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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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Hayne CK, Sekulovski S, Hurtig JE, Stanley RE, Trowitzsch S, van Hoof A. New insights into RNA processing by the eukaryotic tRNA splicing endonuclease. J Biol Chem 2023; 299:105138. [PMID: 37544645 PMCID: PMC10485636 DOI: 10.1016/j.jbc.2023.105138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 07/27/2023] [Accepted: 07/29/2023] [Indexed: 08/08/2023] Open
Abstract
Through its role in intron cleavage, tRNA splicing endonuclease (TSEN) plays a critical function in the maturation of intron-containing pre-tRNAs. The catalytic mechanism and core requirement for this process is conserved between archaea and eukaryotes, but for decades, it has been known that eukaryotic TSENs have evolved additional modes of RNA recognition, which have remained poorly understood. Recent research identified new roles for eukaryotic TSEN, including processing or degradation of additional RNA substrates, and determined the first structures of pre-tRNA-bound human TSEN complexes. These recent discoveries have changed our understanding of how the eukaryotic TSEN targets and recognizes substrates. Here, we review these recent discoveries, their implications, and the new questions raised by these findings.
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Affiliation(s)
- Cassandra K Hayne
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
| | - Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jennifer E Hurtig
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National, Institutes of Health, Research Triangle Park, North Carolina, USA.
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany.
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA.
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3
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Prebiotic Assembly of Cloverleaf tRNA, Its Aminoacylation and the Origin of Coding, Inferred from Acceptor Stem Coding-Triplets. Int J Mol Sci 2022; 23:ijms232415756. [PMID: 36555394 PMCID: PMC9778954 DOI: 10.3390/ijms232415756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/25/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022] Open
Abstract
tRNA is a key component in life's most fundamental process, the translation of the instructions contained in mRNA into proteins. Its role had to be executed as soon as the earliest translation emerged, but the questions of the prebiotic tRNA materialization, aminoacylation, and the origin of the coding triplets it carries are still open. Here, these questions are addressed by utilizing a distinct pattern of coding triplets highly conserved in the acceptor stems from the modern bacterial tRNAs of five early-emerging amino acids. Self-assembly of several copies of a short RNA oligonucleotide that carries a related pattern of coding triplets, via a simple and statistically feasible process, is suggested to result in a proto-tRNA model highly compatible with the cloverleaf secondary structure of the modern tRNA. Furthermore, these stem coding triplets evoke the possibility that they were involved in self-aminoacylation of proto-tRNAs prior to the emergence of the earliest synthetases, a process proposed to underlie the formation of the genetic code. Being capable of autonomous materialization and of self-aminoacylation, this verifiable model of the proto-tRNA advent adds principal components to an initial set of molecules and processes that may have led, exclusively through natural means, to the emergence of life.
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4
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Kato S, Ogasawara A, Itoh T, Sakai HD, Shimizu M, Yuki M, Kaneko M, Takashina T, Ohkuma M. Nanobdella aerobiophila gen. nov., sp. nov., a thermoacidophilic, obligate ectosymbiotic archaeon, and proposal of Nanobdellaceae fam. nov., Nanobdellales ord. nov. and Nanobdellia class. nov. Int J Syst Evol Microbiol 2022; 72. [DOI: 10.1099/ijsem.0.005489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A co-culture of a novel thermoacidophilic, obligate symbiotic archaeon, designated as strain MJ1T, with its specific host archaeon
Metallosphaera sedula
strain MJ1HA was obtained from a terrestrial hot spring in Japan. Strain MJ1T grew in the co-culture under aerobic conditions. Coccoid cells of strain MJ1T were 200–500 nm in diameter, and attached to the MJ1HA cells in the co-culture. The ranges and optima of the growth temperature and pH of strain MJ1T in the co-culture were 60–75 °C (optimum, 65–70 °C) and pH 1.0–4.0 (optimum, pH 2.5), respectively. Core lipids of dialkyl glycerol tetraethers (GDGT)−3 and GDGT-4 were highly abundant in MJ1T cells concentrated from the co-culture. Strain MJ1T has a small genome (0.67 Mbp) lacking genes for biosynthesis of essential biomolecules, such as nucleotides, lipids and ATP. The genomic DNA G+C content was 24.9 mol%. The 16S rRNA gene sequence of strain MJ1T was most closely related to that of the cultivated species, ‘Nanopusillus acidilobi’ strain N7A (85.8 % similarity). Based on phylogenetic and physiological characteristics, we propose the name Nanobdella aerobiophila gen. nov., sp. nov. to accommodate the strain MJ1T (=JCM 33616T=DSM 111728T). In addition, we propose the names Nanobdellaceae fam. nov., Nanobdellales ord. nov., and Nanobdellia class. nov. to accommodate the novel genus.
