1
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Lu G, Shivalila C, Monian P, Yu H, Harding I, Briem S, Byrne M, Faraone A, Friend S, Huth O, Iwamoto N, Kawamoto T, Kumarasamy J, Lamattina A, Longo K, McCarthy L, McGlynn A, Molski A, Pan Q, Pu T, Purcell-Estabrook E, Rossi J, Standley S, Thomas C, Walen A, Yang H, Kandasamy P, Vargeese C. Rational design of base, sugar and backbone modifications improves ADAR-mediated RNA editing. Nucleic Acids Res 2024:gkae681. [PMID: 39149897 DOI: 10.1093/nar/gkae681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 07/20/2024] [Accepted: 07/25/2024] [Indexed: 08/17/2024] Open
Abstract
AIMers are short, chemically modified oligonucleotides that induce A-to-I RNA editing through interaction with endogenous adenosine deaminases acting on RNA (ADAR) enzymes. Here, we describe the development of new AIMer designs with base, sugar and backbone modifications that improve RNA editing efficiency over our previous design. AIMers incorporating a novel pattern of backbone and 2' sugar modifications support enhanced editing efficiency across multiple sequences. Further efficiency gains were achieved through incorporation of an N-3-uridine (N3U), in place of cytidine (C), in the 'orphan base' position opposite the edit site. Molecular modeling suggests that N3U might enhance ADAR catalytic activity by stabilizing the AIMer-ADAR interaction and potentially reducing the energy required to flip the target base into the active site. Supporting this hypothesis, AIMers containing N3U consistently enhanced RNA editing over those containing C across multiple target sequences and multiple nearest neighbor sequence combinations. AIMers combining N3U and the novel pattern of 2' sugar chemistry and backbone modifications improved RNA editing both in vitro and in vivo. We provide detailed N3U synthesis methods and, for the first time, explore the impact of N3U and its analogs on ADAR-mediated RNA editing efficiency and targetable sequence space.
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Affiliation(s)
| | | | | | - Hui Yu
- Wave Life Sciences, Cambridge, MA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Tom Pu
- Wave Life Sciences, Cambridge, MA, USA
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2
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Li M, Cai Z, Song S, Yue X, Lu W, Rao S, Zhang C, Xue C. EcCas6e-based antisense crRNA for gene repression and RNA editing in microorganisms. Nucleic Acids Res 2024; 52:8628-8642. [PMID: 38994565 DOI: 10.1093/nar/gkae612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 07/13/2024] Open
Abstract
Precise gene regulation and programmable RNA editing are vital RNA-level regulatory mechanisms. Gene repression tools grounded in small non-coding RNAs, microRNAs, and CRISPR-dCas proteins, along with RNA editing tools anchored in Adenosine Deaminases acting on RNA (ADARs), have found extensive application in molecular biology and cellular engineering. Here, we introduced a novel approach wherein we developed an EcCas6e mediated crRNA-mRNA annealing system for gene repression in Escherichia coli and RNA editing in Saccharomyces cerevisiae. We found that EcCas6e possesses inherent RNA annealing ability attributed to a secondary positively charged cleft, enhancing crRNA-mRNA hybridization and stability. Based on this, we demonstrated that EcCas6e, along with its cognate crRNA repeat containing a complementary region to the ribosome binding site of a target mRNA, effectively represses gene expression up to 25-fold. Furthermore, we demonstrated that multiple crRNAs can be easily assembled and can simultaneously target up to 13 genes. Lastly, the EcCas6e-crRNA system was developed as an RNA editing tool by fusing it with the ADAR2 deaminase domain. The EcCas6e-crRNA mediated gene repression and RNA editing tools hold broad applications for research and biotechnology.
