1
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Chen Q, Zhou T. Emerging functional principles of tRNA-derived small RNAs and other regulatory small RNAs. J Biol Chem 2023; 299:105225. [PMID: 37673341 PMCID: PMC10562873 DOI: 10.1016/j.jbc.2023.105225] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 08/22/2023] [Accepted: 08/28/2023] [Indexed: 09/08/2023] Open
Abstract
Recent advancements in small RNA sequencing have unveiled a previously hidden world of regulatory small noncoding RNAs (sncRNAs) that extend beyond the well-studied small interfering RNAs, microRNAs, and piwi-interacting RNAs. This exploration, starting with tRNA-derived small RNAs, has led to the discovery of a diverse universe of sncRNAs derived from various longer structured RNAs such as rRNAs, small nucleolar RNAs, small nuclear RNAs, Y RNAs, and vault RNAs, with exciting uncharted functional possibilities. In this perspective, we discuss the emerging functional principles of sncRNAs beyond the well-known RNAi-like mechanisms, focusing on those that operate independent of linear sequence complementarity but rather function in an aptamer-like fashion. Aptamers use 3D structure for specific interactions with ligands and are modulated by RNA modifications and subcellular environments. Given that aptamer-like sncRNA functions are widespread and present in species lacking RNAi, they may represent an ancient functional principle that predates RNAi. We propose a rethinking of the origin of RNAi and its relationship with these aptamer-like functions in sncRNAs and how these complementary mechanisms shape biological processes. Lastly, the aptamer-like function of sncRNAs highlights the need for caution in using small RNA mimics in research and therapeutics, as their specificity is not restricted solely to linear sequence.
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Affiliation(s)
- Qi Chen
- Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, Utah, USA; Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA.
| | - Tong Zhou
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA.
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2
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Horikoshi T, Noguchi H, Umehara T, Mutsuro-Aoki H, Kurihara R, Noguchi R, Hashimoto T, Watanabe Y, Ando T, Kamata K, Park SY, Tamura K. Crystal structure of Nanoarchaeum equitans tyrosyl-tRNA synthetase and its aminoacylation activity toward tRNA Tyr with an extra guanosine residue at the 5'-terminus. Biochem Biophys Res Commun 2021; 575:90-95. [PMID: 34461441 DOI: 10.1016/j.bbrc.2021.08.070] [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: 08/05/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022]
Abstract
tRNATyr of Nanoarchaeum equitans has a remarkable feature with an extra guanosine residue at the 5'-terminus. However, the N. equitans tRNATyr mutant without extra guanosine at the 5'-end was tyrosylated by tyrosyl-tRNA synthase (TyrRS). We solved the crystal structure of N. equitans TyrRS at 2.80 Å resolution. By comparing the present solved structure with the complex structures TyrRS with tRNATyr of Thermus thermophilus and Methanocaldococcus jannaschii, an arginine substitution mutant of N. equitans TyrRS at Ile200 (I200R), which is the putative closest candidate to the 5'-phosphate of C1 of N. equitans tRNATyr, was prepared. The I200R mutant tyrosylated not only wild-type tRNATyr but also the tRNA without the G-1 residue. Further tyrosylation analysis revealed that the second base of the anticodon (U35), discriminator base (A73), and C1:G72 base pair are strong recognition sites.
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Affiliation(s)
- Tatsuya Horikoshi
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroki Noguchi
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Takuya Umehara
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiromi Mutsuro-Aoki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Ryodai Kurihara
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Ryohei Noguchi
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Takahiro Hashimoto
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yuki Watanabe
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Tadashi Ando
- Department of Applied Electronics, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kenichi Kamata
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Sam-Yong Park
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Koji Tamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
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3
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Chan PP, Lin BY, Mak AJ, Lowe TM. tRNAscan-SE 2.0: improved detection and functional classification of transfer RNA genes. Nucleic Acids Res 2021; 49:9077-9096. [PMID: 34417604 PMCID: PMC8450103 DOI: 10.1093/nar/gkab688] [Citation(s) in RCA: 500] [Impact Index Per Article: 166.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 12/17/2022] Open
Abstract
tRNAscan-SE has been widely used for transfer RNA (tRNA) gene prediction for over twenty years, developed just as the first genomes were decoded. With the massive increase in quantity and phylogenetic diversity of genomes, the accurate detection and functional prediction of tRNAs has become more challenging. Utilizing a vastly larger training set, we created nearly one hundred specialized isotype- and clade-specific models, greatly improving tRNAscan-SE’s ability to identify and classify both typical and atypical tRNAs. We employ a new comparative multi-model strategy where predicted tRNAs are scored against a full set of isotype-specific covariance models, allowing functional prediction based on both the anticodon and the highest-scoring isotype model. Comparative model scoring has also enhanced the program's ability to detect tRNA-derived SINEs and other likely pseudogenes. For the first time, tRNAscan-SE also includes fast and highly accurate detection of mitochondrial tRNAs using newly developed models. Overall, tRNA detection sensitivity and specificity is improved for all isotypes, particularly those utilizing specialized models for selenocysteine and the three subtypes of tRNA genes encoding a CAU anticodon. These enhancements will provide researchers with more accurate and detailed tRNA annotation for a wider variety of tRNAs, and may direct attention to tRNAs with novel traits.
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Affiliation(s)
- Patricia P Chan
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California, Santa Cruz, CA 95064, USA
| | - Brian Y Lin
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California, Santa Cruz, CA 95064, USA
| | - Allysia J Mak
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California, Santa Cruz, CA 95064, USA
| | - Todd M Lowe
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California, Santa Cruz, CA 95064, USA
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4
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Zhong Q, Fu X, Zhang T, Zhou T, Yue M, Liu J, Li Z. Phylogeny and evolution of chloroplast tRNAs in Adoxaceae. Ecol Evol 2021; 11:1294-1309. [PMID: 33598131 PMCID: PMC7863635 DOI: 10.1002/ece3.7133] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 11/14/2020] [Accepted: 11/23/2020] [Indexed: 12/24/2022] Open
Abstract
Chloroplasts are semiautonomous organelles found in photosynthetic plants. The major functions of chloroplasts include photosynthesis and carbon fixation, which are mainly regulated by its circular genomes. In the highly conserved chloroplast genome, the chloroplast transfer RNA genes (cp tRNA) play important roles in protein translation within chloroplasts. However, the evolution of cp tRNAs remains unclear. Thus, in the present study, we investigated the evolutionary characteristics of chloroplast tRNAs in five Adoxaceae species using 185 tRNA gene sequences. In total, 37 tRNAs encoding 28 anticodons are found in the chloroplast genome in Adoxaceae species. Some consensus sequences are found within the Ψ-stem and anticodon loop of the tRNAs. Some putative novel structures were also identified, including a new stem located in the variable region of tRNATyr in a similar manner to the anticodon stem. Furthermore, phylogenetic and evolutionary analyses indicated that synonymous tRNAs may have evolved from multiple ancestors and frequent tRNA duplications during the evolutionary process may have been primarily caused by positive selection and adaptive evolution. The transition and transversion rates are uneven among different tRNA isotypes. For all tRNAs, the transition rate is greater with a transition/transversion bias of 3.13. Phylogenetic analysis of cp tRNA suggested that the type I introns in different taxa (including eukaryote organisms and cyanobacteria) share the conserved sequences "U-U-x2-C" and "U-x-G-x2-T," thereby indicating the diverse cyanobacterial origins of organelles. This detailed study of cp tRNAs in Adoxaceae may facilitate further investigations of the evolution, phylogeny, structure, and related functions of chloroplast tRNAs.