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Affiliation(s)
- Shingo Kato
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Ayaka Ogasawara
- Graduate School of Life Sciences, Toyo University, Oura, Gunma 374-0193, Japan
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Takashi Itoh
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Hiroyuki D. Sakai
- Present address: Faculty of Science and Engineering, Soka University, Tokyo 192-8577, Hachioji, Japan
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Michiru Shimizu
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Masahiro Yuki
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Masanori Kaneko
- Research Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8567, Japan
| | - Tomonori Takashina
- Graduate School of Life Sciences, Toyo University, Oura, Gunma 374-0193, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
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5
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Chakrabarti A, Kaushik M, Khan J, Soota D, Ponnusamy K, Saini S, Manvati S, Singhal J, Ranganathan A, Pati S, Dhar PK, Singh S. tREPs-A New Class of Functional tRNA-Encoded Peptides. ACS OMEGA 2022; 7:18361-18373. [PMID: 35694484 PMCID: PMC9178612 DOI: 10.1021/acsomega.2c00661] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
We asked if transfer RNA (tRNA) ever got an opportunity of translating its own sequence during evolution, what would have been the function of such tRNA-encoded peptides (tREPs)? If not, could one artificially synthesize tREPs to study the corresponding functional outcomes? Here, we report a novel, first-in-the-class, chemically synthesized tREP-18 molecule originating from the Escherichia coli tRNA sequence showing potent antileishmanial property. As a first step, E. coli tRNAs were computationally translated into peptide sequence equivalents and a database of full-length hypothetical tREPs was created. The tREP sequences were sent into sequence, structure, and energy filters to narrow down potential peptides for experimental validation. Based on the functional predictions, tREPs were screened against antiparasitic targets, leading to the identification of tREP-18 as a potential antiparasitic peptide. The in vitro assay of chemically synthesized tREP-18 on the Ag83 strain of Leishmania donovani showed its potent antileishmanial property (IC50 value of 22.13 nM). The atomic force microscopy and scanning electron microscopy images indicated significant alteration in the cytoskeletal architecture of tREP-18-treated parasites. Also, tREP-18 seems to destabilize the mitochondrial membrane potential of parasites, disrupting their cellular integrity and leading to parasitic death. The cellular assays of the tREP-18 peptide on the BS12 strain, a clinical isolate of post-kala azar dermal leishmaniasis, demonstrated its significant efficacy at an IC50 value of 15 nM. The tREP-18 peptide showed a toxic effect on the amastigote stage of the parasite, showing macrophage pathogen clearance at a concentration of 22.5 nM. This study provides the proof of the concept of making a new class of functional peptides from tRNA sequences. It also opens a huge untapped tRNA-peptide space toward novel discoveries and applications. In the future, it would be interesting to perform tREP edits and redesign tREPs toward specific applications.
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Affiliation(s)
- Amrita Chakrabarti
- Department of Life Sciences, Shiv Nadar University, Greater Noida 201314, Uttar Pradesh, India
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Monika Kaushik
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Juveria Khan
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Deepanshu Soota
- National Centre for Biological Sciences, Bangalore 560065, India
| | | | - Sunil Saini
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Siddharth Manvati
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Jhalak Singhal
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Anand Ranganathan
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Soumya Pati
- Department of Life Sciences, Shiv Nadar University, Greater Noida 201314, Uttar Pradesh, India
| | - Pawan Kumar Dhar
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
- Special Centre for Systems Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
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6
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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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7
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Wu LF, Su M, Liu Z, Bjork SJ, Sutherland JD. Interstrand Aminoacyl Transfer in a tRNA Acceptor Stem-Overhang Mimic. J Am Chem Soc 2021; 143:11836-11842. [PMID: 34283595 PMCID: PMC8397310 DOI: 10.1021/jacs.1c05746] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Protein-catalyzed aminoacylation
of the 3′-overhang of tRNA
by an aminoacyl-adenylate could not have taken place prior to the
advent of genetically coded peptide synthesis, and yet the latter
process has an absolute requirement for aminoacyl-tRNA. There must
therefore have been an earlier nonprotein-catalyzed means of generating
aminoacyl-tRNA. Here, we demonstrate efficient interstrand aminoacyl
transfer from an aminoacyl phosphate mixed anhydride at the 5′-terminus
of a tRNA acceptor stem mimic to the 2′,3′-diol terminus
of a short 3′-overhang. With certain five-base 3′-overhangs,
the transfer of an alanyl residue is highly stereoselective with the l-enantiomer being favored to the extent of ∼10:1 over
the d-enantiomer and is much more efficient than the transfer
of a glycyl residue. N-Acyl-aminoacyl residues are
similarly transferred from a mixed anhydride with the 5′-phosphate
to the 2′,3′-diol but with a different dependence of
efficiency and stereoselectivity on the 3′-overhang length
and sequence. Given a prebiotically plausible and compatible synthesis
of aminoacyl phosphate mixed anhydrides, these results suggest that
RNA molecules with acceptor stem termini resembling modern tRNAs could
have been spontaneously aminoacylated, in a stereoselective and chemoselective
manner, at their 2′,3′-diol termini prior to the onset
of protein-catalyzed aminoacylation.
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Affiliation(s)
- Long-Fei Wu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Meng Su
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Ziwei Liu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Samuel J Bjork
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - John D Sutherland
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
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8
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Grigoriev A. Transfer RNA and Origins of RNA Interference. Front Mol Biosci 2021; 8:708984. [PMID: 34368233 PMCID: PMC8343393 DOI: 10.3389/fmolb.2021.708984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/08/2021] [Indexed: 01/21/2023] Open
Affiliation(s)
- Andrey Grigoriev
- Department of Biology, Center for Computational and Integrative Biology, Rutgers University, Camden, NY, Uinted States
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9
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Nottebaum S, Weinzierl ROJ. Transcribing Genes the Hard Way: In Vitro Reconstitution of Nanoarchaeal RNA Polymerase Reveals Unusual Active Site Properties. Front Mol Biosci 2021; 8:669314. [PMID: 34141723 PMCID: PMC8204694 DOI: 10.3389/fmolb.2021.669314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
Nanoarchaea represent a highly diverged archaeal phylum that displays many unusual biological features. The Nanoarchaeum equitans genome encodes a complete set of RNA polymerase (RNAP) subunits and basal factors. Several of the standard motifs in the active center contain radical substitutions that are normally expected to render the polymerase catalytically inactive. Here we show that, despite these unusual features, a RNAP reconstituted from recombinant Nanoarchaeum subunits is transcriptionally active. Using a sparse-matrix high-throughput screening method we identified an atypical stringent requirement for fluoride ions to maximize its activity under in vitro transcription conditions.