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Affiliation(s)
- Mutong Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Zhaohui Cai
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Shucheng Song
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xinmin Yue
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Wenyu Lu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Shuquan Rao
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Chuanbo Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Chaoyou Xue
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
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3
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Kiran Kumar KD, Singh S, Schmelzle SM, Vogel P, Fruhner C, Hanswillemenke A, Brun A, Wettengel J, Füll Y, Funk L, Mast V, Botsch JJ, Reautschnig P, Li JB, Stafforst T. An improved SNAP-ADAR tool enables efficient RNA base editing to interfere with post-translational protein modification. Nat Commun 2024; 15:6615. [PMID: 39103360 DOI: 10.1038/s41467-024-50395-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 07/09/2024] [Indexed: 08/07/2024] Open
Abstract
RNA base editing relies on the introduction of adenosine-to-inosine changes into target RNAs in a highly programmable manner in order to repair disease-causing mutations. Here, we propose that RNA base editing could be broadly applied to perturb protein function by removal of regulatory phosphorylation and acetylation sites. We demonstrate the feasibility on more than 70 sites in various signaling proteins and identify key determinants for high editing efficiency and potent down-stream effects. For the JAK/STAT pathway, we demonstrate both, negative and positive regulation. To achieve high editing efficiency over a broad codon scope, we applied an improved version of the SNAP-ADAR tool. The transient nature of RNA base editing enables the comparably fast (hours to days), dose-dependent (thus partial) and reversible manipulation of regulatory sites, which is a key advantage over DNA (base) editing approaches. In summary, PTM interference might become a valuable field of application of RNA base editing.
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Affiliation(s)
| | - Shubhangi Singh
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | | | - Paul Vogel
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Carolin Fruhner
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | | | - Adrian Brun
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jacqueline Wettengel
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Yvonne Füll
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Lukas Funk
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Valentin Mast
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - J Josephine Botsch
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Philipp Reautschnig
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Thorsten Stafforst
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany.
- Gene and RNA Therapy Center (GRTC), Faculty of Medicine University Tübingen, Tübingen, Germany.
- iFIT Cluster of Excellence (EXC2180) "Image-Guided and Functionally Instructed Tumor Therapies, University of Tübingen, Tübingen, Germany.
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4
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Huang WC, Hsu CH, Albu TV, Yang CN. Structural impacts of two disease-linked ADAR1 mutants: a molecular dynamics study. J Comput Aided Mol Des 2024; 38:25. [PMID: 39014124 DOI: 10.1007/s10822-024-00565-1] [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: 05/02/2024] [Accepted: 07/02/2024] [Indexed: 07/18/2024]
Abstract
Adenosine deaminases acting on RNA (ADARs) are pivotal RNA-editing enzymes responsible for converting adenosine to inosine within double-stranded RNA (dsRNA). Dysregulation of ADAR1 editing activity, often arising from genetic mutations, has been linked to elevated interferon levels and the onset of autoinflammatory diseases. However, understanding the molecular underpinnings of this dysregulation is impeded by the lack of an experimentally determined structure for the ADAR1 deaminase domain. In this computational study, we utilized homology modeling and the AlphaFold2 to construct structural models of the ADAR1 deaminase domain in wild-type and two pathogenic variants, R892H and Y1112F, to decipher the structural impact on the reduced deaminase activity. Our findings illuminate the critical role of structural complementarity between the ADAR1 deaminase domain and dsRNA in enzyme-substrate recognition. That is, the relative position of E1008 and K1120 must be maintained so that they can insert into the minor and major grooves of the substrate dsRNA, respectively, facilitating the flipping-out of adenosine to be accommodated within a cavity surrounding E912. Both amino acid replacements studied, R892H at the orthosteric site and Y1112F at the allosteric site, alter K1120 position and ultimately hinder substrate RNA binding.
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Affiliation(s)
- Wen-Chieh Huang
- Institute of Precision Medicine, National Sun Yat-sen University, No. 70 Lien-Hai Road, Kaohsiung, 80424, Taiwan
| | - Chia-Hung Hsu
- Department of Internal Medicine, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan
| | - Titus V Albu
- Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Chia-Ning Yang
- Institute of Precision Medicine, National Sun Yat-sen University, No. 70 Lien-Hai Road, Kaohsiung, 80424, Taiwan.