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Affiliation(s)
- Qiu‐Yi Zhong
- Shaanxi Key Laboratory for Animal ConservationKey Laboratory of Resource Biology and Biotechnology in Western ChinaMinistry of EducationCollege of Life SciencesNorthwest UniversityXi'anChina
- Key Laboratory for Plant Diversity and Biogeography of East AsiaKunming Institute of BotanyChinese Academy of SciencesKunmingChina
| | - Xiao‐Gang Fu
- Shaanxi Key Laboratory for Animal ConservationKey Laboratory of Resource Biology and Biotechnology in Western ChinaMinistry of EducationCollege of Life SciencesNorthwest UniversityXi'anChina
| | - Ting‐Ting Zhang
- Shaanxi Key Laboratory for Animal ConservationKey Laboratory of Resource Biology and Biotechnology in Western ChinaMinistry of EducationCollege of Life SciencesNorthwest UniversityXi'anChina
| | - Tong Zhou
- Shaanxi Key Laboratory for Animal ConservationKey Laboratory of Resource Biology and Biotechnology in Western ChinaMinistry of EducationCollege of Life SciencesNorthwest UniversityXi'anChina
| | - Ming Yue
- Shaanxi Key Laboratory for Animal ConservationKey Laboratory of Resource Biology and Biotechnology in Western ChinaMinistry of EducationCollege of Life SciencesNorthwest UniversityXi'anChina
| | - Jian‐Ni Liu
- Department of GeologyState Key Laboratory of Continental DynamicsEarly Life InstituteNorthwest UniversityXi'anChina
| | - Zhong‐Hu Li
- Shaanxi Key Laboratory for Animal ConservationKey Laboratory of Resource Biology and Biotechnology in Western ChinaMinistry of EducationCollege of Life SciencesNorthwest UniversityXi'anChina
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5
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Schmidt CA, Matera AG. tRNA introns: Presence, processing, and purpose. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1583. [DOI: 10.1002/wrna.1583] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/05/2019] [Accepted: 12/07/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Casey A. Schmidt
- Curriculum in Genetics and Molecular Biology Integrative Program for Biological and Genome Sciences, University of North Carolina Chapel Hill North Carolina
| | - A. Gregory Matera
- Curriculum in Genetics and Molecular Biology Integrative Program for Biological and Genome Sciences, University of North Carolina Chapel Hill North Carolina
- Department of Biology, Lineberger Comprehensive Cancer Center University of North Carolina Chapel Hill North Carolina
- Department of Genetics, Lineberger Comprehensive Cancer Center University of North Carolina Chapel Hill North Carolina
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6
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The Uroboros Theory of Life's Origin: 22-Nucleotide Theoretical Minimal RNA Rings Reflect Evolution of Genetic Code and tRNA-rRNA Translation Machineries. Acta Biotheor 2019; 67:273-297. [PMID: 31388859 DOI: 10.1007/s10441-019-09356-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 07/31/2019] [Indexed: 02/06/2023]
Abstract
Theoretical minimal RNA rings attempt to mimick life's primitive RNAs. At most 25 22-nucleotide-long RNA rings code once for each biotic amino acid, a start and a stop codon and form a stem-loop hairpin, resembling consensus tRNAs. We calculated, for each RNA ring's 22 potential splicing positions, similarities of predicted secondary structures with tRNA vs. rRNA secondary structures. Assuming rRNAs partly derived from tRNA accretions, we predict positive associations between relative secondary structure similarities with rRNAs over tRNAs and genetic code integration orders of RNA ring anticodon cognate amino acids. Analyses consider for each secondary structure all nucleotide triplets as potential anticodon. Anticodons for ancient, chemically inert cognate amino acids are most frequent in the 25 RNA rings. For RNA rings with primordial cognate amino acids according to tRNA-homology-derived anticodons, tRNA-homology and coding sequences coincide, these are separate for predicted cognate amino acids that presumably integrated late the genetic code. RNA ring secondary structure similarity with rRNA over tRNA secondary structures associates best with genetic code integration orders of anticodon cognate amino acids when assuming split anticodons (one and two nucleotides at the spliced RNA ring 5' and 3' extremities, respectively), and at predicted anticodon location in the spliced RNA ring's midst. Results confirm RNA ring homologies with tRNAs and CDs, ancestral status of tRNA half genes split at anticodons, the tRNA-rRNA axis of RNA evolution, and that single theoretical minimal RNA rings potentially produce near-complete proto-tRNA sets. Hence genetic code pre-existence determines 25 short circular gene- and tRNA-like RNAs. Accounting for each potential splicing position, each RNA ring potentially translates most amino acids, realistically mimicks evolution of the tRNA-rRNA translation machinery. These RNA rings 'of creation' remind the uroboros' (snake biting its tail) symbolism for creative regeneration.
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7
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Tosar JP, Gámbaro F, Darré L, Pantano S, Westhof E, Cayota A. Dimerization confers increased stability to nucleases in 5' halves from glycine and glutamic acid tRNAs. Nucleic Acids Res 2019; 46:9081-9093. [PMID: 29893896 PMCID: PMC6158491 DOI: 10.1093/nar/gky495] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/22/2018] [Indexed: 11/22/2022] Open
Abstract
We have previously shown that 5′ halves from tRNAGlyGCC and tRNAGluCUC are the most enriched small RNAs in the extracellular space of human cell lines, and especially in the non-vesicular fraction. Extracellular RNAs are believed to require protection by either encapsulation in vesicles or ribonucleoprotein complex formation. However, deproteinization of non-vesicular tRNA halves does not affect their retention in size-exclusion chromatography. Thus, we considered alternative explanations for their extracellular stability. In-silico analysis of the sequence of these tRNA-derived fragments showed that tRNAGly 5′ halves can form homodimers or heterodimers with tRNAGlu 5′ halves. This capacity is virtually unique to glycine tRNAs. By analyzing synthetic oligonucleotides by size exclusion chromatography, we provide evidence that dimerization is possible in vitro. tRNA halves with single point substitutions preventing dimerization are degraded faster both in controlled nuclease digestion assays and after transfection in cells, showing that dimerization can stabilize tRNA halves against the action of cellular nucleases. Finally, we give evidence supporting dimerization of endogenous tRNAGlyGCC 5′ halves inside cells. Considering recent reports have shown that 5′ tRNA halves from Ala and Cys can form tetramers, our results highlight RNA intermolecular structures as a new layer of complexity in the biology of tRNA-derived fragments.
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Affiliation(s)
- Juan Pablo Tosar
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo 11400, Uruguay
| | - Fabiana Gámbaro
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo 11400, Uruguay
| | - Leonardo Darré
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Group of Biomolecular Simulations, Institut Pasteur de Montevideo. Montevideo 11400, Uruguay
| | - Sergio Pantano
- Group of Biomolecular Simulations, Institut Pasteur de Montevideo. Montevideo 11400, Uruguay
| | - Eric Westhof
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, 15 rue René Descartes, 67084 Strasbourg, France
| | - Alfonso Cayota
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Department of Medicine, Faculty of Medicine, Universidad de la República, Montevideo 11600, Uruguay
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8
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Glycyl-tRNA synthetase from Nanoarchaeum equitans: The first crystal structure of archaeal GlyRS and analysis of its tRNA glycylation. Biochem Biophys Res Commun 2019; 511:228-233. [PMID: 30771900 DOI: 10.1016/j.bbrc.2019.01.142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 01/31/2019] [Indexed: 11/23/2022]
Abstract
This study reports the X-ray crystallographic structure of the glycyl-tRNA synthetase (GlyRS) of Nanoarchaeum equitans - a hyperthermophilic archaeal species. This is the first archaeal GlyRS crystal structure elucidated. The GlyRS comprises an N-terminal catalytic domain and a C-terminal anticodon-binding domain with a long β-sheet inserted between these domains. An unmodified transcript of the wild-type N. equitans tRNAGly was successfully glycylated using GlyRS. Substitution of the discriminator base A73 of tRNAGly with any other nucleotide caused a significant decrease in glycylation activity. Mutational analysis of the second base-pair C2G71 of the acceptor stem of tRNAGly elucidated the importance of the base-pair, especially G71, as an identity element for recognition by GlyRS. Glycylation assays using tRNAGly G71 substitution mutants and a GlyRS mutant where Arg223 is mutated to alanine strengthen the possibility that the carbonyl oxygen at position 6 of G71 would hydrogen-bond with the guanidine nitrogen of Arg223 in N. equitans GlyRS.
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9
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Hirata A. Recent Insights Into the Structure, Function, and Evolution of the RNA-Splicing Endonucleases. Front Genet 2019; 10:103. [PMID: 30809252 PMCID: PMC6379350 DOI: 10.3389/fgene.2019.00103] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/30/2019] [Indexed: 11/13/2022] Open
Abstract
RNA-splicing endonuclease (EndA) cleaves out introns from archaeal and eukaryotic precursor (pre)-tRNA and is essential for tRNA maturation. In archaeal EndA, the molecular mechanisms underlying complex assembly, substrate recognition, and catalysis have been well understood. Recently, certain studies have reported novel findings including the identification of new subunit types in archaeal EndA structures, providing insights into the mechanism underlying broad substrate specificity. Further, metagenomics analyses have enabled the acquisition of numerous DNA sequences of EndAs and intron-containing pre-tRNAs from various species, providing information regarding the co-evolution of substrate specificity of archaeal EndAs and tRNA genetic diversity, and the evolutionary pathway of archaeal and eukaryotic EndAs. Although the complex structure of the heterothermic form of eukaryotic EndAs is unknown, previous reports regarding their functions indicated that mutations in human EndA cause neurological disorders including pontocerebellar hypoplasia and progressive microcephaly, and yeast EndA significantly cleaves mitochondria-localized mRNA encoding cytochrome b mRNA processing 1 (Cpb1) for mRNA maturation. This mini-review summarizes the aforementioned results, discusses their implications, and offers my personal opinion regarding future directions for the analysis of the structure and function of EndAs.
