1
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Sikorski V, Vento A, Kankuri E. Emerging roles of the RNA modifications N6-methyladenosine and adenosine-to-inosine in cardiovascular diseases. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 29:426-461. [PMID: 35991314 PMCID: PMC9366019 DOI: 10.1016/j.omtn.2022.07.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cardiovascular diseases lead the mortality and morbidity disease metrics worldwide. A multitude of chemical base modifications in ribonucleic acids (RNAs) have been linked with key events of cardiovascular diseases and metabolic disorders. Named either RNA epigenetics or epitranscriptomics, the post-transcriptional RNA modifications, their regulatory pathways, components, and downstream effects substantially contribute to the ways our genetic code is interpreted. Here we review the accumulated discoveries to date regarding the roles of the two most common epitranscriptomic modifications, N6-methyl-adenosine (m6A) and adenosine-to-inosine (A-to-I) editing, in cardiovascular disease.
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Affiliation(s)
- Vilbert Sikorski
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Antti Vento
- Heart and Lung Center, Helsinki University Hospital, 00029 Helsinki, Finland
| | - Esko Kankuri
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - IHD-EPITRAN Consortium
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Heart and Lung Center, Helsinki University Hospital, 00029 Helsinki, Finland
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2
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Kokot KE, Kneuer JM, John D, Rebs S, Möbius-Winkler MN, Erbe S, Müller M, Andritschke M, Gaul S, Sheikh BN, Haas J, Thiele H, Müller OJ, Hille S, Leuschner F, Dimmeler S, Streckfuss-Bömeke K, Meder B, Laufs U, Boeckel JN. Reduction of A-to-I RNA editing in the failing human heart regulates formation of circular RNAs. Basic Res Cardiol 2022; 117:32. [PMID: 35737129 PMCID: PMC9226085 DOI: 10.1007/s00395-022-00940-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 01/31/2023]
Abstract
Alterations of RNA editing that affect the secondary structure of RNAs can cause human diseases. We therefore studied RNA editing in failing human hearts. Transcriptome sequencing showed that adenosine-to-inosine (A-to-I) RNA editing was responsible for 80% of the editing events in the myocardium. Failing human hearts were characterized by reduced RNA editing. This was primarily attributable to Alu elements in introns of protein-coding genes. In the failing left ventricle, 166 circRNAs were upregulated and 7 circRNAs were downregulated compared to non-failing controls. Most of the upregulated circRNAs were associated with reduced RNA editing in the host gene. ADAR2, which binds to RNA regions that are edited from A-to-I, was decreased in failing human hearts. In vitro, reduction of ADAR2 increased circRNA levels suggesting a causal effect of reduced ADAR2 levels on increased circRNAs in the failing human heart. To gain mechanistic insight, one of the identified upregulated circRNAs with a high reduction of editing in heart failure, AKAP13, was further characterized. ADAR2 reduced the formation of double-stranded structures in AKAP13 pre-mRNA, thereby reducing the stability of Alu elements and the circularization of the resulting circRNA. Overexpression of circAKAP13 impaired the sarcomere regularity of human induced pluripotent stem cell-derived cardiomyocytes. These data show that ADAR2 mediates A-to-I RNA editing in the human heart. A-to-I RNA editing represses the formation of dsRNA structures of Alu elements favoring canonical linear mRNA splicing and inhibiting the formation of circRNAs. The findings are relevant to diseases with reduced RNA editing and increased circRNA levels and provide insights into the human-specific regulation of circRNA formation.
