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Dodel M, Guiducci G, Dermit M, Krishnamurthy S, Alard EL, Capraro F, Rekad Z, Stojic L, Mardakheh FK. TREX reveals proteins that bind to specific RNA regions in living cells. Nat Methods 2024; 21:423-434. [PMID: 38374261 PMCID: PMC10927567 DOI: 10.1038/s41592-024-02181-1] [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: 08/21/2023] [Accepted: 01/16/2024] [Indexed: 02/21/2024]
Abstract
Different regions of RNA molecules can often engage in specific interactions with distinct RNA-binding proteins (RBPs), giving rise to diverse modalities of RNA regulation and function. However, there are currently no methods for unbiased identification of RBPs that interact with specific RNA regions in living cells and under endogenous settings. Here we introduce TREX (targeted RNase H-mediated extraction of crosslinked RBPs)-a highly sensitive approach for identifying proteins that directly bind to specific RNA regions in living cells. We demonstrate that TREX outperforms existing methods in identifying known interactors of U1 snRNA, and reveals endogenous region-specific interactors of NORAD long noncoding RNA. Using TREX, we generated a comprehensive region-by-region interactome for 45S rRNA, uncovering both established and previously unknown interactions that regulate ribosome biogenesis. With its applicability to different cell types, TREX is an RNA-centric tool for unbiased positional mapping of endogenous RNA-protein interactions in living cells.
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Affiliation(s)
- Martin Dodel
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Giulia Guiducci
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Maria Dermit
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Sneha Krishnamurthy
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Emilie L Alard
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Federica Capraro
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Zeinab Rekad
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Lovorka Stojic
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK.
| | - Faraz K Mardakheh
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London, UK.
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2
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Binothman N, Aljadani M, Alghanem B, Refai MY, Rashid M, Al Tuwaijri A, Alsubhi NH, Alrefaei GI, Khan MY, Sonbul SN, Aljoud F, Alhayyani S, Abdulal RH, Ganash M, Hashem AM. Identification of novel interacts partners of ADAR1 enzyme mediating the oncogenic process in aggressive breast cancer. Sci Rep 2023; 13:8341. [PMID: 37221310 DOI: 10.1038/s41598-023-35517-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/19/2023] [Indexed: 05/25/2023] Open
Abstract
Triple-negative breast cancer (TNBC) subtype is characterized by aggressive clinical behavior and poor prognosis patient outcomes. Here, we show that ADAR1 is more abundantly expressed in infiltrating breast cancer (BC) tumors than in benign tumors. Further, ADAR1 protein expression is higher in aggressive BC cells (MDA-MB-231). Moreover, we identify a novel interacting partners proteins list with ADAR1 in MDA-MB-231, using immunoprecipitation assay and mass spectrometry. Using iLoop, a protein-protein interaction prediction server based on structural features, five proteins with high iloop scores were discovered: Histone H2A.V, Kynureninase (KYNU), 40S ribosomal protein SA, Complement C4-A, and Nebulin (ranged between 0.6 and 0.8). In silico analysis showed that invasive ductal carcinomas had the highest level of KYNU gene expression than the other classifications (p < 0.0001). Moreover, KYNU mRNA expression was shown to be considerably higher in TNBC patients (p < 0.0001) and associated with poor patient outcomes with a high-risk value. Importantly, we found an interaction between ADAR1 and KYNU in the more aggressive BC cells. Altogether, these results propose a new ADAR-KYNU interaction as potential therapeutic targeted therapy in aggressive BC.
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Affiliation(s)
- Najat Binothman
- Department of Chemistry, College of Sciences and Arts, King Abdulaziz University, Rabigh, Saudi Arabia.
- Vaccine and Immunotherapy Unit, King Fahad Medical Research Center, King Abdulaziz University Saudi Arabia, Jeddah, Saudi Arabia.
| | - Majidah Aljadani
- Department of Chemistry, College of Sciences and Arts, King Abdulaziz University, Rabigh, Saudi Arabia
| | - Bandar Alghanem
- Medical Research Core Facility and Platforms (MRCFP), King Abdullah International Medical Research Center/King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), King Abdulaziz Medical City (KAMC), National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Mohammed Y Refai
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Mamoon Rashid
- Department of AI and Bioinformatics, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs, P.O. Box 22490, Riyadh, 11426, Saudi Arabia
| | - Abeer Al Tuwaijri
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
- Clinical Laboratory Sciences Department, College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Nouf H Alsubhi
- Biological Sciences Department, College of Science & Arts, King Abdulaziz University, Rabigh, 21911, Saudi Arabia
| | - Ghadeer I Alrefaei
- Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Muhammad Yasir Khan
- Vaccine and Immunotherapy Unit, King Fahad Medical Research Center, King Abdulaziz University Saudi Arabia, Jeddah, Saudi Arabia
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Sultan N Sonbul
- Biochemistry Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Fadwa Aljoud
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- Regenerative Medicine Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Sultan Alhayyani
- Department of Chemistry, College of Sciences and Arts, King Abdulaziz University, Rabigh, Saudi Arabia
| | - Rwaa H Abdulal
- Vaccine and Immunotherapy Unit, King Fahad Medical Research Center, King Abdulaziz University Saudi Arabia, Jeddah, Saudi Arabia
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Magdah Ganash
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Anwar M Hashem
- Vaccine and Immunotherapy Unit, King Fahad Medical Research Center, King Abdulaziz University Saudi Arabia, Jeddah, Saudi Arabia
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King AbdulAziz University, Jeddah, Saudi Arabia
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3
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Hu X, Zou Q, Yao L, Yang X. Survey of the binding preferences of RNA-binding proteins to RNA editing events. Genome Biol 2022; 23:169. [PMID: 35927743 PMCID: PMC9351184 DOI: 10.1186/s13059-022-02741-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 07/27/2022] [Indexed: 11/20/2022] Open
Abstract
Background Adenosine-to-inosine (A-to-I) editing is an important RNA posttranscriptional process related to a multitude of cellular and molecular activities. However, systematic characterizations of whether and how the events of RNA editing are associated with the binding preferences of RNA sequences to RNA-binding proteins (RBPs) are still lacking. Results With the RNA-seq and RBP eCLIP-seq datasets from the ENCODE project, we quantitatively survey the binding preferences of 150 RBPs to RNA editing events, followed by experimental validations. Such analyses of the RBP-associated RNA editing at nucleotide resolution and genome-wide scale shed light on the involvement of RBPs specifically in RNA editing-related processes, such as RNA splicing, RNA secondary structures, RNA decay, and other posttranscriptional processes. Conclusions These results highlight the relevance of RNA editing in the functions of many RBPs and therefore serve as a resource for further characterization of the functional associations between various RNA editing events and RBPs. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02741-8.
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Affiliation(s)
- Xiaolin Hu
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.,MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084, China.,Center for Synthetic & Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Qin Zou
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.,MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084, China.,Center for Synthetic & Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Li Yao
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084, China.,Center for Synthetic & Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Xuerui Yang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084, China. .,Center for Synthetic & Systems Biology, Tsinghua University, Beijing, 100084, China.
