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Krueger J, Preusse M, Oswaldo Gomez N, Frommeyer YN, Doberenz S, Lorenz A, Kordes A, Grobe S, Müsken M, Depledge DP, Svensson SL, Weiss S, Kaever V, Pich A, Sharma CM, Ignatova Z, Häussler S. tRNA epitranscriptome determines pathogenicity of the opportunistic pathogen Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2024; 121:e2312874121. [PMID: 38451943 PMCID: PMC10945773 DOI: 10.1073/pnas.2312874121] [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: 07/28/2023] [Accepted: 12/29/2023] [Indexed: 03/09/2024] Open
Abstract
The success of bacterial pathogens depends on the coordinated expression of virulence determinants. Regulatory circuits that drive pathogenesis are complex, multilayered, and incompletely understood. Here, we reveal that alterations in tRNA modifications define pathogenic phenotypes in the opportunistic pathogen Pseudomonas aeruginosa. We demonstrate that the enzymatic activity of GidA leads to the introduction of a carboxymethylaminomethyl modification in selected tRNAs. Modifications at the wobble uridine base (cmnm5U34) of the anticodon drives translation of transcripts containing rare codons. Specifically, in P. aeruginosa the presence of GidA-dependent tRNA modifications modulates expression of genes encoding virulence regulators, leading to a cellular proteomic shift toward pathogenic and well-adapted physiological states. Our approach of profiling the consequences of chemical tRNA modifications is general in concept. It provides a paradigm of how environmentally driven tRNA modifications govern gene expression programs and regulate phenotypic outcomes responsible for bacterial adaption to challenging habitats prevailing in the host niche.
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Affiliation(s)
- Jonas Krueger
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
- Research Core Unit Proteomics and Institute for Toxicology, Hannover Medical School, Hannover30625, Germany
| | - Matthias Preusse
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, 38124Braunschweig, Germany
| | - Nicolas Oswaldo Gomez
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, 38124Braunschweig, Germany
| | - Yannick Noah Frommeyer
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
| | - Sebastian Doberenz
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
| | - Anne Lorenz
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, 38124Braunschweig, Germany
| | - Adrian Kordes
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
- Cluster of Excellence “Resolving Infection susceptibility” (RESIST), Hannover Medical School, Hannover30625, Germany
| | - Svenja Grobe
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
- Research Core Unit Metabolomics and Institute of Pharmacology, Hannover Medical School, Hannover 30625, Germany
| | - Mathias Müsken
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig38124, Germany
| | - Daniel P. Depledge
- Cluster of Excellence “Resolving Infection susceptibility” (RESIST), Hannover Medical School, Hannover30625, Germany
- Institute of Virology, Hannover Medical School, Hannover30625, Germany
- German Center for Infection Research, Partner Site Hannover-Braunschweig, Hannover30625, Germany
| | - Sarah L. Svensson
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Siegfried Weiss
- Institute of Immunology, Medical School Hannover, Hannover30625, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics and Institute of Pharmacology, Hannover Medical School, Hannover 30625, Germany
| | - Andreas Pich
- Research Core Unit Proteomics and Institute for Toxicology, Hannover Medical School, Hannover30625, Germany
| | - Cynthia M. Sharma
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Zoya Ignatova
- Institute for Biochemistry and Molecular Biology, University Hamburg, 20146, Germany
| | - Susanne Häussler
- Institute for Molecular Bacteriology, Center of Clinical and Experimental Infection Research (TWINCORE), a joint venture of the Hannover Medical School and the Helmholtz Center for Infection Research, Hannover30625, Germany
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, 38124Braunschweig, Germany
- Cluster of Excellence “Resolving Infection susceptibility” (RESIST), Hannover Medical School, Hannover30625, Germany
- Department of Clinical Microbiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen2100, Denmark
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2
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Handler S, Kirkpatrick CL. New layers of regulation of the general stress response sigma factor RpoS. Front Microbiol 2024; 15:1363955. [PMID: 38505546 PMCID: PMC10948607 DOI: 10.3389/fmicb.2024.1363955] [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: 12/31/2023] [Accepted: 02/21/2024] [Indexed: 03/21/2024] Open
Abstract
The general stress response (GSR) sigma factor RpoS from Escherichia coli has emerged as one of the key paradigms for study of how numerous signal inputs are accepted at multiple levels into a single pathway for regulation of gene expression output. While many studies have elucidated the key pathways controlling the production and activity of this sigma factor, recent discoveries have uncovered still more regulatory mechanisms which feed into the network. Moreover, while the regulon of this sigma factor comprises a large proportion of the E. coli genome, the downstream expression levels of all the RpoS target genes are not identically affected by RpoS upregulation but respond heterogeneously, both within and between cells. This minireview highlights the most recent developments in our understanding of RpoS regulation and expression, in particular those which influence the regulatory network at different levels from previously well-studied pathways.
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Smith TJ, Giles RN, Koutmou KS. Anticodon stem-loop tRNA modifications influence codon decoding and frame maintenance during translation. Semin Cell Dev Biol 2024; 154:105-113. [PMID: 37385829 DOI: 10.1016/j.semcdb.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/01/2023]
Abstract
RNAs are central to protein synthesis, with ribosomal RNA, transfer RNAs and messenger RNAs comprising the core components of the translation machinery. In addition to the four canonical bases (uracil, cytosine, adenine, and guanine) these RNAs contain an array of enzymatically incorporated chemical modifications. Transfer RNAs (tRNAs) are responsible for ferrying amino acids to the ribosome, and are among the most abundant and highly modified RNAs in the cell across all domains of life. On average, tRNA molecules contain 13 post-transcriptionally modified nucleosides that stabilize their structure and enhance function. There is an extensive chemical diversity of tRNA modifications, with over 90 distinct varieties of modifications reported within tRNA sequences. Some modifications are crucial for tRNAs to adopt their L-shaped tertiary structure, while others promote tRNA interactions with components of the protein synthesis machinery. In particular, modifications in the anticodon stem-loop (ASL), located near the site of tRNA:mRNA interaction, can play key roles in ensuring protein homeostasis and accurate translation. There is an abundance of evidence indicating the importance of ASL modifications for cellular health, and in vitro biochemical and biophysical studies suggest that individual ASL modifications can differentially influence discrete steps in the translation pathway. This review examines the molecular level consequences of tRNA ASL modifications in mRNA codon recognition and reading frame maintenance to ensure the rapid and accurate translation of proteins.
