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Kanaji S, Chen W, Morodomi Y, Shapiro R, Kanaji T, Yang XL. Mechanistic perspectives on anti-aminoacyl-tRNA synthetase syndrome. Trends Biochem Sci 2023; 48:288-302. [PMID: 36280495 PMCID: PMC9974581 DOI: 10.1016/j.tibs.2022.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 02/18/2023]
Abstract
Antisynthetase syndrome (ASSD) is an autoimmune disease characterized by circulating autoantibodies against one of eight aminoacyl-tRNA synthetases (aaRSs). Although these autoantibodies are believed to play critical roles in ASSD pathogenesis, the nature of their roles remains unclear. Here we describe ASSD pathogenesis and discuss ASSD-linked aaRSs - from the WHEP domain that may impart immunogenicity to the role of tRNA in eliciting the innate immune response and the secretion of aaRSs from cells. Through these explorations, we propose that ASSD pathogenesis involves the tissue-specific secretion of aaRSs and that extracellular tRNAs or tRNA fragments and their ability to engage Toll-like receptor signaling may be important disease factors.
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Affiliation(s)
- Sachiko Kanaji
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wenqian Chen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Yosuke Morodomi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ryan Shapiro
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Taisuke Kanaji
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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2
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Zhang G, Tang X, Luo L, Zhanag X, Li P, Li G. Subergorgines A–E, Five New Suberosanone-Purine Hybrids from the South China Sea Gorgonian Subergorgia suberosa. Bioorg Chem 2022; 128:106040. [DOI: 10.1016/j.bioorg.2022.106040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/24/2022] [Accepted: 07/16/2022] [Indexed: 11/02/2022]
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3
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Dutta N, Deb I, Sarzynska J, Lahiri A. Inosine and its methyl derivatives: Occurrence, biogenesis, and function in RNA. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 169-170:21-52. [PMID: 35065168 DOI: 10.1016/j.pbiomolbio.2022.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/11/2021] [Accepted: 01/11/2022] [Indexed: 05/21/2023]
Abstract
Inosine is one of the most common post-transcriptional modifications. Since its discovery, it has been noted for its ability to contribute to non-Watson-Crick interactions within RNA. Rapidly accumulating evidence points to the widespread generation of inosine through hydrolytic deamination of adenosine to inosine by different classes of adenosine deaminases. Three naturally occurring methyl derivatives of inosine, i.e., 1-methylinosine, 2'-O-methylinosine and 1,2'-O-dimethylinosine are currently reported in RNA modification databases. These modifications are expected to lead to changes in the structure, folding, dynamics, stability and functions of RNA. The importance of the modifications is indicated by the strong conservation of the modifying enzymes across organisms. The structure, binding and catalytic mechanism of the adenosine deaminases have been well-studied, but the underlying mechanism of the catalytic reaction is not very clear yet. Here we extensively review the existing data on the occurrence, biogenesis and functions of inosine and its methyl derivatives in RNA. We also included the structural and thermodynamic aspects of these modifications in our review to provide a detailed and integrated discussion on the consequences of A-to-I editing in RNA and the contribution of different structural and thermodynamic studies in understanding its role in RNA. We also highlight the importance of further studies for a better understanding of the mechanisms of the different classes of deamination reactions. Further investigation of the structural and thermodynamic consequences and functions of these modifications in RNA should provide more useful information about their role in different diseases.
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Affiliation(s)
- Nivedita Dutta
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata, 700009, West Bengal, India
| | - Indrajit Deb
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata, 700009, West Bengal, India
| | - Joanna Sarzynska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Ansuman Lahiri
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata, 700009, West Bengal, India.