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4
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Kim JI, Nakahama T, Yamasaki R, Costa Cruz PH, Vongpipatana T, Inoue M, Kanou N, Xing Y, Todo H, Shibuya T, Kato Y, Kawahara Y. RNA editing at a limited number of sites is sufficient to prevent MDA5 activation in the mouse brain. PLoS Genet 2021; 17:e1009516. [PMID: 33983932 PMCID: PMC8118328 DOI: 10.1371/journal.pgen.1009516] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/28/2021] [Indexed: 12/22/2022] Open
Abstract
Adenosine deaminase acting on RNA 1 (ADAR1), an enzyme responsible for adenosine-to-inosine RNA editing, is composed of two isoforms: nuclear p110 and cytoplasmic p150. Deletion of Adar1 or Adar1 p150 genes in mice results in embryonic lethality with overexpression of interferon-stimulating genes (ISGs), caused by the aberrant recognition of unedited endogenous transcripts by melanoma differentiation-associated protein 5 (MDA5). However, among numerous RNA editing sites, how many RNA sites require editing, especially by ADAR1 p150, to avoid MDA5 activation and whether ADAR1 p110 contributes to this function remains elusive. In particular, ADAR1 p110 is abundant in the mouse brain where a subtle amount of ADAR1 p150 is expressed, whereas ADAR1 mutations cause Aicardi-Goutières syndrome, in which the brain is one of the most affected organs accompanied by the elevated expression of ISGs. Therefore, understanding RNA editing-mediated prevention of MDA5 activation in the brain is especially important. Here, we established Adar1 p110-specific knockout mice, in which the upregulated expression of ISGs was not observed. This result suggests that ADAR1 p150-mediated RNA editing is enough to suppress MDA5 activation. Therefore, we further created Adar1 p110/Adar2 double knockout mice to identify ADAR1 p150-mediated editing sites. This analysis demonstrated that although the elevated expression of ISGs was not observed, only less than 2% of editing sites were preserved in the brains of Adar1 p110/Adar2 double knockout mice. Of note, we found that some sites were highly edited, which was comparable to those found in wild-type mice, indicating the presence of ADAR1 p150-specific sites. These data suggest that RNA editing at a very limited sites, which is mediated by a subtle amount of ADAR1 p150, is sufficient to prevents MDA5 activation, at least in the mouse brain.
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Affiliation(s)
- Jung In Kim
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Taisuke Nakahama
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Ryuichiro Yamasaki
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Pedro Henrique Costa Cruz
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tuangtong Vongpipatana
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Maal Inoue
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Nao Kanou
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yanfang Xing
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Hiroyuki Todo
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Toshiharu Shibuya
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yuki Kato
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
| | - Yukio Kawahara
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
- Genome Editing Research and Development Center, Graduate School of Medicine, Osaka University, Suita, Japan
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5
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Nie W, Wang S, He R, Xu Q, Wang P, Wu Y, Tian F, Yuan J, Zhu B, Chen G. A-to-I RNA editing in bacteria increases pathogenicity and tolerance to oxidative stress. PLoS Pathog 2020; 16:e1008740. [PMID: 32822429 PMCID: PMC7467310 DOI: 10.1371/journal.ppat.1008740] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 09/02/2020] [Accepted: 06/24/2020] [Indexed: 01/25/2023] Open
Abstract
Adenosine-to-inosine (A-to-I) RNA editing is an important posttranscriptional event in eukaryotes; however, many features remain largely unexplored in prokaryotes. This study focuses on a serine-to-proline recoding event (S128P) that originated in the mRNA of fliC, which encodes a flagellar filament protein; the editing event was observed in RNA-seq samples exposed to oxidative stress. Using Sanger sequencing, we show that the S128P editing event is induced by H2O2. To investigate the in vivo interaction between RNAs and TadA, which is the principal enzyme for A-to-I editing, genome-wide RNA immunoprecipitation–coupled high-throughput sequencing (iRIP-Seq) analysis was performed using HA-tagged TadA from Xanthomonas oryzae pv. oryzicola. We found that TadA can bind to the mRNA of fliC and the binding motif is identical to that previously reported by Bar-Yaacov and colleagues. This editing event increased motility and enhanced tolerance to oxidative stress due to changes in flagellar filament structure, which was modelled in 3D and measured by TEM. The change in filament structure due to the S128P mutant increased biofilm formation, which was measured by the 3D laser scanning confocal microscopy. RNA-seq revealed that a gene cluster that contributes to siderophore biosynthesis and Fe3+ uptake was upregulated in S128P compared with WT. Based on intracellular levels of reactive oxygen species and an oxidative stress survival assay, we found that this gene cluster can contribute to the reduction of the Fenton reaction and increases biofilm formation and bacterial virulence. This oxidative stress response was also confirmed in Pseudomonas putida. Overall, our work demonstrates that A-to-I RNA editing plays a role in bacterial pathogenicity and adaptation to oxidative stress. Adenosine-to-inosine (A-to-I) RNA editing is an important posttranscriptional event in eukaryotes that has only been recently documented in bacteria. In this study, we use multiple ‘omic’ approaches to show that A-to-I RNA editing can occur in fliC, a flagellar filament protein. We show that TadA, which encodes adenosine deaminase, can directly bind to mRNA of target genes through recognition of a GACG motif. This editing event changes a single amino acid residue from serine to proline in FliC, resulting in a structural change in the flagellar filament. This posttranscriptional editing event contributes to virulence and increases tolerance to oxidative stress by enhancing biofilm formation. Our results provide insight into a new mechanism that bacterial pathogens use to adapt to oxidative stress, which can also increase virulence.
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Affiliation(s)
- Wenhan Nie
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Sai Wang
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Rui He
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Qin Xu
- State Key Laboratory of Microbial Metabolism, and SJTU-Yale Joint Center for Biostatistics and Data Science, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Peihong Wang
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Wu
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junhua Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Bo Zhu
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (BZ); (GC)
| | - Gongyou Chen
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (BZ); (GC)
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6
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Vongpipatana T, Nakahama T, Shibuya T, Kato Y, Kawahara Y. ADAR1 Regulates Early T Cell Development via MDA5-Dependent and -Independent Pathways. THE JOURNAL OF IMMUNOLOGY 2020; 204:2156-2168. [DOI: 10.4049/jimmunol.1900929] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 02/11/2020] [Indexed: 11/19/2022]
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7
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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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8
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Chen W, Feng P, Yang H, Ding H, Lin H, Chou KC. iRNA-AI: identifying the adenosine to inosine editing sites in RNA sequences. Oncotarget 2018; 8:4208-4217. [PMID: 27926534 PMCID: PMC5354824 DOI: 10.18632/oncotarget.13758] [Citation(s) in RCA: 199] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/23/2016] [Indexed: 01/14/2023] Open
Abstract
Catalyzed by adenosine deaminase (ADAR), the adenosine to inosine (A-to-I) editing in RNA is not only involved in various important biological processes, but also closely associated with a series of major diseases. Therefore, knowledge about the A-to-I editing sites in RNA is crucially important for both basic research and drug development. Given an uncharacterized RNA sequence that contains many adenosine (A) residues, can we identify which one of them can be of A-to-I editing, and which one cannot? Unfortunately, so far no computational method whatsoever has been developed to address such an important problem based on the RNA sequence information alone. To fill this empty area, we have proposed a predictor called iRNA-AI by incorporating the chemical properties of nucleotides and their sliding occurrence density distribution along a RNA sequence into the general form of pseudo nucleotide composition (PseKNC). It has been shown by the rigorous jackknife test and independent dataset test that the performance of the proposed predictor is quite promising. For the convenience of most experimental scientists, a user-friendly web-server for iRNA-AI has been established at http://lin.uestc.edu.cn/server/iRNA-AI/, by which users can easily get their desired results without the need to go through the mathematical details.
