 20016, USA.
| | - Aneeshkumar G Arimbasseri
- Molecular Genetics Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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45
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Payen C, Sunshine AB, Ong GT, Pogachar JL, Zhao W, Dunham MJ. High-Throughput Identification of Adaptive Mutations in Experimentally Evolved Yeast Populations. PLoS Genet 2016; 12:e1006339. [PMID: 27727276 PMCID: PMC5065121 DOI: 10.1371/journal.pgen.1006339] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 09/05/2016] [Indexed: 11/19/2022] Open
Abstract
High-throughput sequencing has enabled genetic screens that can rapidly identify mutations that occur during experimental evolution. The presence of a mutation in an evolved lineage does not, however, constitute proof that the mutation is adaptive, given the well-known and widespread phenomenon of genetic hitchhiking, in which a non-adaptive or even detrimental mutation can co-occur in a genome with a beneficial mutation and the combined genotype is carried to high frequency by selection. We approximated the spectrum of possible beneficial mutations in Saccharomyces cerevisiae using sets of single-gene deletions and amplifications of almost all the genes in the S. cerevisiae genome. We determined the fitness effects of each mutation in three different nutrient-limited conditions using pooled competitions followed by barcode sequencing. Although most of the mutations were neutral or deleterious, ~500 of them increased fitness. We then compared those results to the mutations that actually occurred during experimental evolution in the same three nutrient-limited conditions. On average, ~35% of the mutations that occurred during experimental evolution were predicted by the systematic screen to be beneficial. We found that the distribution of fitness effects depended on the selective conditions. In the phosphate-limited and glucose-limited conditions, a large number of beneficial mutations of nearly equivalent, small effects drove the fitness increases. In the sulfate-limited condition, one type of mutation, the amplification of the high-affinity sulfate transporter, dominated. In the absence of that mutation, evolution in the sulfate-limited condition involved mutations in other genes that were not observed previously—but were predicted by the systematic screen. Thus, gross functional screens have the potential to predict and identify adaptive mutations that occur during experimental evolution. Experimental evolution allows us to observe evolution in real time. New advances in genome sequencing make it trivial to discover the mutations that have arisen in evolved cultures; however, linking those mutations to particular adaptive traits remains difficult. We evaluated the fitness impacts of thousands of single-gene losses and amplifications in yeast. We discovered that only a fraction of the hundreds of possible beneficial mutations were actually detected in evolution experiments performed previously. Our results provide evidence that 35% of the mutations identified in experimentally evolved populations are advantageous and that the distribution of beneficial fitness effects depends on the genetic background and the selective conditions. Furthermore, we show that it is possible to select for alternative mutations that improve fitness by blocking particularly high-fitness routes to adaptation.
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Affiliation(s)
- Celia Payen
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Anna B. Sunshine
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Giang T. Ong
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Jamie L. Pogachar
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Wei Zhao
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Maitreya J. Dunham
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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46
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Belagal P, Normand C, Shukla A, Wang R, Léger-Silvestre I, Dez C, Bhargava P, Gadal O. Decoding the principles underlying the frequency of association with nucleoli for RNA polymerase III-transcribed genes in budding yeast. Mol Biol Cell 2016; 27:3164-3177. [PMID: 27559135 PMCID: PMC5063623 DOI: 10.1091/mbc.e16-03-0145] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 08/18/2016] [Indexed: 01/09/2023] Open
Abstract
In budding yeast, RNA polymerase III–transcribed genes preferentially associate with the nucleolar and nuclear periphery when permitted by the Rabl-like orientation of interphase chromosomes. The association of RNA polymerase III (Pol III)–transcribed genes with nucleoli seems to be an evolutionarily conserved property of the spatial organization of eukaryotic genomes. However, recent studies of global chromosome architecture in budding yeast have challenged this view. We used live-cell imaging to determine the intranuclear positions of 13 Pol III–transcribed genes. The frequency of association with nucleolus and nuclear periphery depends on linear genomic distance from the tethering elements—centromeres or telomeres. Releasing the hold of the tethering elements by inactivating centromere attachment to the spindle pole body or changing the position of ribosomal DNA arrays resulted in the association of Pol III–transcribed genes with nucleoli. Conversely, ectopic insertion of a Pol III–transcribed gene in the vicinity of a centromere prevented its association with nucleolus. Pol III–dependent transcription was independent of the intranuclear position of the gene, but the nucleolar recruitment of Pol III–transcribed genes required active transcription. We conclude that the association of Pol III–transcribed genes with the nucleolus, when permitted by global chromosome architecture, provides nucleolar and/or nuclear peripheral anchoring points contributing locally to intranuclear chromosome organization.