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Affiliation(s)
- Tyler J Smith
- University of Michigan, Department of Chemistry, 930 N University, Ann Arbor, MI 48109, USA
| | - Rachel N Giles
- University of Michigan, Department of Chemistry, 930 N University, Ann Arbor, MI 48109, USA
| | - Kristin S Koutmou
- University of Michigan, Department of Chemistry, 930 N University, Ann Arbor, MI 48109, USA.
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4
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Majdalani N, Chattopadhyay M, Keller C, Gottesman S. Lack of polyamines leads to cotranslational degradation of the general stress factor RpoS in Escherichia coli. J Biol Chem 2023; 299:104943. [PMID: 37343699 PMCID: PMC10372455 DOI: 10.1016/j.jbc.2023.104943] [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: 04/11/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
The specialized sigma factor RpoS mediates a general stress response in Escherichia coli and related bacteria, activating promoters that allow cells to survive stationary phase and many stresses. RpoS synthesis and stability are regulated at multiple levels. Translation of RpoS is positively regulated by multiple small RNAs in response to stress. Degradation of RpoS, dependent upon the adaptor protein RssB, is rapid during exponential growth and ceases upon starvation or other stresses, increasing accumulation of RpoS. E. coli carrying mutations that block the synthesis of polyamines were previously found to have low levels of RpoS, while levels increased rapidly when polyamines were added. We have used a series of reporters to examine the basis for the lack of RpoS in polyamine-deficient cells. The polyamine requirement was independent of small RNA-mediated positive regulation of RpoS translation. Mutations in rssB stabilize RpoS and significantly bypassed the polyamine deficit, suggesting that lack of polyamines might lead to rapid RpoS degradation. However, rates of degradation of mature RpoS were unaffected by polyamine availability. Codon optimization in rpoS partially relieved the polyamine dependence, suggesting a defect in RpoS translation in the absence of polyamines. Consistent with this, a hyperproofreading allele of ribosomal protein S12, encoded by rpsL, showed a decrease in RpoS levels, and this decrease was also suppressed by either codon optimization or blocking RpoS degradation. We suggest that rpoS codon usage leads it to be particularly sensitive to slowed translation, due to either lack of polyamines or hyperproofreading, leading to cotranslational degradation. We dedicate this study to Herb Tabor and his foundational work on polyamines, including the basis for this study.
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Affiliation(s)
- Nadim Majdalani
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Manas Chattopadhyay
- Laboratory of Biochemistry and Genetics, NIDDK, NIH, Bethesda, Maryland, USA
| | - Christopher Keller
- Laboratory of Biochemistry and Genetics, NIDDK, NIH, Bethesda, Maryland, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, Bethesda, Maryland, USA.
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5
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Fleming BA, Blango MG, Rousek AA, Kincannon WM, Tran A, Lewis A, Russell C, Zhou Q, Baird LM, Barber A, Brannon JR, Beebout C, Bandarian V, Hadjifrangiskou M, Howard M, Mulvey M. A tRNA modifying enzyme as a tunable regulatory nexus for bacterial stress responses and virulence. Nucleic Acids Res 2022; 50:7570-7590. [PMID: 35212379 PMCID: PMC9303304 DOI: 10.1093/nar/gkac116] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 02/02/2022] [Accepted: 02/08/2022] [Indexed: 11/16/2022] Open
Abstract
Post-transcriptional modifications can impact the stability and functionality of many different classes of RNA molecules and are an especially important aspect of tRNA regulation. It is hypothesized that cells can orchestrate rapid responses to changing environmental conditions by adjusting the specific types and levels of tRNA modifications. We uncovered strong evidence in support of this tRNA global regulation hypothesis by examining effects of the well-conserved tRNA modifying enzyme MiaA in extraintestinal pathogenic Escherichia coli (ExPEC), a major cause of urinary tract and bloodstream infections. MiaA mediates the prenylation of adenosine-37 within tRNAs that decode UNN codons, and we found it to be crucial to the fitness and virulence of ExPEC. MiaA levels shifted in response to stress via a post-transcriptional mechanism, resulting in marked changes in the amounts of fully modified MiaA substrates. Both ablation and forced overproduction of MiaA stimulated translational frameshifting and profoundly altered the ExPEC proteome, with variable effects attributable to UNN content, changes in the catalytic activity of MiaA, or availability of metabolic precursors. Cumulatively, these data indicate that balanced input from MiaA is critical for optimizing cellular responses, with MiaA acting much like a rheostat that can be used to realign global protein expression patterns.
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Affiliation(s)
- Brittany A Fleming
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Matthew G Blango
- Junior Research Group RNA Biology of Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Alexis A Rousek
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | | | - Alexander Tran
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Adam J Lewis
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Colin W Russell
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Qin Zhou
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Lisa M Baird
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Amelia E Barber
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - John R Brannon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Connor J Beebout
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Vahe Bandarian
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael T Howard
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Matthew A Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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6
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Soman S, Ram S. MiaA (Rv2727c) mediated tRNA isopentenylation of Mycobacterium tuberculosis H37Rv. MOLECULAR BIOLOGY RESEARCH COMMUNICATIONS 2022; 11:97-104. [PMID: 36059932 PMCID: PMC9336784 DOI: 10.22099/mbrc.2022.43197.1726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
tRNA modifications play a significant role in the structural stability as well as translational fidelity in all organisms from bacteria to humans. They also play a major role in bacterial physiology by regulating translation in response to various environmental stresses. Modifications coming at the anticodon-stem loop (ASL) are particularly important as they stabilize codon-anticodon interactions, ensuring accuracy and speed in decoding mRNAs Addition of isopentenyl group (i6A) at A37 position by tRNA isopentenyltransferase (MiaA) is a well conserved modification from bacteria to human. We studied M. tuberculosis MiaA from strain H37Rv and identified the target tRNAs for this modification based on the A36A37A38 motif. i6A modification of target tRNAs tRNALeuCAA, tRNAPheGAA, tRNATrpCCA and tRNASerCGA were further confirmed by isopentenyltransferase assay providing the substrate DMAPP and recombinant MiaA enzyme.