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Affiliation(s)
- Sven Nottebaum
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Orthomol Pharmazeutische Vertriebs GmbH, Langenfeld, Germany
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10
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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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11
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Di Giulio M. The late appearance of DNA, the nature of the LUCA and ancestors of the domains of life. Biosystems 2020; 202:104330. [PMID: 33352234 DOI: 10.1016/j.biosystems.2020.104330] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 01/27/2023]
Abstract
It has been firmly observed that replicative DNA polymerases of bacteria, archaea and eukaryotes are not homologous proteins. This lack of homology in the replication apparatus among the domains of life is not only compatible with but would seem to imply the view that the emergence of DNA occurred in the fundamental cellular lineages. In consequence, this diversity of DNA polymerase would go back to the level of ancestors of the domains of life and to the evolutionary time in which the DNA emerged. Therefore, the presumed evolutionary stage linked to the RNA- > DNA transition would have occurred only at the level of ancestors of the main lineages of the tree of life. Thus, the high noise associated with this major evolutionary transition and the impossibility for a cellular stage to generate different fundamental genetically profound traits - such as the different replication apparatuses of bacteria, archaea and eukaryotes - would imply not only that the last universal common ancestor (LUCA) was a progenote but that the ancestors of the domains of life were also at this evolutionary stage. So, I criticize the hypotheses which want, instead, that completely different cells - such as, bacteria and archaea - could have originated from a cellular LUCA.
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Affiliation(s)
- Massimo Di Giulio
- The Ionian School, Genetic Code and tRNA Origin Laboratory, Via Roma 19, 67030, Alfedena (L'Aquila), Italy; Institute of Biosciences and Bioresources, National Research Council, Via P. Castellino, 111, 80131, Naples, Italy.
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12
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Abstract
BACKGROUND RNA trans-splicing joins exons from different pre-mRNA transcripts to generate a chimeric product. Trans-splicing can also occur at the protein level, with split inteins mediating the ligation of separate gene products to generate a mature protein. SOURCES OF DATA Comprehensive literature search of published research papers and reviews using Pubmed. AREAS OF AGREEMENT Trans-splicing techniques have been used to target a wide range of diseases in both in vitro and in vivo models, resulting in RNA, protein and functional correction. AREAS OF CONTROVERSY Off-target effects can lead to therapeutically undesirable consequences. In vivo efficacy is typically low, and delivery issues remain a challenge. GROWING POINTS Trans-splicing provides a promising avenue for developing novel therapeutic approaches. However, much more research needs to be done before developing towards preclinical studies. AREAS TIMELY FOR DEVELOPING RESEARCH Increasing trans-splicing efficacy and specificity by rational design, screening and competitive inhibition of endogenous cis-splicing.
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Affiliation(s)
- Elizabeth M Hong
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Carin K Ingemarsdotter
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Andrew M L Lever
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2QQ, UK
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13
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Arutaki M, Kurihara R, Matsuoka T, Inami A, Tokunaga K, Ohno T, Takahashi H, Takano H, Ando T, Mutsuro-Aoki H, Umehara T, Tamura K. G:U-Independent RNA Minihelix Aminoacylation by Nanoarchaeum equitans Alanyl-tRNA Synthetase: An Insight into the Evolution of Aminoacyl-tRNA Synthetases. J Mol Evol 2020; 88:501-509. [DOI: 10.1007/s00239-020-09945-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 04/28/2020] [Indexed: 11/25/2022]
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14
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Di Giulio M. An RNA Ring was Not the Progenitor of the tRNA Molecule. J Mol Evol 2020; 88:228-233. [PMID: 31980854 DOI: 10.1007/s00239-020-09927-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 01/07/2020] [Indexed: 10/25/2022]
Abstract
I analyzed the model that suggests that an RNA ring might have been the progenitor of the tRNA molecule (Demongeot and Moreira in J Theor Biol 249:314-324, 2007; Demongeot and Seligmann in J Mol Evol 1-23, 2019a; Demongeot and Norris in Life 9(2):51, 2019). In particular, I analyze three ways in which this precursor, especially in its RNA hairpin form, could have evolved into the complete tRNA molecule. These three modalities are based on multiple duplication events, and therefore, appear to be less parsimonious than that which assumes that this molecule originated through one duplication of a single hairpin structure. The conclusion is, therefore, that the latter model appears to be preferable with respect to that of the RNA ring, also because there are many independent observations and some of a historical nature that would corroborate it in an extraordinary way.
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Affiliation(s)
- Massimo Di Giulio
- The Ionian School, Genetic Code and tRNA Origin Laboratory, Via Roma 19, 67030, Alfedena, L'Aquila, Italy. .,Institute of Biosciences and Bioresources, National Research Council, Via P. Castellino, 111, 80131, Naples, Italy.