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Affiliation(s)
- Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
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10
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Clouet-d'Orval B, Batista M, Bouvier M, Quentin Y, Fichant G, Marchfelder A, Maier LK. Insights into RNA-processing pathways and associated RNA-degrading enzymes in Archaea. FEMS Microbiol Rev 2018; 42:579-613. [PMID: 29684129 DOI: 10.1093/femsre/fuy016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022] Open
Abstract
RNA-processing pathways are at the centre of regulation of gene expression. All RNA transcripts undergo multiple maturation steps in addition to covalent chemical modifications to become functional in the cell. This includes destroying unnecessary or defective cellular RNAs. In Archaea, information on mechanisms by which RNA species reach their mature forms and associated RNA-modifying enzymes are still fragmentary. To date, most archaeal actors and pathways have been proposed in light of information gathered from Bacteria and Eukarya. In this context, this review provides a state of the art overview of archaeal endoribonucleases and exoribonucleases that cleave and trim RNA species and also of the key small archaeal proteins that bind RNAs. Furthermore, synthetic up-to-date views of processing and biogenesis pathways of archaeal transfer and ribosomal RNAs as well as of maturation of stable small non-coding RNAs such as CRISPR RNAs, small C/D and H/ACA box guide RNAs, and other emerging classes of small RNAs are described. Finally, prospective post-transcriptional mechanisms to control archaeal messenger RNA quality and quantity are discussed.
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Affiliation(s)
- Béatrice Clouet-d'Orval
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Manon Batista
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Marie Bouvier
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Yves Quentin
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Gwennaele Fichant
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
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Abstract
Advances in genome-wide sequence technologies allow for detailed insights into the complexity of RNA landscapes of organisms from all three domains of life. Recent analyses of archaeal transcriptomes identified interaction and regulation networks of noncoding RNAs in this understudied domain. Here, we review current knowledge of small, noncoding RNAs with important functions for the archaeal lifestyle, which often requires adaptation to extreme environments. One focus is RNA metabolism at elevated temperatures in hyperthermophilic archaea, which reveals elevated amounts of RNA-guided RNA modification and virus defense strategies. Genome rearrangement events result in unique fragmentation patterns of noncoding RNA genes that require elaborate maturation pathways to yield functional transcripts. RNA-binding proteins, e.g., L7Ae and LSm, are important for many posttranscriptional control functions of RNA molecules in archaeal cells. We also discuss recent insights into the regulatory potential of their noncoding RNA partners.
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Affiliation(s)
- José Vicente Gomes-Filho
- Prokaryotic Small RNA Biology Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany;, ,
| | - Michael Daume
- Prokaryotic Small RNA Biology Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany;, ,
| | - Lennart Randau
- Prokaryotic Small RNA Biology Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany;, ,
- LOEWE Center for Synthetic Microbiology (Synmikro), 35032 Marburg, Germany
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12
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Structural Basis for tRNA Mimicry by a Bacterial Y RNA. Structure 2018; 26:1635-1644.e3. [PMID: 30318468 DOI: 10.1016/j.str.2018.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/03/2018] [Accepted: 09/10/2018] [Indexed: 12/29/2022]
Abstract
Noncoding Y RNAs are present in both animal cells and many bacteria. In all species examined, Y RNAs tether the Ro60 protein to an effector protein to perform various cellular functions. Recently, a new Y RNA subfamily was identified in bacteria. Bioinformatic analyses of these YrlA (Y RNA-like A) RNAs predict that the effector-binding domain resembles tRNA. We present the structure of this domain, the overall folding of which is strikingly similar to canonical tRNAs. The tertiary interactions that are responsible for stabilizing tRNA are present in YrlA, making it a close tRNA mimic. However, YrlA lacks a free CCA end and contains a kink in the stem corresponding to the anticodon stem. Since nucleotides in the D and T stems are conserved among YrlAs, they may be an interaction site for an unknown factor. Our experiments identify YrlA RNAs as a new class of tRNA mimics.
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13
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Kaneta A, Fujishima K, Morikazu W, Hori H, Hirata A. The RNA-splicing endonuclease from the euryarchaeaon Methanopyrus kandleri is a heterotetramer with constrained substrate specificity. Nucleic Acids Res 2018; 46:1958-1972. [PMID: 29346615 PMCID: PMC5829648 DOI: 10.1093/nar/gky003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/25/2017] [Accepted: 01/03/2018] [Indexed: 11/14/2022] Open
Abstract
Four different types (α4, α'2, (αβ)2 and ϵ2) of RNA-splicing endonucleases (EndAs) for RNA processing are known to exist in the Archaea. Only the (αβ)2 and ϵ2 types can cleave non-canonical introns in precursor (pre)-tRNA. Both enzyme types possess an insert associated with a specific loop, allowing broad substrate specificity in the catalytic α units. Here, the hyperthermophilic euryarchaeon Methanopyrus kandleri (MKA) was predicted to harbor an (αβ)2-type EndA lacking the specific loop. To characterize MKA EndA enzymatic activity, we constructed a fusion protein derived from MKA α and β subunits (fMKA EndA). In vitro assessment demonstrated complete removal of the canonical bulge-helix-bulge (BHB) intron structure from MKA pre-tRNAAsn. However, removal of the relaxed BHB structure in MKA pre-tRNAGlu was inefficient compared to crenarchaeal (αβ)2 EndA, and the ability to process the relaxed intron within mini-helix RNA was not detected. fMKA EndA X-ray structure revealed a shape similar to that of other EndA types, with no specific loop. Mapping of EndA types and their specific loops and the tRNA gene diversity among various Archaea suggest that MKA EndA is evolutionarily related to other (αβ)2-type EndAs found in the Thaumarchaeota, Crenarchaeota and Aigarchaeota but uniquely represents constrained substrate specificity.
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Affiliation(s)
- Ayano Kaneta
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - Wataru Morikazu
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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14
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Mohanta TK, Syed AS, Ameen F, Bae H. Novel Genomic and Evolutionary Perspective of Cyanobacterial tRNAs. Front Genet 2017; 8:200. [PMID: 29321793 PMCID: PMC5733544 DOI: 10.3389/fgene.2017.00200] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 11/21/2017] [Indexed: 11/30/2022] Open
Abstract
Transfer RNA (tRNA) plays a central role in protein synthesis and acts as an adaptor molecule between an mRNA and an amino acid. A tRNA has an L-shaped clover leaf-like structure and contains an acceptor arm, D-arm, D-loop, anti-codon arm, anti-codon loop, variable loop, Ψ-arm and Ψ-loop. All of these arms and loops are important in protein translation. Here, we aimed to delineate the genomic architecture of these arms and loops in cyanobacterial tRNA. Studies from tRNA sequences from 61 cyanobacterial species showed that, except for few tRNAs (tRNAAsn, tRNALeu, tRNAGln, and tRNAMet), all contained a G nucleotide at the 1st position in the acceptor arm. tRNALeu and tRNAMet did not contain any conserved nucleotides at the 1st position whereas tRNAAsn and tRNAGln contained a conserved U1 nucleotide. In several tRNA families, the variable region also contained conserved nucleotides. Except for tRNAMet and tRNAGlu, all other tRNAs contained a conserved A nucleotide at the 1st position in the D-loop. The Ψ-loop contained a conserved U1-U2-C3-x-A5-x-U7 sequence, except for tRNAGly, tRNAAla, tRNAVal, tRNAPhe, tRNAThr, and tRNAGln in which the U7 nucleotide was not conserved. However, in tRNAAsp, the U7 nucleotide was substituted with a C7 nucleotide. Additionally, tRNAArg, tRNAGly, and tRNALys of cyanobacteria contained a group I intron within the anti-codon loop region. Maximum composite likelihood study on the transition/transversion of cyanobacterial tRNA revealed that the rate of transition was higher than the rate of transversion. An evolutionary tree was constructed to understand the evolution of cyanobacterial tRNA and analyses revealed that cyanobacterial tRNA may have evolved polyphyletically with high rate of gene loss.
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Affiliation(s)
- Tapan K Mohanta
- School of Biotechnology, Yeungnam University, Gyeongsan, South Korea
| | - Asad S Syed
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Fuad Ameen
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Hanhong Bae
- School of Biotechnology, Yeungnam University, Gyeongsan, South Korea
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15
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Szafranski P. Intercompartmental Piecewise Gene Transfer. Genes (Basel) 2017; 8:genes8100260. [PMID: 28984842 PMCID: PMC5664110 DOI: 10.3390/genes8100260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 11/16/2022] Open
Abstract
Gene relocation from the residual genomes of organelles to the nuclear genome still continues, although as a scaled down evolutionary phenomenon, limited in occurrence mostly to protists (sensu lato) and land plants. During this process, the structural integrity of transferred genes is usually preserved. However, the relocation of mitochondrial genes that code for respiratory chain and ribosomal proteins is sometimes associated with their fragmentation into two complementary genes. Herein, this review compiles cases of piecewise gene transfer from the mitochondria to the nucleus, and discusses hypothesized mechanistic links between the fission and relocation of those genes.
