1
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Bertotti S, Fleming I, Cámara MDLM, Centeno Cameán C, Carmona SJ, Agüero F, Balouz V, Zahn A, Di Noia JM, Alfonzo JD, Buscaglia CA. Characterization of ADAT2/3 molecules in Trypanosoma cruzi and regulation of mucin gene expression by tRNA editing. Biochem J 2022; 479:561-580. [PMID: 35136964 DOI: 10.1042/bcj20210850] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/28/2022] [Accepted: 02/08/2022] [Indexed: 11/17/2022]
Abstract
Adenosine-to-inosine conversion at position 34 (A34-to-I) of certain tRNAs is essential for expanding their decoding capacity. This reaction is catalyzed by the adenosine deaminase acting on tRNA (ADAT) complex, which in Eukarya is formed by two subunits: ADAT2 and ADAT3. We herein identified and thoroughly characterized the ADAT molecules from the protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas Disease. TcADAT2 and TcADAT3 spontaneously form a catalytically active complex, as shown by expression in engineered bacteria and/or by the increased ex vivo tRNA A-to-I deamination activity of T. cruzi epimastigotes overexpressing TcADAT subunits. Importantly, enhanced TcADAT2/3 activity in transgenic parasites caused a shift in their in vivo tRNAThrAGU signature, which correlated with significant changes in the expression of the Thr-rich TcSMUG proteins. To our knowledge, this is the first evidence indicating that T. cruzi tRNA editing can be modulated in vivo, in turn post-transcriptionally changing the expression of specific genes. Our findings suggest tRNA editing/availability as a forcible step in controlling gene expression and driving codon adaptation in T. cruzi. Moreover, we unveil certain differences between parasite and mammalian host tRNA editing and processing, such as cytosine-to-uridine conversion at position 32 of tRNAThrAGU in T. cruzi, that may be exploited for the identification of novel druggable targets of intervention.
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Affiliation(s)
- Santiago Bertotti
- Laboratory of Molecular Biology of Protozoa, Instituto de Investigaciones Biotecnológicas 'Dr Rodolfo Ugalde' (IIBio, Universidad Nacional de San Martín, UNSAM, and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET), Av. 25 de Mayo y Francia, Campus UNSAM, San Martín (1650), Buenos Aires, Argentina
| | - Ian Fleming
- Department of Microbiology, The Ohio State University, 318 W 12th Ave. (Aronoff Building), Columbus, U.S.A
| | - María de Los Milagros Cámara
- Laboratory of Molecular Biology of Protozoa, Instituto de Investigaciones Biotecnológicas 'Dr Rodolfo Ugalde' (IIBio, Universidad Nacional de San Martín, UNSAM, and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET), Av. 25 de Mayo y Francia, Campus UNSAM, San Martín (1650), Buenos Aires, Argentina
| | - Camila Centeno Cameán
- Laboratory of Molecular Biology of Protozoa, Instituto de Investigaciones Biotecnológicas 'Dr Rodolfo Ugalde' (IIBio, Universidad Nacional de San Martín, UNSAM, and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET), Av. 25 de Mayo y Francia, Campus UNSAM, San Martín (1650), Buenos Aires, Argentina
| | - Santiago J Carmona
- Trypanosomatics Laboratory, IIBio (UNSAM and CONICET), Buenos Aires, Argentina
| | - Fernán Agüero
- Trypanosomatics Laboratory, IIBio (UNSAM and CONICET), Buenos Aires, Argentina
| | - Virginia Balouz
- Laboratory of Molecular Biology of Protozoa, Instituto de Investigaciones Biotecnológicas 'Dr Rodolfo Ugalde' (IIBio, Universidad Nacional de San Martín, UNSAM, and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET), Av. 25 de Mayo y Francia, Campus UNSAM, San Martín (1650), Buenos Aires, Argentina
| | - Astrid Zahn
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, Quebec, Canada
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Javier M Di Noia
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, Quebec, Canada
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Juan D Alfonzo
- Department of Microbiology, The Ohio State University, 318 W 12th Ave. (Aronoff Building), Columbus, U.S.A
| | - Carlos A Buscaglia
- Laboratory of Molecular Biology of Protozoa, Instituto de Investigaciones Biotecnológicas 'Dr Rodolfo Ugalde' (IIBio, Universidad Nacional de San Martín, UNSAM, and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET), Av. 25 de Mayo y Francia, Campus UNSAM, San Martín (1650), Buenos Aires, Argentina
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2
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Lateef OM, Akintubosun MO, Olaoba OT, Samson SO, Adamczyk M. Making Sense of "Nonsense" and More: Challenges and Opportunities in the Genetic Code Expansion, in the World of tRNA Modifications. Int J Mol Sci 2022; 23:938. [PMID: 35055121 PMCID: PMC8779196 DOI: 10.3390/ijms23020938] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/09/2023] Open
Abstract