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15
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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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16
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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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17
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Di Giulio M. A comparison between two models for understanding the origin of the tRNA molecule. J Theor Biol 2019; 480:99-103. [DOI: 10.1016/j.jtbi.2019.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 04/06/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022]
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18
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Mandal UR, Das SS, Chattopadhyay B, Sahoo S. Identified Hybrid tRNA Structure Genes in Archaeal Genome. IRANIAN JOURNAL OF BIOTECHNOLOGY 2019; 17:e2254. [PMID: 32195286 PMCID: PMC7080975 DOI: 10.29252/ijb.2254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Background In Archaea, previous studies have revealed the presence of multiple intron-containing tRNAs and split tRNAs. The full unexpurgated analysis of archaeal tRNA genes remains a challenging task in the field of bioinformatics, because of the presence of various types of hidden tRNA genes in archaea. Here, we suggested a computational method that searched for widely separated genes encoding tRNA halves to generate suppressive variants of missing tRNAs. Objectives The exploration of tRNA genes from a genome with varying hypotheses, among all three domain of life (eukaryotes, bacteria and archaea), has been rapidly identified in different ways in the field of bioinformatics. Like eukaryotic tRNA genes, it has been established that two separated regions of the coding sequence of a tRNA gene are essential and sufficient for promotion of transcription. Our objective is to find out the two essential regions in the genome sequence which comprises two halves of the hidden tRNAs. Material and Methods Considering the existence of split tRNA genes widely separated throughout the genome, we developed our tRNA search algorithm to predict such separated tRNA genes by searching both a conserved terminal 5'- and 3'-motif of tRNA in agreement with the split hypothesis on the basis of cloverleaf prediction and precise insilico determination of bulge-helix-bulge secondary structure at the splice sites. Results By a comprehensive search for all kinds of missing tRNA genes, we have constructed hybrid tRNA genes containing one essential region from tDNA (XYZ) and the other from tDNA (ABC), both from same species in the archaea. We have also found, this type of hybrid tRNA genes are identified in the different species of the archaea (XYZ ASN, ARG and MET; ABC ASP,SER, ARG and PRO).These hybrid split tRNA share a common structural motif called bulge-helix-bulge (BHB) a more relaxed bulge-helix loop (BHL), at the leader exon boundary and suggested to be evolutionary interrelated. Conclusions Analysis of the complete genome sequences of Metallosphaera sedula DSM 5348, Desulfurococcus kamchatkensis 1221n and Ignicoccus hospitalis KIN4/I in archaea by our algorithm revealed that a number of hybrid tRNAs are constructed from different tDNAs . Asymmetric combination of 5' and 3' tRNA halves may have generated the diversity of tRNA molecules. Our study of hybrid tRNA genes will provide a new molecular basis for upcoming tRNA studies.
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Affiliation(s)
- Uttam Roy Mandal
- Department of Mathematics, Raidighi College, Raidighi, W.B., India
| | - Shib Sankar Das
- Department of Mathematics, Uluberia College, Uluberia, Howrah, W.B, India
| | | | - Satyabrata Sahoo
- Department of Physics, Dhruba Chand Halder College, Dakshin Barasat, W.B., India
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19
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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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20
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Gomes‐Filho JV, Randau L. RNA stabilization in hyperthermophilic archaea. Ann N Y Acad Sci 2019; 1447:88-96. [DOI: 10.1111/nyas.14060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/26/2019] [Accepted: 03/10/2019] [Indexed: 12/23/2022]
Affiliation(s)
| | - Lennart Randau
- Prokaryotic Small RNA BiologyMax Planck Institute for Terrestrial Microbiology Marburg Germany
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21
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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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22
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St John E, Flores GE, Meneghin J, Reysenbach AL. Deep-sea hydrothermal vent metagenome-assembled genomes provide insight into the phylum Nanoarchaeota. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:262-270. [PMID: 30768760 DOI: 10.1111/1758-2229.12740] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/06/2019] [Indexed: 06/09/2023]
Abstract
Ectosymbiotic Nanoarchaeota live on the surface of diverse archaeal hosts. Despite being broadly distributed in global geothermal systems, only three Nanoarchaeota have been successfully co-cultivated with their hosts, and until now no nanoarchaeotal cultures or genomes have been described from deep-sea hydrothermal vents. We recovered three nanoarchaeotal metagenome-assembled genomes (MAGs) from deep-sea hydrothermal vent sites at the Eastern Lau Spreading Center (M10-121), Guaymas Basin (Gua-46) and the Mid-Cayman Rise (MC-1). Based on average amino acid identity analysis, M10-121 is a novel species in the candidate genus Nanoclepta, while the other two MAGs represent novel genera in the Nanoarchaeota. Like previously sequenced Nanoarchaeota, each MAG encodes at least one split protein-coding gene. The MAGs also contain a mosaic of key nanoarchaeotal features, including CRISPR repeat regions and marker genes for gluconeogenesis and archaeal flagella. MC-1 also encodes the pentose bisphosphate pathway, which may allow the nanoarchaeote to bypass several steps in glycolysis and produce ATP.