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Affiliation(s)
- Karoline E Kokot
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany
| | - Jasmin M Kneuer
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany
| | - David John
- Institute for Cardiovascular Regeneration, Goethe-University Hospital, Theodor Stern Kai 7, Frankfurt, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Sabine Rebs
- Institute of Pharmacology and Toxicology, Versbacher-Str. 9, Würzburg, Germany
- Heartcenter - Clinic for Cardiology and Pneumology, University Medicine Goettingen, Robert-Koch-Str. 40, Göttingen, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site Göttingen, Göttingen, Germany
| | | | - Stephan Erbe
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany
| | - Marion Müller
- Department of General and Interventional Cardiology/Angiology, Ruhr University of Bochum, Heart-and Diabetes Center North Rhine-Westphalia, Bad Oeynhausen, Germany
| | - Michael Andritschke
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany
| | - Susanne Gaul
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany
| | - Bilal N Sheikh
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany
| | - Jan Haas
- Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg, Germany
| | - Holger Thiele
- Heart Center Leipzig at University of Leipzig and Leipzig Heart Institute, Leipzig, Germany
| | - Oliver J Müller
- Department of Internal Medicine III, University of Kiel, Kiel, Germany
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Susanne Hille
- Department of Internal Medicine III, University of Kiel, Kiel, Germany
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Florian Leuschner
- Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg, Germany
| | - Stefanie Dimmeler
- Institute for Cardiovascular Regeneration, Goethe-University Hospital, Theodor Stern Kai 7, Frankfurt, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Katrin Streckfuss-Bömeke
- Institute of Pharmacology and Toxicology, Versbacher-Str. 9, Würzburg, Germany
- Heartcenter - Clinic for Cardiology and Pneumology, University Medicine Goettingen, Robert-Koch-Str. 40, Göttingen, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site Göttingen, Göttingen, Germany
| | - Benjamin Meder
- Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany
- German Centre for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg, Germany
| | - Ulrich Laufs
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany
| | - Jes-Niels Boeckel
- Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Liebigstrasse 20, Leipzig, Germany.
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3
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Huo XX, Wang SJ, Song H, Li MD, Yu H, Wang M, Gong HX, Qiu XT, Zhu YF, Zhang JY. Roles of Major RNA Adenosine Modifications in Head and Neck Squamous Cell Carcinoma. Front Pharmacol 2021; 12:779779. [PMID: 34899345 PMCID: PMC8657411 DOI: 10.3389/fphar.2021.779779] [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: 09/19/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer malignancy worldwide and is known to have poor prognosis. The pathogenesis behind the development of HNSCC is not fully understood. Modifications on RNA are involved in many pathophysiological processes, such as tumor development and inflammation. Adenosine-related RNA modifications have shown to be linked to cancer and may play a role in cancer occurrence and development. To date, there are at least 170 different chemical RNA modifications that modify coding and non-coding RNAs (ncRNAs). These modifications affect RNA stability and transcription efficiency. In this review, we focus on the current understanding of the four major RNA adenosine modifications (N6-Methyladenosine, N1-Methyladenosine, Alternative Polyadenylation Modification and A-to-I RNA editing) and their potential molecular mechanisms related to HNSCC development and progression. We also touch on how these RNA modifications affect treatment of HNSCCs.
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Affiliation(s)
- Xing-Xing Huo
- Experimental Center of Clinical Research, Scientific Research Department, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, China.,Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Shu-Jie Wang
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Hang Song
- Department of Biochemistry and Molecular Biology, School of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Ming-de Li
- Experimental Center of Clinical Research, Scientific Research Department, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, China
| | - Hua Yu
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China
| | - Meng Wang
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Hong-Xiao Gong
- Experimental Center of Clinical Research, Scientific Research Department, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, China
| | - Xiao-Ting Qiu
- Experimental Center of Clinical Research, Scientific Research Department, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, China
| | - Yong-Fu Zhu
- Experimental Center of Clinical Research, Scientific Research Department, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, China
| | - Jian-Ye Zhang
- Key Laboratory of Molecular Target and Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
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4
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Biology of the mRNA Splicing Machinery and Its Dysregulation in Cancer Providing Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22105110. [PMID: 34065983 PMCID: PMC8150589 DOI: 10.3390/ijms22105110] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
Dysregulation of messenger RNA (mRNA) processing—in particular mRNA splicing—is a hallmark of cancer. Compared to normal cells, cancer cells frequently present aberrant mRNA splicing, which promotes cancer progression and treatment resistance. This hallmark provides opportunities for developing new targeted cancer treatments. Splicing of precursor mRNA into mature mRNA is executed by a dynamic complex of proteins and small RNAs called the spliceosome. Spliceosomes are part of the supraspliceosome, a macromolecular structure where all co-transcriptional mRNA processing activities in the cell nucleus are coordinated. Here we review the biology of the mRNA splicing machinery in the context of other mRNA processing activities in the supraspliceosome and present current knowledge of its dysregulation in lung cancer. In addition, we review investigations to discover therapeutic targets in the spliceosome and give an overview of inhibitors and modulators of the mRNA splicing process identified so far. Together, this provides insight into the value of targeting the spliceosome as a possible new treatment for lung cancer.
