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Cauret CMS, Jordan DC, Kukoly LM, Burton SR, Anele EU, Kwiecien JM, Gansauge MT, Senthillmohan S, Greenbaum E, Meyer M, Horb ME, Evans BJ. Functional dissection and assembly of a small, newly evolved, W chromosome-specific genomic region of the African clawed frog Xenopus laevis. PLoS Genet 2023; 19:e1010990. [PMID: 37792893 PMCID: PMC10578606 DOI: 10.1371/journal.pgen.1010990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 10/16/2023] [Accepted: 09/20/2023] [Indexed: 10/06/2023] Open
Abstract
Genetic triggers for sex determination are frequently co-inherited with other linked genes that may also influence one or more sex-specific phenotypes. To better understand how sex-limited regions evolve and function, we studied a small W chromosome-specific region of the frog Xenopus laevis that contains only three genes (dm-w, scan-w, ccdc69-w) and that drives female differentiation. Using gene editing, we found that the sex-determining function of this region requires dm-w but that scan-w and ccdc69-w are not essential for viability, female development, or fertility. Analysis of mesonephros+gonad transcriptomes during sexual differentiation illustrates masculinization of the dm-w knockout transcriptome, and identifies mostly non-overlapping sets of differentially expressed genes in separate knockout lines for each of these three W-specific gene compared to wildtype sisters. Capture sequencing of almost all Xenopus species and PCR surveys indicate that the female-determining function of dm-w is present in only a subset of species that carry this gene. These findings map out a dynamic evolutionary history of a newly evolved W chromosome-specific genomic region, whose components have distinctive functions that frequently degraded during Xenopus diversification, and evidence the evolutionary consequences of recombination suppression.
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Affiliation(s)
- Caroline M. S. Cauret
- Biology Department, McMaster University, Hamilton, Ontario, Canada
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Danielle C. Jordan
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts United States of America
- The School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | | | - Sarah R. Burton
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts United States of America
| | - Emmanuela U. Anele
- Biology Department, McMaster University, Hamilton, Ontario, Canada
- Department Zoology, Ahmadu Bello University, Zaria, Nigeria
| | - Jacek M. Kwiecien
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Marie-Theres Gansauge
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | - Eli Greenbaum
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Matthias Meyer
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Marko E. Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts United States of America
| | - Ben J. Evans
- Biology Department, McMaster University, Hamilton, Ontario, Canada
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2
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Yuan L, Han Y, Zhao J, Zhang Y, Sun Y. Recognition and cleavage mechanism of intron-containing pre-tRNA by human TSEN endonuclease complex. Nat Commun 2023; 14:6071. [PMID: 37770519 PMCID: PMC10539383 DOI: 10.1038/s41467-023-41845-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 09/18/2023] [Indexed: 09/30/2023] Open
Abstract
Removal of introns from transfer RNA precursors (pre-tRNAs) occurs in all living organisms. This is a vital phase in the maturation and functionality of tRNA. Here we present a 3.2 Å-resolution cryo-EM structure of an active human tRNA splicing endonuclease complex bound to an intron-containing pre-tRNA. TSEN54, along with the unique regions of TSEN34 and TSEN2, cooperatively recognizes the mature body of pre-tRNA and guides the anticodon-intron stem to the correct position for splicing. We capture the moment when the endonucleases are poised for cleavage, illuminating the molecular mechanism for both 3' and 5' cleavage reactions. Two insertion loops from TSEN54 and TSEN2 cover the 3' and 5' splice sites, respectively, trapping the scissile phosphate in the center of the catalytic triad of residues. Our findings reveal the molecular mechanism for eukaryotic pre-tRNA recognition and cleavage, as well as the evolutionary relationship between archaeal and eukaryotic TSENs.
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Affiliation(s)
- Ling Yuan
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yaoyao Han
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Jiazheng Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yixiao Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
| | - Yadong Sun
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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3
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Sekulovski S, Sušac L, Stelzl LS, Tampé R, Trowitzsch S. Structural basis of substrate recognition by human tRNA splicing endonuclease TSEN. Nat Struct Mol Biol 2023:10.1038/s41594-023-00992-y. [PMID: 37231152 DOI: 10.1038/s41594-023-00992-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 04/06/2023] [Indexed: 05/27/2023]
Abstract
Heterotetrameric human transfer RNA (tRNA) splicing endonuclease TSEN catalyzes intron excision from precursor tRNAs (pre-tRNAs), utilizing two composite active sites. Mutations in TSEN and its associated RNA kinase CLP1 are linked to the neurodegenerative disease pontocerebellar hypoplasia (PCH). Despite the essential function of TSEN, the three-dimensional assembly of TSEN-CLP1, the mechanism of substrate recognition, and the structural consequences of disease mutations are not understood in molecular detail. Here, we present single-particle cryogenic electron microscopy reconstructions of human TSEN with intron-containing pre-tRNAs. TSEN recognizes the body of pre-tRNAs and pre-positions the 3' splice site for cleavage by an intricate protein-RNA interaction network. TSEN subunits exhibit large unstructured regions flexibly tethering CLP1. Disease mutations localize far from the substrate-binding interface and destabilize TSEN. Our work delineates molecular principles of pre-tRNA recognition and cleavage by human TSEN and rationalizes mutations associated with PCH.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Lukas Sušac
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Lukas S Stelzl
- Faculty of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
- KOMET 1, Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany.
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4
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Sekulovski S, Trowitzsch S. What connects splicing of transfer RNA precursor molecules with pontocerebellar hypoplasia? Bioessays 2023; 45:e2200130. [PMID: 36517085 DOI: 10.1002/bies.202200130] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 01/19/2023]
Abstract
Transfer RNAs (tRNAs) represent the most abundant class of RNA molecules in the cell and are key players during protein synthesis and cellular homeostasis. Aberrations in the extensive tRNA biogenesis pathways lead to severe neurological disorders in humans. Mutations in the tRNA splicing endonuclease (TSEN) and its associated RNA kinase cleavage factor polyribonucleotide kinase subunit 1 (CLP1) cause pontocerebellar hypoplasia (PCH), a heterogeneous group of neurodegenerative disorders, that manifest as underdevelopment of specific brain regions typically accompanied by microcephaly, profound motor impairments, and child mortality. Recently, we demonstrated that mutations leading to specific PCH subtypes destabilize TSEN in vitro and cause imbalances of immature to mature tRNA ratios in patient-derived cells. However, how tRNA processing defects translate to disease on a systems level has not been understood. Recent findings suggested that other cellular processes may be affected by mutations in TSEN/CLP1 and obscure the molecular mechanisms of PCH emergence. Here, we review PCH disease models linked to the TSEN/CLP1 machinery and discuss future directions to study neuropathogenesis.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
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5
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Karamycheva S, Wolf YI, Persi E, Koonin EV, Makarova KS. Analysis of lineage-specific protein family variability in prokaryotes combined with evolutionary reconstructions. Biol Direct 2022; 17:22. [PMID: 36042479 PMCID: PMC9425974 DOI: 10.1186/s13062-022-00337-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/13/2022] [Indexed: 12/24/2022] Open
Abstract
Background Evolutionary rate is a key characteristic of gene families that is linked to the functional importance of the respective genes as well as specific biological functions of the proteins they encode. Accurate estimation of evolutionary rates is a challenging task that requires precise phylogenetic analysis. Here we present an easy to estimate protein family level measure of sequence variability based on alignment column homogeneity in multiple alignments of protein sequences from Clade-Specific Clusters of Orthologous Genes (csCOGs). Results We report genome-wide estimates of variability for 8 diverse groups of bacteria and archaea and investigate the connection between variability and various genomic and biological features. The variability estimates are based on homogeneity distributions across amino acid sequence alignments and can be obtained for multiple groups of genomes at minimal computational expense. About half of the variance in variability values can be explained by the analyzed features, with the greatest contribution coming from the extent of gene paralogy in the given csCOG. The correlation between variability and paralogy appears to originate, primarily, not from gene duplication, but from acquisition of distant paralogs and xenologs, introducing sequence variants that are more divergent than those that could have evolved in situ during the lifetime of the given group of organisms. Both high-variability and low-variability csCOGs were identified in all functional categories, but as expected, proteins encoded by integrated mobile elements as well as proteins involved in defense functions and cell motility are, on average, more variable than proteins with housekeeping functions. Additionally, using linear discriminant analysis, we found that variability and fraction of genomes carrying a given gene are the two variables that provide the best prediction of gene essentiality as compared to the results of transposon mutagenesis in Sulfolobus islandicus. Conclusions Variability, a measure of sequence diversity within an alignment relative to the overall diversity within a group of organisms, offers a convenient proxy for evolutionary rate estimates and is informative with respect to prediction of functional properties of proteins. In particular, variability is a strong predictor of gene essentiality for the respective organisms and indicative of sub- or neofunctionalization of paralogs. Supplementary Information The online version contains supplementary material available at 10.1186/s13062-022-00337-7.
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Affiliation(s)
- Svetlana Karamycheva
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Erez Persi
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA.
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6
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Figueroa CM, Asencion Diez MD, Ballicora MA, Iglesias AA. Structure, function, and evolution of plant ADP-glucose pyrophosphorylase. PLANT MOLECULAR BIOLOGY 2022; 108:307-323. [PMID: 35006475 DOI: 10.1007/s11103-021-01235-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 12/15/2021] [Indexed: 05/25/2023]
Abstract
This review outlines research performed in the last two decades on the structural, kinetic, regulatory and evolutionary aspects of ADP-glucose pyrophosphorylase, the regulatory enzyme for starch biosynthesis. ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step in the pathway of glycogen and starch synthesis in bacteria and plants, respectively. Plant ADP-Glc PPase is a heterotetramer allosterically regulated by metabolites and post-translational modifications. In this review, we focus on the three-dimensional structure of the plant enzyme, the amino acids that bind the regulatory molecules, and the regions involved in transmitting the allosteric signal to the catalytic site. We provide a model for the evolution of the small and large subunits, which produce heterotetramers with distinct catalytic and regulatory properties. Additionally, we review the various post-translational modifications observed in ADP-Glc PPases from different species and tissues. Finally, we discuss the subcellular localization of the enzyme found in grain endosperm from grasses, such as maize and rice. Overall, this work brings together research performed in the last two decades to better understand the multiple mechanisms involved in the regulation of ADP-Glc PPase. The rational modification of this enzyme could improve the yield and resilience of economically important crops, which is particularly important in the current scenario of climate change and food shortage.