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4
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Shiraishi M, Hidaka M, Iwai S. Endonuclease V from the archaeon Thermococcus kodakarensis is an inosine-specific ribonuclease. Biosci Biotechnol Biochem 2021; 86:313-320. [PMID: 34928335 DOI: 10.1093/bbb/zbab219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/11/2021] [Indexed: 11/14/2022]
Abstract
Endonuclease V (EndoV) is an inosine-specific endonuclease which is highly conserved in all domains of life: Bacteria, Archaea, and Eukarya; and, therefore, may play an important role in nucleic acid processes. It is currently thought that bacterial EndoVs are involved in DNA repair, while eukaryotic EndoVs are involved in RNA editing based on the differences in substrate preferences. However, the role of EndoV proteins, particularly in the archaeal domain, is still poorly understood. Here, we explored the biochemical properties of EndoV from the hyperthermophilic archaeon Thermococcus kodakarensis (TkoEndoV). We show that TkoEndoV has a strong preference for RNA over DNA. Further, we synthesized 1-methylinosine-containing RNA which is a simple TΨC loop mimic of archaeal tRNA and found that TkoEndoV discriminates between 1-methylinosine and inosine, and selectively acts on inosine. Our findings suggest a potential role of archaeal EndoV in regulation of inosine-containing RNA.
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Affiliation(s)
- Miyako Shiraishi
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka, Japan
| | - Michihi Hidaka
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka, Japan
| | - Shigenori Iwai
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka, Japan
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5
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Abstract
Epigenetic modifications have gained attention since they can be potentially changed with environmental stimuli and can be associated with adverse health outcomes. Epitranscriptome field has begun to attract attention with several aspects since RNA modifications have been linked with critical biological processes and implicated in diseases. Several RNA modifications have been identified as reversible indicating the dynamic features of modification which can be altered by environmental cues. Currently, we know more than 150 RNA modifications in different organisms and on different bases which are modified by various chemical groups. RNA editing, which is one of the RNA modifications, occurs after transcription, which results in RNA sequence different from its corresponding DNA sequence. Emerging evidence reveals the functions of RNA editing as well as the association between RNA editing and diseases. However, the RNA editing field is beginning to grow up and needs more empirical evidence in regard to disease and toxicology. Thus, this review aims to provide the current evidence-based studies on RNA editing modifying genes for genotoxicity and cancer. The review presented the association between environmental xenobiotics exposure and RNA editing modifying genes and focused on the association between the expression of RNA editing modifying genes and cancer. Furthermore, we discussed the future directions of scientific studies in the area of RNA modifications, especially in the RNA editing field, and provided a knowledge-based framework for further studies.
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Affiliation(s)
- Akin Cayir
- Vocational Health College, Canakkale Onsekiz Mart University, Canakkale, Turkey
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6
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Torres AG, Martí E. Toward an Understanding of Extracellular tRNA Biology. Front Mol Biosci 2021; 8:662620. [PMID: 33937338 PMCID: PMC8082309 DOI: 10.3389/fmolb.2021.662620] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022] Open
Abstract
Extracellular RNAs (exRNAs) including abundant full length tRNAs and tRNA fragments (tRFs) have recently garnered attention as a promising source of biomarkers and a novel mediator in cell-to-cell communication in eukaryotes. Depending on the physiological state of cells, tRNAs/tRFs are released to the extracellular space either contained in extracellular vesicles (EVs) or free, through a mechanism that is largely unknown. In this perspective article, we propose that extracellular tRNAs (ex-tRNAs) and/or extracellular tRFs (ex-tRFs) are relevant paracrine signaling molecules whose activity depends on the mechanisms of release by source cells and capture by recipient cells. We speculate on how ex-tRNA/ex-tRFs orchestrate the effects in target cells, depending on the type of sequence and the mechanisms of uptake. We further propose that tRNA modifications may be playing important roles in ex-tRNA biology.