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5
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Omata Y, Yamauchi T, Tsuruta A, Matsunaga N, Koyanagi S, Ohdo S. RNA editing enzyme ADAR1 governs the circadian expression of P-glycoprotein in human renal cells by regulating alternative splicing of the ABCB1 gene. J Biol Chem 2021; 296:100601. [PMID: 33781748 PMCID: PMC8095175 DOI: 10.1016/j.jbc.2021.100601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/05/2021] [Accepted: 03/25/2021] [Indexed: 11/04/2022] Open
Abstract
The expression and function of some xenobiotic transporters vary according to the time of the day, causing the dosing time-dependent changes in drug disposition and toxicity. P-glycoprotein (P-gp), encoded by the ABCB1 gene, is highly expressed in the kidneys and functions in the renal elimination of various drugs. The elimination of several P-gp substrates was demonstrated to vary depending on administration time, but the underlying mechanism remains unclear. We found that adenosine deaminase acting on RNA (ADAR1) was involved in the circadian regulation of P-gp expression in human renal proximal tubular epithelial cells (RPTECs). After synchronization of the cellular circadian clock by dexamethasone treatment, the expression of P-gp exhibited a significant 24-h oscillation in RPTECs, but this oscillation was disrupted by the downregulation of ADAR1. Although ADAR1 catalyzes adenosine-to-inosine (A-to-I) RNA editing in double-stranded RNA substrates, no significant ADAR1-regulated editing sites were detected in the human ABCB1 transcripts in RPTECs. On the other hand, downregulation of ADAR1 induced alternative splicing in intron 27 of the human ABCB1 gene, resulting in the production of retained intron transcripts. The aberrant spliced transcript was sensitive to nonsense-mediated mRNA decay, leading to the decreased stability of ABCB1 mRNA and prevention of the 24-h oscillation of P-gp expression. These findings support the notion that ADAR1-mediated regulation of alternative splicing of the ABCB1 gene is a key mechanism of circadian expression of P-gp in RPTECs, and the regulatory mechanism may underlie the dosing time-dependent variations in the renal elimination of P-gp substrates.
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Affiliation(s)
- Yuji Omata
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoaki Yamauchi
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Akito Tsuruta
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Naoya Matsunaga
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Department of Glocal Healthcare Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoru Koyanagi
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Department of Glocal Healthcare Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
| | - Shigehiro Ohdo
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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6
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Huang H, Kapeli K, Jin W, Wong YP, Arumugam TV, Koh JH, Srimasorn S, Mallilankaraman K, Chua JJE, Yeo GW, Soong TW. Tissue-selective restriction of RNA editing of CaV1.3 by splicing factor SRSF9. Nucleic Acids Res 2019; 46:7323-7338. [PMID: 29733375 PMCID: PMC6101491 DOI: 10.1093/nar/gky348] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/30/2018] [Indexed: 12/31/2022] Open
Abstract
Adenosine DeAminases acting on RNA (ADAR) catalyzes adenosine-to-inosine (A-to-I) conversion within RNA duplex structures. While A-to-I editing is often dynamically regulated in a spatial-temporal manner, the mechanisms underlying its tissue-selective restriction remain elusive. We have previously reported that transcripts of voltage-gated calcium channel CaV1.3 are subject to brain-selective A-to-I RNA editing by ADAR2. Here, we show that editing of CaV1.3 mRNA is dependent on a 40 bp RNA duplex formed between exon 41 and an evolutionarily conserved editing site complementary sequence (ECS) located within the preceding intron. Heterologous expression of a mouse minigene that contained the ECS, intermediate intronic sequence and exon 41 with ADAR2 yielded robust editing. Interestingly, editing of CaV1.3 was potently inhibited by serine/arginine-rich splicing factor 9 (SRSF9). Mechanistically, the inhibitory effect of SRSF9 required direct RNA interaction. Selective down-regulation of SRSF9 in neurons provides a basis for the neuron-specific editing of CaV1.3 transcripts.