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Affiliation(s)
- Praveen Belagal
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Christophe Normand
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Ashutosh Shukla
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad 500007, India
| | - Renjie Wang
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Isabelle Léger-Silvestre
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Christophe Dez
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Purnima Bhargava
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad 500007, India
| | - Olivier Gadal
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
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47
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Sagi D, Rak R, Gingold H, Adir I, Maayan G, Dahan O, Broday L, Pilpel Y, Rechavi O. Tissue- and Time-Specific Expression of Otherwise Identical tRNA Genes. PLoS Genet 2016; 12:e1006264. [PMID: 27560950 PMCID: PMC4999229 DOI: 10.1371/journal.pgen.1006264] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/27/2016] [Indexed: 11/18/2022] Open
Abstract
Codon usage bias affects protein translation because tRNAs that recognize synonymous codons differ in their abundance. Although the current dogma states that tRNA expression is exclusively regulated by intrinsic control elements (A- and B-box sequences), we revealed, using a reporter that monitors the levels of individual tRNA genes in Caenorhabditis elegans, that eight tryptophan tRNA genes, 100% identical in sequence, are expressed in different tissues and change their expression dynamically. Furthermore, the expression levels of the sup-7 tRNA gene at day 6 were found to predict the animal's lifespan. We discovered that the expression of tRNAs that reside within introns of protein-coding genes is affected by the host gene's promoter. Pairing between specific Pol II genes and the tRNAs that are contained in their introns is most likely adaptive, since a genome-wide analysis revealed that the presence of specific intronic tRNAs within specific orthologous genes is conserved across Caenorhabditis species.
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Affiliation(s)
- Dror Sagi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Roni Rak
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Hila Gingold
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Idan Adir
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Gadi Maayan
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Orna Dahan
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Limor Broday
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel-Aviv, Israel
| | - Yitzhak Pilpel
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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48
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Gorgoni B, Ciandrini L, McFarland MR, Romano MC, Stansfield I. Identification of the mRNA targets of tRNA-specific regulation using genome-wide simulation of translation. Nucleic Acids Res 2016; 44:9231-9244. [PMID: 27407108 PMCID: PMC5100601 DOI: 10.1093/nar/gkw630] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/02/2016] [Indexed: 01/11/2023] Open
Abstract
tRNA gene copy number is a primary determinant of tRNA abundance and therefore the rate at which each tRNA delivers amino acids to the ribosome during translation. Low-abundance tRNAs decode rare codons slowly, but it is unclear which genes might be subject to tRNA-mediated regulation of expression. Here, those mRNA targets were identified via global simulation of translation. In-silico mRNA translation rates were compared for each mRNA in both wild-type and a \documentclass[12pt]{minimal}
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}{}${\rm{tRNA}}_{{\rm{CUG}}}^{{\rm{Gln}}}$\end{document}sup70-65 mutant, which exhibits a pseudohyphal growth phenotype and a 75% slower CAG codon translation rate. Of 4900 CAG-containing mRNAs, 300 showed significantly reduced in silico translation rates in a simulated tRNA mutant. Quantitative immunoassay confirmed that the reduced translation rates of sensitive mRNAs were \documentclass[12pt]{minimal}
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}{}${\rm{tRNA}}_{{\rm{CUG}}}^{{\rm{Gln}}}$\end{document} concentration-dependent. Translation simulations showed that reduced \documentclass[12pt]{minimal}
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}{}${\rm{tRNA}}_{{\rm{CUG}}}^{{\rm{Gln}}}$\end{document} concentrations triggered ribosome queues, which dissipated at reduced translation initiation rates. To validate this prediction experimentally, constitutive gcn2 kinase mutants were used to reduce in vivo translation initiation rates. This repaired the relative translational rate defect of target mRNAs in the sup70-65 background, and ameliorated sup70-65 pseudohyphal growth phenotypes. We thus validate global simulation of translation as a new tool to identify mRNA targets of tRNA-specific gene regulation.