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Affiliation(s)
- Smitha Soman
- School of Biotechnology, Gautam Buddha University, Gautam Budh Nagar, Greater Noida, Uttar Pradesh, India
| | - Siya Ram
- School of Biotechnology, Gautam Buddha University, Gautam Budh Nagar, Greater Noida, Uttar Pradesh, India,School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi, India,Corresponding Author: School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi-11068, India. Tel: +91 11 29572868, E. mail:
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7
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Bhowmik P, Rajagopal S, Hmar RV, Singh P, Saxena P, Amar P, Thomas T, Ravishankar R, Nagaraj S, Katagihallimath N, Sarangapani RK, Ramachandran V, Datta S. Validated In Silico Model for Biofilm Formation in Escherichia coli. ACS Synth Biol 2022; 11:713-731. [PMID: 35025506 DOI: 10.1021/acssynbio.1c00445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using Escherichia coli as the representative biofilm former, we report here the development of an in silico model built by simulating events that transform a free-living bacterial entity into self-encased multicellular biofilms. Published literature on ∼300 genes associated with pathways involved in biofilm formation was curated, static maps were created, and suitably interconnected with their respective metabolites using ordinary differential equations. Precise interplay of genetic networks that regulate the transitory switching of bacterial growth pattern in response to environmental changes and the resultant multicomponent synthesis of the extracellular matrix were appropriately represented. Subsequently, the in silico model was analyzed by simulating time-dependent changes in the concentration of components by using the R and python environment. The model was validated by simulating and verifying the impact of key gene knockouts (KOs) and systematic knockdowns on biofilm formation, thus ensuring the outcomes were comparable with the reported literature. Similarly, specific gene KOs in laboratory and pathogenic E. coli were constructed and assessed. MiaA, YdeO, and YgiV were found to be crucial in biofilm development. Furthermore, qRT-PCR confirmed the elevation of expression in biofilm-forming clinical isolates. Findings reported in this study offer opportunities for identifying biofilm inhibitors with applications in multiple industries. The application of this model can be extended to the health care sector specifically to develop novel adjunct therapies that prevent biofilms in medical implants and reduce emergence of biofilm-associated resistant polymicrobial-chronic infections. The in silico framework reported here is open source and accessible for further enhancements.
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Affiliation(s)
- Purnendu Bhowmik
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
- The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Sreenath Rajagopal
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Rothangamawi Victoria Hmar
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Purnima Singh
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Pragya Saxena
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Prakruthi Amar
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Teby Thomas
- St. John’s Research Institute, Bengaluru, Karnataka 560034, India
| | - Rajani Ravishankar
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Savitha Nagaraj
- St. John’s Medical College, Bengaluru, Karnataka 560034, India
| | - Nainesh Katagihallimath
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
- The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Ramanujan Kadambi Sarangapani
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Vasanthi Ramachandran
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
- The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Santanu Datta
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
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Antoine L, Bahena-Ceron R, Devi Bunwaree H, Gobry M, Loegler V, Romby P, Marzi S. RNA Modifications in Pathogenic Bacteria: Impact on Host Adaptation and Virulence. Genes (Basel) 2021; 12:1125. [PMID: 34440299 PMCID: PMC8394870 DOI: 10.3390/genes12081125] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/16/2021] [Accepted: 07/19/2021] [Indexed: 12/19/2022] Open
Abstract
RNA modifications are involved in numerous biological processes and are present in all RNA classes. These modifications can be constitutive or modulated in response to adaptive processes. RNA modifications play multiple functions since they can impact RNA base-pairings, recognition by proteins, decoding, as well as RNA structure and stability. However, their roles in stress, environmental adaptation and during infections caused by pathogenic bacteria have just started to be appreciated. With the development of modern technologies in mass spectrometry and deep sequencing, recent examples of modifications regulating host-pathogen interactions have been demonstrated. They show how RNA modifications can regulate immune responses, antibiotic resistance, expression of virulence genes, and bacterial persistence. Here, we illustrate some of these findings, and highlight the strategies used to characterize RNA modifications, and their potential for new therapeutic applications.
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Affiliation(s)
| | | | | | | | | | | | - Stefano Marzi
- Université de Strasbourg, CNRS, Architecture et Réactivité de l’ARN, UPR 9002, F-67000 Strasbourg, France; (L.A.); (R.B.-C.); (H.D.B.); (M.G.); (V.L.); (P.R.)
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9
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de Crécy-Lagard V, Jaroch M. Functions of Bacterial tRNA Modifications: From Ubiquity to Diversity. Trends Microbiol 2020; 29:41-53. [PMID: 32718697 DOI: 10.1016/j.tim.2020.06.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 01/21/2023]
Abstract
Modified nucleotides in tRNA are critical components of the translation apparatus, but their importance in the process of translational regulation had until recently been greatly overlooked. Two breakthroughs have recently allowed a fuller understanding of the importance of tRNA modifications in bacterial physiology. One is the identification of the full set of tRNA modification genes in model organisms such as Escherichia coli K12. The second is the improvement of available analytical tools to monitor tRNA modification patterns. The role of tRNA modifications varies greatly with the specific modification within a given tRNA and with the organism studied. The absence of these modifications or reductions can lead to cell death or pleiotropic phenotypes or may have no apparent visible effect. By linking translation through their decoding functions to metabolism through their biosynthetic pathways, tRNA modifications are emerging as important components of the bacterial regulatory toolbox.
