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Lin XN, Gai BX, Liu L, Cheng L. Advances in the investigation of N 6-isopentenyl adenosine i 6A RNA modification. Bioorg Med Chem 2024; 110:117838. [PMID: 39018794 DOI: 10.1016/j.bmc.2024.117838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Revised: 07/09/2024] [Accepted: 07/09/2024] [Indexed: 07/19/2024]
Abstract
Prenylation (isopentenylation), a key post-transcriptional modification with a hydrophobic prenyl group onto the biomacromolecules such as RNA and proteins, influences their localization and function. Prenyltransferases mediate this process, while cytokinin oxidases degrade the prenylated adenosine in plants. This review summarizes current progress in detecting prenylation modifications in RNA across species and their effects on protein synthesis. Advanced methods have been developed to label and study these modifications in vitro and in vivo, despite challenges posed by the inert chemical properties of prenyl groups. Continued advancements in bioorthogonal chemistry promise new tools for understanding the precise biological functions of prenylated RNA modifications and other related proteins.
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Affiliation(s)
- Xiu-Na Lin
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bo-Xu Gai
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liang Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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2
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Böttcher B, Kienast SD, Leufken J, Eggers C, Sharma P, Leufken CM, Morgner B, Drexler HCA, Schulz D, Allert S, Jacobsen ID, Vylkova S, Leidel SA, Brunke S. A highly conserved tRNA modification contributes to C. albicans filamentation and virulence. Microbiol Spectr 2024; 12:e0425522. [PMID: 38587411 PMCID: PMC11064501 DOI: 10.1128/spectrum.04255-22] [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: 10/18/2022] [Accepted: 01/18/2024] [Indexed: 04/09/2024] Open
Abstract
tRNA modifications play important roles in maintaining translation accuracy in all domains of life. Disruptions in the tRNA modification machinery, especially of the anticodon stem loop, can be lethal for many bacteria and lead to a broad range of phenotypes in baker's yeast. Very little is known about the function of tRNA modifications in host-pathogen interactions, where rapidly changing environments and stresses require fast adaptations. We found that two closely related fungal pathogens of humans, the highly pathogenic Candida albicans and its much less pathogenic sister species, Candida dubliniensis, differ in the function of a tRNA-modifying enzyme. This enzyme, Hma1, exhibits species-specific effects on the ability of the two fungi to grow in the hypha morphology, which is central to their virulence potential. We show that Hma1 has tRNA-threonylcarbamoyladenosine dehydratase activity, and its deletion alters ribosome occupancy, especially at 37°C-the body temperature of the human host. A C. albicans HMA1 deletion mutant also shows defects in adhesion to and invasion into human epithelial cells and shows reduced virulence in a fungal infection model. This links tRNA modifications to host-induced filamentation and virulence of one of the most important fungal pathogens of humans.IMPORTANCEFungal infections are on the rise worldwide, and their global burden on human life and health is frequently underestimated. Among them, the human commensal and opportunistic pathogen, Candida albicans, is one of the major causative agents of severe infections. Its virulence is closely linked to its ability to change morphologies from yeasts to hyphae. Here, this ability is linked-to our knowledge for the first time-to modifications of tRNA and translational efficiency. One tRNA-modifying enzyme, Hma1, plays a specific role in C. albicans and its ability to invade the host. This adds a so-far unknown layer of regulation to the fungal virulence program and offers new potential therapeutic targets to fight fungal infections.
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Affiliation(s)
- Bettina Böttcher
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sandra D. Kienast
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Johannes Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Cristian Eggers
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Puneet Sharma
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Christine M. Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Bianka Morgner
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Hannes C. A. Drexler
- Bioanalytical Mass Spectrometry Unit, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Daniela Schulz
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Ilse D. Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Slavena Vylkova
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sebastian A. Leidel
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
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3
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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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Delaunay S, Helm M, Frye M. RNA modifications in physiology and disease: towards clinical applications. Nat Rev Genet 2024; 25:104-122. [PMID: 37714958 DOI: 10.1038/s41576-023-00645-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2023] [Indexed: 09/17/2023]
Abstract
The ability of chemical modifications of single nucleotides to alter the electrostatic charge, hydrophobic surface and base pairing of RNA molecules is exploited for the clinical use of stable artificial RNAs such as mRNA vaccines and synthetic small RNA molecules - to increase or decrease the expression of therapeutic proteins. Furthermore, naturally occurring biochemical modifications of nucleotides regulate RNA metabolism and function to modulate crucial cellular processes. Studies showing the mechanisms by which RNA modifications regulate basic cell functions in higher organisms have led to greater understanding of how aberrant RNA modification profiles can cause disease in humans. Together, these basic science discoveries have unravelled the molecular and cellular functions of RNA modifications, have provided new prospects for therapeutic manipulation and have led to a range of innovative clinical approaches.
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Affiliation(s)
- Sylvain Delaunay
- Deutsches Krebsforschungszentrum (DKFZ), Division of Mechanisms Regulating Gene Expression, Heidelberg, Germany
| | - Mark Helm
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Michaela Frye
- Deutsches Krebsforschungszentrum (DKFZ), Division of Mechanisms Regulating Gene Expression, Heidelberg, Germany.
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5
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Saleh S, Farabaugh PJ. Posttranscriptional modification to the core of tRNAs modulates translational misreading errors. RNA (NEW YORK, N.Y.) 2023; 30:37-51. [PMID: 37907335 PMCID: PMC10726164 DOI: 10.1261/rna.079797.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/09/2023] [Indexed: 11/02/2023]
Abstract
Protein synthesis on the ribosome involves successive rapid recruitment of cognate aminoacyl-tRNAs and rejection of the much more numerous incorrect near- or non-cognates. The principal feature of translation elongation is that at every step, many incorrect aa-tRNAs unsuccessfully enter the A site for each cognate accepted. Normal levels of translational accuracy require that cognate tRNAs have relatively similar acceptance rates by the ribosome. To achieve that, tRNAs evolved to compensate for differences in amino acid properties and codon-anticodon strength that affect acceptance. Part of that response involved tRNA posttranscriptional modifications, which can affect tRNA decoding efficiency, accuracy, and structural stability. The most intensively modified regions of the tRNA are the anticodon loop and structural core of the tRNA. Anticodon loop modifications directly affect codon-anticodon pairing and therefore modulate accuracy. Core modifications have been thought to ensure consistent decoding rates principally by stabilizing tRNA structure to avoid degradation; however, degradation due to instability appears to only be a significant issue above normal growth temperatures. We suspected that the greater role of modification at normal temperatures might be to tune tRNAs to maintain consistent intrinsic rates of acceptance and peptide transfer and that hypomodification by altering these rates might degrade the process of discrimination, leading to increased translational errors. Here, we present evidence that most tRNA core modifications do modulate the frequency of misreading errors, suggesting that the need to maintain accuracy explains their deep evolutionary conservation.
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Affiliation(s)
- Sima Saleh
- Department of Biological Sciences and Program in Molecular and Cell Biology, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA
| | - Philip J Farabaugh
- Department of Biological Sciences and Program in Molecular and Cell Biology, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA
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6
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Mitchener M, Begley TJ, Dedon PC. Molecular Coping Mechanisms: Reprogramming tRNAs To Regulate Codon-Biased Translation of Stress Response Proteins. Acc Chem Res 2023; 56:3504-3514. [PMID: 37992267 PMCID: PMC10702489 DOI: 10.1021/acs.accounts.3c00572] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/24/2023]
Abstract
As part of the classic central dogma of molecular biology, transfer RNAs (tRNAs) are integral to protein translation as the adaptor molecules that link the genetic code in messenger RNA (mRNA) to the amino acids in the growing peptide chain. tRNA function is complicated by the existence of 61 codons to specify 20 amino acids, with most amino acids coded by two or more synonymous codons. Further, there are often fewer tRNAs with unique anticodons than there are synonymous codons for an amino acid, with a single anticodon able to decode several codons by "wobbling" of the base pairs arising between the third base of the codon and the first position on the anticodon. The complications introduced by synonymous codons and wobble base pairing began to resolve in the 1960s with the discovery of dozens of chemical modifications of the ribonucleotides in tRNA, which, by analogy to the epigenome, are now collectively referred to as the epitranscriptome for not changing the genetic code inherent to all RNA sequences. tRNA modifications were found to stabilize codon-anticodon interactions, prevent misinitiation of translation, and promote translational fidelity, among other functions, with modification deficiencies causing pathological phenotypes. This led to hypotheses that modification-dependent tRNA decoding efficiencies might play regulatory roles in cells. However, it was only with the advent of systems biology and convergent "omic" technologies that the higher level function of synonymous codons and tRNA modifications began to emerge.Here, we describe our laboratories' discovery of tRNA reprogramming and codon-biased translation as a mechanism linking tRNA modifications and synonymous codon usage to regulation of gene expression at the level of translation. Taking a historical approach, we recount how we discovered that the 8-10 modifications in each tRNA molecule undergo unique reprogramming in response to cellular stresses to promote translation of mRNA transcripts with unique codon usage patterns. These modification tunable transcripts (MoTTs) are enriched with specific codons that are differentially decoded by modified tRNAs and that fall into functional families of genes encoding proteins necessary to survive the specific stress. By developing and applying systems-level technologies, we showed that cells lacking specific tRNA modifications are sensitized to certain cellular stresses by mistranslation of proteins, disruption of mitochondrial function, and failure to translate critical stress response proteins. In essence, tRNA reprogramming serves as a cellular coping strategy, enabling rapid translation of proteins required for stress-specific cell response programs. Notably, this phenomenon has now been characterized in all organisms from viruses to humans and in response to all types of environmental changes. We also elaborate on recent findings that cancer cells hijack this mechanism to promote their own growth, metastasis, and chemotherapeutic resistance. We close by discussing how understanding of codon-biased translation in various systems can be exploited to develop new therapeutics and biomanufacturing processes.