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Affiliation(s)
- Przemyslaw Szafranski
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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16
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Suzuki H, Kaneko A, Yamamoto T, Nambo M, Hirasawa I, Umehara T, Yoshida H, Park SY, Tamura K. Binding Properties of Split tRNA to the C-terminal Domain of Methionyl-tRNA Synthetase of Nanoarchaeum equitans. J Mol Evol 2017; 84:267-278. [PMID: 28589220 DOI: 10.1007/s00239-017-9796-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/30/2017] [Indexed: 11/28/2022]
Abstract
The C-terminal domain of methionyl-tRNA synthetase (MetRS-C) from Nanoarchaeum equitans is homologous to a tRNA-binding protein consisting of 111 amino acids (Trbp111) from Aquifex aeolicus. The crystal structure of MetRS-C showed that it existed as a homodimer, and that each monomer possessed an oligonucleotide/oligosaccharide-binding fold (OB-fold). Analysis using a quartz crystal microbalance indicated that MetRS-C freshly isolated from N. equitans was bound to tRNA. However, binding of the split 3'-half tRNA species was stronger than that of the 5'-half species. The T-loop and the 3'-end regions of the split 3'-half tRNA were found to be responsible for the binding. The minimum structure for binding to MetRS-C might be a minihelix-like stem-loop with single-stranded 3'-terminus. After successive duplications of such a small hairpin structure with the assistance of a Trbp-like structure, the interaction of the T-loop region of the 3'-half with a Trbp-like structure could have been evolutionarily replaced by RNA-RNA interactions, along with many combinational tertiary interactions, to form the modern tRNA structure.
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Affiliation(s)
- Hidemichi Suzuki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Akihiro Kaneko
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Taro Yamamoto
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Mahoko Nambo
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Ito Hirasawa
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Takuya Umehara
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Hisashi Yoshida
- Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Sam-Yong Park
- Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Koji Tamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan. .,Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
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17
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Lei Q, Li C, Zuo Z, Huang C, Cheng H, Zhou R. Evolutionary Insights into RNA trans-Splicing in Vertebrates. Genome Biol Evol 2016; 8:562-77. [PMID: 26966239 PMCID: PMC4824033 DOI: 10.1093/gbe/evw025] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pre-RNA splicing is an essential step in generating mature mRNA. RNA trans-splicing combines two separate pre-mRNA molecules to form a chimeric non-co-linear RNA, which may exert a function distinct from its original molecules. Trans-spliced RNAs may encode novel proteins or serve as noncoding or regulatory RNAs. These novel RNAs not only increase the complexity of the proteome but also provide new regulatory mechanisms for gene expression. An increasing amount of evidence indicates that trans-splicing occurs frequently in both physiological and pathological processes. In addition, mRNA reprogramming based on trans-splicing has been successfully applied in RNA-based therapies for human genetic diseases. Nevertheless, clarifying the extent and evolution of trans-splicing in vertebrates and developing detection methods for trans-splicing remain challenging. In this review, we summarize previous research, highlight recent advances in trans-splicing, and discuss possible splicing mechanisms and functions from an evolutionary viewpoint.
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Affiliation(s)
- Quan Lei
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Cong Li
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Zhixiang Zuo
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Chunhua Huang
- Department of Cell Biology, College of Life Sciences, Wuhan University, P.R. China
| | - Hanhua Cheng
- Department of Cell Biology, College of Life Sciences, Wuhan University, P.R. China
| | - Rongjia Zhou
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
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18
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Tran TTT, Belahbib H, Bonnefoy V, Talla E. A Comprehensive tRNA Genomic Survey Unravels the Evolutionary History of tRNA Arrays in Prokaryotes. Genome Biol Evol 2015; 8:282-95. [PMID: 26710853 PMCID: PMC4758250 DOI: 10.1093/gbe/evv254] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2015] [Indexed: 01/12/2023] Open
Abstract
Considering the importance of tRNAs in the translation machinery, scant attention has been paid to tRNA array units defined as genomic regions containing at least 20 tRNA genes with a minimal tRNA gene density of two tRNA genes per kilobase. Our analysis of Acidithiobacillus ferrivorans CF27 and Acidithiobacillus ferrooxidans ATCC 23270(T) genomes showed that both display a tRNA array unit with syntenic conservation which mainly contributed to the tRNA gene redundancy in these two organisms. Our investigations into the occurrence and distribution of tRNA array units revealed that 1) this tRNA organization is limited to few phyla and mainly found in Gram-positive bacteria; and 2) the presence of tRNA arrays favors the redundancy of tRNA genes, in particular those encoding the core tRNA isoacceptors. Finally, comparative array organization revealed that tRNA arrays were acquired through horizontal gene transfer (from Firmicutes or unknown donor), before being subjected to tRNA rearrangements, deletions, and duplications. In Bacilli, the most parsimonious evolutionary history involved two common ancestors and the acquisition of their arrays arose late in evolution, in the genera branches. Functional roles of the array units in organism lifestyle, selective genetic advantage and translation efficiency, as well as the evolutionary advantages of organisms harboring them were proposed. Our study offers new insight into the structural organization and evolution of tRNA arrays in prokaryotic organisms.
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Affiliation(s)
- Tam T T Tran
- Aix Marseille Université, CNRS, IGS, UMR 7256, IMM, France
| | | | | | - Emmanuel Talla
- Aix Marseille Université, CNRS, IGS, UMR 7256, IMM, France
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19
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DiChiacchio L, Sloma MF, Mathews DH. AccessFold: predicting RNA-RNA interactions with consideration for competing self-structure. Bioinformatics 2015; 32:1033-9. [PMID: 26589271 DOI: 10.1093/bioinformatics/btv682] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 11/15/2015] [Indexed: 01/09/2023] Open
Abstract
MOTIVATION There are numerous examples of RNA-RNA complexes, including microRNA-mRNA and small RNA-mRNA duplexes for regulation of translation, guide RNA interactions with target RNA for post-transcriptional modification and small nuclear RNA duplexes for splicing. Predicting the base pairs formed between two interacting sequences remains difficult, at least in part because of the competition between unimolecular and bimolecular structure. RESULTS Two algorithms were developed for improved prediction of bimolecular RNA structure that consider the competition between self-structure and bimolecular structure. These algorithms utilize two novel approaches to evaluate accessibility: free energy density minimization and pseudo-energy minimization. Free energy density minimization minimizes the folding free energy change per nucleotide involved in an intermolecular secondary structure. Pseudo-energy minimization (called AccessFold) minimizes the sum of free energy change and a pseudo-free energy penalty for bimolecular pairing of nucleotides that are unlikely to be accessible for bimolecular structure. The pseudo-free energy, derived from unimolecular pairing probabilities, is applied per nucleotide in bimolecular pairs, and this approach is able to predict binding sites that are split by unimolecular structures. A benchmark set of 17 bimolecular RNA structures was assembled to assess structure prediction. Pseudo-energy minimization provides a statistically significant improvement in sensitivity over the method that was found in a benchmark to be the most accurate previously available method, with an improvement from 36.8% to 57.8% in mean sensitivity for base pair prediction. AVAILABILITY AND IMPLEMENTATION Pseudo-energy minimization is available for download as AccessFold, under an open-source license and as part of the RNAstructure package, at: http://rna.urmc.rochester.edu/RNAstructure.html CONTACT david_mathews@urmc.rochester.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Laura DiChiacchio
- Department of Biochemistry and Biophysics and Center for RNA Biology and
| | - Michael F Sloma
- Department of Biochemistry and Biophysics and Center for RNA Biology and
| | - David H Mathews
- Department of Biochemistry and Biophysics and Center for RNA Biology and Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, NY 14642, USA
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20
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Hamashima K, Kanai A. Alternative genetic code for amino acids and transfer RNA revisited. Biomol Concepts 2015; 4:309-18. [PMID: 25436582 DOI: 10.1515/bmc-2013-0002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 02/20/2013] [Indexed: 11/15/2022] Open
Abstract
The genetic code is highly conserved among all organisms and its evolution is thought to be strictly limited. However, an increasing number of studies have reported non-standard codes in prokaryotic and eukaryotic genomes. Most of these deviations from the standard code are attributable to tRNA changes relating to, for example, codon/anticodon base pairing and tRNA/aminoacyl-tRNA synthetase recognition. In this review, we focus on tRNA, a key molecule in the translation of the genetic code, and summarize the most recently published information on the evolutionary divergence of the tRNAs. Surprisingly, although higher eukaryotes, such as the nematode (worm), utilize the standard genetic code, newly identified nematode-specific tRNAs (nev-tRNAs) translate nucleotides in a manner that transgresses the code. Furthermore, a variety of additional functions of tRNAs, beyond their translation of the genetic code, have emerged rapidly. We also review these intriguing new aspects of tRNA, which have potential impacts on translational control, RNA silencing, antibiotic resistance, RNA biosynthesis, and transcriptional regulation.