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Affiliation(s)
- Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Eulàlia Martí
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Epidemiología y Salud Pública, Madrid, Spain
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7
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Christofi T, Zaravinos A. RNA editing in the forefront of epitranscriptomics and human health. J Transl Med 2019; 17:319. [PMID: 31547885 PMCID: PMC6757416 DOI: 10.1186/s12967-019-2071-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/17/2019] [Indexed: 12/21/2022] Open
Abstract
Post-transcriptional modifications have been recently expanded with the addition of RNA editing, which is predominantly mediated by adenosine and cytidine deaminases acting on DNA and RNA. Here, we review the full spectrum of physiological processes in which these modifiers are implicated, among different organisms. Adenosine to inosine (A-to-I) editors, members of the ADAR and ADAT protein families are important regulators of alternative splicing and transcriptional control. On the other hand, cytidine to uridine (C-to-U) editors, members of the AID/APOBEC family, are heavily implicated in innate and adaptive immunity with important roles in antibody diversification and antiviral response. Physiologically, these enzymes are present in the nucleus and/or the cytoplasm, where they modify various RNA molecules, including miRNAs, tRNAs apart from mRNAs, whereas DNA editing is also possible by some of them. The expansion of next generation sequencing technologies provided a wealth of data regarding such modifications. RNA editing has been implicated in various disorders including cancer, and neurological diseases of the brain or the central nervous system. It is also related to cancer heterogeneity and the onset of carcinogenesis. Response to treatment can also be affected by the RNA editing status where drug efficacy is significantly compromised. Studying RNA editing events can pave the way to the identification of new disease biomarkers, and provide a more personalised therapy to various diseases.
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Affiliation(s)
- Theodoulakis Christofi
- Department of Life Sciences, School of Sciences, European University Cyprus, 2404, Nicosia, Cyprus
| | - Apostolos Zaravinos
- Department of Life Sciences, School of Sciences, European University Cyprus, 2404, Nicosia, Cyprus. .,Centre for Risk and Decision Sciences (CERIDES), 2404, Nicosia, Cyprus.
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8
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Abstract
Noncoding RNAs (ncRNAs) have received much attention due to their central role in gene expression and translational regulation as well as due to their involvement in several biological processes and disease development. Small noncoding RNAs (sncRNAs), such as microRNAs and piwiRNAs, have been thoroughly investigated and functionally characterized. Long noncoding RNAs (lncRNAs), known to play an important role in chromatin-interacting transcription regulation, posttranscriptional regulation, cell-to-cell signaling, and protein regulation, are also being investigated to further elucidate their functional roles.Next-generation sequencing (NGS) technologies have greatly aided in characterizing the ncRNAome. Moreover, the coupling of NGS technology together with bioinformatics tools has been essential to the genome-wide detection of RNA modifications in ncRNAs. RNA editing, a common human co-transcriptional and posttranscriptional modification, is a dynamic biological phenomenon able to alter the sequence and the structure of primary transcripts (both coding and noncoding RNAs) during the maturation process, consequently influencing the biogenesis, as well as the function, of ncRNAs. In particular, the dysregulation of the RNA editing machineries have been associated with the onset of human diseases.In this chapter we discuss the potential functions of ncRNA editing and describe the knowledge base and bioinformatics resources available to investigate such phenomenon.
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9
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Tuorto F, Lyko F. Genome recoding by tRNA modifications. Open Biol 2017; 6:rsob.160287. [PMID: 27974624 PMCID: PMC5204126 DOI: 10.1098/rsob.160287] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/14/2016] [Indexed: 11/12/2022] Open
Abstract
RNA modifications are emerging as an additional regulatory layer on top of the primary RNA sequence. These modifications are particularly enriched in tRNAs where they can regulate not only global protein translation, but also protein translation at the codon level. Modifications located in or in the vicinity of tRNA anticodons are highly conserved in eukaryotes and have been identified as potential regulators of mRNA decoding. Recent studies have provided novel insights into how these modifications orchestrate the speed and fidelity of translation to ensure proper protein homeostasis. This review highlights the prominent modifications in the tRNA anticodon loop: queuosine, inosine, 5-methoxycarbonylmethyl-2-thiouridine, wybutosine, threonyl-carbamoyl-adenosine and 5-methylcytosine. We discuss the functional relevance of these modifications in protein translation and their emerging role in eukaryotic genome recoding during cellular adaptation and disease.