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Affiliation(s)
- Michelle
M. Mitchener
- Antimicrobial
Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore 138602, Singapore
| | - Thomas J. Begley
- Department
of Biological Sciences, University at Albany, Albany, New York 12222, United States
- RNA
Institute, University at Albany, Albany, New York 12222, United States
| | - Peter C. Dedon
- Antimicrobial
Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Centre, Singapore 138602, Singapore
- Department
of Biological Engineering, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
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7
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Bian P, Chai J, Xu B. Research Advances on Deafness Genes Associated with Mitochondrial tRNA-37 Modifications. J Int Adv Otol 2023; 19:414-419. [PMID: 37789629 PMCID: PMC10645192 DOI: 10.5152/iao.2023.231107] [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: 02/23/2023] [Accepted: 06/08/2023] [Indexed: 10/05/2023] Open
Abstract
As the most common cause of speech disorders, the etiological study of deafness is important for the diagnosis and treatment of deafness. The mitochondrial genome has gradually become a hotspot for deafness genetic research. Mitochondria are the core organelles of energy and material metabolism in eukaryotic cells. Human mitochondria contain 20 amino acids, except for tRNALeu and tRNASer, which have 2 iso-receptors, the other 18 amino acids correspond to unique tRNAs one by one, so mutations in any one tRNA may lead to protein translation defects in mitochondria and thus affect their oxidative phosphorylation process resulting in the corresponding disease phenotype. Mitochondrial tRNAs are extensively modified with base modifications that contribute to the correct folding of tRNAs and maintain their stability. Defective mitochondrial tRNA modifications are closely associated with the development of mitochondrial diseases. The in-depth study found that modification defects of mammalian mitochondrial tRNAs are associated with deafness, especially the nucleotide modification defect of mt-tRNA-37. This article reviews the research on mitochondrial tRNAs, nucleotide modification structure of mitochondrial tRNA-37, and nuclear genes related to modification defects to provide new ideas for the etiological study of deafness.
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Affiliation(s)
- Panpan Bian
- Department of Otolaryngology—Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, China
| | - Jing Chai
- Department of Otolaryngology—Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, China
| | - Baicheng Xu
- Department of Otolaryngology—Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, China
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8
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Abstract
The study of eukaryotic tRNA processing has given rise to an explosion of new information and insights in the last several years. We now have unprecedented knowledge of each step in the tRNA processing pathway, revealing unexpected twists in biochemical pathways, multiple new connections with regulatory pathways, and numerous biological effects of defects in processing steps that have profound consequences throughout eukaryotes, leading to growth phenotypes in the yeast Saccharomyces cerevisiae and to neurological and other disorders in humans. This review highlights seminal new results within the pathways that comprise the life of a tRNA, from its birth after transcription until its death by decay. We focus on new findings and revelations in each step of the pathway including the end-processing and splicing steps, many of the numerous modifications throughout the main body and anticodon loop of tRNA that are so crucial for tRNA function, the intricate tRNA trafficking pathways, and the quality control decay pathways, as well as the biogenesis and biology of tRNA-derived fragments. We also describe the many interactions of these pathways with signaling and other pathways in the cell.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, Ohio 43235, USA
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9
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Modopathies Caused by Mutations in Genes Encoding for Mitochondrial RNA Modifying Enzymes: Molecular Mechanisms and Yeast Disease Models. Int J Mol Sci 2023; 24:ijms24032178. [PMID: 36768505 PMCID: PMC9917222 DOI: 10.3390/ijms24032178] [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: 12/28/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/25/2023] Open
Abstract
In eukaryotes, mitochondrial RNAs (mt-tRNAs and mt-rRNAs) are subject to specific nucleotide modifications, which are critical for distinct functions linked to the synthesis of mitochondrial proteins encoded by mitochondrial genes, and thus for oxidative phosphorylation. In recent years, mutations in genes encoding for mt-RNAs modifying enzymes have been identified as being causative of primary mitochondrial diseases, which have been called modopathies. These latter pathologies can be caused by mutations in genes involved in the modification either of tRNAs or of rRNAs, resulting in the absence of/decrease in a specific nucleotide modification and thus on the impairment of the efficiency or the accuracy of the mitochondrial protein synthesis. Most of these mutations are sporadic or private, thus it is fundamental that their pathogenicity is confirmed through the use of a model system. This review will focus on the activity of genes that, when mutated, are associated with modopathies, on the molecular mechanisms through which the enzymes introduce the nucleotide modifications, on the pathological phenotypes associated with mutations in these genes and on the contribution of the yeast Saccharomyces cerevisiae to confirming the pathogenicity of novel mutations and, in some cases, for defining the molecular defects.
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10
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Lin Q, Huang J, Liu Z, Chen Q, Wang X, Yu G, Cheng P, Zhang LH, Xu Z. tRNA modification enzyme MiaB connects environmental cues to activation of Pseudomonas aeruginosa type III secretion system. PLoS Pathog 2022; 18:e1011027. [PMID: 36469533 PMCID: PMC9754610 DOI: 10.1371/journal.ppat.1011027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/15/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa, a major inhabitant of numerous environmental reservoirs, is a momentous opportunistic human pathogen associated with severe infections even death in the patients suffering from immune deficiencies or metabolic diseases. Type III secretion system (T3SS) employed by P. aeruginosa to inject effector proteins into host cells is one of the pivotal virulence factors pertaining to acute infections caused by this pathogen. Previous studies showed that P. aeruginosa T3SS is regulated by various environmental cues such as calcium concentration and the host signal spermidine. However, how T3SS is regulated and expressed particularly under the ever-changing environmental conditions remains largely elusive. In this study, we reported that a tRNA modification enzyme PA3980, designated as MiaB, positively regulated T3SS gene expression in P. aeruginosa and was essential for the induced cytotoxicity of human lung epithelial cells. Further genetic assays revealed that MiaB promoted T3SS gene expression by repressing the LadS-Gac/Rsm signaling pathway and through the T3SS master regulator ExsA. Interestingly, ladS, gacA, rsmY and rsmZ in the LadS-Gac/Rsm signaling pathway seemed potential targets under the independent regulation of MiaB. Moreover, expression of MiaB was found to be induced by the cAMP-dependent global regulator Vfr as well as the spermidine transporter-dependent signaling pathway and thereafter functioned to mediate their regulation on the T3SS gene expression. Together, these results revealed a novel regulatory mechanism for MiaB, with which it integrates different environmental cues to modulate T3SS gene expression in this important bacterial pathogen.
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Affiliation(s)
- Qiqi Lin
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
- School of Food Pharmaceutical Engineering, Zhao Qing University, Zhaoqing, China
| | - Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Zhiqing Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Qunyi Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Xinbo Wang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Guohui Yu
- Institute of Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Ping Cheng
- Institute of Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
- * E-mail: (L-HZ); (ZX)
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
- * E-mail: (L-HZ); (ZX)
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11
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Khalique A, Mattijssen S, Maraia RJ. A versatile tRNA modification-sensitive northern blot method with enhanced performance. RNA (NEW YORK, N.Y.) 2022; 28:418-432. [PMID: 34930808 PMCID: PMC8848930 DOI: 10.1261/rna.078929.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/01/2021] [Indexed: 06/14/2023]
Abstract
The 22 mitochondrial and ∼45 cytosolic tRNAs in human cells contain several dozen different post-transcriptional modified nucleotides such that each carries a unique constellation that complements its function. Many tRNA modifications are linked to altered gene expression, and deficiencies due to mutations in tRNA modification enzymes (TMEs) are responsible for numerous diseases. Easily accessible methods to detect tRNA hypomodifications can facilitate progress in advancing such molecular studies. Our laboratory developed a northern blot method that can quantify relative levels of base modifications on multiple specific tRNAs ∼10 yr ago, which has been used to characterize four different TME deficiencies and is likely further extendable. The assay method depends on differential annealing efficiency of a DNA-oligo probe to the modified versus unmodified tRNA. The signal of this probe is then normalized by a second probe elsewhere on the same tRNA. This positive hybridization in the absence of modification (PHAM) assay has proven useful for i6A37, t6A37, m3C32, and m2,2G26 in multiple laboratories. Yet, over the years we have observed idiosyncratic inconsistency and variability in the assay. Here we document these for some tRNAs and probes and illustrate principles and practices for improved reliability and uniformity in performance. We provide an overview of the method and illustrate benefits of the improved conditions. This is followed by data that demonstrate quantitative validation of PHAM using a TME deletion control, and that nearby modifications can falsely alter the calculated apparent modification efficiency. Finally, we include a calculator tool for matching probe and hybridization conditions.
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Affiliation(s)
- Abdul Khalique
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Sandy Mattijssen
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Richard J Maraia
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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12
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Dannfald A, Favory JJ, Deragon JM. Variations in transfer and ribosomal RNA epitranscriptomic status can adapt eukaryote translation to changing physiological and environmental conditions. RNA Biol 2021; 18:4-18. [PMID: 34159889 PMCID: PMC8677040 DOI: 10.1080/15476286.2021.1931756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 01/27/2023] Open
Abstract
The timely reprogramming of gene expression in response to internal and external cues is essential to eukaryote development and acclimation to changing environments. Chemically modifying molecular receptors and transducers of these signals is one way to efficiently induce proper physiological responses. Post-translation modifications, regulating protein biological activities, are central to many well-known signal-responding pathways. Recently, messenger RNA (mRNA) chemical (i.e. epitranscriptomic) modifications were also shown to play a key role in these processes. In contrast, transfer RNA (tRNA) and ribosomal RNA (rRNA) chemical modifications, although critical for optimal function of the translation apparatus, and much more diverse and quantitatively important compared to mRNA modifications, were until recently considered as mainly static chemical decorations. We present here recent observations that are challenging this view and supporting the hypothesis that tRNA and rRNA modifications dynamically respond to various cell and environmental conditions and contribute to adapt translation to these conditions.