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21
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Hirose Y, Ikeda KT, Noro E, Hiraoka K, Tomita M, Kanai A. Precise mapping and dynamics of tRNA-derived fragments (tRFs) in the development of Triops cancriformis (tadpole shrimp). BMC Genet 2015; 16:83. [PMID: 26168920 PMCID: PMC4501094 DOI: 10.1186/s12863-015-0245-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/30/2015] [Indexed: 12/03/2022] Open
Abstract
Background In a deep sequencing analysis of small RNAs prepared from a living fossil, the tadpole shrimp Triops cancriformis, a 32-nt small RNA was specifically detected in the adult stage. A nucleotide sequence comparison between the 32-nt small RNA and predicted tRNA sequences in the draft nuclear genomic DNA showed that the small RNA was derived from tRNAGly(GCC). To determine the overall features of the tRNA-derived fragments (tRFs) of T. cancriformis, the small RNA sequences in each of the six developmental stages (egg, 1st − 4th instar larvae, and adult) were compared with the mitochondrial and nuclear tRNA sequences. Results We found that the tRFs were derived from mitochondrial and nuclear tRNAs corresponding to 16 and 39 anticodons, respectively. The total read number of nuclear tRFs was approximately 400 times larger than the number of mitochondrial tRFs. Interestingly, the main regions in each parental tRNA from which these tRFs were derived differed, depending on the parental anticodon. Mitochondrial tRFSer(GCU)s were abundantly produced from the 5’ half regions of the parental tRNA, whereas mitochondrial tRFVal(UAC)s were mainly produced from the 3’ end regions. Highly abundant nuclear tRFs, tRFGly(GCC)s, tRFGly(CCC)s, tRFGlu(CUC)s, and tRFLys(CUU)s were derived from the 5’ half regions of the parental tRNAs. Further analysis of the tRF read counts in the individual developmental stages suggested that the expression of mitochondrial and nuclear tRFs differed during the six stages. Based on these data, we precisely summarized the positions of the tRFs in their parental tRNAs and their expression changes during development. Conclusions Our results reveal the entire dynamics of the tRFs from both the nuclear and mitochondrial genomes of T. cancriformis and indicate that the majority of tRFs in the cell are derived from nuclear tRNAs. This study provides the first examples of developmentally expressed mitochondrial tRFs. Electronic supplementary material The online version of this article (doi:10.1186/s12863-015-0245-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuka Hirose
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan. .,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-8520, Japan.
| | - Kahori T Ikeda
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan. .,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-8520, Japan.
| | - Emiko Noro
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan.
| | - Kiriko Hiraoka
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan.
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan. .,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-8520, Japan. .,Faculty of Environment and Information Studies, Keio University, Fujisawa, 252-0882, Japan.
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan. .,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-8520, Japan. .,Faculty of Environment and Information Studies, Keio University, Fujisawa, 252-0882, Japan.
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22
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Smith AM, Abu-Shumays R, Akeson M, Bernick DL. Capture, Unfolding, and Detection of Individual tRNA Molecules Using a Nanopore Device. Front Bioeng Biotechnol 2015; 3:91. [PMID: 26157798 PMCID: PMC4478443 DOI: 10.3389/fbioe.2015.00091] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 06/10/2015] [Indexed: 11/13/2022] Open
Abstract
Transfer RNAs (tRNA) are the most common RNA molecules in cells and have critical roles as both translators of the genetic code and regulators of protein synthesis. As such, numerous methods have focused on studying tRNA abundance and regulation, with the most widely used methods being RNA-seq and microarrays. Though revolutionary to transcriptomics, these assays are limited by an inability to encode tRNA modifications in the requisite cDNA. These modifications are abundant in tRNA and critical to their function. Here, we describe proof-of-concept experiments where individual tRNA molecules are examined as linear strands using a biological nanopore. This method utilizes an enzymatically ligated synthetic DNA adapter to concentrate tRNA at the lipid bilayer of the nanopore device and efficiently denature individual tRNA molecules, as they are pulled through the α-hemolysin (α-HL) nanopore. Additionally, the DNA adapter provides a loading site for ϕ29 DNA polymerase (ϕ29 DNAP), which acts as a brake on the translocating tRNA. This increases the dwell time of adapted tRNA in the nanopore, allowing us to identify the region of the nanopore signal that is produced by the translocating tRNA itself. Using adapter-modified Escherichia coli tRNAfMet and tRNALys, we show that the nanopore signal during controlled translocation is dependent on the identity of the tRNA. This confirms that adapter-modified tRNA can translocate end-to-end through nanopores and provide the foundation for future work in direct sequencing of individual transfer RNA with a nanopore-based device.
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Affiliation(s)
- Andrew M Smith
- Department of Chemistry and Biochemistry, University of California Santa Cruz , Santa Cruz, CA , USA ; Department of Biomolecular Engineering, University of California Santa Cruz , Santa Cruz, CA , USA
| | - Robin Abu-Shumays
- Department of Biomolecular Engineering, University of California Santa Cruz , Santa Cruz, CA , USA
| | - Mark Akeson
- Department of Biomolecular Engineering, University of California Santa Cruz , Santa Cruz, CA , USA ; Genomics Institute, University of California Santa Cruz , Santa Cruz, CA , USA
| | - David L Bernick
- Department of Biomolecular Engineering, University of California Santa Cruz , Santa Cruz, CA , USA
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23
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Pyrobaculum yellowstonensis Strain WP30 Respires on Elemental Sulfur and/or Arsenate in Circumneutral Sulfidic Geothermal Sediments of Yellowstone National Park. Appl Environ Microbiol 2015; 81:5907-16. [PMID: 26092468 DOI: 10.1128/aem.01095-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/16/2015] [Indexed: 11/20/2022] Open
Abstract
Thermoproteales (phylum Crenarchaeota) populations are abundant in high-temperature (>70°C) environments of Yellowstone National Park (YNP) and are important in mediating the biogeochemical cycles of sulfur, arsenic, and carbon. The objectives of this study were to determine the specific physiological attributes of the isolate Pyrobaculum yellowstonensis strain WP30, which was obtained from an elemental sulfur sediment (Joseph's Coat Hot Spring [JCHS], 80°C, pH 6.1, 135 μM As) and relate this organism to geochemical processes occurring in situ. Strain WP30 is a chemoorganoheterotroph and requires elemental sulfur and/or arsenate as an electron acceptor. Growth in the presence of elemental sulfur and arsenate resulted in the formation of thioarsenates and polysulfides. The complete genome of this organism was sequenced (1.99 Mb, 58% G+C content), revealing numerous metabolic pathways for the degradation of carbohydrates, amino acids, and lipids. Multiple dimethyl sulfoxide-molybdopterin (DMSO-MPT) oxidoreductase genes, which are implicated in the reduction of sulfur and arsenic, were identified. Pathways for the de novo synthesis of nearly all required cofactors and metabolites were identified. The comparative genomics of P. yellowstonensis and the assembled metagenome sequence from JCHS showed that this organism is highly related (∼95% average nucleotide sequence identity) to in situ populations. The physiological attributes and metabolic capabilities of P. yellowstonensis provide an important foundation for developing an understanding of the distribution and function of these populations in YNP.
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Abstract
Profiling the RNA production in hyperthermophilic archaea revealed an abundance of small RNA-guided processes near the upper temperature limit of life. Archaea utilize the base-pairing ability of RNA guide sequences to target ribosomal RNAs, transfer RNAs, messenger RNAs, and viral genomes. Cellular processes that are guided by small RNAs include the modification of RNA molecules, trans-splicing, gene regulation, and RNA and DNA degradation. Here, a brief overview of our knowledge on small guide RNA genes in archaeal genomes is provided and examples of their putative roles in genome evolution are described.
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MESH Headings
- Archaea/genetics
- Base Sequence
- Evolution, Molecular
- Gene Expression Regulation, Archaeal
- Genome, Archaeal/genetics
- Hot Temperature
- Models, Genetic
- RNA, Archaeal/genetics
- RNA, Archaeal/metabolism
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
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Affiliation(s)
- Lennart Randau
- Prokaryotic Small RNA Biology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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25
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Gardner PP, Fasold M, Burge SW, Ninova M, Hertel J, Kehr S, Steeves TE, Griffiths-Jones S, Stadler PF. Conservation and losses of non-coding RNAs in avian genomes. PLoS One 2015; 10:e0121797. [PMID: 25822729 PMCID: PMC4378963 DOI: 10.1371/journal.pone.0121797] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/03/2015] [Indexed: 11/21/2022] Open
Abstract
Here we present the results of a large-scale bioinformatics annotation of non-coding RNA loci in 48 avian genomes. Our approach uses probabilistic models of hand-curated families from the Rfam database to infer conserved RNA families within each avian genome. We supplement these annotations with predictions from the tRNA annotation tool, tRNAscan-SE and microRNAs from miRBase. We identify 34 lncRNA-associated loci that are conserved between birds and mammals and validate 12 of these in chicken. We report several intriguing cases where a reported mammalian lncRNA, but not its function, is conserved. We also demonstrate extensive conservation of classical ncRNAs (e.g., tRNAs) and more recently discovered ncRNAs (e.g., snoRNAs and miRNAs) in birds. Furthermore, we describe numerous “losses” of several RNA families, and attribute these to either genuine loss, divergence or missing data. In particular, we show that many of these losses are due to the challenges associated with assembling avian microchromosomes. These combined results illustrate the utility of applying homology-based methods for annotating novel vertebrate genomes.