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Affiliation(s)
- Emily St John
- Department of Biology, Portland State University, Portland, OR 97201, USA
| | - Gilberto E Flores
- Department of Biology, California State University, Northridge, CA 91330, USA
| | - Jennifer Meneghin
- Department of Biology, Portland State University, Portland, OR 97201, USA
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23
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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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24
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Dombrowski N, Lee JH, Williams TA, Offre P, Spang A. Genomic diversity, lifestyles and evolutionary origins of DPANN archaea. FEMS Microbiol Lett 2019; 366:5281434. [PMID: 30629179 PMCID: PMC6349945 DOI: 10.1093/femsle/fnz008] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/07/2019] [Indexed: 12/16/2022] Open
Abstract
Archaea-a primary domain of life besides Bacteria-have for a long time been regarded as peculiar organisms that play marginal roles in biogeochemical cycles. However, this picture changed with the discovery of a large diversity of archaea in non-extreme environments enabled by the use of cultivation-independent methods. These approaches have allowed the reconstruction of genomes of uncultivated microorganisms and revealed that archaea are diverse and broadly distributed in the biosphere and seemingly include a large diversity of putative symbiotic organisms, most of which belong to the tentative archaeal superphylum referred to as DPANN. This archaeal group encompasses at least 10 different lineages and includes organisms with extremely small cell and genome sizes and limited metabolic capabilities. Therefore, many members of DPANN may be obligately dependent on symbiotic interactions with other organisms and may even include novel parasites. In this contribution, we review the current knowledge of the gene repertoires and lifestyles of members of this group and discuss their placement in the tree of life, which is the basis for our understanding of the deep microbial roots and the role of symbiosis in the evolution of life on Earth.
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Affiliation(s)
- Nina Dombrowski
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, P.O. Box 59, NL-1790 AB Den Burg, The Netherlands
- Department of Marine Science, University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78373, USA
| | - Jun-Hoe Lee
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, P.O. Box 596, Husargatan 3, SE-75123 Uppsala, Sweden
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, Bristol BS8 1TQ, UK
| | - Pierre Offre
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, P.O. Box 59, NL-1790 AB Den Burg, The Netherlands
| | - Anja Spang
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, P.O. Box 59, NL-1790 AB Den Burg, The Netherlands
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, P.O. Box 596, Husargatan 3, SE-75123 Uppsala, Sweden
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25
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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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26
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Versatility of Synthetic tRNAs in Genetic Code Expansion. Genes (Basel) 2018; 9:genes9110537. [PMID: 30405060 PMCID: PMC6267555 DOI: 10.3390/genes9110537] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 10/31/2018] [Accepted: 11/05/2018] [Indexed: 12/16/2022] Open
Abstract
Transfer RNA (tRNA) is a dynamic molecule used by all forms of life as a key component of the translation apparatus. Each tRNA is highly processed, structured, and modified, to accurately deliver amino acids to the ribosome for protein synthesis. The tRNA molecule is a critical component in synthetic biology methods for the synthesis of proteins designed to contain non-canonical amino acids (ncAAs). The multiple interactions and maturation requirements of a tRNA pose engineering challenges, but also offer tunable features. Major advances in the field of genetic code expansion have repeatedly demonstrated the central importance of suppressor tRNAs for efficient incorporation of ncAAs. Here we review the current status of two fundamentally different translation systems (TSs), selenocysteine (Sec)- and pyrrolysine (Pyl)-TSs. Idiosyncratic requirements of each of these TSs mandate how their tRNAs are adapted and dictate the techniques used to select or identify the best synthetic variants.
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27
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Hori H, Kawamura T, Awai T, Ochi A, Yamagami R, Tomikawa C, Hirata A. Transfer RNA Modification Enzymes from Thermophiles and Their Modified Nucleosides in tRNA. Microorganisms 2018; 6:E110. [PMID: 30347855 PMCID: PMC6313347 DOI: 10.3390/microorganisms6040110] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 12/11/2022] Open
Abstract
To date, numerous modified nucleosides in tRNA as well as tRNA modification enzymes have been identified not only in thermophiles but also in mesophiles. Because most modified nucleosides in tRNA from thermophiles are common to those in tRNA from mesophiles, they are considered to work essentially in steps of protein synthesis at high temperatures. At high temperatures, the structure of unmodified tRNA will be disrupted. Therefore, thermophiles must possess strategies to stabilize tRNA structures. To this end, several thermophile-specific modified nucleosides in tRNA have been identified. Other factors such as RNA-binding proteins and polyamines contribute to the stability of tRNA at high temperatures. Thermus thermophilus, which is an extreme-thermophilic eubacterium, can adapt its protein synthesis system in response to temperature changes via the network of modified nucleosides in tRNA and tRNA modification enzymes. Notably, tRNA modification enzymes from thermophiles are very stable. Therefore, they have been utilized for biochemical and structural studies. In the future, thermostable tRNA modification enzymes may be useful as biotechnology tools and may be utilized for medical science.