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Affiliation(s)
- Arnaud Dannfald
- CNRS LGDP-UMR5096, Pepignan, France
- Université de Perpignan via Domitia, Perpignan, France
| | - Jean-Jacques Favory
- CNRS LGDP-UMR5096, Pepignan, France
- Université de Perpignan via Domitia, Perpignan, France
| | - Jean-Marc Deragon
- CNRS LGDP-UMR5096, Pepignan, France
- Université de Perpignan via Domitia, Perpignan, France
- Institut Universitaire de France, Paris, France
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13
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Valadon C, Namy O. The Importance of the Epi-Transcriptome in Translation Fidelity. Noncoding RNA 2021; 7:51. [PMID: 34564313 PMCID: PMC8482273 DOI: 10.3390/ncrna7030051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/17/2021] [Accepted: 08/22/2021] [Indexed: 12/11/2022] Open
Abstract
RNA modifications play an essential role in determining RNA fate. Recent studies have revealed the effects of such modifications on all steps of RNA metabolism. These modifications range from the addition of simple groups, such as methyl groups, to the addition of highly complex structures, such as sugars. Their consequences for translation fidelity are not always well documented. Unlike the well-known m6A modification, they are thought to have direct effects on either the folding of the molecule or the ability of tRNAs to bind their codons. Here we describe how modifications found in tRNAs anticodon-loop, rRNA, and mRNA can affect translation fidelity, and how approaches based on direct manipulations of the level of RNA modification could potentially be used to modulate translation for the treatment of human genetic diseases.
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Affiliation(s)
| | - Olivier Namy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France;
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14
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Friedlander JE, Shen N, Zeng A, Korm S, Feng H. Failure to Guard: Mitochondrial Protein Quality Control in Cancer. Int J Mol Sci 2021; 22:ijms22158306. [PMID: 34361072 PMCID: PMC8348654 DOI: 10.3390/ijms22158306] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/20/2021] [Accepted: 07/27/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are energetic and dynamic organelles with a crucial role in bioenergetics, metabolism, and signaling. Mitochondrial proteins, encoded by both nuclear and mitochondrial DNA, must be properly regulated to ensure proteostasis. Mitochondrial protein quality control (MPQC) serves as a critical surveillance system, employing different pathways and regulators as cellular guardians to ensure mitochondrial protein quality and quantity. In this review, we describe key pathways and players in MPQC, such as mitochondrial protein translocation-associated degradation, mitochondrial stress responses, chaperones, and proteases, and how they work together to safeguard mitochondrial health and integrity. Deregulated MPQC leads to proteotoxicity and dysfunctional mitochondria, which contributes to numerous human diseases, including cancer. We discuss how alterations in MPQC components are linked to tumorigenesis, whether they act as drivers, suppressors, or both. Finally, we summarize recent advances that seek to target these alterations for the development of anti-cancer drugs.
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Affiliation(s)
- Joseph E. Friedlander
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Ning Shen
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
- Department of Medicine, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Aozhuo Zeng
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Sovannarith Korm
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Hui Feng
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
- Department of Medicine, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: ; Tel.: +1-617-358-4688; Fax: +1-617-358-1599
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15
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Cherkasova V, Iben JR, Pridham KJ, Kessler AC, Maraia RJ. The leucine-NH4+ uptake regulator Any1 limits growth as part of a general amino acid control response to loss of La protein by fission yeast. PLoS One 2021; 16:e0253494. [PMID: 34153074 PMCID: PMC8216550 DOI: 10.1371/journal.pone.0253494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/04/2021] [Indexed: 11/19/2022] Open
Abstract
The sla1+ gene of Schizosachharoymces pombe encodes La protein which promotes proper processing of precursor-tRNAs. Deletion of sla1 (sla1Δ) leads to disrupted tRNA processing and sensitivity to target of rapamycin (TOR) inhibition. Consistent with this, media containing NH4+ inhibits leucine uptake and growth of sla1Δ cells. Here, transcriptome analysis reveals that genes upregulated in sla1Δ cells exhibit highly significant overalp with general amino acid control (GAAC) genes in relevant transcriptomes from other studies. Growth in NH4+ media leads to additional induced genes that are part of a core environmental stress response (CESR). The sla1Δ GAAC response adds to evidence linking tRNA homeostasis and broad signaling in S. pombe. We provide evidence that deletion of the Rrp6 subunit of the nuclear exosome selectively dampens a subset of GAAC genes in sla1Δ cells suggesting that nuclear surveillance-mediated signaling occurs in S. pombe. To study the NH4+-effects, we isolated sla1Δ spontaneous revertants (SSR) of the slow growth phenotype and found that GAAC gene expression and rapamycin hypersensitivity were also reversed. Genome sequencing identified a F32V substitution in Any1, a known negative regulator of NH4+-sensitive leucine uptake linked to TOR. We show that 3H-leucine uptake by SSR-any1-F32V cells in NH4+-media is more robust than by sla1Δ cells. Moreover, F32V may alter any1+ function in sla1Δ vs. sla1+ cells in a distinctive way. Thus deletion of La, a tRNA processing factor leads to a GAAC response involving reprogramming of amino acid metabolism, and isolation of the any1-F32V rescuing mutant provides an additional specific link.
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Affiliation(s)
- Vera Cherkasova
- Kelly@DeWitt, Inc, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States of America
| | - James R. Iben
- Molecular Genomics Core, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Kevin J. Pridham
- Fralin Biomedical Research Institute at Virginia Tech, Roanoke, VA, United States of America
| | - Alan C. Kessler
- Section on Molecular and Cell Biology, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD United States of America
| | - Richard J. Maraia
- Section on Molecular and Cell Biology, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD United States of America
- * E-mail:
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16
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Coll-SanMartin L, Davalos V, Piñeyro D, Rosselló-Tortella M, Bueno-Costa A, Setien F, Villanueva A, Granada I, Ruiz-Xiviller N, Kotter A, Helm M, Yokota J, Kawabata-Iwakawa R, Kohno T, Esteller M. Gene Amplification-Associated Overexpression of the Selenoprotein tRNA Enzyme TRIT1 Confers Sensitivity to Arsenic Trioxide in Small-Cell Lung Cancer. Cancers (Basel) 2021; 13:1869. [PMID: 33919717 PMCID: PMC8070726 DOI: 10.3390/cancers13081869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/06/2021] [Accepted: 04/12/2021] [Indexed: 12/16/2022] Open
Abstract
The alteration of RNA modification patterns is emerging as a common feature of human malignancies. If these changes affect key RNA molecules for mRNA translation, such as transfer RNA, they can have important consequences for cell transformation. TRIT1 is the enzyme responsible for the hypermodification of adenosine 37 in the anticodon region of human tRNAs containing serine and selenocysteine. Herein, we show that TRIT1 undergoes gene amplification-associated overexpression in cancer cell lines and primary samples of small-cell lung cancer. From growth and functional standpoints, the induced depletion of TRIT1 expression in amplified cells reduces their tumorigenic potential and downregulates the selenoprotein transcripts. We observed that TRIT1-amplified cells are sensitive to arsenic trioxide, a compound that regulates selenoproteins, whereas reduction of TRIT1 levels confers loss of sensitivity to the drug. Overall, our results indicate a role for TRIT1 as a small-cell lung cancer-relevant gene that, when undergoing gene amplification-associated activation, can be targeted with the differentiation agent arsenic trioxide.
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Affiliation(s)
- Laia Coll-SanMartin
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
| | - Veronica Davalos
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
| | - David Piñeyro
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
- Centro de Investigación Biomédica en Red Cáncer (CIBERONC), 28029 Madrid, Spain
| | - Margalida Rosselló-Tortella
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
- Germans Trias i Pujol Health Science Research Institute (IGTP), 08916 Barcelona, Spain
| | - Alberto Bueno-Costa
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
| | - Fernando Setien
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
| | - Alberto Villanueva
- Group of Chemoresistance and Predictive Factors, Subprogram Against Cancer Therapeutic Resistance (ProCURE), Oncobell Program, IDIBELL, Institut Català d’Oncologia (ICO), L’Hospitalet del Llobregat, 08908 Barcelona, Spain;
| | - Isabel Granada
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
- Cytogenetics Platform, Hematology Laboratory Service, Institut Català d’Oncologia (ICO)-Hospital Germans Trias i Pujol (IGTP), 08916 Barcelona, Spain
| | - Neus Ruiz-Xiviller
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
- Cytogenetics Platform, Hematology Laboratory Service, Institut Català d’Oncologia (ICO)-Hospital Germans Trias i Pujol (IGTP), 08916 Barcelona, Spain
| | - Annika Kotter
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany; (A.K.); (M.H.)
| | - Mark Helm
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany; (A.K.); (M.H.)
| | - Jun Yokota
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo 104-0045, Japan; (J.Y.); (R.K.-I.); (T.K.)
| | - Reika Kawabata-Iwakawa
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo 104-0045, Japan; (J.Y.); (R.K.-I.); (T.K.)
- Division of Integrated Oncology Research, Gunma University Initiative for Advanced Research, Gunma 371-8511, Japan
| | - Takashi Kohno
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo 104-0045, Japan; (J.Y.); (R.K.-I.); (T.K.)
- Division of Translational Genomics, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Tokyo 104-0045, Japan
| | - Manel Esteller
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Barcelona, Spain; (L.C.-S.); (V.D.); (D.P.); (M.R.-T.); (A.B.-C.); (F.S.); (I.G.); (N.R.-X.)
- Centro de Investigación Biomédica en Red Cáncer (CIBERONC), 28029 Madrid, Spain
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
- Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona (UB), 08036 Barcelona, Spain
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17
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A substrate binding model for the KEOPS tRNA modifying complex. Nat Commun 2020; 11:6233. [PMID: 33277478 PMCID: PMC7718258 DOI: 10.1038/s41467-020-19990-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/02/2020] [Indexed: 11/09/2022] Open
Abstract
The KEOPS complex, which is conserved across archaea and eukaryotes, is composed of four core subunits; Pcc1, Kae1, Bud32 and Cgi121. KEOPS is crucial for the fitness of all organisms examined. In humans, pathogenic mutations in KEOPS genes lead to Galloway-Mowat syndrome, an autosomal-recessive disease causing childhood lethality. Kae1 catalyzes the universal and essential tRNA modification N6-threonylcarbamoyl adenosine, but the precise roles of all other KEOPS subunits remain an enigma. Here we show using structure-guided studies that Cgi121 recruits tRNA to KEOPS by binding to its 3' CCA tail. A composite model of KEOPS bound to tRNA reveals that all KEOPS subunits form an extended tRNA-binding surface that we have validated in vitro and in vivo to mediate the interaction with the tRNA substrate and its modification. These findings provide a framework for understanding the inner workings of KEOPS and delineate why all KEOPS subunits are essential.