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Affiliation(s)
- Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Bioquímica y Ciencias Biológicas, Santa Fe, Argentina
| | - Matías D Asencion Diez
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Bioquímica y Ciencias Biológicas, Santa Fe, Argentina
| | - Miguel A Ballicora
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, USA.
| | - Alberto A Iglesias
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Bioquímica y Ciencias Biológicas, Santa Fe, Argentina.
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7
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Canpolat N, Liu D, Atayar E, Saygili S, Kara NS, Westfall TA, Ding Q, Brown BJ, Braun TA, Slusarski D, Oguz KK, Ozluk Y, Tuysuz B, Ozturk TT, Sever L, Sezerman OU, Topaloglu R, Caliskan S, Attanasio M, Ozaltin F. A splice site mutation in the TSEN2 causes a new syndrome with craniofacial and central nervous system malformations, and atypical hemolytic uremic syndrome. Clin Genet 2022; 101:346-358. [PMID: 34964109 PMCID: PMC10357464 DOI: 10.1111/cge.14105] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/19/2021] [Accepted: 12/26/2021] [Indexed: 07/22/2023]
Abstract
Recessive mutations in the genes encoding the four subunits of the tRNA splicing endonuclease complex (TSEN54, TSEN34, TSEN15, and TSEN2) cause various forms of pontocerebellar hypoplasia, a disorder characterized by hypoplasia of the cerebellum and the pons, microcephaly, dysmorphisms, and other variable clinical features. Here, we report an intronic recessive founder variant in the gene TSEN2 that results in abnormal splicing of the mRNA of this gene, in six individuals from four consanguineous families affected with microcephaly, multiple craniofacial malformations, radiological abnormalities of the central nervous system, and cognitive retardation of variable severity. Remarkably, unlike patients with previously described mutations in the components of the TSEN complex, all the individuals that we report developed atypical hemolytic uremic syndrome (aHUS) with thrombotic microangiopathy, microangiopathic hemolytic anemia, thrombocytopenia, proteinuria, severe hypertension, and end-stage kidney disease (ESKD) early in life. Bulk RNA sequencing of peripheral blood cells of four affected individuals revealed abnormal tRNA transcripts, indicating an alteration of the tRNA biogenesis. Morpholino-mediated skipping of exon 10 of tsen2 in zebrafish produced phenotypes similar to human patients. Thus, we have identified a novel syndrome accompanied by aHUS suggesting the existence of a link between tRNA biology and vascular endothelium homeostasis, which we propose to name with the acronym TRACK syndrome (TSEN2 Related Atypical hemolytic uremic syndrome, Craniofacial malformations, Kidney failure).
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Affiliation(s)
- Nur Canpolat
- Department of Pediatric Nephrology, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - Dingxiao Liu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Emine Atayar
- Nephrogenetics Laboratory, Department of Pediatric Nephrology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Seha Saygili
- Department of Pediatric Nephrology, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - Nazli Sila Kara
- Biostatistics and Medical Informatics Program, Faculty of Medicine, Graduate School of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | | | - Qiong Ding
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Bartley J. Brown
- Center for Bioinformatics and Computational Biology, University of Iowa, Iowa City, Iowa, USA
| | - Terry A. Braun
- Center for Bioinformatics and Computational Biology, University of Iowa, Iowa City, Iowa, USA
| | - Diane Slusarski
- Center for Bioinformatics and Computational Biology, University of Iowa, Iowa City, Iowa, USA
| | - Kader Karli Oguz
- Department of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Yasemin Ozluk
- Department of Pathology, Istanbul University Faculty of Medicine, Istanbul, Turkey
| | - Beyhan Tuysuz
- Department of Pediatric Genetics, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - Tugba Tastemel Ozturk
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Lale Sever
- Department of Pediatric Nephrology, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - Osman Ugur Sezerman
- Biostatistics and Medical Informatics Program, Faculty of Medicine, Graduate School of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Rezan Topaloglu
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Salim Caliskan
- Department of Pediatric Nephrology, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - Massimo Attanasio
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Fatih Ozaltin
- Nephrogenetics Laboratory, Department of Pediatric Nephrology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
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8
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Peng R, Yoshinari S, Kawano-Sugaya T, Jeelani G, Nozaki T. Identification and Functional Characterization of Divergent 3'-Phosphate tRNA Ligase From Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:746261. [PMID: 34976851 PMCID: PMC8718801 DOI: 10.3389/fcimb.2021.746261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
HSPC117/RtcB, 3'-phosphate tRNA ligase, is a critical enzyme involved in tRNA splicing and maturation. HSPC117/RtcB is also involved in mRNA splicing of some protein-coding genes including XBP-1. Entamoeba histolytica, a protozoan parasite responsible for human amebiasis, possesses two RtcB proteins (EhRtcB1 and 2), but their biological functions remain unknown. Both RtcBs show kinship with mammalian/archaeal type, and all amino acid residues present in the active sites are highly conserved, as suggested by protein alignment and phylogenetic analyses. EhRtcB1 was demonstrated to be localized to the nucleus, while EhRtcB2 was in the cytosol. EhRtcB1, but not EhRtcB2, was required for optimal growth of E. histolytica trophozoites. Both EhRtcB1 (in cooperation with EhArchease) and EhRtcB2 showed RNA ligation activity in vitro. The predominant role of EhRtcB1 in tRNAIle(UAU) processing in vivo was demonstrated in EhRtcB1- and 2-gene silenced strains. Taken together, we have demonstrated the conservation of tRNA splicing and functional diversification of RtcBs in this amoebozoan lineage.
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Affiliation(s)
- Ruofan Peng
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeo Yoshinari
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tetsuro Kawano-Sugaya
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ghulam Jeelani
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Tocchini-Valentini GD, Tocchini-Valentini GP. Archaeal tRNA-Splicing Endonuclease as an Effector for RNA Recombination and Novel Trans-Splicing Pathways in Eukaryotes. J Fungi (Basel) 2021; 7:jof7121069. [PMID: 34947051 PMCID: PMC8707768 DOI: 10.3390/jof7121069] [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: 11/20/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022] Open
Abstract
We have characterized a homodimeric tRNA endonuclease from the euryarchaeota Ferroplasma acidarmanus (FERAC), a facultative anaerobe which can grow at temperatures ranging from 35 to 42 °C. This enzyme, contrary to the eukaryal tRNA endonucleases and the homotetrameric Methanocaldococcus jannaschii (METJA) homologs, is able to cleave minimal BHB (bulge–helix–bulge) substrates at 30 °C. The expression of this enzyme in Schizosaccharomyces pombe (SCHPO) enables the use of its properties as effectors by inserting BHB motif introns into hairpin loops normally seen in mRNA transcripts. In addition, the FERAC endonuclease can create proteins with new functionalities through the recombination of protein domains.
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Affiliation(s)
- Giuseppe D. Tocchini-Valentini
- Istituto di Biochimica e Biologia Cellulare, Campus Internazionale “A. Buzzati-Traverso”, Dipartimento Scienze Biomediche, Consiglio Nazionale delle Ricerche, via Ramarini 32, 00015 Monterotondo, Rome, Italy;
- Dipartimento Scienze Biomediche, European Mouse Mutant Archive (EMMA), INFRAFRONTIER-IMPC, Monterotondo Mouse Clinic, Campus Internazionale “A. Buzzati-Traverso”, Consiglio Nazionale delle Ricerche, via Ramarini 32, 00015 Monterotondo, Rome, Italy
- Correspondence:
| | - Glauco P. Tocchini-Valentini
- Istituto di Biochimica e Biologia Cellulare, Campus Internazionale “A. Buzzati-Traverso”, Dipartimento Scienze Biomediche, Consiglio Nazionale delle Ricerche, via Ramarini 32, 00015 Monterotondo, Rome, Italy;
- Dipartimento Scienze Biomediche, European Mouse Mutant Archive (EMMA), INFRAFRONTIER-IMPC, Monterotondo Mouse Clinic, Campus Internazionale “A. Buzzati-Traverso”, Consiglio Nazionale delle Ricerche, via Ramarini 32, 00015 Monterotondo, Rome, Italy
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10
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Sekulovski S, Devant P, Panizza S, Gogakos T, Pitiriciu A, Heitmeier K, Ramsay EP, Barth M, Schmidt C, Tuschl T, Baas F, Weitzer S, Martinez J, Trowitzsch S. Assembly defects of human tRNA splicing endonuclease contribute to impaired pre-tRNA processing in pontocerebellar hypoplasia. Nat Commun 2021; 12:5610. [PMID: 34584079 PMCID: PMC8479045 DOI: 10.1038/s41467-021-25870-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/03/2021] [Indexed: 02/07/2023] Open
Abstract
Introns of human transfer RNA precursors (pre-tRNAs) are excised by the tRNA splicing endonuclease TSEN in complex with the RNA kinase CLP1. Mutations in TSEN/CLP1 occur in patients with pontocerebellar hypoplasia (PCH), however, their role in the disease is unclear. Here, we show that intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers independently of CLP1. Splice site recognition involves the mature domain and the anticodon-intron base pair of pre-tRNAs. The 2.1-Å resolution X-ray crystal structure of a TSEN15–34 heterodimer and differential scanning fluorimetry analyses show that PCH mutations cause thermal destabilization. While endonuclease activity in recombinant mutant TSEN is unaltered, we observe assembly defects and reduced pre-tRNA cleavage activity resulting in an imbalanced pre-tRNA pool in PCH patient-derived fibroblasts. Our work defines the molecular principles of intron excision in humans and provides evidence that modulation of TSEN stability may contribute to PCH phenotypes. Mutations within subunits of the tRNA splicing endonuclease complex (TSEN) are associated with pontocerebellar hypoplasia (PCH). Here the authors show that tRNA intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers, and provide evidence that modulation of TSEN stability may contribute to PCH phenotypes.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Pascal Devant
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany.,Ph.D. Program in Virology, Harvard Medical School, Boston, MA, USA.,Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Silvia Panizza
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Tasos Gogakos
- Laboratory for RNA Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Anda Pitiriciu
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Katharina Heitmeier
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | | | - Marie Barth
- Interdisciplinary research center HALOmem, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Carla Schmidt
- Interdisciplinary research center HALOmem, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Thomas Tuschl
- Laboratory for RNA Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Frank Baas
- Department of Clinical Genetics, Leiden University, Leiden, Netherlands
| | - Stefan Weitzer
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Javier Martinez
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany.