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Affiliation(s)
- Hua Huang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore
| | - Katannya Kapeli
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Wenhao Jin
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Yuk Peng Wong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore
| | - Thiruma Valavan Arumugam
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Joanne Huifen Koh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Sumitra Srimasorn
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Karthik Mallilankaraman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - John Jia En Chua
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.,Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Gene W Yeo
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California, San Diego, La Jolla, USA.,Molecular Engineering Laboratory, A*STAR, Singapore, Singapore
| | - Tuck Wah Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore
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7
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Nakano M, Fukami T, Nakajima M. Adenosine Deaminases Acting on RNA Downregulate the Expression of Constitutive Androstane Receptor in the Human Liver–Derived Cells by Attenuating Splicing. J Pharmacol Exp Ther 2019; 370:408-415. [DOI: 10.1124/jpet.119.260109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 06/28/2019] [Indexed: 12/18/2022] Open
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8
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Sinigaglia K, Wiatrek D, Khan A, Michalik D, Sambrani N, Sedmík J, Vukić D, O'Connell MA, Keegan LP. ADAR RNA editing in innate immune response phasing, in circadian clocks and in sleep. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:356-369. [DOI: 10.1016/j.bbagrm.2018.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/12/2018] [Accepted: 10/27/2018] [Indexed: 01/24/2023]
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9
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Hsiao YHE, Bahn JH, Yang Y, Lin X, Tran S, Yang EW, Quinones-Valdez G, Xiao X. RNA editing in nascent RNA affects pre-mRNA splicing. Genome Res 2018; 28:812-823. [PMID: 29724793 PMCID: PMC5991522 DOI: 10.1101/gr.231209.117] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/26/2018] [Indexed: 12/21/2022]
Abstract
In eukaryotes, nascent RNA transcripts undergo an intricate series of RNA processing steps to achieve mRNA maturation. RNA editing and alternative splicing are two major RNA processing steps that can introduce significant modifications to the final gene products. By tackling these processes in isolation, recent studies have enabled substantial progress in understanding their global RNA targets and regulatory pathways. However, the interplay between individual steps of RNA processing, an essential aspect of gene regulation, remains poorly understood. By sequencing the RNA of different subcellular fractions, we examined the timing of adenosine-to-inosine (A-to-I) RNA editing and its impact on alternative splicing. We observed that >95% A-to-I RNA editing events occurred in the chromatin-associated RNA prior to polyadenylation. We report about 500 editing sites in the 3' acceptor sequences that can alter splicing of the associated exons. These exons are highly conserved during evolution and reside in genes with important cellular function. Furthermore, we identified a second class of exons whose splicing is likely modulated by RNA secondary structures that are recognized by the RNA editing machinery. The genome-wide analyses, supported by experimental validations, revealed remarkable interplay between RNA editing and splicing and expanded the repertoire of functional RNA editing sites.
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Affiliation(s)
| | - Jae Hoon Bahn
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Yun Yang
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Xianzhi Lin
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Stephen Tran
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Ei-Wen Yang
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | | | - Xinshu Xiao
- Department of Bioengineering
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California 90095, USA
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, California 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, California 90095, USA
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10
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Fu Y, Zhao X, Li Z, Wei J, Tian Y. Splicing variants of ADAR2 and ADAR2-mediated RNA editing in glioma. Oncol Lett 2016; 12:788-792. [PMID: 27446352 DOI: 10.3892/ol.2016.4734] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 05/26/2016] [Indexed: 01/14/2023] Open
Abstract
The roles of alternative splicing and RNA editing in gene regulation and transcriptome diversity are well documented. Adenosine deaminases acting on RNA (ADARs) are responsible for adenosine-to-inosine (A-to-I) editing and exemplify the complex association between RNA editing and alternative splicing. The self-editing activity of ADAR2, which acts on its own pre-mRNA, leads to its alternative splicing. Alternative splicing occurs independently at nine splicing sites on ADAR2 pre-mRNA, generating numerous alternative splicing variants with various catalytic activities. A-to-I RNA editing is important in a range of physiological processes in humans and is associated with several diseases, including amyotrophic lateral sclerosis, mood disorders, epilepsy and glioma. Reduced editing at the glutamine/arginine site of the AMPA receptor subunit GluA2 in glioma, without any alteration in ADAR2 expression, is a notable phenomenon. Several studies have tried to explain this alteration in the catalytic activity of ADAR2; however, the underlying mechanism remains unclear. The present review summarizes the relevant literature and shares experimental results concerning ADAR2 alternative splicing. In particular, the present review demonstrates that shifts in the relative abundance of the active and inactive splicing variants of ADAR2 may reduce the ADAR2 editing activity in glioma. Dominant expression of ADAR2 splicing variant with low enzyme activity causes reduced RNA editing of GluA2 subunit at the glutamine/arginine site in glioma.