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18
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19
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Cheng HP, Yang XH, Lan L, Xie LJ, Chen C, Liu C, Chu J, Li ZY, Liu L, Zhang TQ, Luo DQ, Cheng L. Chemical Deprenylation of N 6 -Isopentenyladenosine (i 6 A) RNA. Angew Chem Int Ed Engl 2020; 59:10645-10650. [PMID: 32198805 DOI: 10.1002/anie.202003360] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/20/2020] [Indexed: 12/19/2022]
Abstract
N6 -isopentenyladenosine (i6 A) is an RNA modification found in cytokinins, which regulate plant growth/differentiation, and a subset of tRNAs, where it improves the efficiency and accuracy of translation. The installation and removal of this modification is mediated by prenyltransferases and cytokinin oxidases, and a chemical approach to selective deprenylation of i6 A has not been developed. We show that a selected group of oxoammonium cations function as artificial deprenylases to promote highly selective deprenylation of i6 A in nucleosides, oligonucleotides, and live cells. Importantly, other epigenetic modifications, amino acid residues, and natural products were not affected. Moreover, a significant phenotype difference in the Arabidopsis thaliana shoot and root development was observed with incubation of the cation. These results establish these small organic molecules as direct chemical regulators/artificial deprenylases of i6 A.
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Affiliation(s)
- Hou-Ping Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Hui Yang
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Life Science, Hebei University, Hebei, 071002, China
| | - Ling Lan
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li-Jun Xie
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuan Chen
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Life Science, Hebei University, Hebei, 071002, China
| | - Cuimei Liu
- National Centre for Plant Gene Research (Beijing), Innovation Academy for Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jinfang Chu
- National Centre for Plant Gene Research (Beijing), Innovation Academy for Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhi-Yan Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Li Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tian-Qi Zhang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai, 200032, China
| | - Du-Qiang Luo
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Life Science, Hebei University, Hebei, 071002, China
| | - Liang Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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20
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Atzmony L, Choate KA. Second-Hit Somatic Mutations in Mevalonate Pathway Genes Underlie Porokeratosis. J Invest Dermatol 2020; 139:2409-2411. [PMID: 31753123 DOI: 10.1016/j.jid.2019.07.723] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/07/2019] [Accepted: 07/11/2019] [Indexed: 10/25/2022]
Abstract
Familial and sporadic porokeratosis are associated with germline heterozygous mutations in mevalonate pathway genes. Kubo et al. show that each skin lesion of disseminated superficial actinic porokeratosis originates from a postnatal keratinocyte clone with a different second-hit genetic event in the wild-type allele of the corresponding gene. They also confirm that linear porokeratosis derives from a single prenatal clone of keratinocytes with a second-hit genetic event.
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Affiliation(s)
- Lihi Atzmony
- Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Keith A Choate
- Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA.
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21
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Khalique A, Mattijssen S, Haddad AF, Chaudhry S, Maraia RJ. Targeting mitochondrial and cytosolic substrates of TRIT1 isopentenyltransferase: Specificity determinants and tRNA-i6A37 profiles. PLoS Genet 2020; 16:e1008330. [PMID: 32324744 PMCID: PMC7200024 DOI: 10.1371/journal.pgen.1008330] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 05/05/2020] [Accepted: 03/18/2020] [Indexed: 11/29/2022] Open
Abstract
The tRNA isopentenyltransferases (IPTases), which add an isopentenyl group to N6 of A37 (i6A37) of certain tRNAs, are among a minority of enzymes that modify cytosolic and mitochondrial tRNAs. Pathogenic mutations to the human IPTase, TRIT1, that decrease i6A37 levels, cause mitochondrial insufficiency that leads to neurodevelopmental disease. We show that TRIT1 encodes an amino-terminal mitochondrial targeting sequence (MTS) that directs mitochondrial import and modification of mitochondrial-tRNAs. Full understanding of IPTase function must consider the tRNAs selected for modification, which vary among species, and in their cytosol and mitochondria. Selection is principally via recognition of the tRNA A36-A37-A38 sequence. An exception is unmodified tRNATrpCCA-A37-A38 in Saccharomyces cerevisiae, whereas tRNATrpCCA is readily modified in Schizosaccharomyces pombe, indicating variable IPTase recognition systems and suggesting that additional exceptions may account for some of the tRNA-i6A37 paucity in higher eukaryotes. Yet TRIT1 had not been characterized for restrictive type substrate-specific recognition. We used i6A37-dependent tRNA-mediated suppression and i6A37-sensitive northern blotting to examine IPTase activities in S. pombe and S. cerevisiae lacking endogenous IPTases on a diversity of tRNA-A36-A37-A38 substrates. Point mutations to the TRIT1 MTS that decrease human mitochondrial import, decrease modification of mitochondrial but not cytosolic tRNAs in both yeasts. TRIT1 exhibits clear substrate-specific restriction against a cytosolic-tRNATrpCCA-A37-A38. Additional data suggest that position 32 of tRNATrpCCA is a conditional determinant for substrate-specific i6A37 modification by the restrictive IPTases, Mod5 and TRIT1. The cumulative biochemical and phylogenetic sequence analyses provide new insights into IPTase activities and determinants of tRNA-i6A37 profiles in cytosol and mitochondria.
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Affiliation(s)
- Abdul Khalique
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sandy Mattijssen
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alexander F. Haddad
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Shereen Chaudhry
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Richard J. Maraia
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
- Commissioned Corps, United States Public Health Service, Rockville, Maryland, United States of America
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22
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Takenouchi T, Wei FY, Suzuki H, Uehara T, Takahashi T, Okazaki Y, Kosaki K, Tomizawa K. Noninvasive diagnosis of TRIT1-related mitochondrial disorder by measuring i 6 A37 and ms 2 i 6 A37 modifications in tRNAs from blood and urine samples. Am J Med Genet A 2019; 179:1609-1614. [PMID: 31140736 DOI: 10.1002/ajmg.a.61211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 05/14/2019] [Accepted: 05/14/2019] [Indexed: 11/08/2022]
Abstract
Subsets of mitochondrial transfer RNA (tRNA) contain the N6 -isopentenyladenosine (i6 A) or 2-methylthio-N6 -isopentenyladenosine (ms2 i6 A) modification at position A37, which is adjacent to an anticodon. These modifications are essential for efficient protein translation in mitochondria and contribute to energy metabolism. The first step in i6 A and ms2 i6 A modifications is catalyzed by tRNA isopentenyltransferase, which is encoded by the TRIT1 gene. Herein, we report a girl with a developmental delay, frequent episodes of seizures induced by febrile illness, and myoclonic epilepsy who had compound heterozygous missense mutations in TRIT1. A mass spectrometry analysis of RNA nucleoside obtained from the subject's peripheral blood and urine showed a marked decrease in both i6 A and ms2 i6 A modifications. These results suggest that the mitochondrial disorder was caused by defective tRNA isopentenylation arising from a loss-of-function mutation in TRIT1. Furthermore, the present observations suggest that noninvasive biochemical analysis using peripheral blood and urine samples are sufficient for the diagnosis of TRIT1-related disorders, making muscle biopsy for the direct measurement of oxidative phosphorylation unnecessary. Such biochemical analyses before the start of antiepileptic medications would be beneficial to avoid hepatotoxicity in patients with possible mitochondrial disorders.
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Affiliation(s)
- Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Takao Takahashi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Yasushi Okazaki
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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23
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Steiner RE, Ibba M. Regulation of tRNA-dependent translational quality control. IUBMB Life 2019; 71:1150-1157. [PMID: 31135095 DOI: 10.1002/iub.2080] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/01/2019] [Accepted: 05/14/2019] [Indexed: 02/06/2023]
Abstract
Translation is the most error-prone process in protein synthesis; however, it is important that accuracy is maintained because erroneous translation has been shown to affect all domains of life. Translational quality control is maintained by both proteins and RNA through intricate processes. The aminoacyl-tRNA synthetases help maintain high levels of translational accuracy through the esterification of tRNA and proofreading mechanisms. tRNA is often recognized by an aminoacyl-tRNA synthetase in a sequence and structurally dependent manner, sometimes involving modified nucleotides. Additionally, some proofreading mechanisms of aminoacyl-tRNA synthetases require tRNA elements for hydrolysis of a noncognate aminoacyl-tRNA. Finally, tRNA is also important for proper decoding of the mRNA message by codon and anticodon pairing. Here, recent developments regarding the importance of tRNA in maintenance of translational accuracy are reviewed. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1150-1157, 2019.