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Affiliation(s)
- Francesca Tuorto
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany
| | - Frank Lyko
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany
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10
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Torres AG, Piñeyro D, Filonava L, Stracker TH, Batlle E, Ribas de Pouplana L. A-to-I editing on tRNAs: biochemical, biological and evolutionary implications. FEBS Lett 2014; 588:4279-86. [PMID: 25263703 DOI: 10.1016/j.febslet.2014.09.025] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 09/16/2014] [Accepted: 09/16/2014] [Indexed: 12/13/2022]
Abstract
Inosine on transfer RNAs (tRNAs) are post-transcriptionally formed by a deamination mechanism of adenosines at positions 34, 37 and 57 of certain tRNAs. Despite its ubiquitous nature, the biological role of inosine in tRNAs remains poorly understood. Recent developments in the study of nucleotide modifications are beginning to indicate that the dynamics of such modifications are used in the control of specific genetic programs. Likewise, the essentiality of inosine-modified tRNAs in genome evolution and animal biology is becoming apparent. Here we review our current understanding on the role of inosine in tRNAs, the enzymes that catalyze the modification and the evolutionary link between such enzymes and other deaminases.
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Affiliation(s)
- Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - David Piñeyro
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - Liudmila Filonava
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain
| | - Eduard Batlle
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain; Catalan Institution for Research and Advanced Studies (ICREA), P/ Lluís Companys 23, Barcelona 08010, Catalonia, Spain
| | - Lluis Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), C/ Baldiri Reixac 10, Barcelona 08028, Catalonia, Spain; Catalan Institution for Research and Advanced Studies (ICREA), P/ Lluís Companys 23, Barcelona 08010, Catalonia, Spain.
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11
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Zhou W, Karcher D, Bock R. Importance of adenosine-to-inosine editing adjacent to the anticodon in an Arabidopsis alanine tRNA under environmental stress. Nucleic Acids Res 2013; 41:3362-72. [PMID: 23355609 PMCID: PMC3597679 DOI: 10.1093/nar/gkt013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In all organisms, transfer RNAs (tRNAs) undergo extensive post-transcriptional modifications. Although base modifications in the anticodon are known to alter decoding specificity or improve decoding accuracy, much less is known about the functional relevance of modifications in other positions of tRNAs. Here, we report the identification of an A-to-I tRNA editing enzyme that modifies the tRNA-Ala(AGC) in the model plant Arabidopsis thaliana. The enzyme is homologous to Tad1p, a yeast tRNA-specific adenosine deaminase, and it selectively deaminates the adenosine in the position 3'-adjacent to the anticodon (A37) to inosine. We show that the AtTAD1 protein is exclusively localized in the nucleus. The tad1 loss-of-function mutants isolated in Arabidopsis show normal accumulation of the tRNA-Ala(AGC), suggesting that the loss of the I37 modification does not affect tRNA stability. The tad1 knockout mutants display no discernible phenotype under standard growth conditions, but produce less biomass under environmental stress conditions. Our results provide the first evidence in support of a physiological relevance of the A37-to-I modification in eukaryotes.
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Affiliation(s)
| | | | - Ralph Bock
- *To whom correspondence should be addressed. Tel: +49 3315 67 8700; Fax: +49 3315 67 8701;
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12
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Decker WK, Xing D, Li S, Robinson SN, Yang H, Steiner D, Komanduri KV, Shpall EJ. Th-1 polarization is regulated by dendritic-cell comparison of MHC class I and class II antigens. Blood 2009; 113:4213-23. [PMID: 19171878 PMCID: PMC2676083 DOI: 10.1182/blood-2008-10-185470] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Accepted: 01/18/2009] [Indexed: 11/20/2022] Open
Abstract
In the control of T-helper type I (Th-1) polarization, dendritic cells (DCs) must interpret a complex array of stimuli, many of which are poorly understood. Here we demonstrate that Th-1 polarization is heavily influenced by DC-autonomous phenomena triggered by the loading of DCs with antigenically matched major histocompatibility complex (MHC) class I and class II determinants, that is, class I and II peptide epitopes exhibiting significant amino acid sequence overlap (such as would be physiologically present during infectious processes requiring Th-1 immunity for clearance). Data were derived from 13 independent antigenic models including whole-cell systems, single-protein systems, and 3 different pairs of overlapping class I and II binding epitopes. Once loaded with matched class I and II antigens, these "Th-1 DCs" exhibited differential cytokine secretion and surface marker expression, a distinct transcriptional signature, and acquired the ability to enhance generation of CD8(+) T lymphocytes. Mechanistically, tRNA-synthetases were implicated as components of a putative sensor complex involved in the comparison of class I and II epitopes. These data provide rigorous conceptual explanations for the process of Th-1 polarization and the antigenic specificity of cognate T-cell help, enhance the understanding of Th-1 responses, and should contribute to the formulation of more effective vaccination strategies.