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Affiliation(s)
- Yao Fu
- Department of Neurosurgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China
| | - Xingli Zhao
- Department of Neurosurgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China
| | - Zhaohui Li
- Department of Neurosurgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China
| | - Jun Wei
- Department of Neurosurgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China
| | - Yu Tian
- Department of Neurosurgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China
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11
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Deffit SN, Hundley HA. To edit or not to edit: regulation of ADAR editing specificity and efficiency. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 7:113-27. [PMID: 26612708 DOI: 10.1002/wrna.1319] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/15/2015] [Accepted: 10/20/2015] [Indexed: 11/08/2022]
Abstract
Hundreds to millions of adenosine (A)-to-inosine (I) modifications are present in eukaryotic transcriptomes and play an essential role in the creation of proteomic and phenotypic diversity. As adenosine and inosine have different base-pairing properties, the functional consequences of these modifications or 'edits' include altering coding potential, splicing, and miRNA-mediated gene silencing of transcripts. However, rather than serving as a static control of gene expression, A-to-I editing provides a means to dynamically rewire the genetic code during development and in a cell-type specific manner. Interestingly, during normal development, in specific cells, and in both neuropathological diseases and cancers, the extent of RNA editing does not directly correlate with levels of the substrate mRNA or the adenosine deaminase that act on RNA (ADAR) editing enzymes, implying that cellular factors are required for spatiotemporal regulation of A-to-I editing. The factors that affect the specificity and extent of ADAR activity have been thoroughly dissected in vitro. Yet, we still lack a complete understanding of how specific ADAR family members can selectively deaminate certain adenosines while others cannot. Additionally, in the cellular environment, ADAR specificity and editing efficiency is likely to be influenced by cellular factors, which is currently an area of intense investigation. Data from many groups have suggested two main mechanisms for controlling A-to-I editing in the cell: (1) regulating ADAR accessibility to target RNAs and (2) protein-protein interactions that directly alter ADAR enzymatic activity. Recent studies suggest cis- and trans-acting RNA elements, heterodimerization and RNA-binding proteins play important roles in regulating RNA editing levels in vivo. WIREs RNA 2016, 7:113-127. doi: 10.1002/wrna.1319.
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Affiliation(s)
- Sarah N Deffit
- Medical Sciences Program, Indiana University, Bloomington, IN, USA
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12
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Daniel C, Behm M, Öhman M. The role of Alu elements in the cis-regulation of RNA processing. Cell Mol Life Sci 2015; 72:4063-76. [PMID: 26223268 PMCID: PMC11113721 DOI: 10.1007/s00018-015-1990-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 07/06/2015] [Accepted: 07/09/2015] [Indexed: 01/18/2023]
Abstract
The human genome is under constant invasion by retrotransposable elements. The most successful of these are the Alu elements; with a copy number of over a million, they occupy about 10 % of the entire genome. Interestingly, the vast majority of these Alu insertions are located in gene-rich regions, and one-third of all human genes contains an Alu insertion. Alu sequences are often embedded in gene sequence encoding pre-mRNAs and mature mRNAs, usually as part of their intron or UTRs. Once transcribed, they can regulate gene expression as well as increase the number of RNA isoforms expressed in a tissue or a species. They also regulate the function of other RNAs, like microRNAs, circular RNAs, and potentially long non-coding RNAs. Mechanistically, Alu elements exert their effects by influencing diverse processes, such as RNA editing, exonization, and RNA processing. In so doing, they have undoubtedly had a profound effect on human evolution.