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Affiliation(s)
- Wei Chen
- Department of Physics, School of Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, Tangshan, China.,Gordon Life Science Institute, Belmont, Massachusetts, United States of America
| | - Pengmian Feng
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan, China
| | - Hui Yang
- Key Laboratory for Neuro-Information of Ministry of Education, School of Life Science and Technology, Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Hui Ding
- Key Laboratory for Neuro-Information of Ministry of Education, School of Life Science and Technology, Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Lin
- Key Laboratory for Neuro-Information of Ministry of Education, School of Life Science and Technology, Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China.,Gordon Life Science Institute, Belmont, Massachusetts, United States of America
| | - Kuo-Chen Chou
- Key Laboratory for Neuro-Information of Ministry of Education, School of Life Science and Technology, Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China.,Gordon Life Science Institute, Belmont, Massachusetts, United States of America
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9
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Integrated sequencing of exome and mRNA of large-sized single cells. Sci Rep 2018; 8:384. [PMID: 29321653 PMCID: PMC5762704 DOI: 10.1038/s41598-017-18730-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/16/2017] [Indexed: 11/08/2022] Open
Abstract
Current approaches of single cell DNA-RNA integrated sequencing are difficult to call SNPs, because a large amount of DNA and RNA is lost during DNA-RNA separation. Here, we performed simultaneous single-cell exome and transcriptome sequencing on individual mouse oocytes. Using microinjection, we kept the nuclei intact to avoid DNA loss, while retaining the cytoplasm inside the cell membrane, to maximize the amount of DNA and RNA captured from the single cell. We then conducted exome-sequencing on the isolated nuclei and mRNA-sequencing on the enucleated cytoplasm. For single oocytes, exome-seq can cover up to 92% of exome region with an average sequencing depth of 10+, while mRNA-sequencing reveals more than 10,000 expressed genes in enucleated cytoplasm, with similar performance for intact oocytes. This approach provides unprecedented opportunities to study DNA-RNA regulation, such as RNA editing at single nucleotide level in oocytes. In future, this method can also be applied to other large cells, including neurons, large dendritic cells and large tumour cells for integrated exome and transcriptome sequencing.
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10
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Sperling J, Sperling R. Structural studies of the endogenous spliceosome - The supraspliceosome. Methods 2017; 125:70-83. [PMID: 28412289 PMCID: PMC5546952 DOI: 10.1016/j.ymeth.2017.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 04/01/2017] [Accepted: 04/10/2017] [Indexed: 12/17/2022] Open
Abstract
Pre-mRNA splicing is executed in mammalian cell nuclei within a huge (21MDa) and highly dynamic molecular machine - the supraspliceosome - that individually package pre-mRNA transcripts of different sizes and number of introns into complexes of a unique structure, indicating their universal nature. Detailed structural analysis of this huge and complex structure requires a stepwise approach using hybrid methods. Structural studies of the supraspliceosome by room temperature electron tomography, cryo-electron tomography, and scanning transmission electron microscope mass measurements revealed that it is composed of four native spliceosomes, each resembling an in vitro assembled spliceosome, which are connected by the pre-mRNA. It also elucidated the arrangement of the native spliceosomes within the intact supraspliceosome. Native spliceosomes and supraspliceosomes contain all five spliceosomal U snRNPs together with other splicing factors, and are active in splicing. The structure of the native spliceosome, at a resolution of 20Å, was determined by cryo-electron microscopy, and a unique spatial arrangement of the spliceosomal U snRNPs within the native spliceosome emerged from in silico studies. The supraspliceosome also harbor components for all pre-mRNA processing activities. Thus the supraspliceosome - the endogenous spliceosome - is a stand-alone complete macromolecular machine capable of performing splicing, alternative splicing, and encompass all nuclear pre-mRNA processing activities that the pre-mRNA has to undergo before it can exit from the nucleus to the cytoplasm to encode for protein. Further high-resolution cryo-electron microscopy studies of the endogenous spliceosome are required to decipher the regulation of alternative splicing, and elucidate the network of processing activities within it.
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Affiliation(s)
- Joseph Sperling
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ruth Sperling
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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11
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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12
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Harrington AW, McKain MR, Michalski D, Bauer KM, Daugherty JM, Steiniger M. Drosophila melanogaster retrotransposon and inverted repeat-derived endogenous siRNAs are differentially processed in distinct cellular locations. BMC Genomics 2017; 18:304. [PMID: 28415970 PMCID: PMC5392987 DOI: 10.1186/s12864-017-3692-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 04/07/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Endogenous small interfering (esi)RNAs repress mRNA levels and retrotransposon mobility in Drosophila somatic cells by poorly understood mechanisms. 21 nucleotide esiRNAs are primarily generated from retrotransposons and two inverted repeat (hairpin) loci in Drosophila culture cells in a Dicer2 dependent manner. Additionally, proteins involved in 3' end processing, such as Symplekin, CPSF73 and CPSR100, have been recently implicated in the esiRNA pathway. RESULTS Here we present evidence of overlap between two essential RNA metabolic pathways: esiRNA biogenesis and mRNA 3' end processing. We have identified a nucleus-specific interaction between the essential esiRNA cleavage enzyme Dicer2 (Dcr2) and Symplekin, a component of the core cleavage complex (CCC) required for 3' end processing of all eukaryotic mRNAs. This interaction is mediated by the N-terminal 271 amino acids of Symplekin; CCC factors CPSF73 and CPSF100 do not contact Dcr2. While Dcr2 binds the CCC, Dcr2 knockdown does not affect mRNA 3' end formation. RNAi-depletion of CCC components Symplekin and CPSF73 causes perturbations in esiRNA abundance that correlate with fluctuations in retrotransposon and hairpin esiRNA precursor levels. We also discovered that esiRNAs generated from retrotransposons and hairpins have distinct physical characteristics including a higher predominance of 22 nucleotide hairpin-derived esiRNAs and differences in 3' and 5' base preference. Additionally, retrotransposon precursors and derived esiRNAs are highly enriched in the nucleus while hairpins and hairpin derived esiRNAs are predominantly cytoplasmic similar to canonical mRNAs. RNAi-depletion of either CPSF73 or Symplekin results in nuclear retention of both hairpin and retrotransposon precursors suggesting that polyadenylation indirectly affects cellular localization of Dcr2 substrates. CONCLUSIONS Together, these observations support a novel mechanism in which differences in localization of esiRNA precursors impacts esiRNA biogenesis. Hairpin-derived esiRNAs are generated in the cytoplasm independent of Dcr2-Symplekin interactions, while retrotransposons are processed in the nucleus.
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Affiliation(s)
| | - Michael R McKain
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO, 63132, USA
| | - Daniel Michalski
- Department of Biology, University of Missouri, St. Louis, MO, 63121, USA
| | - Kaylyn M Bauer
- Department of Biology, University of Missouri, St. Louis, MO, 63121, USA
| | - Joshua M Daugherty
- Department of Biology, University of Missouri, St. Louis, MO, 63121, USA
| | - Mindy Steiniger
- Department of Biology, University of Missouri, St. Louis, MO, 63121, USA.
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13
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Giguère SSB, Guise AJ, Jean Beltran PM, Joshi PM, Greco TM, Quach OL, Kong J, Cristea IM. The Proteomic Profile of Deleted in Breast Cancer 1 (DBC1) Interactions Points to a Multifaceted Regulation of Gene Expression. Mol Cell Proteomics 2015; 15:791-809. [PMID: 26657080 DOI: 10.1074/mcp.m115.054619] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 01/01/2023] Open
Abstract
Deleted in breast cancer 1 (DBC1) has emerged as an important regulator of multiple cellular processes, ranging from gene expression to cell cycle progression. DBC1 has been linked to tumorigenesis both as an inhibitor of histone deacetylases, HDAC3 and sirtuin 1, and as a transcriptional cofactor for nuclear hormone receptors. However, despite mounting interest in DBC1, relatively little is known about the range of its interacting partners and the scope of its functions. Here, we carried out a functional proteomics-based investigation of DBC1 interactions in two relevant cell types, T cells and kidney cells. Microscopy, molecular biology, biochemistry, and mass spectrometry studies allowed us to assess DBC1 mRNA and protein levels, localization, phosphorylation status, and protein interaction networks. The comparison of DBC1 interactions in these cell types revealed conserved regulatory roles for DBC1 in gene expression, chromatin organization and modification, and cell cycle progression. Interestingly, we observe previously unrecognized DBC1 interactions with proteins encoded by cancer-associated genes. Among these interactions are five components of the SWI/SNF complex, the most frequently mutated chromatin remodeling complex in human cancers. Additionally, we identified a DBC1 interaction with TBL1XR1, a component of the NCoR complex, which we validated by reciprocal isolation. Strikingly, we discovered that DBC1 associates with proteins that regulate the circadian cycle, including DDX5, DHX9, and SFPQ. We validated this interaction by colocalization and reciprocal isolation. Functional assessment of this association demonstrated that DBC1 protein levels are important for regulating CLOCK and BMAL1 protein oscillations in synchronized T cells. Our results suggest that DBC1 is integral to the maintenance of the circadian molecular clock. Furthermore, the identified interactions provide a valuable resource for the exploration of pathways involved in DBC1-associated tumorigenesis.