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5
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Reautschnig P, Fruhner C, Wahn N, Wiegand CP, Kragness S, Yung JF, Hofacker DT, Fisk J, Eidelman M, Waffenschmidt N, Feige M, Pfeiffer LS, Schulz AE, Füll Y, Levanon EY, Mandel G, Stafforst T. Precise in vivo RNA base editing with a wobble-enhanced circular CLUSTER guide RNA. Nat Biotechnol 2024:10.1038/s41587-024-02313-0. [PMID: 38997581 DOI: 10.1038/s41587-024-02313-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 05/17/2024] [Indexed: 07/14/2024]
Abstract
Recruiting the endogenous editing enzyme adenosine deaminase acting on RNA (ADAR) with tailored guide RNAs for adenosine-to-inosine (A-to-I) RNA base editing is promising for safely manipulating genetic information at the RNA level. However, the precision and efficiency of editing are often compromised by bystander off-target editing. Here, we find that in 5'-UAN triplets, which dominate bystander editing, G•U wobble base pairs effectively mitigate off-target events while maintaining high on-target efficiency. This strategy is universally applicable to existing A-to-I RNA base-editing systems and complements other suppression methods such as G•A mismatches and uridine (U) depletion. Combining wobble base pairing with a circularized format of the CLUSTER approach achieves highly precise and efficient editing (up to 87%) of a disease-relevant mutation in the Mecp2 transcript in cell culture. Virus-mediated delivery of the guide RNA alone realizes functional MeCP2 protein restoration in the central nervous system of a murine Rett syndrome model with editing yields of up to 19% and excellent bystander control in vivo.
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Affiliation(s)
- Philipp Reautschnig
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Carolin Fruhner
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Nicolai Wahn
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Charlotte P Wiegand
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Sabrina Kragness
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - John F Yung
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Daniel T Hofacker
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Jenna Fisk
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Michelle Eidelman
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
| | - Nils Waffenschmidt
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Maximilian Feige
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Laura S Pfeiffer
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Annika E Schulz
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Yvonne Füll
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Erez Y Levanon
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
| | - Gail Mandel
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Thorsten Stafforst
- Interfaculty Institute of Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany.
- Gene and RNA Therapy Center (GRTC), Faculty of Medicine, University of Tübingen, Tübingen, Germany.
- iFIT Cluster of Excellence (EXC2180) Image-Guided and Functionally Instructed Tumor Therapies, University of Tübingen, Tübingen, Germany.
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6
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Zhang N, Chen P, Cui Z, Zhou X, Hao C, Xie B, Hao P, Ye BC, Li X, Jing X. Revealing Differential RNA Editing Specificity of Human ADAR1 and ADAR2 in Schizosaccharomyces pombe. Genes (Basel) 2024; 15:898. [PMID: 39062677 PMCID: PMC11276115 DOI: 10.3390/genes15070898] [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: 04/17/2024] [Revised: 06/21/2024] [Accepted: 06/28/2024] [Indexed: 07/28/2024] Open
Abstract
Adenosine-to-inosine (A-to-I) RNA editing is an important post-transcriptional modification mediated by the adenosine deaminases acting on RNA (ADAR) family of enzymes, expanding the transcriptome by altering selected nucleotides A to I in RNA molecules. Recently, A-to-I editing has been explored for correcting disease-causing mutations in RNA using therapeutic guide oligonucleotides to direct ADAR editing at specific sites. Humans have two active ADARs whose preferences and specificities are not well understood. To investigate their substrate specificity, we introduced hADAR1 and hADAR2, respectively, into Schizosaccharomyces pombe (S. pombe), which lacks endogenous ADARs, and evaluated their editing activities in vivo. Using transcriptome sequencing of S. pombe cultured at optimal growth temperature (30 °C), we identified 483 A-to-I high-confident editing sites for hADAR1 and 404 for hADAR2, compared with the non-editing wild-type control strain. However, these sites were mostly divergent between hADAR1 and hADAR2-expressing strains, sharing 33 common sites that are less than 9% for each strain. Their differential specificity for substrates was attributed to their differential preference for neighboring sequences of editing sites. We found that at the -3-position relative to the editing site, hADAR1 exhibits a tendency toward T, whereas hADAR2 leans toward A. Additionally, when varying the growth temperature for hADAR1- and hADAR2-expressing strains, we observed increased editing sites for them at both 20 and 35 °C, compared with them growing at 30 °C. However, we did not observe a significant shift in hADAR1 and hADAR2's preference for neighboring sequences across three temperatures. The vast changes in RNA editing sites at lower and higher temperatures were also observed for hADAR2 previously in budding yeast, which was likely due to the influence of RNA folding at these different temperatures, among many other factors. We noticed examples of longer lengths of dsRNA around the editing sites that induced editing at 20 or 35 °C but were absent at the other two temperature conditions. We found genes' functions can be greatly affected by editing of their transcripts, for which over 50% of RNA editing sites for both hADAR1 and hADAR2 in S. pombe were in coding sequences (CDS), with more than 60% of them resulting in amino acid changes in protein products. This study revealed the extensive differences in substrate selectivity between the two active human ADARS, i.e., ADAR1 and ADAR2, and provided novel insight when utilizing the two different enzymes for in vivo treatment of human genetic diseases using the RNA editing approach.