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Affiliation(s)
- Paul P. Gardner
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
- * E-mail:
| | - Mario Fasold
- Bioinformatics Group, Department of Computer Science; and Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany
- ecSeq Bioinformatics, Brandvorwerkstr.43, D-04275 Leipzig, Germany
| | - Sarah W. Burge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge, CB10 1SD, UK
| | - Maria Ninova
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Jana Hertel
- Bioinformatics Group, Department of Computer Science; and Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany
| | - Stephanie Kehr
- Bioinformatics Group, Department of Computer Science; and Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany
| | - Tammy E. Steeves
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Sam Griffiths-Jones
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Peter F. Stadler
- Bioinformatics Group, Department of Computer Science; and Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, D-04103 Leipzig, Germany
- Fraunhofer Institute for Cell Therapy and Immunology, Perlickstrasse 1, D-04103 Leipzig, Germany
- Department of Theoretical Chemistry of the University of Vienna, Währingerstrasse 17, A-1090 Vienna, Austria
- Center for RNA in Technology and Health, Univ. Copenhagen, Grønnegårdsvej 3, Frederiksberg C, Denmark
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe NM 87501, USA
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Germany
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26
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Disrupted tRNA Genes and tRNA Fragments: A Perspective on tRNA Gene Evolution. Life (Basel) 2015; 5:321-31. [PMID: 25629271 PMCID: PMC4390854 DOI: 10.3390/life5010321] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 01/14/2015] [Accepted: 01/21/2015] [Indexed: 01/17/2023] Open
Abstract
Transfer RNAs (tRNAs) are small non-coding RNAs with lengths of approximately 70-100 nt. They are directly involved in protein synthesis by carrying amino acids to the ribosome. In this sense, tRNAs are key molecules that connect the RNA world and the protein world. Thus, study of the evolution of tRNA molecules may reveal the processes that led to the establishment of the central dogma: genetic information flows from DNA to RNA to protein. Thanks to the development of DNA sequencers in this century, we have determined a huge number of nucleotide sequences from complete genomes as well as from transcriptomes in many species. Recent analyses of these large data sets have shown that particular tRNA genes, especially in Archaea, are disrupted in unique ways: some tRNA genes contain multiple introns and some are split genes. Even tRNA molecules themselves are fragmented post-transcriptionally in many species. These fragmented small RNAs are known as tRNA-derived fragments (tRFs). In this review, I summarize the progress of research into the disrupted tRNA genes and the tRFs, and propose a possible model for the molecular evolution of tRNAs based on the concept of the combination of fragmented tRNA halves.
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Experimental confirmation of a whole set of tRNA molecules in two archaeal species. Int J Mol Sci 2015; 16:2187-203. [PMID: 25608653 PMCID: PMC4307357 DOI: 10.3390/ijms16012187] [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: 11/26/2014] [Accepted: 01/14/2015] [Indexed: 11/17/2022] Open
Abstract
Based on the genomic sequences for most archaeal species, only one tRNA gene (isodecoder) is predicted for each triplet codon. This observation promotes analysis of a whole set of tRNA molecules and actual splicing patterns of interrupted tRNA in one organism. The entire genomic sequences of two Creanarchaeota, Aeropyrum pernix and Sulfolobus tokodaii, were determined approximately 15 years ago. In these genome datasets, 47 and 46 tRNA genes were detected, respectively. Among them, 14 and 24 genes, respectively, were predicted to be interrupted tRNA genes. To confirm the actual transcription of these predicted tRNA genes and identify the actual splicing patterns of the predicted interrupted tRNA molecules, RNA samples were prepared from each archaeal species and used to synthesize cDNA molecules with tRNA sequence-specific primers. Comparison of the nucleotide sequences of cDNA clones representing unspliced and spliced forms of interrupted tRNA molecules indicated that some introns were located at positions other than one base 3' from anticodon region and that bulge-helix-bulge structures were detected around the actual splicing sites in each interrupted tRNA molecule. Whole-set analyses of tRNA molecules revealed that the archaeal tRNA splicing mechanism may be essential for efficient splicing of all tRNAs produced from interrupted tRNA genes in these archaea.
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Yoshihisa T. Handling tRNA introns, archaeal way and eukaryotic way. Front Genet 2014; 5:213. [PMID: 25071838 PMCID: PMC4090602 DOI: 10.3389/fgene.2014.00213] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 06/20/2014] [Indexed: 11/25/2022] Open
Abstract
Introns are found in various tRNA genes in all the three kingdoms of life. Especially, archaeal and eukaryotic genomes are good sources of tRNA introns that are removed by proteinaceous splicing machinery. Most intron-containing tRNA genes both in archaea and eukaryotes possess an intron at a so-called canonical position, one nucleotide 3′ to their anticodon, while recent bioinformatics have revealed unusual types of tRNA introns and their derivatives especially in archaeal genomes. Gain and loss of tRNA introns during various stages of evolution are obvious both in archaea and eukaryotes from analyses of comparative genomics. The splicing of tRNA molecules has been studied extensively from biochemical and cell biological points of view, and such analyses of eukaryotic systems provided interesting findings in the past years. Here, I summarize recent progresses in the analyses of tRNA introns and the splicing process, and try to clarify new and old questions to be solved in the next stages.
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Affiliation(s)
- Tohru Yoshihisa
- Graduate School of Life Science, University of Hyogo Ako-gun, Hyogo, Japan
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29
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Fujishima K, Kanai A. tRNA gene diversity in the three domains of life. Front Genet 2014; 5:142. [PMID: 24904642 PMCID: PMC4033280 DOI: 10.3389/fgene.2014.00142] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 04/28/2014] [Indexed: 11/29/2022] Open
Abstract
Transfer RNA (tRNA) is widely known for its key role in decoding mRNA into protein. Despite their necessity and relatively short nucleotide sequences, a large diversity of gene structures and RNA secondary structures of pre-tRNAs and mature tRNAs have recently been discovered in the three domains of life. Growing evidences of disrupted tRNA genes in the genomes of Archaea reveals unique gene structures such as, intron-containing tRNA, split tRNA, and permuted tRNA. Coding sequence for these tRNAs are either separated with introns, fragmented, or permuted at the genome level. Although evolutionary scenario behind the tRNA gene disruption is still unclear, diversity of tRNA structure seems to be co-evolved with their processing enzyme, so-called RNA splicing endonuclease. Metazoan mitochondrial tRNAs (mtRNAs) are known for their unique lack of either one or two arms from the typical tRNA cloverleaf structure, while still maintaining functionality. Recently identified nematode-specific V-arm containing tRNAs (nev-tRNAs) possess long variable arms that are specific to eukaryotic class II tRNASer and tRNALeu but also decode class I tRNA codons. Moreover, many tRNA-like sequences have been found in the genomes of different organisms and viruses. Thus, this review is aimed to cover the latest knowledge on tRNA gene diversity and further recapitulate the evolutionary and biological aspects that caused such uniqueness.
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Affiliation(s)
- Kosuke Fujishima
- NASA Ames Research Center Moffett Field, CA, USA ; Institute for Advanced Biosciences, Keio University Tsuruoka, Japan
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University Tsuruoka, Japan
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Di Giulio M. The split genes of Nanoarchaeum equitans have not originated in its lineage and have been merged in another Nanoarchaeota: A reply to Podar et al. J Theor Biol 2014; 349:167-9. [DOI: 10.1016/j.jtbi.2014.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 01/22/2014] [Accepted: 02/11/2014] [Indexed: 01/28/2023]
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31
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Soma A. Circularly permuted tRNA genes: their expression and implications for their physiological relevance and development. Front Genet 2014; 5:63. [PMID: 24744771 PMCID: PMC3978253 DOI: 10.3389/fgene.2014.00063] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/12/2014] [Indexed: 12/02/2022] Open
Abstract
A number of genome analyses and searches using programs that focus on the RNA-specific bulge-helix-bulge (BHB) motif have uncovered a wide variety of disrupted tRNA genes. The results of these analyses have shown that genetic information encoding functional RNAs is described in the genome cryptically and is retrieved using various strategies. One such strategy is represented by circularly permuted tRNA genes, in which the sequences encoding the 5′-half and 3′-half of the specific tRNA are separated and inverted on the genome. Biochemical analyses have defined a processing pathway in which the termini of tRNA precursors (pre-tRNAs) are ligated to form a characteristic circular RNA intermediate, which is then cleaved at the acceptor-stem to generate the typical cloverleaf structure with functional termini. The sequences adjacent to the processing site located between the 3′-half and the 5′-half of pre-tRNAs potentially form a BHB motif, which is the dominant recognition site for the tRNA-intron splicing endonuclease, suggesting that circularization of pre-tRNAs depends on the splicing machinery. Some permuted tRNAs contain a BHB-mediated intron in their 5′- or 3′-half, meaning that removal of an intron, as well as swapping of the 5′- and 3′-halves, are required during maturation of their pre-tRNAs. To date, 34 permuted tRNA genes have been identified from six species of unicellular algae and one archaeon. Although their physiological significance and mechanism of development remain unclear, the splicing system of BHB motifs seems to have played a key role in the formation of permuted tRNA genes. In this review, current knowledge of circularly permuted tRNA genes is presented and some unanswered questions regarding these species are discussed.