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Affiliation(s)
- Sophie S B Giguère
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Amanda J Guise
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Pierre M Jean Beltran
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Preeti M Joshi
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Todd M Greco
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Olivia L Quach
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Jeffery Kong
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
| | - Ileana M Cristea
- From the ‡Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544
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14
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Liscovitch N, Bazak L, Levanon EY, Chechik G. Positive correlation between ADAR expression and its targets suggests a complex regulation mediated by RNA editing in the human brain. RNA Biol 2015; 11:1447-56. [PMID: 25692240 DOI: 10.4161/15476286.2014.992286] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A-to-I RNA editing by adenosine deaminases acting on RNA is a post-transcriptional modification that is crucial for normal life and development in vertebrates. RNA editing has been shown to be very abundant in the human transcriptome, specifically at the primate-specific Alu elements. The functional role of this wide-spread effect is still not clear; it is believed that editing of transcripts is a mechanism for their down-regulation via processes such as nuclear retention or RNA degradation. Here we combine 2 neural gene expression datasets with genome-level editing information to examine the relation between the expression of ADAR genes with the expression of their target genes. Specifically, we computed the spatial correlation across structures of post-mortem human brains between ADAR and a large set of targets that were found to be edited in their Alu repeats. Surprisingly, we found that a large fraction of the edited genes are positively correlated with ADAR, opposing the assumption that editing would reduce expression. When considering the correlations between ADAR and its targets over development, 2 gene subsets emerge, positively correlated and negatively correlated with ADAR expression. Specifically, in embryonic time points, ADAR is positively correlated with many genes related to RNA processing and regulation of gene expression. These findings imply that the suggested mechanism of regulation of expression by editing is probably not a global one; ADAR expression does not have a genome wide effect reducing the expression of editing targets. It is possible, however, that RNA editing by ADAR in non-coding regions of the gene might be a part of a more complex expression regulation mechanism.
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Affiliation(s)
- Noa Liscovitch
- a Gonda Multidisiplinary Brain Research Center ; Bar-Ilan University ; Ramat Gan , Israel
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15
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Ajamian L, Abel K, Rao S, Vyboh K, García-de-Gracia F, Soto-Rifo R, Kulozik AE, Gehring NH, Mouland AJ. HIV-1 Recruits UPF1 but Excludes UPF2 to Promote Nucleocytoplasmic Export of the Genomic RNA. Biomolecules 2015; 5:2808-39. [PMID: 26492277 PMCID: PMC4693258 DOI: 10.3390/biom5042808] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/09/2015] [Accepted: 09/16/2015] [Indexed: 12/11/2022] Open
Abstract
Unspliced, genomic HIV-1 RNA (vRNA) is a component of several ribonucleoprotein complexes (RNP) during the viral replication cycle. In earlier work, we demonstrated that the host upframeshift protein 1 (UPF1), a key factor in nonsense-mediated mRNA decay (NMD), colocalized and associated to the viral structural protein Gag during viral egress. In this work, we demonstrate a new function for UPF1 in the regulation of vRNA nuclear export. OPEN ACCESS Biomolecules 2015, 5 2809 We establish that the nucleocytoplasmic shuttling of UPF1 is required for this function and demonstrate that UPF1 exists in two essential viral RNPs during the late phase of HIV-1 replication: the first, in a nuclear export RNP that contains Rev, CRM1, DDX3 and the nucleoporin p62, and the second, which excludes these nuclear export markers but contains Gag in the cytoplasm. Interestingly, we observed that both UPF2 and the long isoform of UPF3a, UPF3aL, but not the shorter isoforms UPF3aS and UPF3b, are excluded from the UPF1-Rev-CRM1-DDX3 complex as they are negative regulators of vRNA nuclear export. In silico protein-protein docking analyses suggest that Rev binds UPF1 in a region that overlaps the UPF2 binding site, thus explaining the exclusion of this negative regulatory factor by HIV-1 that is necessary for vRNA trafficking. This work uncovers a novel and unique regulatory circuit involving several UPF proteins that ultimately regulate vRNA nuclear export and trafficking.
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Affiliation(s)
- Lara Ajamian
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research-Sir Mortimer B. Davis Jewish General Hospital, Montréal QC H3T 1E2, Canada.
- Department of Medicine, Division of Experimental Medicine, McGill University, Montréal QC H3A 2B4, Canada.
| | - Karen Abel
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research-Sir Mortimer B. Davis Jewish General Hospital, Montréal QC H3T 1E2, Canada.
- Department of Microbiology and Immunology, McGill University, Montréal QC H3T 1E2, Canada.
| | - Shringar Rao
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research-Sir Mortimer B. Davis Jewish General Hospital, Montréal QC H3T 1E2, Canada.
- Department of Microbiology and Immunology, McGill University, Montréal QC H3T 1E2, Canada.
| | - Kishanda Vyboh
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research-Sir Mortimer B. Davis Jewish General Hospital, Montréal QC H3T 1E2, Canada.
- Department of Microbiology and Immunology, McGill University, Montréal QC H3T 1E2, Canada.
| | - Francisco García-de-Gracia
- Laboratory of Molecular and Cellular Virology, Virology Program, Biomedical Sciences Institute, Faculty of Medicine, Universidad de Chile, Independencia 8389100, Santiago, Chile.
| | - Ricardo Soto-Rifo
- Laboratory of Molecular and Cellular Virology, Virology Program, Biomedical Sciences Institute, Faculty of Medicine, Universidad de Chile, Independencia 8389100, Santiago, Chile.
| | - Andreas E Kulozik
- Department of Pediatric Oncology, Hematology and Immunology, Heidelberg 69120, Germany.
- European Molecular Biology Laboratory, Partnership Unit, University of Heidelberg Molecular Medicine, Heidelberg 69117, Germany.
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, Cologne 50674, Germany.
| | - Andrew J Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research-Sir Mortimer B. Davis Jewish General Hospital, Montréal QC H3T 1E2, Canada.
- Department of Medicine, Division of Experimental Medicine, McGill University, Montréal QC H3A 2B4, Canada.
- Department of Microbiology and Immunology, McGill University, Montréal QC H3T 1E2, Canada.
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16
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Ono M, Yamada K, Avolio F, Afzal V, Bensaddek D, Lamond AI. Targeted Knock-Down of miR21 Primary Transcripts Using snoMEN Vectors Induces Apoptosis in Human Cancer Cell Lines. PLoS One 2015; 10:e0138668. [PMID: 26405811 PMCID: PMC4583369 DOI: 10.1371/journal.pone.0138668] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/02/2015] [Indexed: 11/18/2022] Open
Abstract
We have previously reported an antisense technology, 'snoMEN vectors', for targeted knock-down of protein coding mRNAs using human snoRNAs manipulated to contain short regions of sequence complementarity with the mRNA target. Here we characterise the use of snoMEN vectors to target the knock-down of micro RNA primary transcripts. We document the specific knock-down of miR21 in HeLa cells using plasmid vectors expressing miR21-targeted snoMEN RNAs and show this induces apoptosis. Knock-down is dependent on the presence of complementary sequences in the snoMEN vector and the induction of apoptosis can be suppressed by over-expression of miR21. Furthermore, we have also developed lentiviral vectors for delivery of snoMEN RNAs and show this increases the efficiency of vector transduction in many human cell lines that are difficult to transfect with plasmid vectors. Transduction of lentiviral vectors expressing snoMEN targeted to pri-miR21 induces apoptosis in human lung adenocarcinoma cells, which express high levels of miR21, but not in human primary cells. We show that snoMEN-mediated suppression of miRNA expression is prevented by siRNA knock-down of Ago2, but not by knock-down of Ago1 or Upf1. snoMEN RNAs colocalise with Ago2 in cell nuclei and nucleoli and can be co-immunoprecipitated from nuclear extracts by antibodies specific for Ago2.