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Affiliation(s)
- Niubing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Ping Chen
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zilin Cui
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Xiaojuan Zhou
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Chenhui Hao
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Bingran Xie
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Pei Hao
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bang-Ce Ye
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xuan Li
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Xinyun Jing
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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7
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Jauregui-Matos V, Jacobs O, Ouye R, Mozumder S, Salvador P, Fink K, Beal P. Site-specific regulation of RNA editing with ribose-modified nucleoside analogs in ADAR guide strands. Nucleic Acids Res 2024; 52:6733-6747. [PMID: 38828787 PMCID: PMC11229365 DOI: 10.1093/nar/gkae461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 04/12/2024] [Accepted: 05/26/2024] [Indexed: 06/05/2024] Open
Abstract
Adenosine Deaminases Acting on RNA (ADARs) are enzymes that catalyze the conversion of adenosine to inosine in RNA duplexes. These enzymes can be harnessed to correct disease-causing G-to-A mutations in the transcriptome because inosine is translated as guanosine. Guide RNAs (gRNAs) can be used to direct the ADAR reaction to specific sites. Chemical modification of ADAR guide strands is required to facilitate delivery, increase metabolic stability, and increase the efficiency and selectivity of the editing reaction. Here, we show the ADAR reaction is highly sensitive to ribose modifications (e.g. 4'-C-methylation and Locked Nucleic Acid (LNA) substitution) at specific positions within the guide strand. Our studies were enabled by the synthesis of RNA containing a new, ribose-modified nucleoside analog (4'-C-methyladenosine). Importantly, the ADAR reaction is potently inhibited by LNA or 4'-C-methylation at different positions in the ADAR guide. While LNA at guide strand positions -1 and -2 block the ADAR reaction, 4'-C-methylation only inhibits at the -2 position. These effects are rationalized using high-resolution structures of ADAR-RNA complexes. This work sheds additional light on the mechanism of ADAR deamination and aids in the design of highly selective ADAR guide strands for therapeutic editing using chemically modified RNA.
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Affiliation(s)
| | - Olivia Jacobs
- Department of Chemistry, University of California, Davis, CA, USA
| | - Randall Ouye
- Department of Chemistry, University of California, Davis, CA, USA
| | - Sukanya Mozumder
- Department of Chemistry, University of California, Davis, CA, USA
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | | | - Kyle D Fink
- Department of Neurology, Institute for Regenerative Cures and MIND Institute, University of California, Davis Medical Center, Sacramento, CA, USA
| | - Peter A Beal
- Department of Chemistry, University of California, Davis, CA, USA
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8
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Throll P, G Dolce L, Rico-Lastres P, Arnold K, Tengo L, Basu S, Kaiser S, Schneider R, Kowalinski E. Structural basis of tRNA recognition by the m 3C RNA methyltransferase METTL6 in complex with SerRS seryl-tRNA synthetase. Nat Struct Mol Biol 2024:10.1038/s41594-024-01341-3. [PMID: 38918637 DOI: 10.1038/s41594-024-01341-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 05/29/2024] [Indexed: 06/27/2024]
Abstract
Methylation of cytosine 32 in the anticodon loop of tRNAs to 3-methylcytosine (m3C) is crucial for cellular translation fidelity. Misregulation of the RNA methyltransferases setting this modification can cause aggressive cancers and metabolic disturbances. Here, we report the cryo-electron microscopy structure of the human m3C tRNA methyltransferase METTL6 in complex with seryl-tRNA synthetase (SerRS) and their common substrate tRNASer. Through the complex structure, we identify the tRNA-binding domain of METTL6. We show that SerRS acts as the tRNASer substrate selection factor for METTL6. We demonstrate that SerRS augments the methylation activity of METTL6 and that direct contacts between METTL6 and SerRS are necessary for efficient tRNASer methylation. Finally, on the basis of the structure of METTL6 in complex with SerRS and tRNASer, we postulate a universal tRNA-binding mode for m3C RNA methyltransferases, including METTL2 and METTL8, suggesting that these mammalian paralogs use similar ways to engage their respective tRNA substrates and cofactors.