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Affiliation(s)
- Akiko Soma
- Graduate School of Horticulture, Chiba University Matsudo, Japan
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32
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Soma A, Sugahara J, Onodera A, Yachie N, Kanai A, Watanabe S, Yoshikawa H, Ohnuma M, Kuroiwa H, Kuroiwa T, Sekine Y. Identification of highly-disrupted tRNA genes in nuclear genome of the red alga, Cyanidioschyzon merolae 10D. Sci Rep 2014; 3:2321. [PMID: 23900518 PMCID: PMC3728597 DOI: 10.1038/srep02321] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 07/10/2013] [Indexed: 12/03/2022] Open
Abstract
The limited locations of tRNA introns are crucial for eukaryal tRNA-splicing endonuclease recognition. However, our analysis of the nuclear genome of an early-diverged red alga, Cyanidioschyzon merolae, demonstrated the first evidence of nuclear-encoded tRNA genes that contain ectopic and/or multiple introns. Some genes exhibited both intronic and permuted structures in which the 3′-half of the tRNA coding sequence lies upstream of the 5′-half, and an intron is inserted into either half. These highly disrupted tRNA genes, which account for 63% of all nuclear tRNA genes, are expressed via the orderly and sequential processing of bulge-helix-bulge (BHB) motifs at intron-exon junctions and termini of permuted tRNA precursors, probably by a C. merolae tRNA-splicing endonuclease with an unidentified subunit architecture. The results revealed a considerable diversity in eukaryal tRNA intron properties and endonuclease architectures, which will help to elucidate the acquisition mechanism of the BHB-mediated disrupted tRNA genes.
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Affiliation(s)
- Akiko Soma
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
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33
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Zuo Z, Peng D, Yin X, Zhou X, Cheng H, Zhou R. Genome-wide analysis reveals origin of transfer RNA genes from tRNA halves. Mol Biol Evol 2013; 30:2087-98. [PMID: 23744908 DOI: 10.1093/molbev/mst107] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Transfer RNAs (tRNAs) play an important role linking mitochondrial RNA and amino acids during protein biogenesis. Four types of tRNA genes have been identified in living organisms. However, the evolutionary origin of tRNAs remains largely unknown. In this article, we conduct a deep sequence analysis of diverse genomes that cover all three domains of life to unveil the evolutionary history of tRNA genes from tRNA halves. tRNA half homologs were detected in diverse organisms, and some of them were expressed in mouse tissues. Continuous tRNA genes have a conserved pattern similar to indels, which is, more closely flanking regions have higher single nucleotide substitution rates, whereas tRNA half homologs do not have this pattern. In addition, tRNAs tend to break into tRNA halves when tissues are incubated in vitro, the tendency of tRNA to break into tRNA halves may be a "side-effect" of tRNA genes evolving from tRNA halves. These results suggest that modern tRNAs originated from tRNA halves through a repeat element-mediated mechanism. These findings provide insight into the evolutionary origin of tRNA genes.
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Affiliation(s)
- Zhixiang Zuo
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China
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34
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Zhang Z, Yu J. Does the genetic code have a eukaryotic origin? GENOMICS PROTEOMICS & BIOINFORMATICS 2013; 11:41-55. [PMID: 23402863 PMCID: PMC4357656 DOI: 10.1016/j.gpb.2013.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 01/09/2013] [Accepted: 01/11/2013] [Indexed: 11/29/2022]
Abstract
In the RNA world, RNA is assumed to be the dominant macromolecule performing most, if not all, core “house-keeping” functions. The ribo-cell hypothesis suggests that the genetic code and the translation machinery may both be born of the RNA world, and the introduction of DNA to ribo-cells may take over the informational role of RNA gradually, such as a mature set of genetic code and mechanism enabling stable inheritance of sequence and its variation. In this context, we modeled the genetic code in two content variables—GC and purine contents—of protein-coding sequences and measured the purine content sensitivities for each codon when the sensitivity (% usage) is plotted as a function of GC content variation. The analysis leads to a new pattern—the symmetric pattern—where the sensitivity of purine content variation shows diagonally symmetry in the codon table more significantly in the two GC content invariable quarters in addition to the two existing patterns where the table is divided into either four GC content sensitivity quarters or two amino acid diversity halves. The most insensitive codon sets are GUN (valine) and CAN (CAR for asparagine and CAY for aspartic acid) and the most biased amino acid is valine (always over-estimated) followed by alanine (always under-estimated). The unique position of valine and its codons suggests its key roles in the final recruitment of the complete codon set of the canonical table. The distinct choice may only be attributable to sequence signatures or signals of splice sites for spliceosomal introns shared by all extant eukaryotes.
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Affiliation(s)
- Zhang Zhang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
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35
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Avatar pre-tRNAs help elucidate the properties of tRNA-splicing endonucleases that produce tRNA from permuted genes. Proc Natl Acad Sci U S A 2012; 109:21325-9. [PMID: 23236183 DOI: 10.1073/pnas.1219336110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unusual tRNA genes, found in some algae, have their mature terminal 3' portion in front of their 5' portion in the genome. The transcripts from such genes must be cleaved by a pre-tRNA endonuclease to form a functional tRNA. We present a mechanism for the generation of "corrected" tRNAs from such a "permuted" pre-tRNA configuration. We used two avatar (av) or model pre-tRNAs and two splicing endonucleases with distinct mechanisms of recognition of the pre-tRNA. The splicing results are compatible with an evolutionary route in which permuted genes result from a duplication event followed by DNA rearrangement. The model pre-tRNAs permit description of the features that a transcript, derived from a rearranged duplicated gene, must have to give rise to functional tRNA. The two tRNA endonucleases are a eukaryal enzyme that normally acts in a mature domain-dependent mode and an archaeal enzyme that acts in a mature domain-independent mode. Both av pre-tRNAs are able to fold into two conformations: 1 and 2. We find that only conformation 2 can yield a corrected functional tRNA. This result is consistent with contemporary algae representing snapshots of different evolutionary stages, with duplicated genes preceding recombinatorial events generating a permutated gene. In a scenario elucidated by the use of the av pre-tRNAs, algal permuted tRNA genes could have further lost one of two mature domains, eliminating steric problems for the algal tRNA endonuclease, which remains a typical eukaryal enzyme capable of correcting the permuted transcript to a functional tRNA.
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36
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The ‘recently’ split transfer RNA genes may be close to merging the two halves of the tRNA rather than having just separated them. J Theor Biol 2012; 310:1-2. [DOI: 10.1016/j.jtbi.2012.06.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/14/2012] [Accepted: 06/14/2012] [Indexed: 11/16/2022]
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37
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Hirata A, Fujishima K, Yamagami R, Kawamura T, Banfield JF, Kanai A, Hori H. X-ray structure of the fourth type of archaeal tRNA splicing endonuclease: insights into the evolution of a novel three-unit composition and a unique loop involved in broad substrate specificity. Nucleic Acids Res 2012; 40:10554-66. [PMID: 22941657 PMCID: PMC3488258 DOI: 10.1093/nar/gks826] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cleavage of introns from precursor transfer RNAs (tRNAs) by tRNA splicing endonuclease (EndA) is essential for tRNA maturation in Archaea and Eukarya. In the past, archaeal EndAs were classified into three types (α′2, α4 and α2β2) according to subunit composition. Recently, we have identified a fourth type of archaeal EndA from an uncultivated archaeon Candidatus Micrarchaeum acidiphilum, referred to as ARMAN-2, which is deeply branched within Euryarchaea. The ARMAN-2 EndA forms an ε2 homodimer and has broad substrate specificity like the α2β2 type EndAs found in Crenarchaea and Nanoarchaea. However, the precise architecture of ARMAN-2 EndA was unknown. Here, we report the crystal structure of the ε2 homodimer of ARMAN-2 EndA. The structure reveals that the ε protomer is separated into three novel units (αN, α and βC) fused by two distinct linkers, although the overall structure of ARMAN-2 EndA is similar to those of the other three types of archaeal EndAs. Structural comparison and mutational analyses reveal that an ARMAN-2 type-specific loop (ASL) is involved in the broad substrate specificity and that K161 in the ASL functions as the RNA recognition site. These findings suggest that the broad substrate specificities of ε2 and α2β2 EndAs were separately acquired through different evolutionary processes.