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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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12
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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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13
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Kaneta A, Fujishima K, Morikazu W, Hori H, Hirata A. The RNA-splicing endonuclease from the euryarchaeaon Methanopyrus kandleri is a heterotetramer with constrained substrate specificity. Nucleic Acids Res 2018; 46:1958-1972. [PMID: 29346615 PMCID: PMC5829648 DOI: 10.1093/nar/gky003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/25/2017] [Accepted: 01/03/2018] [Indexed: 11/14/2022] Open
Abstract
Four different types (α4, α'2, (αβ)2 and ϵ2) of RNA-splicing endonucleases (EndAs) for RNA processing are known to exist in the Archaea. Only the (αβ)2 and ϵ2 types can cleave non-canonical introns in precursor (pre)-tRNA. Both enzyme types possess an insert associated with a specific loop, allowing broad substrate specificity in the catalytic α units. Here, the hyperthermophilic euryarchaeon Methanopyrus kandleri (MKA) was predicted to harbor an (αβ)2-type EndA lacking the specific loop. To characterize MKA EndA enzymatic activity, we constructed a fusion protein derived from MKA α and β subunits (fMKA EndA). In vitro assessment demonstrated complete removal of the canonical bulge-helix-bulge (BHB) intron structure from MKA pre-tRNAAsn. However, removal of the relaxed BHB structure in MKA pre-tRNAGlu was inefficient compared to crenarchaeal (αβ)2 EndA, and the ability to process the relaxed intron within mini-helix RNA was not detected. fMKA EndA X-ray structure revealed a shape similar to that of other EndA types, with no specific loop. Mapping of EndA types and their specific loops and the tRNA gene diversity among various Archaea suggest that MKA EndA is evolutionarily related to other (αβ)2-type EndAs found in the Thaumarchaeota, Crenarchaeota and Aigarchaeota but uniquely represents constrained substrate specificity.
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Affiliation(s)
- Ayano Kaneta
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - Wataru Morikazu
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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14
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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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15
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Chiba H, Uchiyama I. Improvement of domain-level ortholog clustering by optimizing domain-specific sum-of-pairs score. BMC Bioinformatics 2014; 15:148. [PMID: 24885064 PMCID: PMC4035852 DOI: 10.1186/1471-2105-15-148] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 05/06/2014] [Indexed: 01/11/2023] Open
Abstract
Background Identification of ortholog groups is a crucial step in comparative analysis of multiple genomes. Although several computational methods have been developed to create ortholog groups, most of those methods do not evaluate orthology at the sub-gene level. In our method for domain-level ortholog clustering, DomClust, proteins are split into domains on the basis of alignment boundaries identified by all-against-all pairwise comparison, but it often fails to determine appropriate boundaries. Results We developed a method to improve domain-level ortholog classification using multiple alignment information. This method is based on a scoring scheme, the domain-specific sum-of-pairs (DSP) score, which evaluates ortholog clustering results at the domain level as the sum total of domain-level alignment scores. We developed a refinement pipeline to improve domain-level clustering, DomRefine, by optimizing the DSP score. We applied DomRefine to domain-level ortholog groups created by DomClust using a dataset obtained from the Microbial Genome Database for Comparative Analysis (MBGD), and evaluated the results using COG clusters and TIGRFAMs models as the reference data. Thus, we observed that the agreement between the resulting classification and the classifications in the reference databases is improved at almost every step in the refinement pipeline. Moreover, the refined classification showed better agreement than the classifications in the eggNOG databases when TIGRFAMs was used as the reference database. Conclusions DomRefine is a useful tool for improving the quality of domain-level ortholog classification among microbial genomes. Combining with a rapid domain-level ortholog clustering method, such as DomClust, it can be used to create a high-quality ortholog database that can serve as a solid basis for various comparative genome analyses.
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Affiliation(s)
| | - Ikuo Uchiyama
- National Institute for Basic Biology, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki 444-8585, Japan.
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17
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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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18
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Dhar R, Bergmiller T, Wagner A. INCREASED GENE DOSAGE PLAYS A PREDOMINANT ROLE IN THE INITIAL STAGES OF EVOLUTION OF DUPLICATE TEM-1 BETA LACTAMASE GENES. Evolution 2014; 68:1775-91. [DOI: 10.1111/evo.12373] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/22/2014] [Indexed: 01/18/2023]
Affiliation(s)
- Riddhiman Dhar
- Institute of Evolutionary Biology and Environmental Studies; University of Zurich; CH-8057 Zurich Switzerland
- The Swiss Institute of Bioinformatics; CH-1015 Lausanne Switzerland
- Centre for Genomic Regulation (CRG); C/Dr. Aiguader 88 08003 Barcelona Spain
| | - Tobias Bergmiller
- ETH Zurich and Eawag; CH-8600 Dübendorf Switzerland
- Institute of Science and Technology; Am Campus 1 3400 Klosterneuburg Austria
| | - Andreas Wagner
- Institute of Evolutionary Biology and Environmental Studies; University of Zurich; CH-8057 Zurich Switzerland
- The Swiss Institute of Bioinformatics; CH-1015 Lausanne Switzerland
- The Santa Fe Institute; Santa Fe; New Mexico 87501
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19
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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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20
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Richter H, Lange SJ, Backofen R, Randau L. Comparative analysis ofCas6b processing and CRISPR RNA stability. RNA Biol 2014; 10:700-7. [PMID: 23392318 DOI: 10.4161/rna.23715] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The prokaryotic antiviral defense systems CRISP R (clustered regularly interspaced short palindromic repeats)/Cas (CRISP Rassociated) employs short crRNAs (CRISP R RNAs) to target invading viral nucleic acids. A short spacer sequence of these crRNAs can be derived from a viral genome and recognizes a reoccurring attack of a virus via base complementarity. We analyzed the effect of spacer sequences on the maturation of crRNAs of the subtype I-B Methanococcus maripaludis C5 CRISP R cluster. The responsible endonuclease, termed Cas6b, bound non-hydrolyzable repeat RNA as a dimer and mature crRNA as a monomer. Comparative analysis of Cas6b processing of individual spacer-repeat-spacer RNA substrates and crRNA stability revealed the potential influence of spacer sequence and length on these parameters. Correlation of these observations with the variable abundance of crRNAs visualized by deep-sequencing analyses is discussed. Finally, insertion of spacer and repeat sequences with archaeal poly-T termination signals is suggested to be prevented in archaeal CRISP R/Cas systems.
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Affiliation(s)
- Hagen Richter
- Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
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21
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Kawaguchi M, Takahashi H, Takehana Y, Naruse K, Nishida M, Yasumasu S. Sub-Functionalization of Duplicated Genes in the Evolution of Nine-Spined Stickleback Hatching Enzyme. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:140-50. [DOI: 10.1002/jez.b.22490] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/16/2013] [Accepted: 01/22/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Mari Kawaguchi
- Department of Materials and Life Sciences; Faculty of Science and Technology, Sophia University; Chiyoda-ku; Tokyo; Japan
| | - Hiroshi Takahashi
- Department of Applied Aquabiology; National Fisheries University; Yamaguchi; Japan
| | - Yusuke Takehana
- Laboratory of Bioresources; National Institute for Basic Biology; Okazaki, Aichi; Japan
| | - Kiyoshi Naruse
- Laboratory of Bioresources; National Institute for Basic Biology; Okazaki, Aichi; Japan
| | - Mutsumi Nishida
- Atmosphere and Ocean Research Institute; The University of Tokyo; Kashiwa; Chiba; Japan
| | - Shigeki Yasumasu
- Department of Materials and Life Sciences; Faculty of Science and Technology, Sophia University; Chiyoda-ku; Tokyo; Japan
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22
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Kuhn ML, Figueroa CM, Iglesias AA, Ballicora MA. The ancestral activation promiscuity of ADP-glucose pyrophosphorylases from oxygenic photosynthetic organisms. BMC Evol Biol 2013; 13:51. [PMID: 23433303 PMCID: PMC3585822 DOI: 10.1186/1471-2148-13-51] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 02/13/2013] [Indexed: 11/30/2022] Open
Abstract
Background ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step in the synthesis of glycogen in bacteria and starch in algae and plants. In oxygenic photosynthetic organisms, ADP-Glc PPase is mainly activated by 3-phosphoglycerate (3-PGA) and to a lesser extent by other metabolites. In this work, we analyzed the activation promiscuity of ADP-Glc PPase subunits from the cyanobacterium Anabaena PCC 7120, the green alga Ostreococcus tauri, and potato (Solanum tuberosum) tuber by comparing a specificity constant for 3-PGA, fructose-1,6-bisphosphate (FBP), fructose-6-phosphate, and glucose-6-phosphate. Results The 3-PGA specificity constant for the enzymes from Anabaena (homotetramer), O. tauri, and potato tuber was considerably higher than for other activators. O. tauri and potato tuber enzymes were heterotetramers comprising homologous small and large subunits. Conversely, the O. tauri small subunit (OtaS) homotetramer was more promiscuous because its FBP specificity constant was similar to that for 3-PGA. To explore the role of both OtaS and OtaL (O. tauri large subunit) in determining the specificity of the heterotetramer, we knocked out the catalytic activity of each subunit individually by site-directed mutagenesis. Interestingly, the mutants OtaSD148A/OtaL and OtaS/OtaLD171A had higher specificity constants for 3-PGA than for FBP. Conclusions After gene duplication, OtaS seemed to have lost specificity for 3-PGA compared to FBP. This was physiologically and evolutionarily feasible because co-expression of both subunits restored the specificity for 3-PGA of the resulting heterotetrameric wild type enzyme. This widespread promiscuity seems to be ancestral and intrinsic to the enzyme family. Its presence could constitute an efficient evolutionary mechanism to accommodate the ADP-Glc PPase regulation to different metabolic needs.