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Affiliation(s)
- Valérie de Crécy-Lagard
- Department of Microbiology and Cell Sciences, University of Florida, Gainesville, FL 32611, USA; Genetics Institute, University of Florida, Gainesville, FL 32611, USA.
| | - Marshall Jaroch
- Department of Microbiology and Cell Sciences, University of Florida, Gainesville, FL 32611, USA
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10
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Dabravolski S. Multi-faceted nature of the tRNA isopentenyltransferase. FUNCTIONAL PLANT BIOLOGY : FPB 2020; 47:475-485. [PMID: 32345433 DOI: 10.1071/fp19255] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/26/2019] [Indexed: 06/11/2023]
Abstract
Transfer RNA isopentenylation an adenine 37 position (A37) is a universal modification known in prokaryotes and eukaryotes. A set of highly homologous enzymes catalyse a series of reactions, leading to tRNA modifications, aimed to increase adaptation to environmental condition through the control of translation efficiency and reading frame maintenance. Transfer RNA-isopentenylation-related (TI-related) functions are well studied in bacteria, mitochondria of yeast and human, but completely unexplored in plants. Transfer RNA-isopentenylation-unrelated (TI-unrelated) functions participate in adaptation to environmental stresses via the regulation of sterol metabolism, gene silencing/suppression and amyloid fibrils formation. TI-unrelated functions are mostly studied in yeast. Finally, the degradation of A37-modified tRNA releases a set of bioactive compounds known as cis-cytokinins. Although all organisms are able to produce cis-cytokinins, its physiological role is still a matter of debates. For several species of bacteria and fungi, cis-cytokinins are known to play a crucial role in pathogenesis. In mammalian and human models cis-cytokinins have tumour-suppressing and anti-inflammation effects. This review aims to summarise current knowledge of the TI-related and TI-unrelated functions and main bioactive by-products of isopentenylated tRNA degradation.
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Affiliation(s)
- Siarhei Dabravolski
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelu 27, 78371 Olomouc, Czech Republic.
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Leonardi A, Evke S, Lee M, Melendez JA, Begley TJ. Epitranscriptomic systems regulate the translation of reactive oxygen species detoxifying and disease linked selenoproteins. Free Radic Biol Med 2019; 143:573-593. [PMID: 31476365 PMCID: PMC7650020 DOI: 10.1016/j.freeradbiomed.2019.08.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 02/07/2023]
Abstract
Here we highlight the role of epitranscriptomic systems in post-transcriptional regulation, with a specific focus on RNA modifying writers required for the incorporation of the 21st amino acid selenocysteine during translation, and the pathologies linked to epitranscriptomic and selenoprotein defects. Epitranscriptomic marks in the form of enzyme-catalyzed modifications to RNA have been shown to be important signals regulating translation, with defects linked to altered development, intellectual impairment, and cancer. Modifications to rRNA, mRNA and tRNA can affect their structure and function, while the levels of these dynamic tRNA-specific epitranscriptomic marks are stress-regulated to control translation. The tRNA for selenocysteine contains five distinct epitranscriptomic marks and the ALKBH8 writer for the wobble uridine (U) has been shown to be vital for the translation of the glutathione peroxidase (GPX) and thioredoxin reductase (TRXR) family of selenoproteins. The reactive oxygen species (ROS) detoxifying selenocysteine containing proteins are a prime examples of how specialized translation can be regulated by specific tRNA modifications working in conjunction with distinct codon usage patterns, RNA binding proteins and specific 3' untranslated region (UTR) signals. We highlight the important role of selenoproteins in detoxifying ROS and provide details on how epitranscriptomic marks and selenoproteins can play key roles in and maintaining mitochondrial function and preventing disease.
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Affiliation(s)
- Andrea Leonardi
- Colleges of Nanoscale Science and Engineering, University at Albany, State University of New York, Albany, NY, USA
| | - Sara Evke
- Colleges of Nanoscale Science and Engineering, State University of New York Polytechnic Institute, Albany, NY, USA
| | - May Lee
- Colleges of Nanoscale Science and Engineering, State University of New York Polytechnic Institute, Albany, NY, USA
| | - J Andres Melendez
- Colleges of Nanoscale Science and Engineering, State University of New York Polytechnic Institute, Albany, NY, USA.
| | - Thomas J Begley
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA; RNA Institute, University at Albany, State University of New York, Albany, NY, USA.
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12
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Gottesman S. Trouble is coming: Signaling pathways that regulate general stress responses in bacteria. J Biol Chem 2019; 294:11685-11700. [PMID: 31197038 DOI: 10.1074/jbc.rev119.005593] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bacteria can rapidly and reversibly respond to changing environments via complex transcriptional and post-transcriptional regulatory mechanisms. Many of these adaptations are specific, with the regulatory output tailored to the inducing signal (for instance, repairing damage to cell components or improving acquisition and use of growth-limiting nutrients). However, the general stress response, activated in bacterial cells entering stationary phase or subjected to nutrient depletion or cellular damage, is unique in that its common, broad output is induced in response to many different signals. In many different bacteria, the key regulator for the general stress response is a specialized sigma factor, the promoter specificity subunit of RNA polymerase. The availability or activity of the sigma factor is regulated by complex regulatory circuits, the majority of which are post-transcriptional. In Escherichia coli, multiple small regulatory RNAs, each made in response to a different signal, positively regulate translation of the general stress response sigma factor RpoS. Stability of RpoS is regulated by multiple anti-adaptor proteins that are also synthesized in response to different signals. In this review, the modes of signaling to and levels of regulation of the E. coli general stress response are discussed. They are also used as a basis for comparison with the general stress response in other bacteria with the aim of extracting key principles that are common among different species and highlighting important unanswered questions.
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Affiliation(s)
- Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
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13
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Koshla O, Yushchuk O, Ostash I, Dacyuk Y, Myronovskyi M, Jäger G, Süssmuth RD, Luzhetskyy A, Byström A, Kirsebom LA, Ostash B. Gene miaA for post-transcriptional modification of tRNA XXA is important for morphological and metabolic differentiation in Streptomyces. Mol Microbiol 2019; 112:249-265. [PMID: 31017319 DOI: 10.1111/mmi.14266] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2019] [Indexed: 12/14/2022]
Abstract
Members of actinobacterial genus Streptomyces possess a sophisticated life cycle and are the deepest source of bioactive secondary metabolites. Although morphogenesis and secondary metabolism are subject to transcriptional co-regulation, streptomycetes employ an additional mechanism to initiate the aforementioned processes. This mechanism is based on delayed translation of rare leucyl codon UUA by the only cognate tRNALeu UAA (encoded by bldA). The bldA-based genetic switch is an extensively documented example of translational regulation in Streptomyces. Yet, after five decades since the discovery of bldA, factors that shape its function and peculiar conditionality remained elusive. Here we address the hypothesis that post-transcriptional tRNA modifications play a role in tRNA-based mechanisms of translational control in Streptomyces. Particularly, we studied two Streptomyces albus J1074 genes, XNR_1074 (miaA) and XNR_1078 (miaB), encoding tRNA (adenosine(37)-N6)-dimethylallyltransferase and tRNA (N6-isopentenyl adenosine(37)-C2)-methylthiotransferase respectively. These enzymes produce, in a sequential manner, a hypermodified ms2 i6 A37 residue in most of the A36-A37-containing tRNAs. We show that miaB and especially miaA null mutant of S. albus possess altered morphogenesis and secondary metabolism. We provide genetic evidence that miaA deficiency impacts translational level of gene expression, most likely through impaired decoding of codons UXX and UUA in particular.