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Affiliation(s)
- Motoharu Ono
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Kayo Yamada
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Fabio Avolio
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Vackar Afzal
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Dalila Bensaddek
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Angus I. Lamond
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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17
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Okada S, Sakurai M, Ueda H, Suzuki T. Biochemical and Transcriptome-Wide Identification of A-to-I RNA Editing Sites by ICE-Seq. Methods Enzymol 2015; 560:331-53. [PMID: 26253977 DOI: 10.1016/bs.mie.2015.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inosine (I) is a modified adenosine (A) in RNA. In Metazoa, I is generated by hydrolytic deamination of A, catalyzed by adenosine deaminase acting RNA (ADAR) in a process called A-to-I RNA editing. A-to-I RNA editing affects various biological processes by modulating gene expression. In addition, dysregulation of A-to-I RNA editing results in pathological consequences. I on RNA strands is converted to guanosine (G) during cDNA synthesis by reverse transcription. Thus, the conventional method used to identify A-to-I RNA editing sites compares cDNA sequences with their corresponding genomic sequences. Combined with deep sequencing, this method has been applied to transcriptome-wide screening of A-to-I RNA editing sites. This approach, however, produces a large number of false positives mainly owing to mapping errors. To address this issue, we developed a biochemical method called inosine chemical erasing (ICE) to reliably identify genuine A-to-I RNA editing sites. In addition, we applied the ICE method combined with RNA-seq, referred to as ICE-seq, to identify transcriptome-wide A-to-I RNA editing sites. In this chapter, we describe the detailed protocol for ICE-seq, which can be applied to various sources and taxa.
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Affiliation(s)
- Shunpei Okada
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masayuki Sakurai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroki Ueda
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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18
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Suzuki T, Ueda H, Okada S, Sakurai M. Transcriptome-wide identification of adenosine-to-inosine editing using the ICE-seq method. Nat Protoc 2015; 10:715-32. [PMID: 25855956 DOI: 10.1038/nprot.2015.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Inosine (I), a modified base found in the double-stranded regions of RNA in metazoans, has various roles in biological processes by modulating gene expression. Inosine is generated from adenosine (A) catalyzed by ADAR (adenosine deaminase acting on RNA) enzymes in a process called A-to-I RNA editing. As inosine is converted to guanosine (G) by reverse transcription, the editing sites can be identified by simply comparing cDNA sequences with the corresponding genomic sequence. One approach to screening I sites is by deep sequencing based on A-to-G conversion from genomic sequence to cDNA; however, this approach produces a high rate of false positives because it cannot efficiently eliminate G signals arising from inevitable mapping errors. To address this issue, we developed a biochemical method to identify inosines called inosine chemical erasing (ICE), which is based on cyanoethylation combined with reverse transcription. ICE was subsequently combined with deep sequencing (ICE-seq) for the reliable identification of transcriptome-wide A-to-I editing sites. Here we describe a protocol for the practical application of ICE-seq, which can be completed within 22 d, and which allows the accurate identification of transcriptome-wide A-to-I RNA editing sites.
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Affiliation(s)
- Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo, Japan
| | - Hiroki Ueda
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo, Japan
| | - Shunpei Okada
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo, Japan
| | - Masayuki Sakurai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo, Japan
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19
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de Jesus AA, Canna SW, Liu Y, Goldbach-Mansky R. Molecular mechanisms in genetically defined autoinflammatory diseases: disorders of amplified danger signaling. Annu Rev Immunol 2015; 33:823-74. [PMID: 25706096 DOI: 10.1146/annurev-immunol-032414-112227] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Patients with autoinflammatory diseases present with noninfectious fever flares and systemic and/or disease-specific organ inflammation. Their excessive proinflammatory cytokine and chemokine responses can be life threatening and lead to organ damage over time. Studying such patients has revealed genetic defects that have helped unravel key innate immune pathways, including excessive IL-1 signaling, constitutive NF-κB activation, and, more recently, chronic type I IFN signaling. Discoveries of monogenic defects that lead to activation of proinflammatory cytokines have inspired the use of anticytokine-directed treatment approaches that have been life changing for many patients and have led to the approval of IL-1-blocking agents for a number of autoinflammatory conditions. In this review, we describe the genetically characterized autoinflammatory diseases, we summarize our understanding of the molecular pathways that drive clinical phenotypes and that continue to inspire the search for novel treatment targets, and we provide a conceptual framework for classification.
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Affiliation(s)
- Adriana Almeida de Jesus
- Translational Autoinflammatory Diseases Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, Maryland 20892;
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20
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Guo Y, Zhao S, Bjoring M, Han L. Advanced Datamining Using RNAseq Data. BIG DATA ANALYTICS IN BIOINFORMATICS AND HEALTHCARE 2015. [DOI: 10.4018/978-1-4666-6611-5.ch001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In recent years, RNA sequencing (RNAseq) technology has experienced a rapid rise in popularity. Often seen as a competitor of and the ultimate successor to microarray technology given its more accurate and quantitative gene expression measurement, RNAseq also offers a wealth of additional information that is often overlooked, and given the massive accumulation of RNAseq data available in public data repositories over the past few years, these data are ripe for discovery. Abundant opportunities exist for researchers to conduct in-depth, non-traditional analyses that take advantage of these secondary uses and for bioinformaticians to develop tools to make these data more accessible. This is discussed in this chapter.
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21
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Yang S, Deng P, Zhu Z, Zhu J, Wang G, Zhang L, Chen AF, Wang T, Sarkar SN, Billiar TR, Wang Q. Adenosine deaminase acting on RNA 1 limits RIG-I RNA detection and suppresses IFN production responding to viral and endogenous RNAs. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:3436-45. [PMID: 25172485 PMCID: PMC4169998 DOI: 10.4049/jimmunol.1401136] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Type I IFNs play central roles in innate immunity; however, overproduction of IFN can lead to immunopathology. In this study, we demonstrate that adenosine deaminase acting on RNA 1 (ADAR1), an RNA-editing enzyme induced by IFN, is essential for cells to avoid inappropriate sensing of cytosolic RNA in an inducible knockout cell model-the primary mouse embryo fibroblast derived from ADAR1 lox/lox and Cre-ER mice as well as in HEK293 cells. ADAR1 suppresses viral and cellular RNA detection by retinoic acid-inducible gene I (RIG-I) through its RNA binding rather than its RNA editing activity. dsRNA binds to both ADAR1 and RIG-I, but ADAR1 reduces RIG-I RNA binding. In the absence of ADAR1, cellular RNA stimulates type I IFN production without viral infection or exogenous RNA stimulation. Moreover, we showed in the ADAR1-inducible knockout mice that ADAR1 gene disruption results in high-level IFN production in neuronal tissues-the hallmark of Aicardi-Goutières syndrome, a heritable autoimmune disease recently found to be associated with ADAR1 gene mutations. In summary, this study found that ADAR1 limits cytosolic RNA sensing by RIG-I through its RNA binding activity; therefore, ADAR1 suppresses type I IFN production stimulated by viral and cellular RNAs. These results explain why loss of ADARA1 causes IFN induction and also indicates a mechanism for the involvement of ADAR1 in autoimmune diseases such as Aicardi-Goutières syndrome.