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Affiliation(s)
- Chammiran Daniel
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden
| | - Mikaela Behm
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden
| | - Marie Öhman
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, 106 91, Stockholm, Sweden.
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LI ZHAOHUI, TIAN YU, TIAN NAN, ZHAO XINGLI, DU CHAO, HAN LIANG, ZHANG HAISHAN. Aberrant alternative splicing pattern of ADAR2 downregulates adenosine-to-inosine editing in glioma. Oncol Rep 2015; 33:2845-52. [DOI: 10.3892/or.2015.3907] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/20/2015] [Indexed: 11/05/2022] Open
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Abstract
Adenosine-to-inosine (A-to-I) RNA editing, the most prevalent mode of transcript modification in higher eukaryotes, is catalysed by the adenosine deaminases acting on RNA (ADARs). A-to-I editing imposes an additional layer of gene regulation as it dictates various aspects of RNA metabolism, including RNA folding, processing, localization and degradation. Furthermore, editing events in exonic regions contribute to proteome diversity as translational machinery decodes inosine as guanosine. Although it has been demonstrated that dysregulated A-to-I editing contributes to various diseases, the precise regulatory mechanisms governing this critical cellular process have yet to be fully elucidated. However, integration of previous studies revealed that regulation of A-to-I editing is multifaceted, weaving an intricate network of auto- and transregulations, including the involvement of virus-originated factors like adenovirus-associated RNA. Taken together, it is apparent that tipping of any regulatory components will have profound effects on A-to-I editing, which in turn contributes to both normal and aberrant physiological conditions. A complete understanding of this intricate regulatory network may ultimately be translated into new therapeutic strategies against diseases driven by perturbed RNA editing events. Herein, we review the current state of knowledge on the regulatory mechanisms governing A-to-I editing and propose the role of other co-factors that may be involved in this complex regulatory process. This review discusses the current state of knowledge on the mechanisms adopted in regulation of Adenosine-to-Inosine RNA editing.
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Shefer K, Sperling J, Sperling R. The Supraspliceosome - A Multi-Task Machine for Regulated Pre-mRNA Processing in the Cell Nucleus. Comput Struct Biotechnol J 2014; 11:113-22. [PMID: 25408845 PMCID: PMC4232567 DOI: 10.1016/j.csbj.2014.09.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 01/23/2023] Open
Abstract
Pre-mRNA splicing of Pol II transcripts is executed in the mammalian cell nucleus within a huge (21 MDa) and highly dynamic RNP machine — the supraspliceosome. It is composed of four splicing active native spliceosomes, each resembling an in vitro assembled spliceosome, which are connected by the pre-mRNA. Supraspliceosomes harbor protein splicing factors and all the five-spliceosomal U snRNPs. Recent analysis of specific supraspliceosomes at defined splicing stages revealed that they harbor all five spliceosomal U snRNAs at all splicing stages. Supraspliceosomes harbor additional pre-mRNA processing components, such as the 5′-end and 3′-end processing components, and the RNA editing enzymes ADAR1 and ADAR2. The structure of the native spliceosome, at a resolution of 20 Å, was determined by cryo-EM. A unique spatial arrangement of the spliceosomal U snRNPs within the native spliceosome emerged from in-silico studies, localizing the five U snRNPs mostly within its large subunit, and sheltering the active core components deep within the spliceosomal cavity. The supraspliceosome provides a platform for coordinating the numerous processing steps that the pre-mRNA undergoes: 5′ and 3′-end processing activities, RNA editing, constitutive and alternative splicing, and processing of intronic microRNAs. It also harbors a quality control mechanism termed suppression of splicing (SOS) that, under normal growth conditions, suppresses splicing at abundant intronic latent 5′ splice sites in a reading frame-dependent fashion. Notably, changes in these regulatory processing activities are associated with human disease and cancer. These findings emphasize the supraspliceosome as a multi-task master regulator of pre-mRNA processing in the cell nucleus.