The evolutional development of the RNA translation process that leads to protein synthesis based on naturally occurring amino acids has its continuation via synthetic biology, the so-called rational bioengineering. Genetic code expansion (GCE) explores beyond the natural translational processes to further enhance the structural properties and augment the functionality of a wide range of proteins. Prokaryotic and eukaryotic ribosomal machinery have been proven to accept engineered tRNAs from orthogonal organisms to efficiently incorporate noncanonical amino acids (ncAAs) with rationally designed side chains. These side chains can be reactive or functional groups, which can be extensively utilized in biochemical, biophysical, and cellular studies. Genetic code extension offers the contingency of introducing more than one ncAA into protein through frameshift suppression, multi-site-specific incorporation of ncAAs, thereby increasing the vast number of possible applications. However, different mediating factors reduce the yield and efficiency of ncAA incorporation into synthetic proteins. In this review, we comment on the recent advancements in genetic code expansion to signify the relevance of systems biology in improving ncAA incorporation efficiency. We discuss the emerging impact of tRNA modifications and metabolism in protein design. We also provide examples of the latest successful accomplishments in synthetic protein therapeutics and show how codon expansion has been employed in various scientific and biotechnological applications.
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Affiliation(s)
- Olubodun Michael Lateef
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | | | - Olamide Tosin Olaoba
- Laboratory of Functional and Structural Biochemistry, Federal University of Sao Carlos, Sao Carlos 13565-905, SP, Brazil;
| | - Sunday Ocholi Samson
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | - Malgorzata Adamczyk
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
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3
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Li J, Zhu WY, Yang WQ, Li CT, Liu RJ. The occurrence order and cross-talk of different tRNA modifications. SCIENCE CHINA. LIFE SCIENCES 2021; 64:1423-1436. [PMID: 33881742 DOI: 10.1007/s11427-020-1906-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
Chemical modifications expand the composition of RNA molecules from four standard nucleosides to over 160 modified nucleosides, which greatly increase the complexity and utility of RNAs. Transfer RNAs (tRNAs) are the most heavily modified cellular RNA molecules and contain the largest variety of modifications. Modification of tRNAs is pivotal for protein synthesis and also precisely regulates the noncanonical functions of tRNAs. Defects in tRNA modifications lead to numerous human diseases. Up to now, more than 100 types of modifications have been found in tRNAs. Intriguingly, some modifications occur widely on all tRNAs, while others only occur on a subgroup of tRNAs or even only a specific tRNA. The modification frequency of each tRNA is approximately 7% to 25%, with 5-20 modification sites present on each tRNA. The occurrence and modulation of tRNA modifications are specifically noticeable as plenty of interplays among different sites and modifications have been discovered. In particular, tRNA modifications are responsive to environmental changes, indicating their dynamic and highly organized nature. In this review, we summarized the known occurrence order, cross-talk, and cooperativity of tRNA modifications.
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Affiliation(s)
- Jing Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Wen-Yu Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Wen-Qing Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Cai-Tao Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Ru-Juan Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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4
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Rafels-Ybern À, Torres AG, Camacho N, Herencia-Ropero A, Roura Frigolé H, Wulff TF, Raboteg M, Bordons A, Grau-Bove X, Ruiz-Trillo I, Ribas de Pouplana L. The Expansion of Inosine at the Wobble Position of tRNAs, and Its Role in the Evolution of Proteomes. Mol Biol Evol 2019; 36:650-662. [PMID: 30590541 DOI: 10.1093/molbev/msy245] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The modification of adenosine to inosine at the first position of transfer RNA (tRNA) anticodons (I34) is widespread among bacteria and eukaryotes. In bacteria, the modification is found in tRNAArg and is catalyzed by tRNA adenosine deaminase A, a homodimeric enzyme. In eukaryotes, I34 is introduced in up to eight different tRNAs by the heterodimeric adenosine deaminase acting on tRNA. This substrate expansion significantly influenced the evolution of eukaryotic genomes in terms of codon usage and tRNA gene composition. However, the selective advantages driving this process remain unclear. Here, we have studied the evolution of I34, tRNA adenosine deaminase A, adenosine deaminase acting on tRNA, and their relevant codons in a large set of bacterial and eukaryotic species. We show that a functional expansion of I34 to tRNAs other than tRNAArg also occurred within bacteria, in a process likely initiated by the emergence of unmodified A34-containing tRNAs. In eukaryotes, we report on a large variability in the use of I34 in protists, in contrast to a more uniform presence in fungi, plans, and animals. Our data support that the eukaryotic expansion of I34-tRNAs was driven by the improvement brought by these tRNAs to the synthesis of proteins highly enriched in certain amino acids.