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Affiliation(s)
- Shengyong Yang
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Peng Deng
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; Department of Pathophysiology, Southern Medical University, Guangzhou, China 510515
| | - Zhaowei Zhu
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Jianzhong Zhu
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; and
| | - Guoliang Wang
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Liyong Zhang
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Alex F Chen
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Tony Wang
- Department of Immunology and Infectious Disease, SRI Biosciences, Lexington Park, MD 20653
| | - Saumendra N Sarkar
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; and
| | - Timothy R Billiar
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213;
| | - Qingde Wang
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213;
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22
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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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23
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Supraspliceosomes at defined functional states portray the pre-assembled nature of the pre-mRNA processing machine in the cell nucleus. Int J Mol Sci 2014; 15:11637-64. [PMID: 24983480 PMCID: PMC4139805 DOI: 10.3390/ijms150711637] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/05/2014] [Accepted: 06/18/2014] [Indexed: 02/02/2023] Open
Abstract
When isolated from mammalian cell nuclei, all nuclear pre-mRNAs are packaged in multi-subunit large ribonucleoprotein complexes-supraspliceosomes-composed of four native spliceosomes interconnected by the pre-mRNA. Supraspliceosomes contain all five spliceosomal U snRNPs, together with other splicing factors, and are functional in splicing. Supraspliceosomes studied thus far represent the steady-state population of nuclear pre-mRNAs that were isolated at different stages of the splicing reaction. To analyze specific splicing complexes, here, we affinity purified Pseudomonas aeruginosa phage 7 (PP7)-tagged splicing complexes assembled in vivo on Adenovirus Major Late (AdML) transcripts at specific functional stages, and characterized them using molecular techniques including mass spectrometry. First, we show that these affinity purified splicing complexes assembled on PP7-tagged AdML mRNA or on PP7-tagged AdML pre-mRNA are assembled in supraspliceosomes. Second, similar to the general population of supraspliceosomes, these defined supraspliceosomes populations are assembled with all five U snRNPs at all splicing stages. This study shows that dynamic changes in base-pairing interactions of U snRNA:U snRNA and U snRNA:pre-mRNA that occur in vivo during the splicing reaction do not require changes in U snRNP composition of the supraspliceosome. Furthermore, there is no need to reassemble a native spliceosome for the splicing of each intron, and rearrangements of the interactions will suffice.
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Agranat-Tamir L, Shomron N, Sperling J, Sperling R. Interplay between pre-mRNA splicing and microRNA biogenesis within the supraspliceosome. Nucleic Acids Res 2014; 42:4640-51. [PMID: 24464992 PMCID: PMC3985634 DOI: 10.1093/nar/gkt1413] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
MicroRNAs (miRNAs) are central regulators of gene expression, and a large fraction of them are encoded in introns of RNA polymerase II transcripts. Thus, the biogenesis of intronic miRNAs by the microprocessor and the splicing of their host introns by the spliceosome require coordination between these processing events. This cross-talk is addressed here. We show that key microprocessor proteins Drosha and DGCR8 as well as pre-miRNAs cosediment with supraspliceosomes, where nuclear posttranscriptional processing is executed. We further show that inhibition of splicing increases miRNAs expression, whereas knock-down of Drosha increases splicing. We identified a novel splicing event in intron 13 of MCM7, where the miR-106b-25 cluster is located. The unique splice isoform includes a hosted pre-miRNA in the extended exon and excludes its processing. This indicates a possible mechanism of altering the levels of different miRNAs originating from the same transcript. Altogether, our study indicates interplay between the splicing and microprocessor machineries within a supraspliceosome context.
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Affiliation(s)
- Lily Agranat-Tamir
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel, Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel and Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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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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Ono M, Yamada K, Endo A, Avolio F, Lamond AI. Analysis of human protein replacement stable cell lines established using snoMEN-PR vector. PLoS One 2013; 8:e62305. [PMID: 23638031 PMCID: PMC3636044 DOI: 10.1371/journal.pone.0062305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/19/2013] [Indexed: 11/20/2022] Open
Abstract
The study of the function of many human proteins is often hampered by technical limitations, such as cytotoxicity and phenotypes that result from overexpression of the protein of interest together with the endogenous version. Here we present the snoMEN (snoRNA Modulator of gene ExpressioN) vector technology for generating stable cell lines where expression of the endogenous protein can be reduced and replaced by an exogenous protein, such as a fluorescent protein (FP)-tagged version. SnoMEN are snoRNAs engineered to contain complementary sequences that can promote knock-down of targeted RNAs. We have established and characterised two such partial protein replacement human cell lines (snoMEN-PR). Quantitative mass spectrometry was used to analyse the specificity of knock-down and replacement at the protein level and also showed an increased pull-down efficiency of protein complexes containing exogenous, tagged proteins in the protein replacement cell lines, as compared with conventional co-expression strategies. The snoMEN approach facilitates the study of mammalian proteins, particularly those that have so far been difficult to investigate by exogenous expression and has wide applications in basic and applied gene-expression research.
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Affiliation(s)
- Motoharu Ono
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Kayo Yamada
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Akinori Endo
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Fabio Avolio
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Angus I. Lamond
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail:
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27
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Abstract
RNA-seq data can be mined for sequence differences relative to the reference genome to identify both genomic SNPs and RNA editing events. We analyzed the long, polyA-selected, unstranded, deeply sequenced RNA-seq data from the ENCODE Project across 14 human cell lines for candidate RNA editing events. On average, 43% of the RNA sequencing variants that are not in dbSNP and are within gene boundaries are A-to-G(I) RNA editing candidates. The vast majority of A-to-G(I) edits are located in introns and 3′ UTRs, with only 123 located in protein-coding sequence. In contrast, the majority of non–A-to-G variants (60%–80%) map near exon boundaries and have the characteristics of splice-mapping artifacts. After filtering out all candidates with evidence of private genomic variation using genome resequencing or ChIP-seq data, we find that up to 85% of the high-confidence RNA variants are A-to-G(I) editing candidates. Genes with A-to-G(I) edits are enriched in Gene Ontology terms involving cell division, viral defense, and translation. The distribution and character of the remaining non–A-to-G variants closely resemble known SNPs. We find no reproducible A-to-G(I) edits that result in nonsynonymous substitutions in all three lymphoblastoid cell lines in our study, unlike RNA editing in the brain. Given that only a fraction of sites are reproducibly edited in multiple cell lines and that we find a stronger association of editing and specific genes suggests that the editing of the transcript is more important than the editing of any individual site.
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Affiliation(s)
- Eddie Park
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California 92697, USA
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Yu S, Sharma R, Nie D, Jiao H, Im HJ, Lai Y, Zhao Z, Zhu K, Fan J, Chen D, Wang Q, Xiao G. ADAR1 ablation decreases bone mass by impairing osteoblast function in mice. Gene 2013; 513:101-10. [PMID: 23123729 PMCID: PMC3514579 DOI: 10.1016/j.gene.2012.10.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 10/24/2012] [Indexed: 10/27/2022]
Abstract
Bone mass is controlled through a delicate balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. We show here that RNA editing enzyme adenosine deaminase acting on RNA 1 (ADAR1) is critical for proper control of bone mass. Postnatal conditional knockout of Adar1 (the gene encoding ADAR1) resulted in a severe osteopenic phenotype. Ablation of the Adar1 gene significantly suppressed osteoblast differentiation without affecting osteoclast differentiation in bone. In vitro deletion of the Adar1 gene decreased expression of osteoblast-specific osteocalcin and bone sialoprotein genes, alkaline phosphatase activity, and mineralization, suggesting a direct intrinsic role of ADAR1 in osteoblasts. ADAR1 regulates osteoblast differentiation by, at least in part, modulation of osterix expression, which is essential for bone formation. Further, ablation of the Adar1 gene decreased the proliferation and survival of bone marrow stromal cells and inhibited the differentiation of mesenchymal stem cells towards osteoblast lineage. Finally, shRNA knockdown of the Adar1 gene in MC-4 pre-osteoblasts reduced cyclin D1 and cyclin A1 expression and cell growth. Our results identify ADAR1 as a new key regulator of bone mass and suggest that ADAR1 functions in this process mainly through modulation of the intrinsic properties of osteoblasts (i.e., proliferation, survival and differentiation).