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Affiliation(s)
| | | | - Palma Rico-Lastres
- Institute of Functional Epigenetics, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Katharina Arnold
- Institute of Functional Epigenetics, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Laura Tengo
- European Molecular Biology Laboratory, Grenoble, France
| | - Shibom Basu
- European Molecular Biology Laboratory, Grenoble, France
| | - Stefanie Kaiser
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Robert Schneider
- Institute of Functional Epigenetics, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Eva Kowalinski
- European Molecular Biology Laboratory, Grenoble, France.
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9
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Flemmich L, Bereiter R, Micura R. Chemical Synthesis of Modified RNA. Angew Chem Int Ed Engl 2024; 63:e202403063. [PMID: 38529723 DOI: 10.1002/anie.202403063] [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: 02/12/2024] [Revised: 03/16/2024] [Accepted: 03/26/2024] [Indexed: 03/27/2024]
Abstract
Ribonucleic acids (RNAs) play a vital role in living organisms. Many of their cellular functions depend critically on chemical modification. Methods to modify RNA in a controlled manner-both in vitro and in vivo-are thus essential to evaluate and understand RNA biology at the molecular and mechanistic levels. The diversity of modifications, combined with the size and uniformity of RNA (made up of only 4 nucleotides) makes its site-specific modification a challenging task that needs to be addressed by complementary approaches. One such approach is solid-phase RNA synthesis. We discuss recent developments in this field, starting with new protection concepts in the ongoing effort to overcome current size limitations. We continue with selected modifications that have posed significant challenges for their incorporation into RNA. These include deazapurine bases required for atomic mutagenesis to elucidate mechanistic aspects of catalytic RNAs, and RNA containing xanthosine, N4-acetylcytidine, 5-hydroxymethylcytidine, 3-methylcytidine, 2'-OCF3, and 2'-N3 ribose modifications. We also discuss the all-chemical synthesis of 5'-capped mRNAs and the enzymatic ligation of chemically synthesized oligoribonucleotides to obtain long RNA with multiple distinct modifications, such as those needed for single-molecule FRET studies. Finally, we highlight promising developments in RNA-catalyzed RNA modification using cofactors that transfer bioorthogonal functionalities.
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Affiliation(s)
- Laurin Flemmich
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Raphael Bereiter
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
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10
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Ashley CN, Broni E, Miller WA. ADAR Family Proteins: A Structural Review. Curr Issues Mol Biol 2024; 46:3919-3945. [PMID: 38785511 PMCID: PMC11120146 DOI: 10.3390/cimb46050243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
This review aims to highlight the structures of ADAR proteins that have been crucial in the discernment of their functions and are relevant to future therapeutic development. ADAR proteins can correct or diversify genetic information, underscoring their pivotal contribution to protein diversity and the sophistication of neuronal networks. ADAR proteins have numerous functions in RNA editing independent roles and through the mechanisms of A-I RNA editing that continue to be revealed. Provided is a detailed examination of the ADAR family members-ADAR1, ADAR2, and ADAR3-each characterized by distinct isoforms that offer both structural diversity and functional variability, significantly affecting RNA editing mechanisms and exhibiting tissue-specific regulatory patterns, highlighting their shared features, such as double-stranded RNA binding domains (dsRBD) and a catalytic deaminase domain (CDD). Moreover, it explores ADARs' extensive roles in immunity, RNA interference, and disease modulation, demonstrating their ambivalent nature in both the advancement and inhibition of diseases. Through this comprehensive analysis, the review seeks to underline the potential of targeting ADAR proteins in therapeutic strategies, urging continued investigation into their biological mechanisms and health implications.