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Affiliation(s)
- Àlbert Rafels-Ybern
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Noelia Camacho
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Andrea Herencia-Ropero
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Helena Roura Frigolé
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Thomas F Wulff
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Marina Raboteg
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Albert Bordons
- Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Xavier Grau-Bove
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain.,Departament de Genètica, Microbiología i Estadística, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain.,Departament de Genètica, Microbiología i Estadística, Universitat de Barcelona, Barcelona, Catalonia, Spain.,ICREA, Barcelona, Catalonia, Spain
| | - Lluís Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain.,ICREA, Barcelona, Catalonia, Spain
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5
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The Versatile Roles of the tRNA Epitranscriptome during Cellular Responses to Toxic Exposures and Environmental Stress. TOXICS 2019; 7:toxics7010017. [PMID: 30934574 PMCID: PMC6468425 DOI: 10.3390/toxics7010017] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 12/11/2022]
Abstract
Living organisms respond to environmental changes and xenobiotic exposures by regulating gene expression. While heat shock, unfolded protein, and DNA damage stress responses are well-studied at the levels of the transcriptome and proteome, tRNA-mediated mechanisms are only recently emerging as important modulators of cellular stress responses. Regulation of the stress response by tRNA shows a high functional diversity, ranging from the control of tRNA maturation and translation initiation, to translational enhancement through modification-mediated codon-biased translation of mRNAs encoding stress response proteins, and translational repression by stress-induced tRNA fragments. tRNAs need to be heavily modified post-transcriptionally for full activity, and it is becoming increasingly clear that many aspects of tRNA metabolism and function are regulated through the dynamic introduction and removal of modifications. This review will discuss the many ways that nucleoside modifications confer high functional diversity to tRNAs, with a focus on tRNA modification-mediated regulation of the eukaryotic response to environmental stress and toxicant exposures. Additionally, the potential applications of tRNA modification biology in the development of early biomarkers of pathology will be highlighted.
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6
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Dixit S, Henderson JC, Alfonzo JD. Multi-Substrate Specificity and the Evolutionary Basis for Interdependence in tRNA Editing and Methylation Enzymes. Front Genet 2019; 10:104. [PMID: 30838029 PMCID: PMC6382703 DOI: 10.3389/fgene.2019.00104] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/30/2019] [Indexed: 12/12/2022] Open
Abstract
Among tRNA modification enzymes there is a correlation between specificity for multiple tRNA substrates and heteromultimerization. In general, enzymes that modify a conserved residue in different tRNA sequences adopt a heterodimeric structure. Presumably, such changes in the oligomeric state of enzymes, to gain multi-substrate recognition, are driven by the need to accommodate and catalyze a particular reaction in different substrates while maintaining high specificity. This review focuses on two classes of enzymes where the case for multimerization as a way to diversify molecular recognition can be made. We will highlight several new themes with tRNA methyltransferases and will also discuss recent findings with tRNA editing deaminases. These topics will be discussed in the context of several mechanisms by which heterodimerization may have been achieved during evolution and how these mechanisms might impact modifications in different systems.