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Affiliation(s)
- Misty L Kuhn
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1032 W, Sheridan Rd, Chicago, IL 60660, USA
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23
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Avatar pre-tRNAs help elucidate the properties of tRNA-splicing endonucleases that produce tRNA from permuted genes. Proc Natl Acad Sci U S A 2012; 109:21325-9. [PMID: 23236183 DOI: 10.1073/pnas.1219336110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unusual tRNA genes, found in some algae, have their mature terminal 3' portion in front of their 5' portion in the genome. The transcripts from such genes must be cleaved by a pre-tRNA endonuclease to form a functional tRNA. We present a mechanism for the generation of "corrected" tRNAs from such a "permuted" pre-tRNA configuration. We used two avatar (av) or model pre-tRNAs and two splicing endonucleases with distinct mechanisms of recognition of the pre-tRNA. The splicing results are compatible with an evolutionary route in which permuted genes result from a duplication event followed by DNA rearrangement. The model pre-tRNAs permit description of the features that a transcript, derived from a rearranged duplicated gene, must have to give rise to functional tRNA. The two tRNA endonucleases are a eukaryal enzyme that normally acts in a mature domain-dependent mode and an archaeal enzyme that acts in a mature domain-independent mode. Both av pre-tRNAs are able to fold into two conformations: 1 and 2. We find that only conformation 2 can yield a corrected functional tRNA. This result is consistent with contemporary algae representing snapshots of different evolutionary stages, with duplicated genes preceding recombinatorial events generating a permutated gene. In a scenario elucidated by the use of the av pre-tRNAs, algal permuted tRNA genes could have further lost one of two mature domains, eliminating steric problems for the algal tRNA endonuclease, which remains a typical eukaryal enzyme capable of correcting the permuted transcript to a functional tRNA.
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24
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Hirata A, Fujishima K, Yamagami R, Kawamura T, Banfield JF, Kanai A, Hori H. X-ray structure of the fourth type of archaeal tRNA splicing endonuclease: insights into the evolution of a novel three-unit composition and a unique loop involved in broad substrate specificity. Nucleic Acids Res 2012; 40:10554-66. [PMID: 22941657 PMCID: PMC3488258 DOI: 10.1093/nar/gks826] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cleavage of introns from precursor transfer RNAs (tRNAs) by tRNA splicing endonuclease (EndA) is essential for tRNA maturation in Archaea and Eukarya. In the past, archaeal EndAs were classified into three types (α′2, α4 and α2β2) according to subunit composition. Recently, we have identified a fourth type of archaeal EndA from an uncultivated archaeon Candidatus Micrarchaeum acidiphilum, referred to as ARMAN-2, which is deeply branched within Euryarchaea. The ARMAN-2 EndA forms an ε2 homodimer and has broad substrate specificity like the α2β2 type EndAs found in Crenarchaea and Nanoarchaea. However, the precise architecture of ARMAN-2 EndA was unknown. Here, we report the crystal structure of the ε2 homodimer of ARMAN-2 EndA. The structure reveals that the ε protomer is separated into three novel units (αN, α and βC) fused by two distinct linkers, although the overall structure of ARMAN-2 EndA is similar to those of the other three types of archaeal EndAs. Structural comparison and mutational analyses reveal that an ARMAN-2 type-specific loop (ASL) is involved in the broad substrate specificity and that K161 in the ASL functions as the RNA recognition site. These findings suggest that the broad substrate specificities of ε2 and α2β2 EndAs were separately acquired through different evolutionary processes.
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Affiliation(s)
- Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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25
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Dhungel N, Hopper AK. Beyond tRNA cleavage: novel essential function for yeast tRNA splicing endonuclease unrelated to tRNA processing. Genes Dev 2012; 26:503-14. [PMID: 22391451 DOI: 10.1101/gad.183004.111] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Pre-tRNA splicing is an essential process in all eukaryotes. In yeast and vertebrates, the enzyme catalyzing intron removal from pre-tRNA is a heterotetrameric complex (splicing endonuclease [SEN] complex). Although the SEN complex is conserved, the subcellular location where pre-tRNA splicing occurs is not. In yeast, the SEN complex is located at the cytoplasmic surface of mitochondria, whereas in vertebrates, pre-tRNA splicing is nuclear. We engineered yeast to mimic the vertebrate cell biology and demonstrate that all three steps of pre-tRNA splicing, as well as tRNA nuclear export and aminoacylation, occur efficiently when the SEN complex is nuclear. However, nuclear pre-tRNA splicing fails to complement growth defects of cells with defective mitochondrial-located splicing, suggesting that the yeast SEN complex surprisingly serves a novel and essential function in the cytoplasm that is unrelated to tRNA splicing. The novel function requires all four SEN complex subunits and the catalytic core. A subset of pre-rRNAs accumulates when the SEN complex is restricted to the nucleus, indicating that the SEN complex moonlights in rRNA processing. Thus, findings suggest that selection for the subcellular distribution of the SEN complex may reside not in its canonical, but rather in a novel, activity.
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Affiliation(s)
- Nripesh Dhungel
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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26
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Popow J, Schleiffer A, Martinez J. Diversity and roles of (t)RNA ligases. Cell Mol Life Sci 2012; 69:2657-70. [PMID: 22426497 PMCID: PMC3400036 DOI: 10.1007/s00018-012-0944-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/01/2012] [Accepted: 02/13/2012] [Indexed: 12/29/2022]
Abstract
The discovery of discontiguous tRNA genes triggered studies dissecting the process of tRNA splicing. As a result, we have gained detailed mechanistic knowledge on enzymatic removal of tRNA introns catalyzed by endonuclease and ligase proteins. In addition to the elucidation of tRNA processing, these studies facilitated the discovery of additional functions of RNA ligases such as RNA repair and non-conventional mRNA splicing events. Recently, the identification of a new type of RNA ligases in bacteria, archaea, and humans closed a long-standing gap in the field of tRNA processing. This review summarizes past and recent findings in the field of tRNA splicing with a focus on RNA ligation as it preferentially occurs in archaea and humans. In addition to providing an integrated view of the types and phyletic distribution of RNA ligase proteins known to date, this survey also aims at highlighting known and potential accessory biological functions of RNA ligases.
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Affiliation(s)
- Johannes Popow
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Dr. Bohrgasse 3, 1030 Vienna, Austria
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27
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Zhang H, Zhang CQ, Sun ZZ, Yu W, Gu MH, Liu QQ, Li YS. A major locus qS12, located in a duplicated segment of chromosome 12, causes spikelet sterility in an indica-japonica rice hybrid. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 123:1247-56. [PMID: 21792631 DOI: 10.1007/s00122-011-1663-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Accepted: 07/09/2011] [Indexed: 05/06/2023]
Abstract
Chromosome segment duplications are integral in genome evolution by providing a source for the origin of new genes. In the rice genome, besides an ancient polyploidy event known in the rice common ancestor, it had been identified that there was a special segmental duplication involving chromosomes 11 and 12, but the biological role of this duplication remains unknown. In this study, by using a set of chromosome segment substitution lines (CSSLs) and near isogenic lines (NILs) derived from the indica cultivar 9311 and japonica cultivar Nipponbare, a major QTL (qS12) resulting in hybrid male sterility was mapped within ~400 kb region adjacent to the special duplicated segment on the short arm of chromosome 12. Compared to the japonica cultivar Nipponbare, the two sides of the qS12 candidate region were inverted in the indica cultivar 9311. Among 47 of the 111 rice genotypes evaluated by molecular markers, the inverted sides were detected, and found completely homologous to indica cultivar 9311. These results suggested that the two inverted sides protect the sequence in the qS12 regions from recombination. On the short-arm of chromosome 12, two QTLs S-e and S25, in addition to qS12, were previously detected as a distinct segregation distortion and pollen semi-sterility loci. We propose these three hybrid sterility loci are the same locus, and the duplicated segment on chromosome 12 may play a prominent role in diversification, i.e., sub-speciation of cultivated rice.