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Affiliation(s)
- Rebecca E Steiner
- The Ohio State University Biochemistry Program, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Michael Ibba
- The Ohio State University Biochemistry Program, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Microbiology, The Ohio State University, Columbus, OH, USA
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24
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Aoki MM, Seegobin M, Kisiala A, Noble A, Brunetti C, Emery RJN. Phytohormone metabolism in human cells: Cytokinins are taken up and interconverted in HeLa cell culture. FASEB Bioadv 2019; 1:320-331. [PMID: 32123835 PMCID: PMC6996375 DOI: 10.1096/fba.2018-00032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/06/2019] [Accepted: 02/07/2019] [Indexed: 01/30/2023] Open
Abstract
Cytokinins (CKs) encompass a group of phytohormones, known to orchestrate many critical processes in plant development. Excluding Archaea, CKs are pervasive among all kingdoms, but much less is reported about their metabolism beyond plants. Recent evidence from mammalian tissues indicates the presence of six additional CK forms beyond the previously identified, single mammalian CK, N6-isopentenyladenosine (i6A). There is limited understanding of CK biosynthesis pathways in mammalian systems; therefore, human cervical cancer (HeLa) cells were used to further characterize CK processing by tracking the interconversion of CKs into their various structural derivatives in mammalian cells in a time-course study. Through high-performance liquid chromatography-positive electrospray ionization-tandem mass spectrometry (HPLC-(+ESI)-MS/MS), we document changes in the functional profiles of endogenous CKs in a human cell line following metabolism by HeLa cell cultures. The nucleotide CK fraction (iPRP) was found exclusively within the cell pellet (0.34 pmol/106 cells), and the active free base (FB) form (iP) and riboside fraction (iPR) were found in greater abundance extracellularly (1.67 and 0.10 nmol/L respectively). For further confirmation, we demonstrate that HeLa cells metabolize an exogenously supplied CK, N6-benzyladenosine (BAR). In the HeLa culture supernatant, a 12-fold decrease in BAR concentration was observed within the first 24 hours of incubation accompanied by a fivefold increase in the FB form, N6-benzyladenine (BA). These findings support the hypothesis that HeLa cells have the enzymatic pathways required for the metabolism of both endogenous and exogenous CKs.
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Affiliation(s)
- Megan M. Aoki
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
| | - Mark Seegobin
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
| | - Anna Kisiala
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
| | | | - Craig Brunetti
- Department of BiologyTrent UniversityPeterboroughOntarioCanada
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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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Joshi K, Cao L, Farabaugh PJ. The problem of genetic code misreading during protein synthesis. Yeast 2019; 36:35-42. [DOI: 10.1002/yea.3374] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 02/01/2023] Open
Affiliation(s)
- Kartikeya Joshi
- Department of Biological Sciences; University of Maryland Baltimore County; Baltimore Maryland, USA
| | - Ling Cao
- Department of Biological Sciences; University of Maryland Baltimore County; Baltimore Maryland, USA
| | - Philip J. Farabaugh
- Department of Biological Sciences; University of Maryland Baltimore County; Baltimore Maryland, USA
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27
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Rebelo-Guiomar P, Powell CA, Van Haute L, Minczuk M. The mammalian mitochondrial epitranscriptome. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:429-446. [PMID: 30529456 PMCID: PMC6414753 DOI: 10.1016/j.bbagrm.2018.11.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/16/2018] [Accepted: 11/23/2018] [Indexed: 01/08/2023]
Abstract
Correct expression of the mitochondrially-encoded genes is critical for the production of the components of the oxidative phosphorylation machinery. Post-transcriptional modifications of mitochondrial transcripts have been emerging as an important regulatory feature of mitochondrial gene expression. Here we review the current knowledge on how the mammalian mitochondrial epitranscriptome participates in regulating mitochondrial homeostasis. In particular, we focus on the latest breakthroughs made towards understanding the roles of the modified nucleotides in mitochondrially-encoded ribosomal and transfer RNAs, the enzymes responsible for introducing these modifications and on recent transcriptome-wide studies reporting modifications to mitochondrial messenger RNAs. This article is part of a Special Issue entitled: mRNA modifications in gene expression control edited by Dr. Matthias Soller and Dr. Rupert Fray. Human mtDNA encodes 13 proteins and all the RNAs necessary for their expression Post-transcriptional modifications of RNA, the epitranscriptome, play a regulatory role in mitochondrial gene expression Several enzymes involved in the shaping of the mitochondrial epitranscriptome have recently been characterised. Our understanding of the extent and nature of mtRNA modifications is rapidly expanding. Recent transcriptome-wide studies suggest modifications in mitochondrial mRNAs
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Affiliation(s)
- Pedro Rebelo-Guiomar
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK; Graduate Program in Areas of Basic and Applied Biology (GABBA), University of Porto, Porto, Portugal
| | | | - Lindsey Van Haute
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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28
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Joshi K, Bhatt MJ, Farabaugh PJ. Codon-specific effects of tRNA anticodon loop modifications on translational misreading errors in the yeast Saccharomyces cerevisiae. Nucleic Acids Res 2018; 46:10331-10339. [PMID: 30060218 PMCID: PMC6212777 DOI: 10.1093/nar/gky664] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 01/10/2023] Open
Abstract
Protein synthesis requires both high speed and accuracy to ensure a healthy cellular environment. Estimates of errors during protein synthesis in Saccharomyces cerevisiae have varied from 10-3 to 10-4 errors per codon. Here, we show that errors made by ${\rm{tRNA}}^{\rm Glu}_{\rm UUC}$ in yeast can vary 100-fold, from 10-6 to 10-4 errors per codon. The most frequent errors require a G•U mismatch at the second position for the near cognate codon GGA (Gly). We also show, contrary to our previous results, that yeast tRNAs can make errors involving mismatches at the wobble position but with low efficiency. We have also assessed the effect on misreading frequency of post-transcriptional modifications of tRNAs, which are known to regulate cognate codon decoding in yeast. We tested the roles of mcm5s2U34 and t6A37 and show that their effects depend on details of the codon anticodon interaction including the position of the modification with respect to the base mismatch and the nature of that mismatch. Both mcm5 and s2 modification of wobble uridine strongly stabilizes G2•U35 mismatches when ${\rm{tRNA}}^{\rm Glu}_{\rm UUC}$ misreads the GGA Gly codon but has weaker effects on other mismatches. By contrast, t6A37 destabilizes U1•U36 mismatches when ${\rm{tRNA}}^{\rm Lys}_{\rm UUU}$ misreads UAA or UAG but stabilizes mismatches at the second and wobble positions.
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Affiliation(s)
- Kartikeya Joshi
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Monika J Bhatt
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Philip J Farabaugh
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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29
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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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30
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Yin J, Bao L, Chen R, Gao W, Gao X, Yao W. Enhanced expression and distinctive characterization of a long-acting FGF21 and its potential to alleviate nonalcoholic steatohepatitis. Biochimie 2018; 151:166-175. [PMID: 29870802 DOI: 10.1016/j.biochi.2018.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/31/2018] [Indexed: 01/20/2023]
Abstract
We have previously constructed a novel polypeptide, PsTag, that should be useful in the development of biologics with properties comparable to those achievable by PEGylation, but with potentially less side effects. However, the low fermentation yields of polypeptide fusion proteins may limit the application of this technology. We suspected that when polypeptide fusion protein was expressed in E. coli, the corresponding 8 tRNAs were needed to transport a large number of repetitive 5 amino acids to the ribosomes and thus, resulting in a relative deficiency of these tRNAs. PsTag600-FGF21, a long-acting FGF21 fusion protein, was used as a model for studying the effects of these non-rare tRNAs on the efficiency of heterologous protein production in E. coli. To further enhance the expression level and facilitate purification, secretory expressions of PsTag600-FGF21 were achieved by fusion with three signal peptides. Meanwhile, a comparison of several distinctive characterizations was carried out between PsTag600-FGF21 and PEG20K-FGF21. We investigated the protective effects of PsTag600-FGF21 in a nonalcoholic steatohepatitis model induced by methionine- and choline-deficient diet. Our results showed that the provision of 8 tRNAs and secretory expression remarkably increased the expression levels of PsTag fusion protein, meanwhile there were no significant effects on E. coli growth states. PsTag600-FGF21 had a larger hydrodynamic volume, a higher affinity and a longer plasma half-life than PEG20K-FGF21, while avoiding vacuole formation in mice. In NASH mice, administration of PsTag600-FGF21 reduced hepatic steatosis, fibrosis and inflammation. Therefore, PsTag600-FGF21 with higher expression level may be further developed for potentially application in clinics.
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Affiliation(s)
- Jun Yin
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Lichen Bao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Rong Chen
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Wen Gao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Xiangdong Gao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
| | - Wenbing Yao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
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31
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Manipulation of cytokinin level in the ergot fungus Claviceps purpurea emphasizes its contribution to virulence. Curr Genet 2018; 64:1303-1319. [PMID: 29850931 DOI: 10.1007/s00294-018-0847-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/15/2018] [Accepted: 05/28/2018] [Indexed: 11/30/2022]
Abstract
Pathogen-derived cytokinins (CKs) have been recognized as important virulence factor in several host-pathogen interactions and it was demonstrated multiple times that phytopathogenic fungi form CKs via the tRNA degradation pathway. In contrast to previous studies, the focus of this study is on the second step of CK formation and CK degradation to improve our understanding of the biosynthesis in fungi on the one hand, and to understand CK contribution to the infection process of Claviceps purpurea on the other hand. The ergot fungus Claviceps purpurea is a biotrophic phytopathogen with a broad host range including economically important crops causing harvest intoxication upon infection. Its infection process is restricted to unfertilized ovaries without causing macroscopic defense symptoms. Thus, sophisticated host manipulation strategies are implicated. The cytokinin (CK) plant hormones are known to regulate diverse plant cell processes, and several plant pathogens alter CK levels during infection. C. purpurea synthesizes CKs via two mechanisms, and fungus-derived CKs influence the host-pathogen interaction but not fungus itself. CK deficiency in fungi with impact on virulence has only been achieved to date by deletion of a tRNA-ipt gene that is also involved in a process of translation regulation. To obtain a better understanding of CK biosynthesis and CKs' contribution to the plant-fungus interaction, we applied multiple approaches to generate strains with altered or depleted CK content. The first approach is based on deletion of the two CK phosphoribohydrolase (LOG)-encoding genes, which are believed to be essential for the release of active CKs. Single and double deletion strains were able to produce all types of CKs. Apparently, log gene products are dispensable for the formation of CKs and so alternative activation pathways must be present. The CK biosynthesis pathway remains unaffected in the second approach, because it is based on heterologous overexpression of CK-degrading enzymes from maize (ZmCKX1). Zmckx1 overexpressing C. purpurea strains shows strong CKX activity and drastically reduced CK levels. The strains are impaired in virulence, which reinforces the assumption that fungal-derived CKs are crucial for full virulence. Taken together, this study comprises the first analysis of a log depletion mutant that proved the presence of alternative cytokinin activation pathways in fungi and showed that heterologous CKX expression is a suitable approach for CK level reduction.