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Affiliation(s)
- Carolyn N. Ashley
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
| | - Emmanuel Broni
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
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11
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Bass BL. Adenosine deaminases that act on RNA, then and now. RNA (NEW YORK, N.Y.) 2024; 30:521-529. [PMID: 38531651 PMCID: PMC11019741 DOI: 10.1261/rna.079990.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 02/11/2024] [Indexed: 03/28/2024]
Abstract
In this article, I recount my memories of key experiments that led to my entry into the RNA editing/modification field. I highlight initial observations made by the pioneers in the ADAR field, and how they fit into our current understanding of this family of enzymes. I discuss early mysteries that have now been solved, as well as those that still linger. Finally, I discuss important, outstanding questions and acknowledge my hope for the future of the RNA editing/modification field.
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Affiliation(s)
- Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112, USA
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12
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Jarmoskaite I, Li JB. Multifaceted roles of RNA editing enzyme ADAR1 in innate immunity. RNA (NEW YORK, N.Y.) 2024; 30:500-511. [PMID: 38531645 PMCID: PMC11019752 DOI: 10.1261/rna.079953.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 02/09/2024] [Indexed: 03/28/2024]
Abstract
Innate immunity must be tightly regulated to enable sensitive pathogen detection while averting autoimmunity triggered by pathogen-like host molecules. A hallmark of viral infection, double-stranded RNAs (dsRNAs) are also abundantly encoded in mammalian genomes, necessitating surveillance mechanisms to distinguish "self" from "nonself." ADAR1, an RNA editing enzyme, has emerged as an essential safeguard against dsRNA-induced autoimmunity. By converting adenosines to inosines (A-to-I) in long dsRNAs, ADAR1 covalently marks endogenous dsRNAs, thereby blocking the activation of the cytoplasmic dsRNA sensor MDA5. Moreover, beyond its editing function, ADAR1 binding to dsRNA impedes the activation of innate immune sensors PKR and ZBP1. Recent landmark studies underscore the utility of silencing ADAR1 for cancer immunotherapy, by exploiting the ADAR1-dependence developed by certain tumors to unleash an antitumor immune response. In this perspective, we summarize the genetic and mechanistic evidence for ADAR1's multipronged role in suppressing dsRNA-mediated autoimmunity and explore the evolving roles of ADAR1 as an immuno-oncology target.
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Affiliation(s)
- Inga Jarmoskaite
- Department of Genetics, Stanford University, Stanford, California 94305, USA
- AIRNA Corporation, Cambridge, Massachusetts 02142, USA
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, California 94305, USA
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13
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Wong BL, Mendoza HG, Jacobsen CS, Beal PA. RNA sequences that direct selective ADAR editing from a SELEX library bearing 8-azanebularine. Bioorg Med Chem 2024; 104:117700. [PMID: 38583236 DOI: 10.1016/j.bmc.2024.117700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/20/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
Adenosine Deaminases Acting on RNA (ADARs) catalyze the deamination of adenosine to inosine in double-stranded RNA (dsRNA). ADARs' ability to recognize and edit dsRNA is dependent on local sequence context surrounding the edited adenosine and the length of the duplex. A deeper understanding of how editing efficiency is affected by mismatches, loops, and bulges around the editing site would aid in the development of therapeutic gRNAs for ADAR-mediated site-directed RNA editing (SDRE). Here, a SELEX (systematic evolution of ligands by exponential enrichment) approach was employed to identify dsRNA substrates that bind to the deaminase domain of human ADAR2 (hADAR2d) with high affinity. A library of single-stranded RNAs was hybridized with a fixed-sequence target strand containing the nucleoside analog 8-azanebularine that mimics the adenosine deamination transition state. The presence of this nucleoside analog in the library biased the screen to identify hit sequences compatible with adenosine deamination at the site of 8-azanebularine modification. SELEX also identified non-duplex structural elements that supported editing at the target site while inhibiting editing at bystander sites.