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Affiliation(s)
- Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Takuya Kawamura
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Takako Awai
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Anna Ochi
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Ryota Yamagami
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Chie Tomikawa
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
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28
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St John E, Liu Y, Podar M, Stott MB, Meneghin J, Chen Z, Lagutin K, Mitchell K, Reysenbach AL. A new symbiotic nanoarchaeote (Candidatus Nanoclepta minutus) and its host (Zestosphaera tikiterensis gen. nov., sp. nov.) from a New Zealand hot spring. Syst Appl Microbiol 2018; 42:94-106. [PMID: 30195930 DOI: 10.1016/j.syapm.2018.08.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/08/2018] [Accepted: 08/08/2018] [Indexed: 01/22/2023]
Abstract
Three thermophilic Nanoarchaeota-Crenarchaeota symbiotic systems have been described. We obtained another stable anaerobic enrichment culture at 80°C, pH 6.0 from a New Zealand hot spring. The nanoarchaeote (Ncl-1) and its host (NZ3T) were isolated in co-culture and their genomes assembled. The small (∼200nm) flagellated cocci were often attached to larger cocci. Based on 16S rRNA gene similarity (88.4%) and average amino acid identity (52%), Ncl-1 is closely related to Candidatus Nanopusillus acidilobi. Their genomes both encode for archaeal flagella and partial glycolysis and gluconeogenesis pathways, but lack ATP synthase genes. Like Nanoarchaeum equitans, Ncl-1 has a CRISPR-Cas system. Ncl-1 also relies on its crenarchaeotal host for most of its biosynthetic needs. The host NZ3T was isolated and grows on proteinaceous substrates but not on sugars, alcohols, or fatty acids. NZ3T requires thiosulfate and grows best at 82°C, pH 6.0. NZ3T is most closely related to the Desulfurococcaceae, Ignisphaera aggregans (∼92% 16S rRNA gene sequence similarity, 45% AAI). Based on phylogenetic, physiological and genomic data, Ncl-1 and NZ3T represent novel genera in the Nanoarchaeota and the Desulfurococcaceae, respectively, with the proposed names Candidatus Nanoclepta minutus and Zestosphaera tikiterensis gen. nov., sp. nov., type strain NZ3T (=DSMZ 107634T=OCM 1213T).
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Affiliation(s)
- Emily St John
- Biology Department, Portland State University, Portland, OR 97201, USA
| | - Yitai Liu
- Biology Department, Portland State University, Portland, OR 97201, USA
| | - Mircea Podar
- Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA; Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - Matthew B Stott
- School of Biological Sciences, University of Canterbury, Christchurch 8140, New Zealand
| | - Jennifer Meneghin
- Biology Department, Portland State University, Portland, OR 97201, USA
| | - Zhiqiang Chen
- Center for Electron Microscopy and Nanofabrication, Portland State University, Portland, OR 97201, USA
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Lopez-Fernandez M, Broman E, Turner S, Wu X, Bertilsson S, Dopson M. Investigation of viable taxa in the deep terrestrial biosphere suggests high rates of nutrient recycling. FEMS Microbiol Ecol 2018; 94:5040220. [PMID: 29931252 PMCID: PMC6030916 DOI: 10.1093/femsec/fiy121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/15/2018] [Indexed: 11/14/2022] Open
Abstract
The deep biosphere is the largest 'bioreactor' on earth, and microbes inhabiting this biome profoundly influence global nutrient and energy cycles. An important question for deep biosphere microbiology is whether or not specific populations are viable. To address this, we used quantitative PCR and high throughput 16S rRNA gene sequencing of total and viable cells (i.e. with an intact cellular membrane) from three groundwaters with different ages and chemical constituents. There were no statistically significant differences in 16S rRNA gene abundances and microbial diversity between total and viable communities. This suggests that populations were adapted to prevailing oligotrophic conditions and that non-viable cells are rapidly degraded and recycled into new biomass. With higher concentrations of organic carbon, the modern marine and undefined mixed waters hosted a community with a larger range of predicted growth strategies than the ultra-oligotrophic old saline water. These strategies included fermentative and potentially symbiotic lifestyles by candidate phyla that typically have streamlined genomes. In contrast, the old saline waters had more 16S rRNA gene sequences in previously cultured lineages able to oxidize hydrogen and fix carbon dioxide. This matches the paradigm of a hydrogen and carbon dioxide-fed chemolithoautotrophic deep biosphere.
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Affiliation(s)
- Margarita Lopez-Fernandez
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Barlastgatan 11, Kalmar, Sweden
| | - Elias Broman
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Barlastgatan 11, Kalmar, Sweden
| | - Stephanie Turner
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Barlastgatan 11, Kalmar, Sweden
| | - Xiaofen Wu
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Barlastgatan 11, Kalmar, Sweden
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Norbyvägen 18D, Uppsala, Sweden
| | - Mark Dopson
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Barlastgatan 11, Kalmar, Sweden
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30
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Wu Y, Wu P, Wang B, Shao ZQ. Genome-Wide Analysis Reveals Ancestral Lack of Seventeen Different tRNAs and Clade-Specific Loss of tRNA-CNNs in Archaea. Front Microbiol 2018; 9:1245. [PMID: 29930548 PMCID: PMC6000648 DOI: 10.3389/fmicb.2018.01245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 05/23/2018] [Indexed: 12/02/2022] Open
Abstract
Transfer RNA (tRNA) is a category of RNAs that specifically decode messenger RNAs (mRNAs) into proteins by recognizing a set of 61 codons commonly adopted by different life domains. The composition and abundance of tRNAs play critical roles in shaping codon usage and pairing bias, which subsequently modulate mRNA translation efficiency and accuracy. Over the past few decades, effort has been concentrated on evaluating the specificity and redundancy of different tRNA families. However, the mechanism and processes underlying tRNA evolution have only rarely been investigated. In this study, by surveying tRNA genes in 167 completely sequenced genomes, we systematically investigated the composition and evolution of tRNAs in Archaea from a phylogenetic perspective. Our data revealed that archaeal genomes are compact in both tRNA types and copy number. Generally, no more than 44 different types of tRNA are present in archaeal genomes to decode the 61 canonical codons, and most of them have only one gene copy per genome. Among them, tRNA-Met was significantly overrepresented, with an average of three copies per genome. In contrast, the tRNA-UAU and 16 tRNAs with A-starting anticodons (tRNA-ANNs) were rarely detected in all archaeal genomes. The conspicuous absence of these tRNAs across the archaeal phylogeny suggests they might have not been evolved in the common ancestor of Archaea, rather than have lost independently from different clades. Furthermore, widespread absence of tRNA-CNNs in the Methanococcales and Methanobacteriales genomes indicates convergent loss of these tRNAs in the two clades. This clade-specific tRNA loss may be attributing to the reductive evolution of their genomes. Our data suggest that the current tRNA profiles in Archaea are contributed not only by the ancestral tRNA composition, but also by differential maintenance and loss of redundant tRNAs.