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32
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Koh CS, Sarin LP. Transfer RNA modification and infection – Implications for pathogenicity and host responses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:419-432. [DOI: 10.1016/j.bbagrm.2018.01.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/04/2018] [Accepted: 01/19/2018] [Indexed: 12/19/2022]
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33
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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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34
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Tuorto F, Lyko F. Genome recoding by tRNA modifications. Open Biol 2017; 6:rsob.160287. [PMID: 27974624 PMCID: PMC5204126 DOI: 10.1098/rsob.160287] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/14/2016] [Indexed: 11/12/2022] Open
Abstract
RNA modifications are emerging as an additional regulatory layer on top of the primary RNA sequence. These modifications are particularly enriched in tRNAs where they can regulate not only global protein translation, but also protein translation at the codon level. Modifications located in or in the vicinity of tRNA anticodons are highly conserved in eukaryotes and have been identified as potential regulators of mRNA decoding. Recent studies have provided novel insights into how these modifications orchestrate the speed and fidelity of translation to ensure proper protein homeostasis. This review highlights the prominent modifications in the tRNA anticodon loop: queuosine, inosine, 5-methoxycarbonylmethyl-2-thiouridine, wybutosine, threonyl-carbamoyl-adenosine and 5-methylcytosine. We discuss the functional relevance of these modifications in protein translation and their emerging role in eukaryotic genome recoding during cellular adaptation and disease.
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Affiliation(s)
- Francesca Tuorto
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany
| | - Frank Lyko
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany
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35
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Dewe JM, Fuller BL, Lentini JM, Kellner SM, Fu D. TRMT1-Catalyzed tRNA Modifications Are Required for Redox Homeostasis To Ensure Proper Cellular Proliferation and Oxidative Stress Survival. Mol Cell Biol 2017; 37:e00214-17. [PMID: 28784718 PMCID: PMC5640816 DOI: 10.1128/mcb.00214-17] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/17/2017] [Accepted: 07/29/2017] [Indexed: 02/07/2023] Open
Abstract
Mutations in the tRNA methyltransferase 1 (TRMT1) gene have been identified as the cause of certain forms of autosomal-recessive intellectual disability (ID). However, the molecular pathology underlying ID-associated TRMT1 mutations is unknown, since the biological role of the encoded TRMT1 protein remains to be determined. Here, we have elucidated the molecular targets and function of TRMT1 to uncover the cellular effects of ID-causing TRMT1 mutations. Using human cells that have been rendered deficient in TRMT1, we show that TRMT1 is responsible for catalyzing the dimethylguanosine (m2,2G) base modification in both nucleus- and mitochondrion-encoded tRNAs. TRMT1-deficient cells exhibit decreased proliferation rates, alterations in global protein synthesis, and perturbations in redox homeostasis, including increased endogenous ROS levels and hypersensitivity to oxidizing agents. Notably, ID-causing TRMT1 variants are unable to catalyze the formation of m2,2G due to defects in RNA binding and cannot rescue oxidative stress sensitivity. Our results uncover a biological role for TRMT1-catalyzed tRNA modification in redox metabolism and show that individuals with TRMT1-associated ID are likely to have major perturbations in cellular homeostasis due to the lack of m2,2G modifications.
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Affiliation(s)
- Joshua M Dewe
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, New York, USA
| | - Benjamin L Fuller
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, New York, USA
| | - Jenna M Lentini
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, New York, USA
| | | | - Dragony Fu
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, New York, USA
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36
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Marín M, Fernández-Calero T, Ehrlich R. Protein folding and tRNA biology. Biophys Rev 2017; 9:573-588. [PMID: 28944442 PMCID: PMC5662057 DOI: 10.1007/s12551-017-0322-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/28/2017] [Indexed: 12/14/2022] Open
Abstract
Polypeptides can fold into tertiary structures while they are synthesized by the ribosome. In addition to the amino acid sequence, protein folding is determined by several factors within the cell. Among others, the folding pathway of a nascent polypeptide can be affected by transient interactions with other proteins, ligands, or the ribosome, as well as by the translocation through membrane pores. Particularly, the translation machinery and the population of tRNA under different physiological or adaptive responses can dramatically affect protein folding. This review summarizes the scientific evidence describing the role of translation kinetics and tRNA populations on protein folding and addresses current efforts to better understand tRNA biology. It is organized into three main parts, which are focused on: (i) protein folding in the cellular context; (ii) tRNA biology and the complexity of the tRNA population; and (iii) available methods and technical challenges in the characterization of tRNA pools. In this manner, this work illustrates the ways by which functional properties of proteins may be modulated by cellular tRNA populations.
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Affiliation(s)
- Mónica Marín
- Biochemistry-Molecular Biology Section, Cellular and Molecular Biology Department, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
| | - Tamara Fernández-Calero
- Biochemistry-Molecular Biology Section, Cellular and Molecular Biology Department, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
- Bioinformatics Unit, Institut Pasteur Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay
| | - Ricardo Ehrlich
- Biochemistry-Molecular Biology Section, Cellular and Molecular Biology Department, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
- Institut Pasteur Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay
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37
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Bacusmo JM, Orsini SS, Hu J, DeMott M, Thiaville PC, Elfarash A, Paulines MJ, Rojas-Benítez D, Meineke B, Deutsch C, Iwata-Reuyl D, Limbach PA, Dedon PC, Rice KC, Shuman S, Crécy-Lagard VD. The t 6A modification acts as a positive determinant for the anticodon nuclease PrrC, and is distinctively nonessential in Streptococcus mutans. RNA Biol 2017; 15:508-517. [PMID: 28726545 DOI: 10.1080/15476286.2017.1353861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Endoribonuclease toxins (ribotoxins) are produced by bacteria and fungi to respond to stress, eliminate non-self competitor species, or interdict virus infection. PrrC is a bacterial ribotoxin that targets and cleaves tRNALysUUU in the anticodon loop. In vitro studies suggested that the post-transcriptional modification threonylcarbamoyl adenosine (t6A) is required for PrrC activity but this prediction had never been validated in vivo. Here, by using t6A-deficient yeast derivatives, it is shown that t6A is a positive determinant for PrrC proteins from various bacterial species. Streptococcus mutans is one of the few bacteria where the t6A synthesis gene tsaE (brpB) is dispensable and its genome encodes a PrrC toxin. We had previously shown using an HPLC-based assay that the S. mutans tsaE mutant was devoid of t6A. However, we describe here a novel and a more sensitive hybridization-based t6A detection method (compared to HPLC) that showed t6A was still present in the S. mutans ΔtsaE, albeit at greatly reduced levels (93% reduced compared with WT). Moreover, mutants in 2 other S. mutans t6A synthesis genes (tsaB and tsaC) were shown to be totally devoid of the modification thus confirming its dispensability in this organism. Furthermore, analysis of t6A modification ratios and of t6A synthesis genes mRNA levels in S. mutans suggest they may be regulated by growth phase.
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Affiliation(s)
- Jo Marie Bacusmo
- a Department of Microbiology and Cell Science, IFAS , University of Florida , Gainesville , FL , USA
| | - Silvia S Orsini
- a Department of Microbiology and Cell Science, IFAS , University of Florida , Gainesville , FL , USA
| | - Jennifer Hu
- b Center for Environmental Health Sciences, Department of Biological Engineering , Massachusetts Institute of Technology , Cambridge , MA , USA
| | - Michael DeMott
- b Center for Environmental Health Sciences, Department of Biological Engineering , Massachusetts Institute of Technology , Cambridge , MA , USA
| | - Patrick C Thiaville
- a Department of Microbiology and Cell Science, IFAS , University of Florida , Gainesville , FL , USA.,c Genetics and Genomics Graduate Program , University of Florida , Gainesville , USA.,d University of Florida Genetics Institute, University of Florida , Gainesville , FL , USA
| | - Ameer Elfarash
- a Department of Microbiology and Cell Science, IFAS , University of Florida , Gainesville , FL , USA.,e Genetic Department, Faculty of Agriculture , Assiut University , Assuit , Egypt
| | - Mellie June Paulines
- f Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry , University of Cincinnati , Cincinnati OH , USA
| | - Diego Rojas-Benítez
- g Centro de Regulación del Genoma. Facultad de Ciencias - Universidad de Chile , Santiago , Chile
| | - Birthe Meineke
- h Molecular Biology Program , Sloan-Kettering Institute , New York , NY , USA
| | - Chris Deutsch
- i Department of Chemistry , Portland State University , Portland , OR , USA
| | - Dirk Iwata-Reuyl
- i Department of Chemistry , Portland State University , Portland , OR , USA
| | - Patrick A Limbach
- f Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry , University of Cincinnati , Cincinnati OH , USA
| | - Peter C Dedon
- b Center for Environmental Health Sciences, Department of Biological Engineering , Massachusetts Institute of Technology , Cambridge , MA , USA
| | - Kelly C Rice
- a Department of Microbiology and Cell Science, IFAS , University of Florida , Gainesville , FL , USA
| | - Stewart Shuman
- h Molecular Biology Program , Sloan-Kettering Institute , New York , NY , USA
| | - Valérie de Crécy-Lagard
- a Department of Microbiology and Cell Science, IFAS , University of Florida , Gainesville , FL , USA.,d University of Florida Genetics Institute, University of Florida , Gainesville , FL , USA
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Wang J, Forster AC. Translational roles of the C75 2'OH in an in vitro tRNA transcript at the ribosomal A, P and E sites. Sci Rep 2017; 7:6709. [PMID: 28751745 PMCID: PMC5532260 DOI: 10.1038/s41598-017-06991-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/21/2017] [Indexed: 11/26/2022] Open
Abstract
Aminoacyl-tRNAs containing a deoxy substitution in the penultimate nucleotide (C75 2′OH → 2′H) have been widely used in translation for incorporation of unnatural amino acids (AAs). However, this supposedly innocuous modification surprisingly increased peptidyl-tRNAAlaugc drop off in biochemical assays of successive incorporations. Here we predict the function of this tRNA 2′OH in the ribosomal A, P and E sites using recent co-crystal structures of ribosomes and tRNA substrates and test these structure-function models by systematic kinetics analyses. Unexpectedly, the C75 2′H did not affect A- to P-site translocation nor peptidyl donor activity of tRNAAlaugc. Rather, the peptidyl acceptor activity of the A-site Ala-tRNAAlaugc and the translocation of the P-site deacylated tRNAAlaugc to the E site were impeded. Delivery by EF-Tu was not significantly affected. This broadens our view of the roles of 2′OH groups in tRNAs in translation.