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Affiliation(s)
- Hua Zhang
- State Key Laboratory of Hybrid Rice, Key Laboratory of Plant Developmental Biology of Ministry of Education, College of Life Sciences, Wuhan University, Wuhan, 430072, Hubei, China
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Fujishima K, Sugahara J, Miller CS, Baker BJ, Di Giulio M, Takesue K, Sato A, Tomita M, Banfield JF, Kanai A. A novel three-unit tRNA splicing endonuclease found in ultrasmall Archaea possesses broad substrate specificity. Nucleic Acids Res 2011; 39:9695-704. [PMID: 21880595 PMCID: PMC3239211 DOI: 10.1093/nar/gkr692] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
tRNA splicing endonucleases, essential enzymes found in Archaea and Eukaryotes, are involved in the processing of pre-tRNA molecules. In Archaea, three types of splicing endonuclease [homotetrameric: α4, homodimeric: α2, and heterotetrameric: (αβ)2] have been identified, each representing different substrate specificity during the tRNA intron cleavage. Here, we discovered a fourth type of archaeal tRNA splicing endonuclease (ε2) in the genome of the acidophilic archaeon Candidatus Micrarchaeum acidiphilum, referred to as ARMAN-2 and its closely related species, ARMAN-1. The enzyme consists of two duplicated catalytic units and one structural unit encoded on a single gene, representing a novel three-unit architecture. Homodimeric formation was confirmed by cross-linking assay, and site-directed mutagenesis determined that the conserved L10-pocket interaction between catalytic and structural unit is necessary for the assembly. A tRNA splicing assay reveal that ε2 endonuclease cleaves both canonical and non-canonical bulge–helix–bulge motifs, similar to that of (αβ)2 endonuclease. Unlike other ARMAN and Euryarchaeota, tRNAs found in ARMAN-2 are highly disrupted by introns at various positions, which again resemble the properties of archaeal species with (αβ)2 endonuclease. Thus, the discovery of ε2 endonuclease in an archaeon deeply branched within Euryarchaeota represents a new example of the coevolution of tRNA and their processing enzymes.
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Affiliation(s)
- Kosuke Fujishima
- Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0017, Japan
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29
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Abstract
The self-splicing group I introns are removed by an autocatalytic mechanism that involves a series of transesterification reactions. They require RNA binding proteins to act as chaperones to correctly fold the RNA into an active intermediate structure in vivo. Pre-tRNA introns in Bacteria and in higher eukaryote plastids are typical examples of self-splicing group I introns. By contrast, two striking features characterize RNA splicing in the archaeal world. First, self-splicing group I introns cannot be found, to this date, in that kingdom. Second, the RNA splicing scenario in Archaea is uniform: All introns, whether in pre-tRNA or elsewhere, are removed by tRNA splicing endonucleases. We suggest that in Archaea, the protein recruited for splicing is the preexisting tRNA splicing endonuclease and that this enzyme, together with the ligase, takes over the task of intron removal in a more efficient fashion than the ribozyme. The extinction of group I introns in Archaea would then be a consequence of recruitment of the tRNA splicing endonuclease. We deal here with comparative genome analysis, focusing specifically on the integration of introns into genes coding for 23S rRNA molecules, and how this newly acquired intron has to be removed to regenerate a functional RNA molecule. We show that all known oligomeric structures of the endonuclease can recognize and cleave a ribosomal intron, even when the endonuclease derives from a strain lacking rRNA introns. The persistence of group I introns in mitochondria and chloroplasts would be explained by the inaccessibility of these introns to the endonuclease.
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Mao D, Yu H, Liu T, Yang G, Xing Y. Two complementary recessive genes in duplicated segments control etiolation in rice. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 122:373-383. [PMID: 20872210 DOI: 10.1007/s00122-010-1453-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2010] [Accepted: 09/08/2010] [Indexed: 05/29/2023]
Abstract
The main objective of this study was to identify the genes causing etiolation in a rice mutant, the thylakoids of which were scattered. Three populations were employed to map the genes for etiolation using bulked segregant analysis. Genetic analysis confirmed that etiolation was controlled by two recessive genes, et11 and et12, which were fine mapped to an approximately 147-kb region and an approximately 209-kb region on the short arms of chromosomes 11 and 12, respectively. Both regions were within the duplicated segments on chromosomes 11 and 12. They possessed a highly similar sequence of 38 kb at the locations of a pair of duplicated genes with protein sequences very similar to that of HCF152 in Arabidopsis that are required for the processing of chloroplast RNA. These genes are likely the candidates for et11 and et12. Expression profiling was used to compare the expression patterns of paralogs in the duplicated segments. Expression profiling indicated that the duplicated segments had been undergone concerted evolution, and a large number of the paralogs within the duplicated segments were functionally redundant like et11 and et12.
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Affiliation(s)
- Donghai Mao
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
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31
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Okuda M, Shiba T, Inaoka DK, Kita K, Kurisu G, Mineki S, Harada S, Watanabe YI, Yoshinari S. A conserved lysine residue in the crenarchaea-specific loop is important for the crenarchaeal splicing endonuclease activity. J Mol Biol 2010; 405:92-104. [PMID: 21050862 DOI: 10.1016/j.jmb.2010.10.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 10/26/2010] [Accepted: 10/27/2010] [Indexed: 11/25/2022]
Abstract
In Archaea, splicing endonuclease (EndA) recognizes and cleaves precursor RNAs to remove introns. Currently, EndAs are classified into three families according to their subunit structures: homotetramer, homodimer, and heterotetramer. The crenarchaeal heterotetrameric EndAs can be further classified into two subfamilies based on the size of the structural subunit. Subfamily A possesses a structural subunit similar in size to the catalytic subunit, whereas subfamily B possesses a structural subunit significantly smaller than the catalytic subunit. Previously, we solved the crystal structure of an EndA from Pyrobaculum aerophilum. The endonuclease was classified into subfamily B, and the structure revealed that the enzyme lacks an N-terminal subdomain in the structural subunit. However, no structural information is available for crenarchaeal heterotetrameric EndAs that are predicted to belong to subfamily A. Here, we report the crystal structure of the EndA from Aeropyrum pernix, which is predicted to belong to subfamily A. The enzyme possesses the N-terminal subdomain in the structural subunit, revealing that the two subfamilies of heterotetrameric EndAs are structurally distinct. EndA from A. pernix also possesses an extra loop region that is characteristic of crenarchaeal EndAs. Our mutational study revealed that the conserved lysine residue in the loop is important for endonuclease activity. Furthermore, the sequence characteristics of the loops and the positions towards the substrate RNA according to a docking model prompted us to propose that crenarchaea-specific loops and an extra amino acid sequence at the catalytic loop of nanoarchaeal EndA are derived by independent convergent evolution and function for recognizing noncanonical bulge-helix-bulge motif RNAs as substrates.
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Affiliation(s)
- Maho Okuda
- Department of Biomedical Chemistry, University of Tokyo, Tokyo 113-0033, Japan
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32
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Abstract
Computational studies predict the simultaneous presence of two and even three introns in certain crenarchaeal tRNA genes. In these multiple-intron-containing pretRNAs, the introns are nested one inside the other and the pretRNA folds into a conformation that is anticipated to allow splicing of the last intron only after splicing the others. A set of operations, each consisting of two cleavages and one ligation, therefore needs to be carried out sequentially. PretRNAs containing multiple introns are predicted to fold, forming bulge-helix-bulge (BHB) and BHB-like motifs. The tRNA splicing endonuclease should recognize these motifs. To test this hypothetical scenario, we used the homotetrameric enzyme from Methanocaldococcus jannaschii (METJA) and the heterotetrameric enzyme from Sulfolobus solfataricus (SULSO). On the basis of our previous studies, the METJA enzyme should cleave only the BHB structure motif, while the SULSO enzyme can in addition cleave variant substrate structures, like the bulge-helix-loop (BHL). We show here that the processing of multiple-intron-containing pretRNA can be observed in vitro.
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Disrupted tRNA gene diversity and possible evolutionary scenarios. J Mol Evol 2009; 69:497-504. [PMID: 19826747 DOI: 10.1007/s00239-009-9294-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 10/02/2009] [Indexed: 10/20/2022]
Abstract
The following unusual tRNAs have recently been discovered in the genomes of Archaea and primitive Eukaryota: multiple-intron-containing tRNAs, which have more than one intron; split tRNAs, which are produced from two pieces of RNA transcribed from separate genes; tri-split tRNAs, which are produced from three separate genes; and permuted tRNA, in which the 5' and 3' halves are encoded with permuted orientations within a single gene. All these disrupted tRNA genes can form mature contiguous tRNA, which is aminoacylated after processing by cis or trans splicing. The discovery of such tRNA disruptions has raised the question of when and why these complex tRNA processing pathways emerged during the evolution of life. Many previous reports have noted that tRNA genes contain a single intron in the anticodon loop region, a feature common throughout all three domains of life, suggesting an ancient trait of the last universal common ancestor. In this context, these unique tRNA disruptions recently found only in Archaea and primitive Eukaryota provide new insight into the origin and evolution of tRNA genes, encouraging further research in this field. In this paper, we summarize the phylogeny, structure, and processing machinery of all known types of disrupted tRNAs and discuss possible evolutionary scenarios for these tRNA genes.