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Affiliation(s)
- Shibing Yu
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15240
| | - Rohit Sharma
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15240
| | - Daibang Nie
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15240
| | - Hongli Jiao
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Hee-Jeong Im
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612
| | - Yumei Lai
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612
| | - Zhongfong Zhao
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ke Zhu
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jie Fan
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15240
| | - Di Chen
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612
| | - Qingde Wang
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15240
| | - Guozhi Xiao
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612
- College of Life Sciences, Nankai University, Tianjin 300071, China
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29
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Refsland EW, Harris RS. The APOBEC3 family of retroelement restriction factors. Curr Top Microbiol Immunol 2013; 371:1-27. [PMID: 23686230 DOI: 10.1007/978-3-642-37765-5_1] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ability to regulate and even target mutagenesis is an extremely valuable cellular asset. Enzyme-catalyzed DNA cytosine deamination is a molecular strategy employed by vertebrates to promote antibody diversity and defend against foreign nucleic acids. Ten years ago, a family of cellular enzymes was first described with several proving capable of deaminating DNA and inhibiting HIV-1 replication. Ensuing studies on the apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) restriction factors have uncovered a broad-spectrum innate defense network that suppresses the replication of numerous endogenous and exogenous DNA-based parasites. Although many viruses possess equally elaborate counter-defense mechanisms, the APOBEC3 enzymes offer a tantalizing possibility of leveraging innate immunity to fend off viral infection. Here, we focus on mechanisms of retroelement restriction by the APOBEC3 family of restriction enzymes, and we consider the therapeutic benefits, as well as the possible pathological consequences, of arming cells with active DNA deaminases.
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Affiliation(s)
- Eric W Refsland
- Department of Biochemistry, University of Minnesota, Minneapolis, MN 55455, USA
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30
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Wang Q. RNA editing catalyzed by ADAR1 and its function in mammalian cells. BIOCHEMISTRY (MOSCOW) 2012; 76:900-11. [PMID: 22022963 DOI: 10.1134/s0006297911080050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In mammalian cells two active enzymes, ADAR1 and ADAR2, carry out A-to-I RNA editing. These two editases share many common features in their protein structures, catalytic activities, and substrate requirements. However, the phenotypes of the knockout animals are remarkably different, which indicate the distinct functions they play. The most striking effect of ADAR1 knockout is cell death and interruption of embryonic development that are not observed in ADAR2 knockout. Evidences have shown that ADAR1 plays critical roles in the differentiating cells in embryo and adult tissues to support the cell's survival and permit their further differentiation and maturation. However, our knowledge in understanding of the mechanism by which ADAR1 exerts its unique effects is very limited. Many efforts had been made trying to understand why ADAR1 is so important that it is indispensible for animal survival, including studies that identify the RNA editing substrates and studies on non-editing mechanisms. The interest of this review is focused on the question why ADAR1 and not ADAR2 is required for cell survival. Therefore, only the data, published and unpublished, potentially connecting ADAR1 to its cell death effect is selectively cited and discussed here. The features of cell death caused by ADAR1 deletion are summarized. Potential involvement of interferon and protein kinase RNA-activated (PKR) pathways is proposed, but obviously more experimental evaluations are needed.
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Affiliation(s)
- Qingde Wang
- University of Pittsburgh, Department of Medicine, Division of Hematology and Oncology, University of Pittsburgh Cancer Institute, PA 15232, USA.
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31
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Affiliation(s)
- Aravinda Chakravarti
- Center for Complex Disease Genomics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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32
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Abstract
Double-stranded RNA (dsRNA) functions both as a substrate of ADARs and also as a molecular trigger of innate immune responses. ADARs, adenosine deaminases that act on RNA, catalyze the deamination of adenosine (A) to produce inosine (I) in dsRNA. ADARs thereby can destablize RNA structures, because the generated I:U mismatch pairs are less stable than A:U base pairs. Additionally, I is read as G instead of A by ribosomes during translation and by viral RNA-dependent RNA polymerases during RNA replication. Members of several virus families have the capacity to produce dsRNA during viral genome transcription and replication. Sequence changes (A-G, and U-C) characteristic of A-I editing can occur during virus growth and persistence. Foreign viral dsRNA also mediates both the induction and the action of interferons. In this chapter our current understanding of the role and significance of ADARs in the context of innate immunity, and as determinants of the outcome of viral infection, will be considered.
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Affiliation(s)
- Charles E Samuel
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
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33
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Samuel CE. Adenosine deaminases acting on RNA (ADARs) are both antiviral and proviral. Virology 2011; 411:180-93. [PMID: 21211811 DOI: 10.1016/j.virol.2010.12.004] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 12/04/2010] [Indexed: 12/18/2022]
Abstract
A-to-I RNA editing, the deamination of adenosine (A) to inosine (I) that occurs in regions of RNA with double-stranded character, is catalyzed by a family of Adenosine Deaminases Acting on RNA (ADARs). In mammals there are three ADAR genes. Two encode proteins that possess demonstrated deaminase activity: ADAR1, which is interferon-inducible, and ADAR2 which is constitutively expressed. ADAR3, by contrast, has not yet been shown to be an active enzyme. The specificity of the ADAR1 and ADAR2 deaminases ranges from highly site-selective to non-selective, dependent on the duplex structure of the substrate RNA. A-to-I editing is a form of nucleotide substitution editing, because I is decoded as guanosine (G) instead of A by ribosomes during translation and by polymerases during RNA-dependent RNA replication. Additionally, A-to-I editing can alter RNA structure stability as I:U mismatches are less stable than A:U base pairs. Both viral and cellular RNAs are edited by ADARs. A-to-I editing is of broad physiologic significance. Among the outcomes of A-to-I editing are biochemical changes that affect how viruses interact with their hosts, changes that can lead to either enhanced or reduced virus growth and persistence depending upon the specific virus.
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Affiliation(s)
- Charles E Samuel
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
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George CX, Gan Z, Liu Y, Samuel CE. Adenosine deaminases acting on RNA, RNA editing, and interferon action. J Interferon Cytokine Res 2010; 31:99-117. [PMID: 21182352 DOI: 10.1089/jir.2010.0097] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) catalyze adenosine (A) to inosine (I) editing of RNA that possesses double-stranded (ds) structure. A-to-I RNA editing results in nucleotide substitution, because I is recognized as G instead of A both by ribosomes and by RNA polymerases. A-to-I substitution can also cause dsRNA destabilization, as I:U mismatch base pairs are less stable than A:U base pairs. Three mammalian ADAR genes are known, of which two encode active deaminases (ADAR1 and ADAR2). Alternative promoters together with alternative splicing give rise to two protein size forms of ADAR1: an interferon-inducible ADAR1-p150 deaminase that binds dsRNA and Z-DNA, and a constitutively expressed ADAR1-p110 deaminase. ADAR2, like ADAR1-p110, is constitutively expressed and binds dsRNA. A-to-I editing occurs with both viral and cellular RNAs, and affects a broad range of biological processes. These include virus growth and persistence, apoptosis and embryogenesis, neurotransmitter receptor and ion channel function, pancreatic cell function, and post-transcriptional gene regulation by microRNAs. Biochemical processes that provide a framework for understanding the physiologic changes following ADAR-catalyzed A-to-I ( = G) editing events include mRNA translation by changing codons and hence the amino acid sequence of proteins; pre-mRNA splicing by altering splice site recognition sequences; RNA stability by changing sequences involved in nuclease recognition; genetic stability in the case of RNA virus genomes by changing sequences during viral RNA replication; and RNA-structure-dependent activities such as microRNA production or targeting or protein-RNA interactions.