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Affiliation(s)
- Jinfan Wang
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, Uppsala, 75124, Sweden
| | - Anthony C Forster
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, Uppsala, 75124, Sweden.
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39
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Koshla O, Lopatniuk M, Rokytskyy I, Yushchuk O, Dacyuk Y, Fedorenko V, Luzhetskyy A, Ostash B. Properties of Streptomyces albus J1074 mutant deficient in tRNALeu UAA gene bldA. Arch Microbiol 2017; 199:1175-1183. [DOI: 10.1007/s00203-017-1389-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/06/2017] [Accepted: 05/16/2017] [Indexed: 11/28/2022]
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40
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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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41
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Väre VYP, Eruysal ER, Narendran A, Sarachan KL, Agris PF. Chemical and Conformational Diversity of Modified Nucleosides Affects tRNA Structure and Function. Biomolecules 2017; 7:E29. [PMID: 28300792 PMCID: PMC5372741 DOI: 10.3390/biom7010029] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/06/2017] [Accepted: 03/06/2017] [Indexed: 12/21/2022] Open
Abstract
RNAs are central to all gene expression through the control of protein synthesis. Four major nucleosides, adenosine, guanosine, cytidine and uridine, compose RNAs and provide sequence variation, but are limited in contributions to structural variation as well as distinct chemical properties. The ability of RNAs to play multiple roles in cellular metabolism is made possible by extensive variation in length, conformational dynamics, and the over 100 post-transcriptional modifications. There are several reviews of the biochemical pathways leading to RNA modification, but the physicochemical nature of modified nucleosides and how they facilitate RNA function is of keen interest, particularly with regard to the contributions of modified nucleosides. Transfer RNAs (tRNAs) are the most extensively modified RNAs. The diversity of modifications provide versatility to the chemical and structural environments. The added chemistry, conformation and dynamics of modified nucleosides occurring at the termini of stems in tRNA's cloverleaf secondary structure affect the global three-dimensional conformation, produce unique recognition determinants for macromolecules to recognize tRNAs, and affect the accurate and efficient decoding ability of tRNAs. This review will discuss the impact of specific chemical moieties on the structure, stability, electrochemical properties, and function of tRNAs.
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Affiliation(s)
- Ville Y P Väre
- The RNA Institute, Departments of Biological Sciences and Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
| | - Emily R Eruysal
- The RNA Institute, Departments of Biological Sciences and Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
| | - Amithi Narendran
- The RNA Institute, Departments of Biological Sciences and Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
| | - Kathryn L Sarachan
- The RNA Institute, Departments of Biological Sciences and Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
| | - Paul F Agris
- The RNA Institute, Departments of Biological Sciences and Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
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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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43
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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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Waller TJ, Read DF, Engelke DR, Smaldino PJ. The human tRNA-modifying protein, TRIT1, forms amyloid fibers in vitro. Gene 2016; 612:19-24. [PMID: 27984194 DOI: 10.1016/j.gene.2016.10.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/24/2016] [Accepted: 10/27/2016] [Indexed: 12/19/2022]
Abstract
TRIT1 is a highly conserved tRNA isopentenyl transferase that modifies a subset of tRNAs in human cells and is a candidate tumor suppressor in lung cancer in certain ethnic populations. The yeast homologue, Mod5, has similar tRNA-modifying functions in the cytoplasm and is required for the transcriptional silencing activity of RNA polymerase II promoters near tRNA genes in the nucleus, a phenomenon termed tRNA gene mediated (tgm) silencing. Furthermore, Mod5 can fold into amyloid fibers in vitro and in vivo, which confers resistance to certain fungicides in yeast. Since TRIT1 complements both tRNA modifying and tgm-silencing activities in yeast where the Mod5 gene has been deleted, it seemed possible that TRIT1 might also have amyloid-forming capabilities. Here we show that TRIT1, like Mod5, directly binds to tRNAs that are both substrate and non-substrates for modification with similar affinity, and to an unstructured, non-tRNA. Binding appears to involve distinct protein-RNA multimers which decrease in electrophoretic mobility as the protein to RNA ratio increases. Furthermore, we characterize TRIT1 as a novel human amyloid fiber forming protein. We discuss these data in light of TRIT1's functional roles and possible implications for disease.
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Affiliation(s)
- T J Waller
- Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - D F Read
- Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - D R Engelke
- Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, United States; University of Denver, Aurora, CO 80045, United States.
| | - P J Smaldino
- Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, United States; Biology, Ball State University, Muncie, IN 47306, United States.
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45
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Arimbasseri AG, Iben J, Wei FY, Rijal K, Tomizawa K, Hafner M, Maraia RJ. Evolving specificity of tRNA 3-methyl-cytidine-32 (m3C32) modification: a subset of tRNAsSer requires N6-isopentenylation of A37. RNA (NEW YORK, N.Y.) 2016; 22:1400-10. [PMID: 27354703 PMCID: PMC4986895 DOI: 10.1261/rna.056259.116] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/24/2016] [Indexed: 05/10/2023]
Abstract
Post-transcriptional modifications of anticodon loop (ACL) nucleotides impact tRNA structure, affinity for the ribosome, and decoding activity, and these activities can be fine-tuned by interactions between nucleobases on either side of the anticodon. A recently discovered ACL modification circuit involving positions 32, 34, and 37 is disrupted by a human disease-associated mutation to the gene encoding a tRNA modification enzyme. We used tRNA-HydroSeq (-HySeq) to examine (3)methyl-cytidine-32 (m(3)C32), which is found in yeast only in the ACLs of tRNAs(Ser) and tRNAs(Thr) In contrast to that reported for Saccharomyces cerevisiae in which all m(3)C32 depends on a single gene, TRM140, the m(3)C32 of tRNAs(Ser) and tRNAs(Thr) of the fission yeast S. pombe, are each dependent on one of two related genes, trm140(+) and trm141(+), homologs of which are found in higher eukaryotes. Interestingly, mammals and other vertebrates contain a third homolog and also contain m(3)C at new sites, positions 32 on tRNAs(Arg) and C47:3 in the variable arm of tRNAs(Ser) More significantly, by examining S. pombe mutants deficient for other modifications, we found that m(3)C32 on the three tRNAs(Ser) that contain anticodon base A36, requires N(6)-isopentenyl modification of A37 (i(6)A37). This new C32-A37 ACL circuitry indicates that i(6)A37 is a pre- or corequisite for m(3)C32 on these tRNAs. Examination of the tRNA database suggests that such circuitry may be more expansive than observed here. The results emphasize two contemporary themes, that tRNA modifications are interconnected, and that some specific modifications on tRNAs of the same anticodon identity are species-specific.
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Affiliation(s)
- Aneeshkumar G Arimbasseri
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - James Iben
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 860-0862 Kumamoto, Japan
| | - Keshab Rijal
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 860-0862 Kumamoto, Japan
| | - Markus Hafner
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard J Maraia
- Commissioned Corps, US Public Health Service, Washington, DC 20201, USA
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Duechler M, Leszczyńska G, Sochacka E, Nawrot B. Nucleoside modifications in the regulation of gene expression: focus on tRNA. Cell Mol Life Sci 2016; 73:3075-95. [PMID: 27094388 PMCID: PMC4951516 DOI: 10.1007/s00018-016-2217-y] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/25/2016] [Accepted: 04/04/2016] [Indexed: 01/10/2023]
Abstract
Both, DNA and RNA nucleoside modifications contribute to the complex multi-level regulation of gene expression. Modified bases in tRNAs modulate protein translation rates in a highly dynamic manner. Synonymous codons, which differ by the third nucleoside in the triplet but code for the same amino acid, may be utilized at different rates according to codon-anticodon affinity. Nucleoside modifications in the tRNA anticodon loop can favor the interaction with selected codons by stabilizing specific base pairs. Similarly, weakening of base pairing can discriminate against binding to near-cognate codons. mRNAs enriched in favored codons are translated in higher rates constituting a fine-tuning mechanism for protein synthesis. This so-called codon bias establishes a basic protein level, but sometimes it is necessary to further adjust the production rate of a particular protein to actual requirements, brought by, e.g., stages in circadian rhythms, cell cycle progression or exposure to stress. Such an adjustment is realized by the dynamic change of tRNA modifications resulting in the preferential translation of mRNAs coding for example for stress proteins to facilitate cell survival. Furthermore, tRNAs contribute in an entirely different way to another, less specific stress response consisting in modification-dependent tRNA cleavage that contributes to the general down-regulation of protein synthesis. In this review, we summarize control functions of nucleoside modifications in gene regulation with a focus on recent findings on protein synthesis control by tRNA base modifications.