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Affiliation(s)
- Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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38
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The origin of the tRNA molecule: Independent data favor a specific model of its evolution. Biochimie 2012; 94:1464-6. [DOI: 10.1016/j.biochi.2012.01.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 01/18/2012] [Indexed: 10/14/2022]
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39
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Proceedings of the Eleventh Annual UT-ORNL-KBRIN Bioinformatics Summit 2012. BMC Bioinformatics 2012; 13 Suppl 12:A1-24. [PMID: 22873757 PMCID: PMC3409059 DOI: 10.1186/1471-2105-13-s12-a1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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40
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Sugahara J, Fujishima K, Nunoura T, Takaki Y, Takami H, Takai K, Tomita M, Kanai A. Genomic heterogeneity in a natural archaeal population suggests a model of tRNA gene disruption. PLoS One 2012; 7:e32504. [PMID: 22403667 PMCID: PMC3293823 DOI: 10.1371/journal.pone.0032504] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/31/2012] [Indexed: 11/27/2022] Open
Abstract
Understanding the mechanistic basis of the disruption of tRNA genes, as manifested in the intron-containing and split tRNAs found in Archaea, will provide considerable insight into the evolution of the tRNA molecule. However, the evolutionary processes underlying these disruptions have not yet been identified. Previously, a composite genome of the deep-branching archaeon Caldiarchaeum subterraneum was reconstructed from a community genomic library prepared from a C. subterraneum–dominated microbial mat. Here, exploration of tRNA genes from the library reveals that there are at least three types of heterogeneity at the tRNAThr(GGU) gene locus in the Caldiarchaeum population. All three involve intronic gain and splitting of the tRNA gene. Of two fosmid clones found that encode tRNAThr(GGU), one (tRNAThr-I) contains a single intron, whereas another (tRNAThr-II) contains two introns. Notably, in the clone possessing tRNAThr-II, a 5′ fragment of the tRNAThr-I (tRNAThr-F) gene was observed 1.8-kb upstream of tRNAThr-II. The composite genome contains both tRNAThr-II and tRNAThr-F, although the loci are >500 kb apart. Given that the 1.8-kb sequence flanked by tRNAThr-F and tRNAThr-II is predicted to encode a DNA recombinase and occurs in six regions of the composite genome, it may be a transposable element. Furthermore, its dinucleotide composition is most similar to that of the pNOB8-type plasmid, which is known to integrate into archaeal tRNA genes. Based on these results, we propose that the gain of the tRNA intron and the scattering of the tRNA fragment occurred within a short time frame via the integration and recombination of a mobile genetic element.
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Affiliation(s)
- Junichi Sugahara
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Kosuke Fujishima
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Takuro Nunoura
- Subsurface Geobiology & Advanced Research Project, Extremobiosphere Research Program, Institute of Biogeosciences, Japan Agency for Marine–Earth Science & Technology, Yokosuka, Japan
| | - Yoshihiro Takaki
- Microbial Genome Research Group, Extremobiosphere Research Program, Institute of Biogeosciences, Japan Agency for Marine–Earth Science & Technology, Yokosuka, Japan
| | - Hideto Takami
- Microbial Genome Research Group, Extremobiosphere Research Program, Institute of Biogeosciences, Japan Agency for Marine–Earth Science & Technology, Yokosuka, Japan
| | - Ken Takai
- Subsurface Geobiology & Advanced Research Project, Extremobiosphere Research Program, Institute of Biogeosciences, Japan Agency for Marine–Earth Science & Technology, Yokosuka, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
- * E-mail:
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41
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Szenes A, Pál G. Mapping hidden potential identity elements by computing the average discriminating power of individual tRNA positions. DNA Res 2012; 19:245-58. [PMID: 22378766 PMCID: PMC3372374 DOI: 10.1093/dnares/dss008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The recently published discrete mathematical method, extended consensus partition (ECP), identifies nucleotide types at each position that are strictly absent from a given sequence set, while occur in other sets. These are defined as discriminating elements (DEs). In this study using the ECP approach, we mapped potential hidden identity elements that discriminate the 20 different tRNA identities. We filtered the tDNA data set for the obligatory presence of well-established tRNA features, and then separately for each identity set, the presence of already experimentally identified strictly present identity elements. The analysis was performed on the three kingdoms of life. We determined the number of DE, e.g. the number of sets discriminated by the given position, for each tRNA position of each tRNA identity set. Then, from the positional DE numbers obtained from the 380 pairwise comparisons of the 20 identity sets, we calculated the average excluding value (AEV) for each tRNA position. The AEV provides a measure on the overall discriminating power of each position. Using a statistical analysis, we show that positional AEVs correlate with the number of already identified identity elements. Positions having high AEV but lacking published identity elements predict hitherto undiscovered tRNA identity elements.
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Affiliation(s)
- Aron Szenes
- Department of Biochemistry, Eötvös University, Budapest, Hungary
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42
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Hamashima K, Fujishima K, Masuda T, Sugahara J, Tomita M, Kanai A. Nematode-specific tRNAs that decode an alternative genetic code for leucine. Nucleic Acids Res 2011; 40:3653-62. [PMID: 22187151 PMCID: PMC3333845 DOI: 10.1093/nar/gkr1226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Class II transfer RNAs (tRNAs), including tRNALeu and tRNASer, have an additional stem and loop structure, the long variable arm (V-arm). Here, we describe Class II tRNAs with a unique anticodon corresponding to neither leucine nor serine. Because these tRNAs are specifically conserved among the nematodes, we have called them ‘nematode-specific V-arm-containing tRNAs’ (nev-tRNAs). The expression of nev-tRNA genes in Caenorhabditis elegans was confirmed experimentally. A comparative sequence analysis suggested that the nev-tRNAs derived phylogenetically from tRNALeu. In vitro aminoacylation assays showed that nev-tRNAGly and nev-tRNAIle are only charged with leucine, which is inconsistent with their anticodons. Furthermore, the deletion and mutation of crucial determinants for leucylation in nev-tRNA led to a marked loss of activity. An in vitro translation analysis showed that nev-tRNAGly decodes GGG as leucine instead of the universal glycine code, indicating that nev-tRNAs can be incorporated into ribosomes and participate in protein biosynthesis. Our findings provide the first example of unexpected tRNAs that do not consistently obey the general translation rules for higher eukaryotes.
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Affiliation(s)
- Kiyofumi Hamashima
- Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0017, Japan
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43
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Chan PP, Holmes AD, Smith AM, Tran D, Lowe TM. The UCSC Archaeal Genome Browser: 2012 update. Nucleic Acids Res 2011; 40:D646-52. [PMID: 22080555 PMCID: PMC3245099 DOI: 10.1093/nar/gkr990] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The UCSC Archaeal Genome Browser (http://archaea.ucsc.edu) offers a graphical web-based resource for exploration and discovery within archaeal and other selected microbial genomes. By bringing together existing gene annotations, gene expression data, multiple-genome alignments, pre-computed sequence comparisons and other specialized analysis tracks, the genome browser is a powerful aggregator of varied genomic information. The genome browser environment maintains the current look-and-feel of the vertebrate UCSC Genome Browser, but also integrates archaeal and bacterial-specific tracks with a few graphic display enhancements. The browser currently contains 115 archaeal genomes, plus 31 genomes of viruses known to infect archaea. Some of the recently developed or enhanced tracks visualize data from published high-throughput RNA-sequencing studies, the NCBI Conserved Domain Database, sequences from pre-genome sequencing studies, predicted gene boundaries from three different protein gene prediction algorithms, tRNAscan-SE gene predictions with RNA secondary structures and CRISPR locus predictions. We have also developed a companion resource, the Archaeal COG Browser, to provide better search and display of arCOG gene function classifications, including their phylogenetic distribution among available archaeal genomes.
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Affiliation(s)
- Patricia P Chan
- Department of Biomolecular Engineering, University of California, Santa Cruz, 1156 High Street, SOE-2, Santa Cruz, CA 95064, USA
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44
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Giegé R, Jühling F, Pütz J, Stadler P, Sauter C, Florentz C. Structure of transfer RNAs: similarity and variability. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:37-61. [DOI: 10.1002/wrna.103] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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45
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Fujishima K, Sugahara J, Miller CS, Baker BJ, Di Giulio M, Takesue K, Sato A, Tomita M, Banfield JF, Kanai A. A novel three-unit tRNA splicing endonuclease found in ultrasmall Archaea possesses broad substrate specificity. Nucleic Acids Res 2011; 39:9695-704. [PMID: 21880595 PMCID: PMC3239211 DOI: 10.1093/nar/gkr692] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
tRNA splicing endonucleases, essential enzymes found in Archaea and Eukaryotes, are involved in the processing of pre-tRNA molecules. In Archaea, three types of splicing endonuclease [homotetrameric: α4, homodimeric: α2, and heterotetrameric: (αβ)2] have been identified, each representing different substrate specificity during the tRNA intron cleavage. Here, we discovered a fourth type of archaeal tRNA splicing endonuclease (ε2) in the genome of the acidophilic archaeon Candidatus Micrarchaeum acidiphilum, referred to as ARMAN-2 and its closely related species, ARMAN-1. The enzyme consists of two duplicated catalytic units and one structural unit encoded on a single gene, representing a novel three-unit architecture. Homodimeric formation was confirmed by cross-linking assay, and site-directed mutagenesis determined that the conserved L10-pocket interaction between catalytic and structural unit is necessary for the assembly. A tRNA splicing assay reveal that ε2 endonuclease cleaves both canonical and non-canonical bulge–helix–bulge motifs, similar to that of (αβ)2 endonuclease. Unlike other ARMAN and Euryarchaeota, tRNAs found in ARMAN-2 are highly disrupted by introns at various positions, which again resemble the properties of archaeal species with (αβ)2 endonuclease. Thus, the discovery of ε2 endonuclease in an archaeon deeply branched within Euryarchaeota represents a new example of the coevolution of tRNA and their processing enzymes.
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Affiliation(s)
- Kosuke Fujishima
- Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0017, Japan
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