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Affiliation(s)
- Oksana Koshla
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho st., Lviv, 79005, Ukraine
| | - Oleksandr Yushchuk
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho st., Lviv, 79005, Ukraine
| | - Iryna Ostash
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho st., Lviv, 79005, Ukraine
| | - Yuriy Dacyuk
- Department of Physics of Earth, Ivan Franko National University of Lviv, 4 Hrushevskoho st., Lviv, 79005, Ukraine
| | - Maksym Myronovskyi
- Helmholtz Institute for Pharmaceutical Research, Saarland Campus, Building C2.3, Saarbrucken, 66123, Germany
| | - Gunilla Jäger
- Department of Molecular Biology, Umeå University, 6K och 6L, Sjukhusområdet, Umeå, 90197, Sweden
| | - Roderich D Süssmuth
- Institut für Chemie, Technische Universität Berlin, Straβe des 17 Juni 124/TC2, Berlin, 10623, Germany
| | - Andriy Luzhetskyy
- Helmholtz Institute for Pharmaceutical Research, Saarland Campus, Building C2.3, Saarbrucken, 66123, Germany
| | - Anders Byström
- Department of Molecular Biology, Umeå University, 6K och 6L, Sjukhusområdet, Umeå, 90197, Sweden
| | - Leif A Kirsebom
- Uppsala Biomedicinska Centrum BMC, Uppsala University, Husargatan 3, Box 596, Uppsala, 75124, Sweden
| | - Bohdan Ostash
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, 4 Hrushevskoho st., Lviv, 79005, Ukraine
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14
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Sehin Y, Koshla O, Dacyuk Y, Zhao R, Ross R, Myronovskyi M, Limbach PA, Luzhetskyy A, Walker S, Fedorenko V, Ostash B. Gene ssfg_01967 (miaB) for tRNA modification influences morphogenesis and moenomycin biosynthesis in Streptomyces ghanaensis ATCC14672. MICROBIOLOGY (READING, ENGLAND) 2019; 165:233-245. [PMID: 30543507 PMCID: PMC7003650 DOI: 10.1099/mic.0.000747] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 10/31/2018] [Indexed: 12/26/2022]
Abstract
Streptomyces ghanaensis ATCC14672 is remarkable for its production of phosphoglycolipid compounds, moenomycins, which serve as a blueprint for the development of a novel class of antibiotics based on inhibition of peptidoglycan glycosyltransferases. Here we employed mariner transposon (Tn) mutagenesis to find new regulatory genes essential for moenomycin production. We generated a library of 3000 mutants which were screened for altered antibiotic activity. Our focus centred on a single mutant, HIM5, which accumulated lower amounts of moenomycin and was impaired in morphogenesis as compared to the parental strain. HIM5 carried the Tn insertion within gene ssfg_01967 for putative tRNA (N6-isopentenyl adenosine(37)-C2)-methylthiotransferase, or MiaB, and led to a reduced level of thiomethylation at position 37 in the anticodon of S. ghanaensis transfer ribonucleic acid (tRNA). It is likely that the mutant phenotype of HIM5 stems from the way in which ssfg_01967::Tn influences translation of the rare leucine codon UUA in several genes for moenomycin production and life cycle progression in S. ghanaensis. This is the first report showing that quantitative changes in tRNA modification status in Streptomyces have physiological consequences.
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Affiliation(s)
- Yuliia Sehin
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine
| | - Oksana Koshla
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine
| | - Yuriy Dacyuk
- Department of Physics of the Earth, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine
| | - Ruoxia Zhao
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, 318 College Dr, 404 Crosley Tower, Cincinnati OH 45221-0172, USA
| | - Robert Ross
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, 318 College Dr, 404 Crosley Tower, Cincinnati OH 45221-0172, USA
| | - Maksym Myronovskyi
- Helmholtz Institute for Pharmaceutical Research Saarland Campus, Building C2.3, 66123 Saarbrucken, Germany
| | - Patrick A. Limbach
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, 318 College Dr, 404 Crosley Tower, Cincinnati OH 45221-0172, USA
| | - Andriy Luzhetskyy
- Helmholtz Institute for Pharmaceutical Research Saarland Campus, Building C2.3, 66123 Saarbrucken, Germany
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard Medical School, 4 Blackfan Circle, Boston, MA 02115, USA
| | - Victor Fedorenko
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine
| | - Bohdan Ostash
- Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine
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15
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Pollo-Oliveira L, de Crécy-Lagard V. Can Protein Expression Be Regulated by Modulation of tRNA Modification Profiles? Biochemistry 2018; 58:355-362. [PMID: 30511849 DOI: 10.1021/acs.biochem.8b01035] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
tRNAs are the central adaptor molecules in translation. Their decoding properties are influenced by post-transcriptional modifications, particularly in the critical anticodon-stem-loop (ASL) region. Synonymous codon choice, also called codon usage bias, affects both translation efficiency and accuracy, and ASL modifications play key roles in both of these processes. In combination with a handful of historical examples, recent studies integrating ribosome profiling, proteomics, codon-usage analyses, and modification quantifications show that levels of tRNA modifications can change under stress, during development, or under specific metabolic conditions and can modulate the expression of specific genes. Deconvoluting the different responses (global or specific) to tRNA modification deficiencies can be difficult because of pleiotropic effects, but, as more cases emerge, it does seem that tRNA modification changes could add another layer of regulation in the transfer of information from DNA to protein.