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Affiliation(s)
- Markus Duechler
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Lodz, Poland.
| | - Grażyna Leszczyńska
- Institute of Organic Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland
| | - Elzbieta Sochacka
- Institute of Organic Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland
| | - Barbara Nawrot
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Lodz, Poland
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Hluska T, Dobrev PI, Tarkowská D, Frébortová J, Zalabák D, Kopečný D, Plíhal O, Kokáš F, Briozzo P, Zatloukal M, Motyka V, Galuszka P. Cytokinin metabolism in maize: Novel evidence of cytokinin abundance, interconversions and formation of a new trans-zeatin metabolic product with a weak anticytokinin activity. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 247:127-37. [PMID: 27095406 DOI: 10.1016/j.plantsci.2016.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 05/10/2023]
Abstract
Cytokinins (CKs) are an important group of phytohormones. Their tightly regulated and balanced levels are essential for proper cell division and plant organ development. Here we report precise quantification of CK metabolites and other phytohormones in maize reproductive organs in the course of pollination and kernel maturation. A novel enzymatic activity dependent on NADP(+) converting trans-zeatin (tZ) to 6-(3-methylpyrrol-1-yl)purine (MPP) was detected. MPP shows weak anticytokinin properties and inhibition of CK dehydrogenases due to their ability to bind to an active site in the opposite orientation than substrates. Although the physiological significance of tZ side-chain cyclization is not anticipated as the MPP occurrence in maize tissue is very low, properties of the novel CK metabolite indicate its potential for utilization in plant in vitro tissue culture. Furthermore, feeding experiments with different isoprenoid CKs revealed distinct preferences in glycosylation of tZ and cis-zeatin (cZ). While tZ is preferentially glucosylated at the N9 position, cZ forms mainly O-glucosides. Since O-glucosides, in contrast to N9-glucosides, are resistant to irreversible cleavage catalyzed by CK dehydrogenases, the observed preference of maize CK glycosyltransferases to O-glycosylate zeatin in the cis-position might be a reason why cZ derivatives are over-accumulated in different maize tissues and organs.
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Affiliation(s)
- Tomáš Hluska
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Petre I Dobrev
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague, Czech Republic
| | - Dana Tarkowská
- Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Jitka Frébortová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - David Zalabák
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - David Kopečný
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Ondřej Plíhal
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Filip Kokáš
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Pierre Briozzo
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Route de Saint-Cyr, F-78026, Versailles, France
| | - Marek Zatloukal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Václav Motyka
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague, Czech Republic
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
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Aubee JI, Olu M, Thompson KM. The i6A37 tRNA modification is essential for proper decoding of UUX-Leucine codons during rpoS and iraP translation. RNA (NEW YORK, N.Y.) 2016; 22:729-742. [PMID: 26979278 PMCID: PMC4836647 DOI: 10.1261/rna.053165.115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
The translation of rpoS(σ(S)), the general stress/stationary phase sigma factor, is tightly regulated at the post-transcriptional level by several factors via mechanisms that are not clearly defined. One of these factors is MiaA, the enzyme necessary for the first step in theN(6)-isopentyl-2-thiomethyl adenosinemethyl adenosine 37 (ms(2)i(6)A37) tRNA modification. We tested the hypothesis that an elevated UUX-Leucine/total leucine codon ratio can be used to identify transcripts whose translation would be sensitive to loss of the MiaA-dependent modification. We identified iraPas another candidate MiaA-sensitive gene, based on the UUX-Leucine/total leucine codon ratio. AniraP-lacZ fusion was significantly decreased in the abse nce of MiaA, consistent with our predictive model. To determine the role of MiaA in UUX-Leucine decoding in rpoS and iraP, we measured β-galactosidase-specific activity of miaA(-)rpo Sandira P translational fusions upon overexpression of leucine tRNAs. We observed suppression of the MiaA effect on rpoS, and notira P, via overexpression of tRNA(LeuX)but not tRNA(LeuZ) We also tested the hypothesis that the MiaA requirement for rpoS and iraP translation is due to decoding of UUX-Leucine codons within the rpoS and iraP transcripts, respectively. We observed a partial suppression of the MiaA requirement for rpoS and iraP translational fusions containing one or both UUX-Leucine codons removed. Taken together, this suggests that MiaA is necessary for rpoS and iraP translation through proper decoding of UUX-Leucine codons and that rpoS and iraP mRNAs are both modification tunable transcripts (MoTTs) via the presence of the modification.
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Affiliation(s)
- Joseph I Aubee
- Department of Microbiology, College of Medicine, Howard University, Washington, DC 20059, USA
| | - Morenike Olu
- Department of Microbiology, College of Medicine, Howard University, Washington, DC 20059, USA Department of Biology, Howard University, Washington, DC 20059, USA
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University, Washington, DC 20059, USA
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Lamichhane TN, Arimbasseri AG, Rijal K, Iben JR, Wei FY, Tomizawa K, Maraia RJ. Lack of tRNA-i6A modification causes mitochondrial-like metabolic deficiency in S. pombe by limiting activity of cytosolic tRNATyr, not mito-tRNA. RNA (NEW YORK, N.Y.) 2016; 22:583-96. [PMID: 26857223 PMCID: PMC4793213 DOI: 10.1261/rna.054064.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/28/2015] [Indexed: 05/17/2023]
Abstract
tRNA-isopentenyl transferases (IPTases) are highly conserved enzymes that form isopentenyl-N(6)-A37 (i6A37) on subsets of tRNAs, enhancing their translation activity. Nuclear-encoded IPTases modify select cytosolic (cy-) and mitochondrial (mt-) tRNAs. Mutation in human IPTase, TRIT1, causes disease phenotypes characteristic of mitochondrial translation deficiency due to mt-tRNA dysfunction. Deletion of the Schizosaccharomyces pombe IPTase (tit1-Δ) causes slow growth in glycerol, as well as in rapamycin, an inhibitor of TOR kinase that maintains metabolic homeostasis. Schizosaccharomyces pombe IPTase modifies three different cy-tRNAs(Ser) as well as cy-tRNA(Tyr), cy-tRNA(Trp), and mt-tRNA(Trp). We show that lower ATP levels in tit1-Δ relative to tit1(+) cells are also more decreased by an inhibitor of oxidative phosphorylation, indicative of mitochondrial dysfunction. Here we asked if the tit1-Δ phenotypes are due to hypomodification of cy-tRNA or mt-tRNA. A cytosol-specific IPTase that modifies cy-tRNA, but not mt-tRNA, fully rescues the tit1-Δ phenotypes. Moreover, overexpression of cy-tRNAs also rescues the phenotypes, and cy-tRNA(Tyr) alone substantially does so. Bioinformatics indicate that cy-tRNA(Tyr) is most limiting for codon demand in tit1-Δ cells and that the cytosolic mRNAs most loaded with Tyr codons encode carbon metabolilizing enzymes, many of which are known to localize to mitochondria. Thus, S. pombe i6A37 hypomodification-associated metabolic deficiency results from hypoactivity of cy-tRNA, mostly tRNA(Tyr), and unlike human TRIT1-deficiency does not impair mitochondrial translation due to mt-tRNA hypomodification. We discuss species-specific aspects of i6A37. Specifically relevant to mitochondria, we show that its hypermodified version, ms2i6A37 (2-methylthiolated), which occurs on certain mammalian mt-tRNAs (but not cy-tRNAs), is not found in yeast.
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Affiliation(s)
- Tek N Lamichhane
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Aneeshkumar G Arimbasseri
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Keshab Rijal
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - James R Iben
- Molecular Genetics Laboratory, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Fan Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 860-0862 Kumamoto, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 860-0862 Kumamoto, Japan
| | - Richard J Maraia
- Section on Molecular and Cell Biology, Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA Commissioned Corps, US Public Health Service, Rockville, Maryland 20016, USA
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Thiaville PC, Legendre R, Rojas-Benítez D, Baudin-Baillieu A, Hatin I, Chalancon G, Glavic A, Namy O, de Crécy-Lagard V. Global translational impacts of the loss of the tRNA modification t 6A in yeast. MICROBIAL CELL 2016; 3:29-45. [PMID: 26798630 PMCID: PMC4717488 DOI: 10.15698/mic2016.01.473] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The universal tRNA modification t6A is found at position 37 of nearly
all tRNAs decoding ANN codons. The absence of t6A37 leads
to severe growth defects in baker’s yeast, phenotypes similar to those caused by
defects in mcm5s2U34 synthesis. Mutants in
mcm5s2U34 can be suppressed by
overexpression of tRNALysUUU, but we show t6A
phenotypes could not be suppressed by expressing any individual ANN decoding
tRNA, and t6A and mcm5s2U are not determinants
for each other’s formation. Our results suggest that t6A deficiency,
like mcm5s2U deficiency, leads to protein folding defects,
and show that the absence of t6A led to stress sensitivities (heat,
ethanol, salt) and sensitivity to TOR pathway inhibitors. Additionally,
L-homoserine suppressed the slow growth phenotype seen in
t6A-deficient strains, and proteins aggregates and Advanced Glycation
End-products (AGEs) were increased in the mutants. The global consequences on
translation caused by t6A absence were examined by ribosome
profiling. Interestingly, the absence of t6A did not lead to global
translation defects, but did increase translation initiation at upstream non-AUG
codons and increased frame-shifting in specific genes. Analysis of codon
occupancy rates suggests that one of the major roles of t6A is to
homogenize the process of elongation by slowing the elongation rate at codons
decoded by high abundance tRNAs and I34:C3 pairs while
increasing the elongation rate of rare tRNAs and G34:U3
pairs. This work reveals that the consequences of t6A absence are
complex and multilayered and has set the stage to elucidate the molecular basis
of the observed phenotypes.
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Affiliation(s)
- Patrick C Thiaville
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL 32610, USA; University of Florida Genetics Institute, University of Florida, Gainesville, FL 32610, USA; Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 400, 91400 Orsay, France
| | - Rachel Legendre
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 400, 91400 Orsay, France
| | - Diego Rojas-Benítez
- Centro de Regulación del Genoma. Facultad de Ciencias - Universidad de Chile, Santiago, Chile
| | - Agnès Baudin-Baillieu
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 400, 91400 Orsay, France
| | - Isabelle Hatin
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 400, 91400 Orsay, France
| | - Guilhem Chalancon
- Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Alvaro Glavic
- Centro de Regulación del Genoma. Facultad de Ciencias - Universidad de Chile, Santiago, Chile
| | - Olivier Namy
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 400, 91400 Orsay, France
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; University of Florida Genetics Institute, University of Florida, Gainesville, FL 32610, USA
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