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Affiliation(s)
- Yue Wu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.,Institute of Bioinformatics, University of Georgia, Athens, GA, United States
| | - Ping Wu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Bin Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Zhu-Qing Shao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
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31
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Di Giulio M. On Earth, there would be a number of fundamental kinds of primary cells – cellular domains – greater than or equal to four. J Theor Biol 2018; 443:10-17. [DOI: 10.1016/j.jtbi.2018.01.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/10/2018] [Accepted: 01/19/2018] [Indexed: 11/15/2022]
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32
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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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33
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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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34
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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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35
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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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36
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Wurch L, Giannone RJ, Belisle BS, Swift C, Utturkar S, Hettich RL, Reysenbach AL, Podar M. Genomics-informed isolation and characterization of a symbiotic Nanoarchaeota system from a terrestrial geothermal environment. Nat Commun 2016; 7:12115. [PMID: 27378076 PMCID: PMC4935971 DOI: 10.1038/ncomms12115] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/01/2016] [Indexed: 02/06/2023] Open
Abstract
Biological features can be inferred, based on genomic data, for many microbial lineages that remain uncultured. However, cultivation is important for characterizing an organism's physiology and testing its genome-encoded potential. Here we use single-cell genomics to infer cultivation conditions for the isolation of an ectosymbiotic Nanoarchaeota (‘Nanopusillus acidilobi') and its host (Acidilobus, a crenarchaeote) from a terrestrial geothermal environment. The cells of ‘Nanopusillus' are among the smallest known cellular organisms (100–300 nm). They appear to have a complete genetic information processing machinery, but lack almost all primary biosynthetic functions as well as respiration and ATP synthesis. Genomic and proteomic comparison with its distant relative, the marine Nanoarchaeum equitans illustrate an ancient, common evolutionary history of adaptation of the Nanoarchaeota to ectosymbiosis, so far unique among the Archaea. Many microbial lineages have not yet been cultured, which hampers our understanding of their physiology. Here, Wurch et al. use single-cell genomics to infer cultivation conditions for the isolation of a tiny ectosymbiotic nanoarchaeon and its crenarchaeota host from a geothermal spring.
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Affiliation(s)
- Louie Wurch
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | - Bernard S Belisle
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Carolyn Swift
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Sagar Utturkar
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Robert L Hettich
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | - Mircea Podar
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, USA
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37
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Bhattacharyya S, Varshney U. Evolution of initiator tRNAs and selection of methionine as the initiating amino acid. RNA Biol 2016; 13:810-9. [PMID: 27322343 DOI: 10.1080/15476286.2016.1195943] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Transfer RNAs (tRNAs) have been important in shaping biomolecular evolution. Initiator tRNAs (tRNAi), a special class of tRNAs, carry methionine (or its derivative, formyl-methionine) to ribosomes to start an enormously energy consuming but a highly regulated process of protein synthesis. The processes of tRNAi evolution, and selection of methionine as the universal initiating amino acid remain an enigmatic problem. We constructed phylogenetic trees using the whole sequence, the acceptor-TψC arm ('minihelix'), and the anticodon-dihydrouridine arm regions of tRNAi from 158 species belonging to all 3 domains of life. All the trees distinctly assembled into 3 domains of life. Large trees, generated using data for all the tRNAs of a vast number of species, fail to reveal the major evolutionary events and identity of the probable elongator tRNA sequences that could be ancestor of tRNAi. Therefore, we constructed trees using the minihelix or the whole sequence of species specific tRNAs, and iterated our analysis on 50 eubacterial species. We identified tRNA(Pro), tRNA(Glu), or tRNA(Thr) (but surprisingly not elongator tRNA(Met)) as probable ancestors of tRNAi. We then determined the factors imposing selection of methionine as the initiating amino acid. Overall frequency of occurrence of methionine, whose metabolic cost of synthesis is the highest among all amino acids, remains almost unchanged across the 3 domains of life. Our correlation analysis shows that its high metabolic cost is independent of many physicochemical properties of the side chain. Our results indicate that selection of methionine, as the initiating amino acid was possibly a consequence of the evolution of one-carbon metabolism, which plays an important role in regulating translation initiation.