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Affiliation(s)
- Cyril X George
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, USA
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35
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Inosine cyanoethylation identifies A-to-I RNA editing sites in the human transcriptome. Nat Chem Biol 2010; 6:733-40. [PMID: 20835228 DOI: 10.1038/nchembio.434] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 08/06/2010] [Indexed: 12/13/2022]
Abstract
Adenosine-to-inosine (A-to-I) RNA editing is a post-transcriptional processing event involved in diversifying the transcriptome responsible for various biological processes. Although bioinformatic approaches have predicted a number of A-to-I editing sites in cDNAs, the human transcriptome is thought to still harbor large numbers of as-yet-unknown editing sites. Exploring new editing sites requires a biochemical method to accurately identify inosines on RNA strands. We here describe a chemical method to identify inosines, called inosine chemical erasing (ICE), that is based on cyanoethylation combined with reverse transcription. We carried out a large-scale verification of the ICE method focusing on 642 regions in human cDNA and identified 5,072 editing sites, including 4,395 new sites. Functional study revealed that A-to-I intronic editing in the SARS gene mediated by ADAR1 is involved in preventing aberrant exonization of Alu sequence into mature mRNA.
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36
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Abstract
One type of RNA editing converts adenosines to inosines (A-->I editing) in double-stranded RNA (dsRNA) substrates. A-->I RNA editing is mediated by adenosine deaminase acting on RNA (ADAR) enzymes. A-->I RNA editing of protein-coding sequences of a limited number of mammalian genes results in recoding and subsequent alterations of their functions. However, A-->I RNA editing most frequently targets repetitive RNA sequences located within introns and 5' and 3' untranslated regions (UTRs). Although the biological significance of noncoding RNA editing remains largely unknown, several possibilities, including its role in the control of endogenous short interfering RNAs (esiRNAs), have been proposed. Furthermore, recent studies have revealed that the biogenesis and functions of certain microRNAs (miRNAs) are regulated by the editing of their precursors. Here, I review the recent findings that indicate new functions for A-->I editing in the regulation of noncoding RNAs and for interactions between RNA editing and RNA interference mechanisms.
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Affiliation(s)
- Kazuko Nishikura
- Department of Gene Expression and Regulation, The Wistar Institute, Philadelphia, Pennsylvania 19104-4268, USA.
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37
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Anthony K, Gallo JM. Aberrant RNA processing events in neurological disorders. Brain Res 2010; 1338:67-77. [DOI: 10.1016/j.brainres.2010.03.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 02/24/2010] [Accepted: 03/03/2010] [Indexed: 12/12/2022]
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Farajollahi S, Maas S. Molecular diversity through RNA editing: a balancing act. Trends Genet 2010; 26:221-30. [PMID: 20395010 PMCID: PMC2865426 DOI: 10.1016/j.tig.2010.02.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/11/2010] [Accepted: 02/12/2010] [Indexed: 01/26/2023]
Abstract
RNA editing by adenosine deamination fuels the generation of RNA and protein diversity in eukaryotes, particularly in higher organisms. This includes the recoding of translated exons, widespread editing of retrotransposon-derived repeat elements and sequence modification of microRNA (miRNA) transcripts. Such changes can bring about specific amino acid substitutions, alternative splicing and changes in gene expression levels. Although the overall prevalence of adenosine-to-inosine (A-to-I) editing and its specific functional impact on many of the affected genes is not yet known, the importance of balancing RNA modification levels across time and space is becoming increasingly evident. In particular, transcriptome instabilities in the form of too much or too little RNA editing activity, or misguided editing, manifest in several human disease phenotypes and can disrupt that balance.
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Affiliation(s)
- Sanaz Farajollahi
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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39
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Agranat L, Sperling J, Sperling R. A novel tissue-specific alternatively spliced form of the A-to-I RNA editing enzyme ADAR2. RNA Biol 2010; 7:253-62. [PMID: 20215858 DOI: 10.4161/rna.7.2.11568] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
ADAR2, a member of the adenosine deaminase family of proteins, is the enzyme that edits the Q/R site in the GluR-B transcript, an important physiological A-to-I editing event. ADAR2 pre-mRNA undergoes a number of known alternative splicing events, affecting its function. Here we describe a novel alternatively spliced exon, located within intron 7 of the human gene, which we term "exon 7a". This alternatively spliced exon is highly conserved in the mammalian ADAR2 gene. It has stop codons in all three frames and is down regulated by NMD. We show that the level of exon 7a inclusion differs between different human tissues, with the highest levels of inclusion in skeletal muscle, heart and testis. In the brain, where the level of editing is known to be high, the level of exon 7a inclusion is low. The new alternative form was also found in supraspliceosomes, which constitute the nuclear pre-mRNA processing machine. The high conservation of the novel ADAR2 alternative exon in mammals indicates a physiological importance for this exon.
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Affiliation(s)
- Lily Agranat
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem, Israel
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40
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Sperling J, Azubel M, Sperling R. Structure and function of the Pre-mRNA splicing machine. Structure 2009; 16:1605-15. [PMID: 19000813 DOI: 10.1016/j.str.2008.08.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 08/22/2008] [Accepted: 08/27/2008] [Indexed: 12/14/2022]
Abstract
Most eukaryotic pre-mRNAs contain non-coding sequences (introns) that must be removed in order to accurately place the coding sequences (exons) in the correct reading frame. This critical regulatory pre-mRNA splicing event is fundamental in development and cancer. It occurs within a mega-Dalton multicomponent machine composed of RNA and proteins, which undergoes dynamic changes in RNA-RNA, RNA-protein, and protein-protein interactions during the splicing reaction. Recent years have seen progress in functional and structural analyses of the splicing machine and its subcomponents, and this review is focused on structural aspects of the pre-mRNA splicing machine and their mechanistic implications on the splicing of multi-intronic pre-mRNAs. It brings together, in a comparative manner, structural information on spliceosomes and their intermediates in the stepwise assembly process in vitro, and on the preformed supraspliceosomes, which are isolated from living cell nuclei, with a view of portraying a consistent picture.
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Affiliation(s)
- Joseph Sperling
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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41
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Steele EJ. Mechanism of somatic hypermutation: critical analysis of strand biased mutation signatures at A:T and G:C base pairs. Mol Immunol 2008; 46:305-20. [PMID: 19062097 DOI: 10.1016/j.molimm.2008.10.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Accepted: 10/14/2008] [Indexed: 12/17/2022]
Abstract
The DNA sequence data of the somatic hypermutation (SHM) field published since 1984 has been critically reviewed. The analysis has revealed three strand biased mutation signatures. The first concerns the mutations generated at G:C base pairs in mice genetically deficient in uracil-DNA glycosylase and MSH2-MSH6-mediated mismatch repair. Such mice display the AID deaminase footprint and here C mutations exceed G mutations at least 1.5-fold. This supports earlier and more recent studies claiming that dC-to-dU deaminations occur preferentially in the single stranded DNA regions of the displaced nontranscribed strand (NTS) during transcription. The second concerns the signature generated in immunised mice where G mutations exceed C mutations by at least 1.7-fold. This is a newly identified strand bias which has previously gone undetected. It is consistent with the polynucleotide polymerisation signature of RNA polymerase II copying the template DNA strand carrying AID-mediated lesions generated at C bases, viz. uracils and abasic sites. A reverse transcription step would then need to intervene to fix the mutation pattern in DNA. The third concerns the long recognised strand biased signature generated in normal aged or actively immunised mice whereby A mutations exceed T mutations by two- to three-fold. It is argued that this pattern is best understood as a combination of adenosine-to-inosine (A-to-I) RNA editing followed by a reverse transcription step fixing the A-to-G, as well as A-to-T and A-to-C, as strand biased mutation signatures in DNA. The reasons why the AID-linked RNA polymerase II mutation signature had previously gone undetected are discussed with regard to limitations of standard PCR-based SHM assay techniques. It is concluded that the most economical SHM mechanism involves both DNA and RNA deaminations coupled to a reverse transcription process, most likely involving DNA polymerase eta acting in its reverse transcriptase mode. Experimental approaches to differentiate this RNA-based model from the standard DNA deamination model are discussed.
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Affiliation(s)
- Edward J Steele
- Genomic Interactions Group and CILR, Research School of Biological Sciences, The Institute of Advanced Studies, Australian National University, Canberra, ACT 2601, Australia.
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