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Affiliation(s)
- Leticia Pollo-Oliveira
- Department of Microbiology and Cell Science , University of Florida , Gainesville , Florida 32603 , United States
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science , University of Florida , Gainesville , Florida 32603 , United States.,University of Florida Genetics Institute , Gainesville , Florida 32608 , United States
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16
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Chambers AE, Richardson AE, Read DF, Waller TJ, Bernstein DA, Smaldino PJ. An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity. J Vis Exp 2018. [PMID: 30346392 DOI: 10.3791/58100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
N6-isopentenyladenosine RNA modifications are functionally diverse and highly conserved among prokaryotes and eukaryotes. One of the most highly conserved N6-isopentenyladenosine modifications occurs at the A37 position in a subset of tRNAs. This modification improves translation efficiency and fidelity by increasing the affinity of the tRNA for the ribosome. Mutation of enzymes responsible for this modification in eukaryotes are associated with several disease states, including mitochondrial dysfunction and cancer. Therefore, understanding the substrate specificity and biochemical activities of these enzymes is important for understanding of normal and pathologic eukaryotic biology. A diverse array of methods has been employed to characterize i6A modifications. Herein is described a direct approach for the detection of isopentenylation by Mod5. This method utilizes incubation of RNAs with a recombinant isopentenyl transferase, followed by RNase T1 digestion, and 1-dimensional gel electrophoresis analysis to detect i6A modifications. In addition, the potential adaptability of this protocol to characterize other RNA-modifying enzymes is discussed.
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Affiliation(s)
| | | | - David F Read
- Department of Genome Sciences, University of Washington
| | - Thomas J Waller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan
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17
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Baldridge KC, Jora M, Maranhao AC, Quick MM, Addepalli B, Brodbelt JS, Ellington AD, Limbach PA, Contreras LM. Directed Evolution of Heterologous tRNAs Leads to Reduced Dependence on Post-transcriptional Modifications. ACS Synth Biol 2018; 7:1315-1327. [PMID: 29694026 DOI: 10.1021/acssynbio.7b00421] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Heterologous tRNA:aminoacyl tRNA synthetase pairs are often employed for noncanonical amino acid incorporation in the quest for an expanded genetic code. In this work, we investigated one possible mechanism by which directed evolution can improve orthogonal behavior for a suite of Methanocaldococcus jannaschii ( Mj) tRNATyr-derived amber suppressor tRNAs. Northern blotting demonstrated that reduced expression of heterologous tRNA variants correlated with improved orthogonality. We suspected that reduced expression likely minimized nonorthogonal interactions with host cell machinery. Despite the known abundance of post-transcriptional modifications in tRNAs across all domains of life, few studies have investigated how host enzymes may affect behavior of heterologous tRNAs. Therefore, we measured tRNA orthogonality using a fluorescent reporter assay in several modification-deficient strains, demonstrating that heterologous tRNAs with high expression are strongly affected by some native E. coli RNA-modifying enzymes, whereas low abundance evolved heterologous tRNAs are less affected by these same enzymes. We employed mass spectrometry to map ms2i6A37 and Ψ39 in the anticodon arm of two high abundance tRNAs (Nap1 and tRNAOptCUA), which provides (to our knowledge) the first direct evidence that MiaA and TruA post-transcriptionally modify evolved heterologous amber suppressor tRNAs. Changes in total tRNA modification profiles were observed by mass spectrometry in cells hosting these and other evolved suppressor tRNAs, suggesting that the demonstrated interactions with host enzymes might disturb native tRNA modification networks. Together, these results suggest that heterologous tRNAs engineered for specialized amber suppression can evolve highly efficient suppression capacity within the native post-transcriptional modification landscape of host RNA processing machinery.
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Affiliation(s)
- Kevin C. Baldridge
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Manasses Jora
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Andre C. Maranhao
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Matthew M. Quick
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | | | - Jennifer S. Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Andrew D. Ellington
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Patrick A. Limbach
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Lydia M. Contreras
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
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18
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Arimbasseri GA. Interactions between RNAP III transcription machinery and tRNA processing factors. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:354-360. [PMID: 29428193 DOI: 10.1016/j.bbagrm.2018.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 10/18/2022]
Abstract
Eukaryotes have at least three nuclear RNA polymerases to carry out transcription. While RNA polymerases I and II are responsible for ribosomal RNA transcription and messenger RNA transcription, respectively, RNA Polymerase III transcribes approximately up to 300 nt long noncoding RNAs, including tRNA. For all three RNAPs, the nascent transcripts generated undergo extensive post-transcriptional processing. Transcription of mRNAs by RNAP II and their processing are coupled with the aid of the C-terminal domain of the RNAP II. RNAP I transcription and the processing of its transcripts are co-localized to the nucleolus and to some extent, rRNA processing occurs co-transcriptionally. Here, I review the current evidence for the interaction between tRNA processing factors and RNA polymerase III. These interactions include the moonlighting functions of tRNA processing factors in RNAP III transcription and the indirect effect of tRNA transcription levels on tRNA modification machinery.
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Affiliation(s)
- G Aneeshkumar Arimbasseri
- Molecular Genetics Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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19
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Translational fidelity and mistranslation in the cellular response to stress. Nat Microbiol 2017; 2:17117. [PMID: 28836574 DOI: 10.1038/nmicrobiol.2017.117] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/20/2017] [Indexed: 11/08/2022]
Abstract
Faithful translation of mRNA into the corresponding polypeptide is a complex multistep process, requiring accurate amino acid selection, transfer RNA (tRNA) charging and mRNA decoding on the ribosome. Key players in this process are aminoacyl-tRNA synthetases (aaRSs), which not only catalyse the attachment of cognate amino acids to their respective tRNAs, but also selectively hydrolyse incorrectly activated non-cognate amino acids and/or misaminoacylated tRNAs. This aaRS proofreading provides quality control checkpoints that exclude non-cognate amino acids during translation, and in so doing helps to prevent the formation of an aberrant proteome. However, despite the intrinsic need for high accuracy during translation, and the widespread evolutionary conservation of aaRS proofreading pathways, requirements for translation quality control vary depending on cellular physiology and changes in growth conditions, and translation errors are not always detrimental. Recent work has demonstrated that mistranslation can also be beneficial to cells, and some organisms have selected for a higher degree of mistranslation than others. The aims of this Review Article are to summarize the known mechanisms of protein translational fidelity and explore the diversity and impact of mistranslation events as a potentially beneficial response to environmental and cellular stress.