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Affiliation(s)
| | | | - Juan D. Alfonzo
- Department of Microbiology, The Ohio State Biochemistry Program, The Center for RNA Biology, The Ohio State University, Columbus, OH, United States
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7
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Han L, Phizicky EM. A rationale for tRNA modification circuits in the anticodon loop. RNA (NEW YORK, N.Y.) 2018; 24:1277-1284. [PMID: 30026310 PMCID: PMC6140457 DOI: 10.1261/rna.067736.118] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The numerous post-transcriptional modifications of tRNA play a crucial role in tRNA function. While most modifications are introduced to tRNA independently, several sets of modifications are found to be interconnected such that the presence of one set of modifications drives the formation of another modification. The vast majority of these modification circuits are found in the anticodon loop (ACL) region where the largest variety and highest density of modifications occur compared to the other parts of the tRNA and where there is relatively limited sequence and structural information. We speculate here that the modification circuits in the ACL region arise to enhance enzyme modification specificity by direct or indirect use of the first modification in the circuit as an additional recognition element for the second modification. We also describe the five well-studied modification circuits in the ACL, and outline possible mechanisms by which they may act. The prevalence of these modification circuits in the ACL and the phylogenetic conservation of some of them suggest that a number of other modification circuits will be found in this region in different organisms.
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Affiliation(s)
- Lu Han
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Eric M Phizicky
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
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8
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Sarcar SN, Miller DL. A specific, promoter-independent activity of T7 RNA polymerase suggests a general model for DNA/RNA editing in single subunit RNA Polymerases. Sci Rep 2018; 8:13885. [PMID: 30224735 PMCID: PMC6141538 DOI: 10.1038/s41598-018-32231-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/31/2018] [Indexed: 01/23/2023] Open
Abstract
Insertional RNA editing has been observed and characterized in mitochondria of myxomycetes. The single subunit mitochondrial RNA polymerase adds nontemplated nucleotides co-transcriptionally to produce functional tRNA, rRNA and mRNAs with full genetic information. Addition of nontemplated nucleotides to the 3′ ends of RNAs have been observed in polymerases related to the mitochondrial RNA polymerase. This activity has been observed with T7 RNA polymerase (T7 RNAP), the well characterized prototype of the single subunit polymerases, as a nonspecific addition of nucleotides to the 3′ end of T7 RNAP transcripts in vitro. Here we show that this novel activity is an editing activity that can add specific ribonucleotides to 3′ ends of RNA or DNA when oligonucleotides, able to form intramolecular or intermolecular hairpin loops with recessed 3′ ends, are added to T7 RNA polymerase in the presence of at least one ribonucleotide triphosphate. Specific ribonucleotides are added to the recessed 3′ ends through Watson-Crick base pairing with the non-base paired nucleotide adjacent to the 3′ end. Optimization of this activity is obtained through alteration of the lengths of the 5′-extension, hairpin loop, and hairpin duplex. These properties define a T7 RNAP activity different from either transcriptional elongation or initiation.
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Affiliation(s)
- Subha Narayan Sarcar
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, 75083-0688, USA
| | - Dennis L Miller
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, 75083-0688, USA.
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9
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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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10
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de Freitas Nascimento J, Kelly S, Sunter J, Carrington M. Codon choice directs constitutive mRNA levels in trypanosomes. eLife 2018; 7:e32467. [PMID: 29543152 PMCID: PMC5896880 DOI: 10.7554/elife.32467] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/27/2018] [Indexed: 11/13/2022] Open
Abstract
Selective transcription of individual protein coding genes does not occur in trypanosomes and the cellular copy number of each mRNA must be determined post-transcriptionally. Here, we provide evidence that codon choice directs the levels of constitutively expressed mRNAs. First, a novel codon usage metric, the gene expression codon adaptation index (geCAI), was developed that maximised the relationship between codon choice and the measured abundance for a transcriptome. Second, geCAI predictions of mRNA levels were tested using differently coded GFP transgenes and were successful over a 25-fold range, similar to the variation in endogenous mRNAs. Third, translation was necessary for the accelerated mRNA turnover resulting from codon choice. Thus, in trypanosomes, the information determining the levels of most mRNAs resides in the open reading frame and translation is required to access this information.