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Affiliation(s)
- Kinneret Shefer
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Joseph Sperling
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ruth Sperling
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Abnormal expression of an ADAR2 alternative splicing variant in gliomas downregulates adenosine-to-inosine RNA editing. Acta Neurochir (Wien) 2014; 156:1135-42. [PMID: 24509948 PMCID: PMC4030101 DOI: 10.1007/s00701-014-2004-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 01/18/2014] [Indexed: 12/11/2022]
Abstract
Background RNA editing is catalyzed by adenosine deaminases acting on RNA (ADARs). ADAR2 is the main enzyme responsible for recoding editing in humans. Adenosine-to-inosine (A-to-I) editing at the Q/R site is reported to be decreased in gliomas; however, the expression of ADAR2 mRNA was not greatly affected. Methods We determined ADAR2 mRNA expression in human glioblastoma cell lines and in normal human glial cells by real-time RT-PCR. We also determined ADAR2 mRNA expression in 44 glioma tissues and normal white matter. After identifying an alternative splicing variant (ASV) of ADAR2 in gliomas, we performed sequencing. We then classified glioblastomas based on the presence (+) or absence (–) of the ASV to determine the correlations between ASV + and malignant features of glioblastomas, such as invasion, peritumoral brain edema, and survival time. Results There were no significant differences in ADAR2 mRNA expression among human glioblastoma cell lines or in gliomas compared with normal white matter (all p > 0.05). The ASV, which contained a 47-nucleotide insertion in the ADAR2 mRNA transcript, was detected in the U251 and BT325 cell lines, and in some glioma tissues. The expression rate of ASV differed among gliomas of different grades. ASV + glioblastomas were more malignant than ASV – glioblastomas. Conclusions ADAR2 is a family of enzymes in which ASVs result in differences in enzymatic activity. The ADAR2 ASV may be correlated with the invasiveness of gliomas. Identification of the mechanistic characterization of ADAR2 ASV may have future potential for individualized molecular targeted-therapy for glioma.
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Sakurai M, Ueda H, Yano T, Okada S, Terajima H, Mitsuyama T, Toyoda A, Fujiyama A, Kawabata H, Suzuki T. A biochemical landscape of A-to-I RNA editing in the human brain transcriptome. Genome Res 2014; 24:522-34. [PMID: 24407955 PMCID: PMC3941116 DOI: 10.1101/gr.162537.113] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Inosine is an abundant RNA modification in the human transcriptome and is essential for many biological processes in modulating gene expression at the post-transcriptional level. Adenosine deaminases acting on RNA (ADARs) catalyze the hydrolytic deamination of adenosines to inosines (A-to-I editing) in double-stranded regions. We previously established a biochemical method called "inosine chemical erasing" (ICE) to directly identify inosines on RNA strands with high reliability. Here, we have applied the ICE method combined with deep sequencing (ICE-seq) to conduct an unbiased genome-wide screening of A-to-I editing sites in the transcriptome of human adult brain. Taken together with the sites identified by the conventional ICE method, we mapped 19,791 novel sites and newly found 1258 edited mRNAs, including 66 novel sites in coding regions, 41 of which cause altered amino acid assignment. ICE-seq detected novel editing sites in various repeat elements as well as in short hairpins. Gene ontology analysis revealed that these edited mRNAs are associated with transcription, energy metabolism, and neurological disorders, providing new insights into various aspects of human brain functions.