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Affiliation(s)
- Souvik Bhattacharyya
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
| | - Umesh Varshney
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India.,b Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur , Bangalore , India
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38
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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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39
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Plagens A, Daume M, Wiegel J, Randau L. Circularization restores signal recognition particle RNA functionality in Thermoproteus. eLife 2015; 4. [PMID: 26499493 PMCID: PMC4731332 DOI: 10.7554/elife.11623] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 10/23/2015] [Indexed: 11/15/2022] Open
Abstract
Signal recognition particles (SRPs) are universal ribonucleoprotein complexes found in all three domains of life that direct the cellular traffic and secretion of proteins. These complexes consist of SRP proteins and a single, highly structured SRP RNA. Canonical SRP RNA genes have not been identified for some Thermoproteus species even though they contain SRP19 and SRP54 proteins. Here, we show that genome rearrangement events in Thermoproteus tenax created a permuted SRP RNA gene. The 5'- and 3'-termini of this SRP RNA are located close to a functionally important loop present in all known SRP RNAs. RNA-Seq analyses revealed that these termini are ligated together to generate circular SRP RNA molecules that can bind to SRP19 and SRP54. The circularization site is processed by the tRNA splicing endonuclease. This moonlighting activity of the tRNA splicing machinery permits the permutation of the SRP RNA and creates highly stable and functional circular RNA molecules. DOI:http://dx.doi.org/10.7554/eLife.11623.001 Cells make many proteins that are eventually released outside the cell or inserted into the cell’s membrane. As these proteins are still being made, they are captured by a “signal recognition particle” (or SRP); this molecular machine then guides the newly forming protein to the cell’s membrane. SRPs are found in all living organisms on Earth and contain several different proteins and a short RNA molecule. However, a few species belonging to the archaeal domain of life did not seem to contain an identifiable gene for the RNA component of the SRP. Now Plagens et al. have sought to solve the mystery of the “missing” component of this essential protein-targeting machine. This involved searching through the RNAs that are produced by an archaeon called Thermoproteus tenax, a single-celled microbe which grows in the absence of oxygen and at temperatures of up to 95°C. Plagens et al. discovered that the “missing” SRP RNA gene had not yet been identified because rearrangements in this archaeon’s genome had swapped the left and right portions of the SRP RNA gene. Further experiments revealed that the correct sequence order is restored in mature SRP RNA molecules by the two ends of the molecule being linked to form a circle. These RNA circles are made by the cellular machinery that normally removes the unneeded sections from other RNA molecules (called transfer RNAs). Circular RNA is much more stable at high temperatures and does not degrade easily, and Plagens et al. suggest that this particular arrangement is therefore especially advantageous for this species. Future work will now aim to work out which selective pressures favor the evolution of such fragmented RNAs. DOI:http://dx.doi.org/10.7554/eLife.11623.002
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Affiliation(s)
- André Plagens
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Michael Daume
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Julia Wiegel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Lennart Randau
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.,LOEWE Center for Synthetic Microbiology, Synmikro, Marburg, Germany
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40
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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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41
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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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42
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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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43
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Petitjean C, Deschamps P, López-García P, Moreira D. Rooting the domain archaea by phylogenomic analysis supports the foundation of the new kingdom Proteoarchaeota. Genome Biol Evol 2014; 7:191-204. [PMID: 25527841 PMCID: PMC4316627 DOI: 10.1093/gbe/evu274] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The first 16S rRNA-based phylogenies of the Archaea showed a deep division between two groups, the kingdoms Euryarchaeota and Crenarchaeota. This bipartite classification has been challenged by the recent discovery of new deeply branching lineages (e.g., Thaumarchaeota, Aigarchaeota, Nanoarchaeota, Korarchaeota, Parvarchaeota, Aenigmarchaeota, Diapherotrites, and Nanohaloarchaeota) which have also been given the same taxonomic status of kingdoms. However, the phylogenetic position of some of these lineages is controversial. In addition, phylogenetic analyses of the Archaea have often been carried out without outgroup sequences, making it difficult to determine if these taxa actually define lineages at the same level as the Euryarchaeota and Crenarchaeota. We have addressed the question of the position of the root of the Archaea by reconstructing rooted archaeal phylogenetic trees using bacterial sequences as outgroup. These trees were based on commonly used conserved protein markers (32 ribosomal proteins) as well as on 38 new markers identified through phylogenomic analysis. We thus gathered a total of 70 conserved markers that we analyzed as a concatenated data set. In contrast with previous analyses, our trees consistently placed the root of the archaeal tree between the Euryarchaeota (including the Nanoarchaeota and other fast-evolving lineages) and the rest of archaeal species, which we propose to class within the new kingdom Proteoarchaeota. This implies the relegation of several groups previously classified as kingdoms (e.g., Crenarchaeota, Thaumarchaeota, Aigarchaeota, and Korarchaeota) to a lower taxonomic rank. In addition to taxonomic implications, this profound reorganization of the archaeal phylogeny has also consequences on our appraisal of the nature of the last archaeal ancestor, which most likely was a complex organism with a gene-rich genome.
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Affiliation(s)
- Céline Petitjean
- Unité d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Orsay, France
| | - Philippe Deschamps
- Unité d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Orsay, France
| | | | - David Moreira
- Unité d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Orsay, France
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44
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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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45
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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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46
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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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48
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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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49
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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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50
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Abstract
Many RNA families, i.e., groups of homologous RNA genes, belong to RNA classes, such as tRNAs, snoRNAs, or microRNAs, that are characterized by common sequence motifs and/or common secondary structure features. The detection of new members of RNA classes, as well as the comprehensive annotation of genomes with members of RNA classes is a challenging task that goes beyond simple homology search. Computational methods addressing this problem typically use a three-tiered approach: In the first step an efficient and sensitive filter is employed. In the second step the candidate set is narrowed down using computationally expensive methods geared towards specificity. In the final step the hits are annotated with class-specific features and scored. Here we review the tools that are currently available for a diverse set of RNA classes.
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