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Affiliation(s)
| | - Steven Kelly
- Department of Plant SciencesUniversity of OxfordOxfordUnited Kingdom
| | - Jack Sunter
- Department of BiochemistryUniversity of CambridgeCambridgeUnited Kingdom
| | - Mark Carrington
- Department of BiochemistryUniversity of CambridgeCambridgeUnited Kingdom
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11
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McKenney KM, Rubio MAT, Alfonzo JD. Binding synergy as an essential step for tRNA editing and modification enzyme codependence in Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2018; 24:56-66. [PMID: 29042505 PMCID: PMC5733570 DOI: 10.1261/rna.062893.117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/02/2017] [Indexed: 05/10/2023]
Abstract
Transfer RNAs acquire a variety of naturally occurring chemical modifications during their maturation; these fine-tune their structure and decoding properties in a manner critical for protein synthesis. We recently reported that in the eukaryotic parasite, Trypanosoma brucei, a methylation and deamination event are unexpectedly interconnected, whereby the tRNA adenosine deaminase (TbADAT2/3) and the 3-methylcytosine methyltransferase (TbTrm140) strictly rely on each other for activity, leading to formation of m3C and m3U at position 32 in several tRNAs. Still however, it is not clear why these two enzymes, which work independently in other systems, are strictly codependent in T. brucei Here, we show that these enzymes exhibit binding synergism, or a mutual increase in binding affinity, that is more than the sum of the parts, when added together in a reaction. Although these enzymes interact directly with each other, tRNA binding assays using enzyme variants mutated in critical binding and catalytic sites indicate that the observed binding synergy stems from contributions from tRNA-binding domains distal to their active sites. These results provide a rationale for the known interactions of these proteins, while also speaking to the modulation of substrate specificity between seemingly unrelated enzymes. This information should be of value in furthering our understanding of how tRNA modification enzymes act together to regulate gene expression at the post-transcriptional level and provide a basis for the interdependence of such activities.
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Affiliation(s)
- Katherine M McKenney
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
| | - Mary Anne T Rubio
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Juan D Alfonzo
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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12
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Kessler AC, Silveira d'Almeida G, Alfonzo JD. The role of intracellular compartmentalization on tRNA processing and modification. RNA Biol 2017; 15:554-566. [PMID: 28850002 DOI: 10.1080/15476286.2017.1371402] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
A signature of most eukaryotic cells is the presence of intricate membrane systems. Intracellular organization presumably evolved to provide order, and add layers for regulation of intracellular processes; compartmentalization also forcibly led to the appearance of sophisticated transport systems. With nucleus-encoded tRNAs, it led to the uncoupling of tRNA synthesis from many of the maturation steps it undergoes. It is now clear that tRNAs are actively transported across intracellular membranes and at any point, in any compartment, they can be post-transcriptionally modified; modification enzymes themselves may localize to any of the genome-containing compartments. In the following pages, we describe a number of well-known examples of how intracellular compartmentalization of tRNA processing and modification activities impact the function and fate of tRNAs. We raise the possibility that rates of intracellular transport may influence the level of modification and as such increase the diversity of differentially modified tRNAs in cells.
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Affiliation(s)
- Alan C Kessler
- a Department of Microbiology , The Ohio State University , Columbus , Ohio , USA.,b The Center for RNA Biology , The Ohio State University , Columbus , Ohio , USA
| | - Gabriel Silveira d'Almeida
- a Department of Microbiology , The Ohio State University , Columbus , Ohio , USA.,b The Center for RNA Biology , The Ohio State University , Columbus , Ohio , USA
| | - Juan D Alfonzo
- a Department of Microbiology , The Ohio State University , Columbus , Ohio , USA.,b The Center for RNA Biology , The Ohio State University , Columbus , Ohio , USA.,c The Ohio State Biochemistry Program , The Ohio State University , Columbus, Ohio , USA
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13
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Editing and methylation at a single site by functionally interdependent activities. Nature 2017; 542:494-497. [PMID: 28230119 DOI: 10.1038/nature21396] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/18/2017] [Indexed: 02/02/2023]
Abstract
Nucleic acids undergo naturally occurring chemical modifications. Over 100 different modifications have been described and every position in the purine and pyrimidine bases can be modified; often the sugar is also modified. Despite recent progress, the mechanism for the biosynthesis of most modifications is not fully understood, owing, in part, to the difficulty associated with reconstituting enzyme activity in vitro. Whereas some modifications can be efficiently formed with purified components, others may require more intricate pathways. A model for modification interdependence, in which one modification is a prerequisite for another, potentially explains a major hindrance in reconstituting enzymatic activity in vitro. This model was prompted by the earlier discovery of tRNA cytosine-to-uridine editing in eukaryotes, a reaction that has not been recapitulated in vitro and the mechanism of which remains unknown. Here we show that cytosine 32 in the anticodon loop of Trypanosoma brucei tRNAThr is methylated to 3-methylcytosine (m3C) as a pre-requisite for C-to-U deamination. Formation of m3C in vitro requires the presence of both the T. brucei m3C methyltransferase TRM140 and the deaminase ADAT2/3. Once formed, m3C is deaminated to 3-methyluridine (m3U) by the same set of enzymes. ADAT2/3 is a highly mutagenic enzyme, but we also show that when co-expressed with the methyltransferase its mutagenicity is kept in check. This helps to explain how T. brucei escapes 'wholesale deamination' of its genome while harbouring both enzymes in the nucleus. This observation has implications for the control of another mutagenic deaminase, human AID, and provides a rationale for its regulation.