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Kuhn ML, Falaschetti CA, Ballicora MA. Ostreococcus tauri ADP-glucose pyrophosphorylase reveals alternative paths for the evolution of subunit roles. J Biol Chem 2009; 284:34092-102. [PMID: 19737928 DOI: 10.1074/jbc.m109.037614] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ADP-glucose pyrophosphorylase controls starch synthesis in plants and is an interesting case to study the evolution and differentiation of roles in heteromeric enzymes. It includes two homologous subunits, small (S) and large (L), that originated from a common photosynthetic eukaryotic ancestor. In present day organisms, these subunits became complementary after loss of certain roles in a process described as subfunctionalization. For instance, the potato tuber enzyme has a noncatalytic L subunit that complements an S subunit with suboptimal allosteric properties. To understand the evolution of catalysis and regulation in this family, we artificially synthesized both subunit genes from the unicellular alga Ostreococcus tauri. This is among the most ancient species in the green lineage that diverged from the ancestor of all green plants and algae. After heterologous gene expression, we purified and characterized the proteins. The O. tauri enzyme was not redox-regulated, suggesting that redox regulation of ADP-glucose pyrophosphorylases appeared later in evolution. The S subunit had a typical low apparent affinity for the activator 3-phosphoglycerate, but it was atypically defective in the catalytic efficiency (V(max)/K(m)) for the substrate Glc-1-P. The L subunit needed the S subunit for soluble expression. In the presence of a mutated S subunit (to avoid interference), the L subunit had a high apparent affinity for 3-phosphoglycerate and substrates suggesting a leading role in catalysis. Therefore, the subfunctionalization of the O. tauri enzyme was different from previously described cases. To the best of our knowledge, this is the first biochemical description of a system with alternative subfunctionalization paths.
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Affiliation(s)
- Misty L Kuhn
- Department of Chemistry, Loyola University Chicago, Chicago, Illinois 60626, USA
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Yokobori SI, Itoh T, Yoshinari S, Nomura N, Sako Y, Yamagishi A, Oshima T, Kita K, Watanabe YI. Gain and loss of an intron in a protein-coding gene in Archaea: the case of an archaeal RNA pseudouridine synthase gene. BMC Evol Biol 2009; 9:198. [PMID: 19671140 PMCID: PMC2738675 DOI: 10.1186/1471-2148-9-198] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 08/11/2009] [Indexed: 01/13/2023] Open
Abstract
Background We previously found the first examples of splicing of archaeal pre-mRNAs for homologs of the eukaryotic CBF5 protein (also known as dyskerin in humans) in Aeropyrum pernix, Sulfolobus solfataricus, S. tokodaii, and S. acidocaldarirus, and also showed that crenarchaeal species in orders Desulfurococcales and Sulfolobales, except for Hyperthermus butylicus, Pyrodictium occultum, Pyrolobus fumarii, and Ignicoccus islandicus, contain the (putative) cbf5 intron. However, the exact timing of the intron insertion was not determined and verification of the putative secondary loss of the intron in some lineages was not performed. Results In the present study, we determined approximately two-thirds of the entire coding region of crenarchaeal Cbf5 sequences from 43 species. A phylogenetic analysis of our data and information from the available genome sequences suggested that the (putative) cbf5 intron existed in the common ancestor of the orders Desulfurococcales and Sulfolobales and that probably at least two independent lineages in the order Desulfurococcales lost the (putative) intron. Conclusion This finding is the first observation of a lineage-specific loss of a pre-mRNA intron in Archaea. As the insertion or deletion of introns in protein-coding genes in Archaea has not yet been seriously considered, our finding suggests the possible difficulty of accurately and completely predicting protein-coding genes in Archaea.
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Affiliation(s)
- Shin-ichi Yokobori
- Department of Molecular Biology, School of Life Science, Tokyo University of Pharmacy and Life Science, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
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Mitchell M, Xue S, Erdman R, Randau L, Söll D, Li H. Crystal structure and assembly of the functional Nanoarchaeum equitans tRNA splicing endonuclease. Nucleic Acids Res 2009; 37:5793-802. [PMID: 19578064 PMCID: PMC2761253 DOI: 10.1093/nar/gkp537] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The RNA splicing and processing endonuclease from Nanoarchaeum equitans (NEQ) belongs to the recently identified (αβ)2 family of splicing endonucleases that require two different subunits for splicing activity. N. equitans splicing endonuclease comprises the catalytic subunit (NEQ205) and the structural subunit (NEQ261). Here, we report the crystal structure of the functional NEQ enzyme at 2.1 Å containing both subunits, as well as that of the NEQ261 subunit alone at 2.2 Å. The functional enzyme resembles previously known α2 and α4 endonucleases but forms a heterotetramer: a dimer of two heterodimers of the catalytic subunit (NEQ205) and the structural subunit (NEQ261). Surprisingly, NEQ261 alone forms a homodimer, similar to the previously known homodimer of the catalytic subunit. The homodimers of isolated subunits are inhibitory to heterodimerization as illustrated by a covalently linked catalytic homodimer that had no RNA cleavage activity upon mixing with the structural subunit. Detailed structural comparison reveals a more favorable hetero- than homodimerization interface, thereby suggesting a possible regulation mechanism of enzyme assembly through available subunits. Finally, the uniquely flexible active site of the NEQ endonuclease provides a possible explanation for its broader substrate specificity.
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Affiliation(s)
- Michelle Mitchell
- Department of Chemistry and Biochemistry, Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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Yoshinari S, Shiba T, Inaoka DK, Itoh T, Kurisu G, Harada S, Kita K, Watanabe YI. Functional importance of crenarchaea-specific extra-loop revealed by an X-ray structure of a heterotetrameric crenarchaeal splicing endonuclease. Nucleic Acids Res 2009; 37:4787-98. [PMID: 19515941 PMCID: PMC2724299 DOI: 10.1093/nar/gkp506] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Archaeal splicing endonucleases (EndAs) are currently classified into three groups. Two groups require a single subunit protein to form a homodimer or homotetramer. The third group requires two nonidentical protein components for the activity. To elucidate the molecular architecture of the two-subunit EndA system, we studied a crenarchaeal splicing endonuclease from Pyrobaculum aerophilum. In the present study, we solved a crystal structure of the enzyme at 1.7-Å resolution. The enzyme adopts a heterotetrameric form composed of two catalytic and two structural subunits. By connecting the structural and the catalytic subunits of the heterotetrameric EndA, we could convert the enzyme to a homodimer that maintains the broad substrate specificity that is one of the characteristics of heterotetrameric EndA. Meanwhile, a deletion of six amino acids in a Crenarchaea-specific loop abolished the endonuclease activity even on a substrate with canonical BHB motif. These results indicate that the subunit architecture is not a major factor responsible for the difference of substrate specificity between single- and two-subunit EndA systems. Rather, the structural basis for the broad substrate specificity is built into the crenarchaeal splicing endonuclease itself.
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Affiliation(s)
- Shigeo Yoshinari
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Kanai A, Sato A, Fukuda Y, Okada K, Matsuda T, Sakamoto T, Muto Y, Yokoyama S, Kawai G, Tomita M. Characterization of a heat-stable enzyme possessing GTP-dependent RNA ligase activity from a hyperthermophilic archaeon, Pyrococcus furiosus. RNA (NEW YORK, N.Y.) 2009; 15:420-431. [PMID: 19155324 PMCID: PMC2657004 DOI: 10.1261/rna.1122109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 11/24/2008] [Indexed: 05/27/2023]
Abstract
Using an expression protein library of a hyperthermophilic archaeon, Pyrococcus furiosus, we identified a gene (PF0027) that encodes a protein with heat-stable cyclic nucleotide phosphodiesterase (CPDase) activity. The PF0027 gene encoded a 21-kDa protein and an amino acid sequence that showed approximately 27% identity to that of the 2'-5' tRNA ligase protein, ligT (20 kDa), from Escherichia coli. We found that the purified PF0027 protein possessed GTP-dependent RNA ligase activity and that synthetic tRNA halves bearing 2',3'-cyclic phosphate and 5'-OH termini were substrates for the ligation reaction in vitro. GTP hydrolysis was not required for the reaction, and GTPgammaS enhanced the tRNA ligation activity of PF0027 protein, suggesting that the ligation step is regulated by a novel mechanism. In comparison to the strong CPDase activity of the PF0027 protein, the RNA ligase activity itself was quite weak, and the ligation product was unstable during in vitro reaction. Finally, we used NMR to determine the solution structure of the PF0027 protein and discuss the implications of our results in understanding the role of the PF0027 protein.
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Affiliation(s)
- Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan.
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Sato Y, Hashiguchi Y, Nishida M. Evolution of multiple phosphodiesterase isoforms in stickleback involved in cAMP signal transduction pathway. BMC SYSTEMS BIOLOGY 2009; 3:23. [PMID: 19232106 PMCID: PMC2653465 DOI: 10.1186/1752-0509-3-23] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 02/20/2009] [Indexed: 11/10/2022]
Abstract
Background Duplicate genes are considered to have evolved through the partitioning of ancestral functions among duplicates (subfunctionalization) and/or the acquisition of novel functions from a beneficial mutation (neofunctionalization). Additionally, an increase in gene dosage resulting from duplication may also confer an advantageous effect, as has been suggested for histone, tRNA, and rRNA genes. Currently, there is little understanding of the effect of increased gene dosage on subcellular networks like signal transduction pathways. Addressing this issue may provide further insights into the evolution by gene duplication. Results We analyzed the evolution of multiple stickleback phosphodiesterase (PDE, EC: 3.1.4.17) 1C genes involved in the cyclic nucleotide signaling pathway. Stickleback has 8–9 copies of this gene, whereas only one or two loci exist in other model vertebrates. Our phylogenetic and synteny analyses suggested that the multiple PDE1C genes in stickleback were generated by repeated duplications of >100-kbp chromosome segments. Sequence evolution analysis did not provide strong evidence for neofunctionalization in the coding sequences of stickleback PDE1C isoforms. On the other hand, gene expression analysis suggested that the derived isoforms acquired expression in new organs, implying their neofunctionalization in terms of expression patterns. In addition, at least seven isoforms of the stickleback PDE1C were co-expressed with olfactory-type G-proteins in the nose, suggesting that PDE1C dosage is increased in the stickleback olfactory transduction (OT) pathway. In silico simulations of OT implied that the increased PDE1C dosage extends the longevity of the depolarization signals of the olfactory receptor neuron. Conclusion The predicted effect of the increase in PDE1C products on the OT pathway may play an important role in stickleback behavior and ecology. However, this possibility should be empirically examined. Our analyses imply that an increase in gene product sometimes has a significant, yet unexpected, effect on the functions of subcellular networks.