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20
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TrmL and TusA Are Necessary for rpoS and MiaA Is Required for hfq Expression in Escherichia coli. Biomolecules 2017; 7:biom7020039. [PMID: 28471404 PMCID: PMC5485728 DOI: 10.3390/biom7020039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 03/31/2017] [Accepted: 04/12/2017] [Indexed: 12/18/2022] Open
Abstract
Previous work demonstrated that efficient RNA Polymerase sigma S-subunit (RpoS) translation requires the N6-isopentenyladenosine i6A37 transfer RNA (tRNA) modification for UUX-Leu decoding. Here we investigate the effect of two additional tRNA modification systems on RpoS translation; the analysis was also extended to another High UUX-leucine codon (HULC) protein, Host Factor for phage Qβ (Hfq). One tRNA modification, the addition of the 2’-O-methylcytidine/uridine 34 (C/U34m) tRNA modification by tRNA (cytidine/uridine-2’O)-ribose methyltransferase L (TrmL), requires the presence of the N6-isopentenyladenosine 37 (i6A37) and therefore it seemed possible that the defect in RpoS translation in the absence of i6A37 prenyl transferase (MiaA) was in fact due to the inability to add the C/U34m modification to UUX-Leu tRNAs. The second modification, addition of 2-thiouridine (s2U), part of (mnm5s2U34), is dependent on tRNA 2-thiouridine synthesizing protein A (TusA), previously shown to affect RpoS levels. We compared expression of PBAD-rpoS990-lacZ translational fusions carrying wild-type UUX leucine codons with derivatives in which UUX codons were changed to CUX codons, in the presence and absence of TrmL or TusA. The absence of these proteins, and therefore presumably the modifications they catalyze, both abolished PBAD-rpoS990-lacZ translation activity. UUX-Leu to CUX-Leu codon mutations in rpoS suppressed the trmL requirement for PBAD-rpoS990-lacZ expression. Thus, it is likely that the C/U34m and s2U34 tRNA modifications are necessary for full rpoS translation. We also measured PBAD-hfq306-lacZ translational fusion activity in the absence of C/U34m (trmL) or i6A37 (miaA). The absence of i6A37 resulted in decreased PBAD-hfq306-lacZ expression, consistent with a role for i6A37 tRNA modification for hfq translation.
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21
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Agris PF, Narendran A, Sarachan K, Väre VYP, Eruysal E. The Importance of Being Modified: The Role of RNA Modifications in Translational Fidelity. Enzymes 2017; 41:1-50. [PMID: 28601219 DOI: 10.1016/bs.enz.2017.03.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The posttranscriptional modifications of tRNA's anticodon stem and loop (ASL) domain represent a third level, a third code, to the accuracy and efficiency of translating mRNA codons into the correct amino acid sequence of proteins. Modifications of tRNA's ASL domain are enzymatically synthesized and site specifically located at the anticodon wobble position-34 and 3'-adjacent to the anticodon at position-37. Degeneracy of the 64 Universal Genetic Codes and the limitation in the number of tRNA species require some tRNAs to decode more than one codon. The specific modification chemistries and their impact on the tRNA's ASL structure and dynamics enable one tRNA to decode cognate and "wobble codons" or to expand recognition to synonymous codons, all the while maintaining the translational reading frame. Some modified nucleosides' chemistries prestructure tRNA to read the two codons of a specific amino acid that shares a twofold degenerate codon box, and other chemistries allow a different tRNA to respond to all four codons of a fourfold degenerate codon box. Thus, tRNA ASL modifications are critical and mutations in genes for the modification enzymes and tRNA, the consequences of which is a lack of modification, lead to mistranslation and human disease. By optimizing tRNA anticodon chemistries, structure, and dynamics in all organisms, modifications ensure translational fidelity of mRNA transcripts.
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Affiliation(s)
- Paul F Agris
- The RNA Institute, State University of New York, Albany, NY, United States.
| | - Amithi Narendran
- The RNA Institute, State University of New York, Albany, NY, United States
| | - Kathryn Sarachan
- The RNA Institute, State University of New York, Albany, NY, United States
| | - Ville Y P Väre
- The RNA Institute, State University of New York, Albany, NY, United States
| | - Emily Eruysal
- The RNA Institute, State University of New York, Albany, NY, United States
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22
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Abstract
The efficiency of codon translation in vivo is controlled by many factors, including codon context. At a site early in the Salmonella flgM gene, the effects on translation of replacing codons Thr6 and Pro8 of flgM with synonymous alternates produced a 600-fold range in FlgM activity. Synonymous changes at Thr6 and Leu9 resulted in a twofold range in FlgM activity. The level of FlgM activity produced by any codon arrangement was directly proportional to the degree of in vivo ribosome stalling at synonymous codons. Synonymous codon suppressors that corrected the effect of a translation-defective synonymous flgM allele were restricted to two codons flanking the translation-defective codon. The various codon arrangements had no apparent effects on flgM mRNA stability or predicted mRNA secondary structures. Our data suggest that efficient mRNA translation is determined by a triplet-of-triplet genetic code. That is, the efficiency of translating a particular codon is influenced by the nature of the immediately adjacent flanking codons. A model explains these codon-context effects by suggesting that codon recognition by elongation factor-bound aminoacyl-tRNA is initiated by hydrogen bond interactions between the first two nucleotides of the codon and anticodon and then is stabilized by base-stacking energy over three successive codons.
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23
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Maraia RJ, Arimbasseri AG. Factors That Shape Eukaryotic tRNAomes: Processing, Modification and Anticodon-Codon Use. Biomolecules 2017; 7:biom7010026. [PMID: 28282871 PMCID: PMC5372738 DOI: 10.3390/biom7010026] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/24/2017] [Indexed: 01/24/2023] Open
Abstract
Transfer RNAs (tRNAs) contain sequence diversity beyond their anticodons and the large variety of nucleotide modifications found in all kingdoms of life. Some modifications stabilize structure and fit in the ribosome whereas those to the anticodon loop modulate messenger RNA (mRNA) decoding activity more directly. The identities of tRNAs with some universal anticodon loop modifications vary among distant and parallel species, likely to accommodate fine tuning for their translation systems. This plasticity in positions 34 (wobble) and 37 is reflected in codon use bias. Here, we review convergent evidence that suggest that expansion of the eukaryotic tRNAome was supported by its dedicated RNA polymerase III transcription system and coupling to the precursor-tRNA chaperone, La protein. We also review aspects of eukaryotic tRNAome evolution involving G34/A34 anticodon-sparing, relation to A34 modification to inosine, biased codon use and regulatory information in the redundancy (synonymous) component of the genetic code. We then review interdependent anticodon loop modifications involving position 37 in eukaryotes. This includes the eukaryote-specific tRNA modification, 3-methylcytidine-32 (m3C32) and the responsible gene, TRM140 and homologs which were duplicated and subspecialized for isoacceptor-specific substrates and dependence on i6A37 or t6A37. The genetics of tRNA function is relevant to health directly and as disease modifiers.