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14
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Torres AG, Piñeyro D, Rodríguez-Escribà M, Camacho N, Reina O, Saint-Léger A, Filonava L, Batlle E, Ribas de Pouplana L. Inosine modifications in human tRNAs are incorporated at the precursor tRNA level. Nucleic Acids Res 2015; 43:5145-57. [PMID: 25916855 PMCID: PMC4446420 DOI: 10.1093/nar/gkv277] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 03/20/2015] [Indexed: 11/12/2022] Open
Abstract
Transfer RNAs (tRNAs) are key adaptor molecules of the genetic code that are heavily modified post-transcriptionally. Inosine at the first residue of the anticodon (position 34; I34) is an essential widespread tRNA modification that has been poorly studied thus far. The modification in eukaryotes results from a deamination reaction of adenine that is catalyzed by the heterodimeric enzyme adenosine deaminase acting on tRNA (hetADAT), composed of two subunits: ADAT2 and ADAT3. Using high-throughput small RNA sequencing (RNAseq), we show that this modification is incorporated to human tRNAs at the precursor tRNA level and during maturation. We also functionally validated the human genes encoding for hetADAT and show that the subunits of this enzyme co-localize in nucleus in an ADAT2-dependent manner. Finally, by knocking down HsADAT2, we demonstrate that variations in the cellular levels of hetADAT will result in changes in the levels of I34 modification in all its potential substrates. Altogether, we present RNAseq as a powerful tool to study post-transcriptional tRNA modifications at the precursor tRNA level and give the first insights on the biology of I34 tRNA modification in metazoans.
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Affiliation(s)
- Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - David Piñeyro
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - Marta Rodríguez-Escribà
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - Noelia Camacho
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - Oscar Reina
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - Adélaïde Saint-Léger
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - Liudmila Filonava
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain
| | - Eduard Batlle
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain Catalan Institution for Research and Advanced Studies (ICREA), P/Lluis Companys 23, Barcelona, 08010 Catalonia, Spain
| | - Lluís Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona, 08028 Catalonia, Spain Catalan Institution for Research and Advanced Studies (ICREA), P/Lluis Companys 23, Barcelona, 08010 Catalonia, Spain
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15
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Shen PS, Park J, Qin Y, Li X, Parsawar K, Larson MH, Cox J, Cheng Y, Lambowitz AM, Weissman JS, Brandman O, Frost A. Protein synthesis. Rqc2p and 60S ribosomal subunits mediate mRNA-independent elongation of nascent chains. Science 2015; 347:75-8. [PMID: 25554787 DOI: 10.1126/science.1259724] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In Eukarya, stalled translation induces 40S dissociation and recruitment of the ribosome quality control complex (RQC) to the 60S subunit, which mediates nascent chain degradation. Here we report cryo-electron microscopy structures revealing that the RQC components Rqc2p (YPL009C/Tae2) and Ltn1p (YMR247C/Rkr1) bind to the 60S subunit at sites exposed after 40S dissociation, placing the Ltn1p RING (Really Interesting New Gene) domain near the exit channel and Rqc2p over the P-site transfer RNA (tRNA). We further demonstrate that Rqc2p recruits alanine- and threonine-charged tRNA to the A site and directs the elongation of nascent chains independently of mRNA or 40S subunits. Our work uncovers an unexpected mechanism of protein synthesis, in which a protein--not an mRNA--determines tRNA recruitment and the tagging of nascent chains with carboxy-terminal Ala and Thr extensions ("CAT tails").