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Affiliation(s)
- Masayuki Sakurai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan
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Affiliation(s)
- Chen Gao
- Departments of Anesthesiology, Physiology and Medicine, Molecular Biology Institute, David Geffen School of Medicine at University of California at Los Angeles
| | - Yibin Wang
- Departments of Anesthesiology, Physiology and Medicine, Molecular Biology Institute, David Geffen School of Medicine at University of California at Los Angeles
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Tariq A, Garncarz W, Handl C, Balik A, Pusch O, Jantsch MF. RNA-interacting proteins act as site-specific repressors of ADAR2-mediated RNA editing and fluctuate upon neuronal stimulation. Nucleic Acids Res 2012; 41:2581-93. [PMID: 23275536 PMCID: PMC3575830 DOI: 10.1093/nar/gks1353] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
RNA editing by adenosine deaminases that act on RNA (ADARs) diversifies the transcriptome by changing adenosines to inosines. In mammals, editing levels vary in different tissues, during development, and also in pathogenic conditions. From a screen for repressors of editing we have isolated three proteins that repress ADAR2-mediated RNA editing. The three proteins RPS14, SFRS9 and DDX15 interact with RNA. Overexpression or depletion of these proteins can decrease or increase editing levels by 15%, thus allowing a modulation of RNA editing up to 30%. Interestingly, the three proteins alter RNA editing in a substrate-specific manner that correlates with their RNA binding preferences. In mammalian cells, SFRS9 significantly affects editing of the two substrates CFLAR and cyFIP2, while the ribosomal protein RPS14 mostly inhibits editing of cyFIP2 messenger RNA. The helicase DDX15, in turn, has a strong effect on editing in Caenorhabditis elegans. Expression of the three factors decreases during mouse brain development. Moreover, expression levels of SFRS9 and DDX15 respond strongly to neuronal stimulation or repression, showing an inverse correlation with editing levels. Colocalization and immunoprecipitation studies demonstrate a direct interaction of SFRS9 and RPS14 with ADAR2, while DDX15 associates with other helicases and splicing factors. Our data show that different editing sites can be specifically altered in their editing pattern by changing the local RNP landscape.
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Affiliation(s)
- Aamira Tariq
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr Gasse 1, A-1030 Vienna, Austria
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Abstract
MicroRNAs refer to a subfamily of small non-coding RNA species that are designed to influence gene expression in nearly all cell types studied to date. Studies from the past decade have demonstrated that microRNAs are atypically expressed in the cardiovascular system under specific pathological conditions. Gain- and loss-of-function studies using in vitro and in vivo models have revealed distinct roles for specific microRNAs in cardiovascular development, physiological functions, and cardiac pathological conditions. In this review, the current relevant findings on the role of microRNAs in cardiac hypertrophic growth are updated, the target genes of these microRNAs are summarized, and the future of microRNAs as potential therapeutic targets is discussed.
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Affiliation(s)
- Paula A Da Costa Martins
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
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21
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Abstract
MicroRNAs (miRNAs) are important regulators of gene expression and fundamentally impact on cardiovascular function in health and disease. A tight control of miRNA expression is crucial for the maintenance of tissue homeostasis. However, a comprehensive understanding of the various levels of miRNA regulation is in its infancy. We here summarize the current knowledge about regulation of cardiovascular miRNAs at the transcriptional level by transcription factors, during processing by the Drosha and Dicer complexes and the importance of miRNA modification, editing, and decay mechanisms. As an example, miRNA regulation in diabetic and hypoxic cardiovascular disease conditions is discussed. Better knowledge about regulatory mechanisms of miRNAs in cardiovascular disease will probably lead to improved and novel miRNA-based therapeutic therapies.
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Affiliation(s)
- Johann Bauersachs
- Hannover Medical School, Institute of Molecular and Translational Therapeutic Strategies, Carl-Neuberg-Strasse 1, Hannover, Germany.
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Gallo A, Locatelli F. ADARs: allies or enemies? The importance of A-to-I RNA editing in human disease: from cancer to HIV-1. Biol Rev Camb Philos Soc 2011; 87:95-110. [PMID: 21682836 DOI: 10.1111/j.1469-185x.2011.00186.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosine (A) to inosine (I) in nuclear-encoded RNAs and viral RNAs. The activity of ADARs has been demonstrated to be essential in mammals and serves to fine-tune different proteins and modulate many molecular pathways. Recent findings have shown that ADAR activity is altered in many pathological tissues. Moreover, it has been shown that modulation of RNA editing is important for cell proliferation and migration, and has a protective effect on ischaemic insults. This review summarises available recent knowledge on A-to-I RNA editing and ADAR enzymes, with particular attention given to the emerging role played by these enzymes in cancer, some infectious diseases and immune-mediated disorders.
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Affiliation(s)
- Angela Gallo
- RNA Editing Laboratory, Oncohaematology Department, IRCCS, Ospedale Pediatrico "Bambino Gesù", Rome, Italy.
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