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Affiliation(s)
- Yukuto Sato
- Division of Molecular Marine Biology, Ocean Research Institute, The University of Tokyo, Tokyo, Japan.
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40
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Doyle JJ, Flagel LE, Paterson AH, Rapp RA, Soltis DE, Soltis PS, Wendel JF. Evolutionary genetics of genome merger and doubling in plants. Annu Rev Genet 2009; 42:443-61. [PMID: 18983261 DOI: 10.1146/annurev.genet.42.110807.091524] [Citation(s) in RCA: 428] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polyploidy is a common mode of evolution in flowering plants. The profound effects of polyploidy on gene expression appear to be caused more by hybridity than by genome doubling. Epigenetic mechanisms underlying genome-wide changes in expression are as yet poorly understood; only methylation has received much study, and its importance varies among polyploids. Genetic diploidization begins with the earliest responses to genome merger and doubling; less is known about chromosomal diploidization. Polyploidy duplicates every gene in the genome, providing the raw material for divergence or partitioning of function in homoeologous copies. Preferential retention or loss of genes occurs in a wide range of taxa, suggesting that there is an underlying set of principles governing the fates of duplicated genes. Further studies are required for general patterns to be elucidated, involving different plant families, kinds of polyploidy, and polyploids of different ages.
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Affiliation(s)
- Jeff J Doyle
- Department of Plant Biology, Cornell University, Ithaca, New York 14850, USA.
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Tri-split tRNA is a transfer RNA made from 3 transcripts that provides insight into the evolution of fragmented tRNAs in archaea. Proc Natl Acad Sci U S A 2009; 106:2683-7. [PMID: 19190180 DOI: 10.1073/pnas.0808246106] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transfer RNA (tRNA) is essential for decoding the genome sequence into proteins. In Archaea, previous studies have revealed unique multiple intron-containing tRNAs and tRNAs that are encoded on 2 separate genes, so-called split tRNAs. Here, we discovered 10 fragmented tRNA genes in the complete genome of the hyperthermoacidophilic Archaeon Caldivirga maquilingensis that are individually transcribed and further trans-spliced to generate all of the missing tRNAs encoding glycine, alanine, and glutamate. Notably, the 3 mature tRNA(Gly)'s with synonymous codons are created from 1 constitutive 3' half transcript and 4 alternatively switching transcripts, representing tRNA made from a total of 3 transcripts named a "tri-split tRNA." Expression and nucleotide sequences of 10 split tRNA genes and their joined tRNA products were experimentally verified. The intervening sequences of split tRNA have high identity to tRNA intron sequences located at the same positions in intron-containing tRNAs in related Thermoproteales species. This suggests that an evolutionary relationship between intron-containing and split tRNAs exists. Our findings demonstrate the first example of split tRNA genes in a free-living organism and a unique tri-split tRNA gene that provides further insight into the evolution of fragmented tRNAs.
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42
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Sugahara J, Kikuta K, Fujishima K, Yachie N, Tomita M, Kanai A. Comprehensive analysis of archaeal tRNA genes reveals rapid increase of tRNA introns in the order thermoproteales. Mol Biol Evol 2008; 25:2709-16. [PMID: 18832079 DOI: 10.1093/molbev/msn216] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The analysis of archaeal tRNA genes is becoming more important to evaluate the origin and evolution of tRNA molecule. Even with the recent accumulation of complete genomes of numerous archaeal species, several tRNA genes are still required for a full complement of the codon table. We conducted comprehensive screening of tRNA genes from 47 archaeal genomes by using a combination of different types of tRNA prediction programs and extracted a total of 2,143 reliable tRNA gene candidates including 437 intron-containing tRNA genes, which covered more than 99.9% of the codon tables in Archaea. Previously, the content of intron-containing tRNA genes in Archaea was estimated to be approximately 15% of the whole tRNA genes, and most of the introns were known to be located at canonical positions (nucleotide position between 37 and 38) of precursor tRNA (pre-tRNA). Surprisingly, we observed marked enrichment of tRNA introns in five species of the archaeal order Thermoproteales; about 70% of tRNA gene candidates were found to be intron-containing tRNA genes, half of which contained multiple introns, and the introns were located at various noncanonical positions. Sequence similarity analysis revealed that approximately half of the tRNA introns found at Thermoproteales-specific intron locations were highly conserved among several tRNA genes. Intriguingly, identical tRNA intron sequences were found within different types of tRNA genes that completely lacked exon sequence similarity, suggesting that the tRNA introns in Thermoproteales could have been gained via intron insertion events at a later stage of tRNA evolution. Moreover, although the CCA sequence at the 3' terminal of pre-tRNA is added by a CCA-adding enzyme after gene transcription in Archaea, most of the tRNA genes containing highly conserved introns already encode the CCA sequence at their 3' terminal. Based on these results, we propose possible models explaining the rapid increase of tRNA introns as a result of intron insertion events via retrotransposition of pre-tRNAs. The sequences and secondary structures of the tRNA genes and their bulge-helix-bulge motifs were registered in SPLITSdb (http://splits.iab.keio.ac.jp/splitsdb/), a novel and comprehensive database for archaeal tRNA genes.
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Affiliation(s)
- Junichi Sugahara
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
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Sandve SR, Rudi H, Asp T, Rognli OA. Tracking the evolution of a cold stress associated gene family in cold tolerant grasses. BMC Evol Biol 2008; 8:245. [PMID: 18775065 PMCID: PMC2542378 DOI: 10.1186/1471-2148-8-245] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 09/05/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Grasses are adapted to a wide range of climatic conditions. Species of the subfamily Pooideae, which includes wheat, barley and important forage grasses, have evolved extreme frost tolerance. A class of ice binding proteins that inhibit ice re-crystallisation, specific to the Pooideae subfamily lineage, have been identified in perennial ryegrass and wheat, and these proteins are thought to have evolved from a leucine-rich repeat phytosulfokine receptor kinase (LRR-PSR)-like ancestor gene. Even though the ice re-crystallisation inhibition function of these proteins has been studied extensively in vitro, little is known about the evolution of these genes on the molecular level. RESULTS We identified 15 putative novel ice re-crystallisation inhibition (IRI)-like protein coding genes in perennial ryegrass, barley, and wheat. Using synonymous divergence estimates we reconstructed the evolution of the IRI-like gene family. We also explored the hypothesis that the IRI-domain has evolved through repeated motif expansion and investigated the evolutionary relationship between a LRR-domain containing IRI coding gene in carrot and the Pooideae IRI-like genes. Our analysis showed that the main expansion of the IRI-gene family happened ~36 million years ago (Mya). In addition to IRI-like paralogs, wheat contained several sequences that likely were products of polyploidisation events (homoeologs). Through sequence analysis we identified two short motifs in the rice LRR-PSR gene highly similar to the repeat motifs of the IRI-domain in cold tolerant grasses. Finally we show that the LRR-domain of carrot and grass IRI proteins both share homology to an Arabidopsis thaliana LRR-trans membrane protein kinase (LRR-TPK). CONCLUSION The diverse IRI-like genes identified in this study tell a tale of a complex evolutionary history including birth of an ice binding domain, a burst of gene duplication events after cold tolerant grasses radiated from rice, protein domain structure differentiation between paralogs, and sub- and/or neofunctionalisation of IRI-like proteins. From our sequence analysis we provide evidence for IRI-domain evolution probably occurring through increased copy number of a repeated motif. Finally, we discuss the possibility of parallel evolution of LRR domain containing IRI proteins in carrot and grasses through two completely different molecular adaptations.
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Affiliation(s)
- Simen R Sandve
- Department of Plant and Environmental Sciences, University of Life Sciences, As, Norway.
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Abstract
The short genes encoding transfer RNA (tRNA) molecules are highly conserved in both sequence and structure, reflecting the central role of tRNA in protein biosynthesis. The frequent occurrence of fragmented intron-containing tRNAs that require processing to form contiguous molecules is therefore surprising. Recent discoveries of permuted and split tRNA genes have added to the apparent creativity of nature regarding the organization of these fragmented genes. Here, we provide an overview of the various types of fragmented tRNA genes and examine the hypothesis that the integration of mobile genetic elements--including viruses and plasmids--established such genes in pieces.
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Cis- and trans-splicing of mRNAs mediated by tRNA sequences in eukaryotic cells. Proc Natl Acad Sci U S A 2008; 105:6864-9. [PMID: 18458335 DOI: 10.1073/pnas.0800420105] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The formation of chimeric mRNAs is a strategy used by human cells to increase the complexity of their proteome, as revealed by the ENCODE project. Here, we use Saccharomyces cerevisiae to show a way by which trans-spliced mRNAs can be generated. We demonstrate that a pretRNA inserted into a premRNA context directs the splicing reaction precisely to the sites of the tRNA intron. A suppressor pretRNA gene was inserted, in cis, into the sequence encoding the third cytoplasmic loop of the Ste2 or Ste3 G protein-coupled receptor. The hybrid RNAs are spliced at the specific pretRNA splicing sites, releasing both functional tRNAs that suppress nonsense mutations and translatable mRNAs that activate the signal transduction pathway. The RNA molecules extracted from yeast cells were amplified by RT-PCR, and their sequences were determined, confirming the identity of the splice junctions. We then constructed two fusions between the premRNA sequence (STE2 or STE3) and the 5'- or 3'-pretRNA half, so that the two hybrid RNAs can associate with each other, in trans, through their tRNA halves. Splicing occurs at the predicted pretRNA sites, producing a chimeric STE3-STE2 receptor mRNA. RNA trans-splicing mediated by tRNA sequences, therefore, is a mechanism capable of producing new kinds of RNAs, which could code for novel proteins.