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Affiliation(s)
- Peter S Shen
- Department of Biochemistry, University of Utah, UT 84112, USA
| | - Joseph Park
- Department of Biochemistry, Stanford University, Palo Alto, CA 94305, USA
| | - Yidan Qin
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA. Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Xueming Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Krishna Parsawar
- Mass Spectrometry and Proteomics Core Facility, University of Utah, UT 84112, USA
| | - Matthew H Larson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA. Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA. California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA 94158, USA. Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - James Cox
- Department of Biochemistry, University of Utah, UT 84112, USA. Mass Spectrometry and Proteomics Core Facility, University of Utah, UT 84112, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA. Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA. Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA. California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA 94158, USA. Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Onn Brandman
- Department of Biochemistry, Stanford University, Palo Alto, CA 94305, USA.
| | - Adam Frost
- Department of Biochemistry, University of Utah, UT 84112, USA. Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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16
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Torres AG, Piñeyro D, Filonava L, Stracker TH, Batlle E, Ribas de Pouplana L. A-to-I editing on tRNAs: biochemical, biological and evolutionary implications. FEBS Lett 2014; 588:4279-86. [PMID: 25263703 DOI: 10.1016/j.febslet.2014.09.025] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 09/16/2014] [Accepted: 09/16/2014] [Indexed: 12/13/2022]
Abstract
Inosine on transfer RNAs (tRNAs) are post-transcriptionally formed by a deamination mechanism of adenosines at positions 34, 37 and 57 of certain tRNAs. Despite its ubiquitous nature, the biological role of inosine in tRNAs remains poorly understood. Recent developments in the study of nucleotide modifications are beginning to indicate that the dynamics of such modifications are used in the control of specific genetic programs. Likewise, the essentiality of inosine-modified tRNAs in genome evolution and animal biology is becoming apparent. Here we review our current understanding on the role of inosine in tRNAs, the enzymes that catalyze the modification and the evolutionary link between such enzymes and other deaminases.
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Affiliation(s)
- Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - David Piñeyro
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - Liudmila Filonava
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - Eduard Batlle
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain; Catalan Institution for Research and Advanced Studies (ICREA), P/ Lluís Companys 23, Barcelona 08010, Catalonia, Spain
| | - Lluis Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain; Catalan Institution for Research and Advanced Studies (ICREA), P/ Lluís Companys 23, Barcelona 08010, Catalonia, Spain.
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17
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Su AAH, Randau L. A-to-I and C-to-U editing within transfer RNAs. BIOCHEMISTRY (MOSCOW) 2011; 76:932-7. [DOI: 10.1134/s0006297911080098] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Knoop V. When you can't trust the DNA: RNA editing changes transcript sequences. Cell Mol Life Sci 2011; 68:567-86. [PMID: 20938709 PMCID: PMC11114842 DOI: 10.1007/s00018-010-0538-9] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/13/2010] [Accepted: 09/23/2010] [Indexed: 12/25/2022]
Abstract
RNA editing describes targeted sequence alterations in RNAs so that the transcript sequences differ from their DNA template. Since the original discovery of RNA editing in trypanosomes nearly 25 years ago more than a dozen such processes of nucleotide insertions, deletions, and exchanges have been identified in evolutionarily widely separated groups of the living world including plants, animals, fungi, protists, bacteria, and viruses. In many cases gene expression in mitochondria is affected, but RNA editing also takes place in chloroplasts and in nucleocytosolic genetic environments. While some RNA editing systems largely seem to repair defect genes (cryptogenes), others have obvious functions in modulating gene activities. The present review aims for an overview on the current states of research in the different systems of RNA editing by following a historic timeline along the respective original discoveries.
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Affiliation(s)
- Volker Knoop
- Abteilung Molekulare Evolution, Institut für Zelluläre und Molekulare Botanik (IZMB), Bonn, Germany.
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19
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Phizicky EM, Alfonzo JD. Do all modifications benefit all tRNAs? FEBS Lett 2009; 584:265-71. [PMID: 19931536 DOI: 10.1016/j.febslet.2009.11.049] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 10/20/2022]
Abstract
Despite the universality of tRNA modifications, some tRNAs lacking specific modifications are subject to degradation pathways, while other tRNAs lacking the same modifications are resistant. Here, we suggest a model in which some modifications have minor, possibly redundant, roles in specific tRNAs. This model is consistent with the low specificity of some modification enzymes. Limitations of this model include the limited assays and growth conditions on which these conclusions are based, as well as the high specificity exhibited by many modification enzymes with important roles in translation. The specificity of these enzymes is often enhanced by complex substrate recognition patterns and sub-cellular compartmentalization.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA.
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