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Affiliation(s)
- William K Decker
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M D Anderson Cancer Center, Houston, TX 77030, USA.
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13
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Controlled potential electrolysis of inosine: Dependence of the selected potential on the nature of the electrooxidised products. J Electroanal Chem (Lausanne) 2006. [DOI: 10.1016/j.jelechem.2006.03.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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15
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Narukulla R, Shuker DEG, Xu YZ. Post-synthetic and site-specific modification of endocyclic nitrogen atoms of purines in DNA and its potential for biological and structural studies. Nucleic Acids Res 2005; 33:1767-78. [PMID: 15788749 PMCID: PMC1069512 DOI: 10.1093/nar/gki315] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 03/02/2005] [Accepted: 03/02/2005] [Indexed: 11/25/2022] Open
Abstract
Site-specific modification of the N1-position of purine was explored at the nucleoside and oligomer levels. 2'-deoxyinosine was converted into an N1-2,4-dinitrophenyl derivative 2 that was readily transformed to the desired N1-substituted 2'-deoxyinosine analogues. This approach was used to develop a post-synthetic method for the modification of the endocyclic N1-position of purine at the oligomer level. The phosphoramidite monomer of N1-(2,4-dinitrophenyl)-2'-deoxyinosine 9 was prepared from 2'-deoxyinosine in four steps and incorporated into oligomers using an automated DNA synthesizer. The modified base, N1-(2,4-dinitrophenyl)-hypoxanthine, in synthesized oligomers, upon treatment with respective agents, was converted into corresponding N1-substituted hypoxanthines, including N1-15N-hypoxanthine, N1-methylhypoxanthine and N1-(2-aminoethyl)-hypoxanthine. These modified oligomers can be easily separated and high purity oligomers obtained. Melting curve studies show the oligomer containing N1-methylhypoxanthine or N1-(2-aminoethyl)-hypoxanthine has a reduced thermostability with no particular pairing preference to either cytosine or thymine. The developed method could be adapted for the preparation of oligomers containing mutagenic N1-beta-hydroxyalkyl-hypoxanthines and the availability of the rare base-modified oligomers should offer novel tools for biological and structural studies.
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Affiliation(s)
- Raman Narukulla
- Department of Chemistry, The Open UniversityWalton Hall, Milton Keynes, MK7 6AA, UK
| | - David E. G. Shuker
- Department of Chemistry, The Open UniversityWalton Hall, Milton Keynes, MK7 6AA, UK
| | - Yao-Zhong Xu
- Department of Chemistry, The Open UniversityWalton Hall, Milton Keynes, MK7 6AA, UK
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16
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Hengstman GJ, van Engelen BG, Vree Egberts WT, van Venrooij WJ. Myositis-specific autoantibodies: overview and recent developments. Curr Opin Rheumatol 2001; 13:476-82. [PMID: 11698723 DOI: 10.1097/00002281-200111000-00004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Myositis-specific autoantibodies (MSAs) are found in almost half the patients with an idiopathic inflammatory myopathy (IIM). Several clinical and epidemiological studies have suggested that MSAs are associated with specific clinical characteristics. Some of these associations are well-defined and are of clinical significance ( eg, anti-Jo-1 and the anti-synthetase syndrome), others are less well established and can cause unnecessary anxiety for both patients and physicians ( eg, anti-SRP and cardiac involvement). In this review, an overview is given of the various MSAs, their biochemical background, their clinical usefulness, and the promises they hold for a better understanding of IIM.