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Affiliation(s)
- Richard J Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
- Commissioned Corps, U.S. Public Health Service, Rockville, MD, 20016, USA.
| | - Aneeshkumar G Arimbasseri
- Molecular Genetics Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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24
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Schweizer U, Bohleber S, Fradejas-Villar N. The modified base isopentenyladenosine and its derivatives in tRNA. RNA Biol 2017; 14:1197-1208. [PMID: 28277934 PMCID: PMC5699536 DOI: 10.1080/15476286.2017.1294309] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Base 37 in tRNA, 3′-adjacent to the anticodon, is occupied by a purine base that is thought to stabilize codon recognition by stacking interactions on the first Watson-Crick base pair. If the first codon position forms an A.U or U.A base pair, the purine is likely further modified in all domains of life. One of the first base modifications found in tRNA is N6-isopentenyl adenosine (i6A) present in a fraction of tRNAs in bacteria and eukaryotes, which can be further modified to 2-methyl-thio-N6-isopentenyladenosine (ms2i6A) in a subset of tRNAs. Homologous tRNA isopentenyl transferase enzymes have been identified in bacteria (MiaA), yeast (Mod5, Tit1), roundworm (GRO-1), and mammals (TRIT1). In eukaryotes, isopentenylation of cytoplasmic and mitochondrial tRNAs is mediated by products of the same gene. Accordingly, a patient with homozygous mutations in TRIT1 has mitochondrial disease. The role of i6A in a subset of tRNAs in gene expression has been linked with translational fidelity, speed of translation, skewed gene expression, and non-sense suppression. This review will not cover the action of i6A as a cytokinin in plants or the potential function of Mod5 as a prion in yeast.
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Affiliation(s)
- Ulrich Schweizer
- a Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn , Bonn , Germany
| | - Simon Bohleber
- a Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn , Bonn , Germany
| | - Noelia Fradejas-Villar
- a Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn , Bonn , Germany
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25
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Yu JM, Wang D, Pierson LS, Pierson EA. Disruption of MiaA provides insights into the regulation of phenazine biosynthesis under suboptimal growth conditions in Pseudomonas chlororaphis 30-84. MICROBIOLOGY-SGM 2017; 163:94-108. [PMID: 27926818 DOI: 10.1099/mic.0.000409] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many products of secondary metabolism are activated by quorum sensing (QS), yet even at cell densities sufficient for QS, their production may be repressed under suboptimal growth conditions via mechanisms that still require elucidation. For many beneficial plant-associated bacteria, secondary metabolites such as phenazines are important for their competitive survival and plant-protective activities. Previous work established that phenazine biosynthesis in Pseudomonas chlororaphis 30-84 is regulated by the PhzR/PhzI QS system, which in turn is regulated by transcriptional regulator Pip, two-component system RpeA/RpeB and stationary phase/stress sigma factor RpoS. Disruption of MiaA, a tRNA modification enzyme, altered primary metabolism and growth leading to widespread effects on secondary metabolism, including reduced phenazine production and oxidative stress tolerance. Thus, the miaA mutant provided the opportunity to examine the regulation of phenazine production in response to altered metabolism and growth or stress tolerance. Despite the importance of MiaA for translation efficiency, the most significant effect of miaA disruption on phenazine production was the reduction in the transcription of phzR, phzI and pip, whereas neither the transcription nor translation of RpeB, a transcriptional regulator of pip, was affected. Constitutive expression of rpeB or pip in the miaA mutant completely restored phenazine production, but it resulted in further growth impairment. Constitutive expression of RpoS alleviated sensitivity to oxidative stress resulting from RpoS translation inefficiency in the miaA mutant, but it did not restore phenazine production. Our results support the model that cells curtail phenazine biosynthesis under suboptimal growth conditions via RpeB/Pip-mediated regulation of QS.
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Affiliation(s)
- Jun Myoung Yu
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77943-2133, USA
| | - Dongping Wang
- Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM 87544, USA
| | - Leland S Pierson
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77943-2133, USA
| | - Elizabeth A Pierson
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77943-2133, USA.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77943-2133, USA
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Abstract
There are more than 70 genes in the flagellar and chemosensory regulon of Salmonella enterica. These genes are organized into a transcriptional hierarchy of three promoter classes. At the top of the transcriptional hierarchy is the flhDC operon, also called the flagellar master operon, which is transcribed from the flagellar class 1 promoter region. The protein products of the flhDC operon form a hetero-multimeric complex, FlhD4C2, which directs σ70 RNA polymerase to transcribe from class 2 flagellar promoters. Products of flagellar class 2 transcription are required for the structure and assembly of the hook-basal body (HBB) complex. One of the class 2 flagellar genes, fliA, encodes an alternative sigma transcription factor, σ28, which directs transcription from flagellar class 3 promoters. The class 3 promoters direct transcription of gene products needed after HBB completion including the motor force generators, the filament, and the chemosensory genes. Flagellar gene transcription is coupled to assembly at the level of hook-basal body completion. Two key proteins, σ28 and FliT, play assembly roles prior to HBB completion and upon HBB completion act as positive and negative regulators, respectively. HBB completion signals a secretion-specificity switch in the flagellar type III secretion system, which results in the secretion of σ28 and FliT antigonists allowing these proteins to perform their roles in transcriptional regulation of flagellar genes. Genetic methods have provided the principle driving forces in our understanding of how flagellar gene expression is controlled and coupled to the assembly process.
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Affiliation(s)
- Fabienne F V Chevance
- Department of Biology, University of Utah, 257 1400 E. #201, Salt Lake City, UT, 84112, USA
| | - Kelly T Hughes
- Department of Biology, University of Utah, 257 1400 E. #201, Salt Lake City, UT, 84112, USA.
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