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Abstract
Many genes duplicated by whole-genome duplications (WGDs) are more similar to one another than expected. We investigated whether concerted evolution through conversion and crossing over, well-known to affect tandem gene clusters, also affects dispersed paralogs. Genome sequences for two Oryza subspecies reveal appreciable gene conversion in the approximately 0.4 MY since their divergence, with a gradual progression toward independent evolution of older paralogs. Since divergence from subspecies indica, approximately 8% of japonica paralogs produced 5-7 MYA on chromosomes 11 and 12 have been affected by gene conversion and several reciprocal exchanges of chromosomal segments, while approximately 70-MY-old "paleologs" resulting from a genome duplication (GD) show much less conversion. Sequence similarity analysis in proximal gene clusters also suggests more conversion between younger paralogs. About 8% of paleologs may have been converted since rice-sorghum divergence approximately 41 MYA. Domain-encoding sequences are more frequently converted than nondomain sequences, suggesting a sort of circularity--that sequences conserved by selection may be further conserved by relatively frequent conversion. The higher level of concerted evolution in the 5-7 MY-old segmental duplication may reflect the behavior of many genomes within the first few million years after duplication or polyploidization.
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Sato Y, Nishida M. Post-duplication charge evolution of phosphoglucose isomerases in teleost fishes through weak selection on many amino acid sites. BMC Evol Biol 2007; 7:204. [PMID: 17963532 PMCID: PMC2176064 DOI: 10.1186/1471-2148-7-204] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 10/29/2007] [Indexed: 11/21/2022] Open
Abstract
Background The partitioning of ancestral functions among duplicated genes by neutral evolution, or subfunctionalization, has been considered the primary process for the evolution of novel proteins (neofunctionalization). Nonetheless, how a subfunctionalized protein can evolve into a more adaptive protein is poorly understood, mainly due to the limitations of current analytical methods, which can detect only strong selection for amino acid substitutions involved in adaptive molecular evolution. In this study, we employed a comparative evolutionary approach to this question, focusing on differences in the structural properties of a protein, specifically the electric charge, encoded by fish-specific duplicated phosphoglucose isomerase (Pgi) genes. Results Full-length cDNA cloning, RT-PCR based gene expression analyses, and comparative sequence analyses showed that after subfunctionalization with respect to the expression organ of duplicate Pgi genes, the net electric charge of the PGI-1 protein expressed mainly in internal tissues became more negative, and that of PGI-2 expressed mainly in muscular tissues became more positive. The difference in net protein charge was attributable not to specific amino acid sites but to the sum of various amino acid sites located on the surface of the PGI molecule. Conclusion This finding suggests that the surface charge evolution of PGI proteins was not driven by strong selection on individual amino acid sites leading to permanent fixation of a particular residue, but rather was driven by weak selection on a large number of amino acid sites and consequently by steady directional and/or purifying selection on the overall structural properties of the protein, which is derived from many modifiable sites. The mode of molecular evolution presented here may be relevant to various cases of adaptive modification in proteins, such as hydrophobic properties, molecular size, and electric charge.
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Affiliation(s)
- Yukuto Sato
- Division of Molecular Marine Biology, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164-8639, Japan.
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Kim YK, Mizutani K, Rhee KH, Nam KH, Lee WH, Lee EH, Kim EE, Park SY, Hwang KY. Structural and mutational analysis of tRNA intron-splicing endonuclease from Thermoplasma acidophilum DSM 1728: catalytic mechanism of tRNA intron-splicing endonucleases. J Bacteriol 2007; 189:8339-46. [PMID: 17827289 PMCID: PMC2168659 DOI: 10.1128/jb.00713-07] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In archaea, RNA endonucleases that act specifically on RNA with bulge-helix-bulge motifs play the main role in the recognition and excision of introns, while the eukaryal enzymes use a measuring mechanism to determine the positions of the universally positioned splice sites relative to the conserved domain of pre-tRNA. Two crystallographic structures of tRNA intron-splicing endonuclease from Thermoplasma acidophilum DSM 1728 (EndA(Ta)) have been solved to 2.5-A and 2.7-A resolution by molecular replacement, using the 2.7-A resolution data as the initial model and the single-wavelength anomalous-dispersion phasing method using selenomethionine as anomalous signals, respectively. The models show that EndA(Ta) is a homodimer and that it has overall folding similar to that of other archaeal tRNA endonucleases. From structural and mutational analyses of H236A, Y229F, and K265I in vitro, we have demonstrated that they play critical roles in recognizing the splice site and in cleaving the pre-tRNA substrate.
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Affiliation(s)
- Young Kwan Kim
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, South Korea
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Brügger K, Chen L, Stark M, Zibat A, Redder P, Ruepp A, Awayez M, She Q, Garrett RA, Klenk HP. The genome of Hyperthermus butylicus: a sulfur-reducing, peptide fermenting, neutrophilic Crenarchaeote growing up to 108 degrees C. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2007; 2:127-35. [PMID: 17350933 PMCID: PMC2686385 DOI: 10.1155/2007/745987] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hyperthermus butylicus, a hyperthermophilic neutrophile and anaerobe, is a member of the archaeal kingdom Crenarchaeota. Its genome consists of a single circular chromosome of 1,667,163 bp with a 53.7% G+C content. A total of 1672 genes were annotated, of which 1602 are protein-coding, and up to a third are specific to H. butylicus. In contrast to some other crenarchaeal genomes, a high level of GUG and UUG start codons are predicted. Two cdc6 genes are present, but neither could be linked unambiguously to an origin of replication. Many of the predicted metabolic gene products are associated with the fermentation of peptide mixtures including several peptidases with diverse specificities, and there are many encoded transporters. Most of the sulfur-reducing enzymes, hydrogenases and electron-transfer proteins were identified which are associated with energy production by reducing sulfur to H(2)S. Two large clusters of regularly interspaced repeats (CRISPRs) are present, one of which is associated with a crenarchaeal-type cas gene superoperon; none of the spacer sequences yielded good sequence matches with known archaeal chromosomal elements. The genome carries no detectable transposable or integrated elements, no inteins, and introns are exclusive to tRNA genes. This suggests that the genome structure is quite stable, possibly reflecting a constant, and relatively uncompetitive, natural environment.
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Affiliation(s)
- Kim Brügger
- Danish Archaea Centre, Institute of Molecular Biology, Copenhagen University, Sølvgade 83H, 1307 Copenhagen K, Denmark
- These authors contributed equally to the project
| | - Lanming Chen
- Danish Archaea Centre, Institute of Molecular Biology, Copenhagen University, Sølvgade 83H, 1307 Copenhagen K, Denmark
- These authors contributed equally to the project
| | - Markus Stark
- e.gene Biotechnologie GmbH, Poeckinger Fussweg 7a, 82340 Feldafing, Germany
- Formerly EPIDAUROS Biotechnologie AG, Genes and Genome Analysis Team
| | - Arne Zibat
- Formerly EPIDAUROS Biotechnologie AG, Genes and Genome Analysis Team
| | - Peter Redder
- Danish Archaea Centre, Institute of Molecular Biology, Copenhagen University, Sølvgade 83H, 1307 Copenhagen K, Denmark
| | - Andreas Ruepp
- Formerly EPIDAUROS Biotechnologie AG, Genes and Genome Analysis Team
- Present address: Institut für Bioinformatik, GSF-Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Mariana Awayez
- Danish Archaea Centre, Institute of Molecular Biology, Copenhagen University, Sølvgade 83H, 1307 Copenhagen K, Denmark
| | - Qunxin She
- Danish Archaea Centre, Institute of Molecular Biology, Copenhagen University, Sølvgade 83H, 1307 Copenhagen K, Denmark
| | - Roger A. Garrett
- Danish Archaea Centre, Institute of Molecular Biology, Copenhagen University, Sølvgade 83H, 1307 Copenhagen K, Denmark
- Editing author
| | - Hans-Peter Klenk
- e.gene Biotechnologie GmbH, Poeckinger Fussweg 7a, 82340 Feldafing, Germany
- Formerly EPIDAUROS Biotechnologie AG, Genes and Genome Analysis Team
- Corresponding author ()
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Tocchini-Valentini GD, Fruscoloni P, Tocchini-Valentini GP. The dawn of dominance by the mature domain in tRNA splicing. Proc Natl Acad Sci U S A 2007; 104:12300-5. [PMID: 17636125 PMCID: PMC1941465 DOI: 10.1073/pnas.0705537104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The relationship between enzyme architecture and substrate specificity among archaeal pre-tRNA splicing endonucleases has been investigated more deeply, by using biochemical assays and model building. The enzyme from Archeoglobus fulgidus (AF) is particularly interesting: it cleaves the bulge-helix-bulge target without requiring the mature tRNA domain, but, when the target is a bulge-helix-loop, the mature domain is required. A model of AF based on its electrostatic potential shows three polar patches interacting with the pre-tRNA substrate. A simple deletion mutant of the AF endonuclease lacking two of the three polar patches no longer cleaves the bulge-helix-loop substrate with or without the mature domain. This single deletion shows a possible path for the evolution of eukaryal splicing endonucleases from the archaeal enzyme.
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Affiliation(s)
- Giuseppe D. Tocchini-Valentini
- *Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A, Buzzati-Traverso, Via Ramarini 32, Monterotondo Scalo, 00016 Rome, Italy; and
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Paolo Fruscoloni
- *Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A, Buzzati-Traverso, Via Ramarini 32, Monterotondo Scalo, 00016 Rome, Italy; and
| | - Glauco P. Tocchini-Valentini
- *Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A, Buzzati-Traverso, Via Ramarini 32, Monterotondo Scalo, 00016 Rome, Italy; and
- To whom correspondence should be addressed. E-mail:
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