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Affiliation(s)
- G J Hengstman
- Neuromuscular Centre Nijmegen, Institute of Neurology, University Medical Centre Nijmegen, Nijmegen, The Netherlands.
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17
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Abstract
Myositis-specific autoantibodies or myositis-associated autoantibodies can often be found in serum of patients with polymyositis and dermatomyositis. The presence of these autoantibodies can be significant in patient diagnosis and classification. Recent studies have provided new information about many of these specific autoantibodies. Among the more important developments were identification of a new antisynthetase, reacting with asparaginyl-tRNA synthetase; the detection of antibodies to the tRNA(his) in a over a third of anti-Jo-1 sera; and the description of distinctive features of the histopathology of patients with anti-Jo-1. New information about the cellular role of the antigens was discovered, including a role for Mi-2 antigen in chromosomally-mediated regulation of transcription as part of a nucleosome remodeling complex, and a potential role for PM-Scl antigen in ribosomal RNA processing as part of an exosome. The reason for the production of the autoantibodies, and the reason particular antigens are targeted, are key questions. Recent studies have suggested that antigen cleavage during apoptosis, particularly by granzyme B, may be an important factor. Whether the antibodies play a role in tissue injury remains unknown.
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Affiliation(s)
- I N Targoff
- Veterans Affairs Medical Center, Oklahoma City, University of Oklahoma Health Sciences Center, Oklahoma Medical Research Foundation, 73104, USA.
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18
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Keegan LP, Gerber AP, Brindle J, Leemans R, Gallo A, Keller W, O'Connell MA. The properties of a tRNA-specific adenosine deaminase from Drosophila melanogaster support an evolutionary link between pre-mRNA editing and tRNA modification. Mol Cell Biol 2000; 20:825-33. [PMID: 10629039 PMCID: PMC85199 DOI: 10.1128/mcb.20.3.825-833.2000] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pre-mRNA editing involving the conversion of adenosine to inosine is mediated by adenosine deaminases that act on RNA (ADAR1 and ADAR2). ADARs contain multiple double-stranded RNA(dsRNA)-binding domains in addition to an adenosine deaminase domain. An adenosine deaminase acting on tRNAs, scTad1p (also known as scADAT1), cloned from Saccharomyces cerevisiae has a deaminase domain related to the ADARs but lacks dsRNA-binding domains. We have identified a gene homologous to scADAT1 in the region of Drosophila melanogaster Adh chromosome II. Recombinant Drosophila ADAT1 (dADAT1) has been expressed in the yeast Pichia pastoris and purified. The enzyme has no activity on dsRNA substrates but is a tRNA deaminase with specificity for adenosine 37 of insect alanine tRNA. dADAT1 shows greater similarity to vertebrate ADARs than to yeast Tad1p, supporting the hypothesis of a common evolutionary origin for ADARs and ADATs. dAdat1 transcripts are maternally supplied in the egg. Zygotic expression is widespread initially and later concentrates in the central nervous system.
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MESH Headings
- 5' Untranslated Regions/genetics
- Adenosine Deaminase/chemistry
- Adenosine Deaminase/genetics
- Adenosine Deaminase/metabolism
- Amino Acid Sequence
- Animals
- Binding Sites
- Bombyx
- Cloning, Molecular
- Drosophila melanogaster/embryology
- Drosophila melanogaster/enzymology
- Drosophila melanogaster/genetics
- Evolution, Molecular
- Gene Expression Regulation, Developmental
- Genes, Insect
- Humans
- Molecular Sequence Data
- Phylogeny
- RNA Editing
- RNA Processing, Post-Transcriptional
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Transfer, Ala/metabolism
- RNA-Binding Proteins
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Saccharomyces cerevisiae
- Sequence Alignment
- Sequence Homology, Amino Acid
- Substrate Specificity
- Transcription, Genetic
- Vertebrates
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Affiliation(s)
- L P Keegan
- MRC Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
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