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Affiliation(s)
- Barbara Gorgoni
- University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Luca Ciandrini
- DIMNP - UMR 5235 & CNRS, Université de Montpellier, 34095 Montpellier, France.,Laboratoire Charles Coulomb UMR5221 & CNRS, Université de Montpellier, 34095 Montpellier, France
| | - Matthew R McFarland
- University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - M Carmen Romano
- University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK.,University of Aberdeen, Institute for Complex Systems and Mathematical Biology, King's College, Aberdeen AB24 3UE, UK
| | - Ian Stansfield
- University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
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49
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Rudolph KLM, Schmitt BM, Villar D, White RJ, Marioni JC, Kutter C, Odom DT. Codon-Driven Translational Efficiency Is Stable across Diverse Mammalian Cell States. PLoS Genet 2016; 12:e1006024. [PMID: 27166679 PMCID: PMC4864286 DOI: 10.1371/journal.pgen.1006024] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 04/12/2016] [Indexed: 11/19/2022] Open
Abstract
Whether codon usage fine-tunes mRNA translation in mammals remains controversial, with recent papers suggesting that production of proteins in specific Gene Ontological (GO) pathways can be regulated by actively modifying the codon and anticodon pools in different cellular conditions. In this work, we compared the sequence content of genes in specific GO categories with the exonic genome background. Although a substantial fraction of variability in codon usage could be explained by random sampling, almost half of GO sets showed more variability in codon usage than expected by chance. Nevertheless, by quantifying translational efficiency in healthy and cancerous tissues in human and mouse, we demonstrated that a given tRNA pool can equally well translate many different sets of mRNAs, irrespective of their cell-type specificity. This disconnect between variations in codon usage and the stability of translational efficiency is best explained by differences in GC content between gene sets. GC variation across the mammalian genome is most likely a result of the interplay between genome repair and gene duplication mechanisms, rather than selective pressures caused by codon-driven translational rates. Consequently, codon usage differences in mammalian transcriptomes are most easily explained by well-understood mutational biases acting on the underlying genome.
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Affiliation(s)
- Konrad L. M. Rudolph
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, United Kingdom
| | - Bianca M. Schmitt
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom
| | - Diego Villar
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom
| | - Robert J. White
- University of York, Department of Biology, York, United Kingdom
| | - John C. Marioni
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Claudia Kutter
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom
- Science for Life Laboratory, Karolinska Institute, Department of Microbiology, Tumor and Cell Biology, Stockholm, Sweden
| | - Duncan T. Odom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
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50
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Li C, Qian W, Maclean CJ, Zhang J. The fitness landscape of a tRNA gene. Science 2016; 352:837-40. [PMID: 27080104 DOI: 10.1126/science.aae0568] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/23/2016] [Indexed: 12/14/2022]
Abstract
Fitness landscapes describe the genotype-fitness relationship and represent major determinants of evolutionary trajectories. However, the vast genotype space, coupled with the difficulty of measuring fitness, has hindered the empirical determination of fitness landscapes. Combining precise gene replacement and next-generation sequencing, we quantified Darwinian fitness under a high-temperature challenge for more than 65,000 yeast strains, each carrying a unique variant of the single-copy tRNA(CCU)(Arg) gene at its native genomic location. Approximately 1% of single point mutations in the gene were beneficial and 42% were deleterious. Almost half of all mutation pairs exhibited statistically significant epistasis, which had a strong negative bias, except when the mutations occurred at Watson-Crick paired sites. Fitness was broadly correlated with the predicted fraction of correctly folded transfer RNA (tRNA) molecules, thereby revealing a biophysical basis of the fitness landscape.
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Affiliation(s)
- Chuan Li
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wenfeng Qian
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Calum J Maclean
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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