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Affiliation(s)
- Bailey L Wong
- Department of Chemistry, University of California, Davis, CA 95616, United States
| | - Herra G Mendoza
- Department of Chemistry, University of California, Davis, CA 95616, United States
| | - Casey S Jacobsen
- Department of Chemistry, University of California, Davis, CA 95616, United States
| | - Peter A Beal
- Department of Chemistry, University of California, Davis, CA 95616, United States.
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14
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de Reuver R, Maelfait J. Novel insights into double-stranded RNA-mediated immunopathology. Nat Rev Immunol 2024; 24:235-249. [PMID: 37752355 DOI: 10.1038/s41577-023-00940-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2023] [Indexed: 09/28/2023]
Abstract
Recent progress in human and mouse genetics has transformed our understanding of the molecular mechanisms by which recognition of self double-stranded RNA (self-dsRNA) causes immunopathology. Novel mouse models recapitulate loss-of-function mutations in the RNA editing enzyme ADAR1 that are found in patients with Aicardi-Goutières syndrome (AGS) - a monogenic inflammatory disease associated with increased levels of type I interferon. Extensive analyses of the genotype-phenotype relationships in these mice have now firmly established a causal relationship between increased intracellular concentrations of endogenous immunostimulatory dsRNA and type I interferon-driven immunopathology. Activation of the dsRNA-specific immune sensor MDA5 perpetuates the overproduction of type I interferons, and chronic engagement of the interferon-inducible innate immune receptors PKR and ZBP1 by dsRNA drives immunopathology by activating an integrated stress response or by inducing excessive cell death. Biochemical and genetic data support a role for the p150 isoform of ADAR1 in the cytosol in suppressing the spontaneous, pathological response to self-dsRNA.
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Affiliation(s)
- Richard de Reuver
- VIB-UGent Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Jonathan Maelfait
- VIB-UGent Center for Inflammation Research, Ghent, Belgium.
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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15
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Schneider N, Steinberg R, Ben-David A, Valensi J, David-Kadoch G, Rosenwasser Z, Banin E, Levanon EY, Sharon D, Ben-Aroya S. A pipeline for identifying guide RNA sequences that promote RNA editing of nonsense mutations that cause inherited retinal diseases. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102130. [PMID: 38375504 PMCID: PMC10875612 DOI: 10.1016/j.omtn.2024.102130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 01/24/2024] [Indexed: 02/21/2024]
Abstract
Adenosine deaminases acting on RNA (ADARs) are endogenous enzymes catalyzing the deamination of adenosines to inosines, which are then read as guanosines during translation. This ability to recode makes ADAR an attractive therapeutic tool to edit genetic mutations and reprogram genetic information at the mRNA level. Using the endogenous ADARs and guiding them to a selected target has promising therapeutic potential. Indeed, different studies have reported several site-directed RNA-editing approaches for making targeted base changes in RNA molecules. The basic strategy has been to use guide RNAs (gRNAs) that hybridize and form a double-stranded RNA (dsRNA) structure with the desired RNA target because of ADAR activity in regions of dsRNA formation. Here we report on a novel pipeline for identifying disease-causing variants as candidates for RNA editing, using a yeast-based screening system to select efficient gRNAs for editing of nonsense mutations, and test them in a human cell line reporter system. We have used this pipeline to modify the sequence of transcripts carrying nonsense mutations that cause inherited retinal diseases in the FAM161A, KIZ, TRPM1, and USH2A genes. Our approach can serve as a basis for gene therapy intervention in knockin mouse models and ultimately in human patients.
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Affiliation(s)
- Nina Schneider
- Division of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Ricky Steinberg
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Building 206, Room B-840, Ramat Gan 52900, Israel
| | - Amit Ben-David
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Building 206, Room B-840, Ramat Gan 52900, Israel
| | - Johanna Valensi
- Division of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Galit David-Kadoch
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Building 206, Room B-840, Ramat Gan 52900, Israel
| | - Zohar Rosenwasser
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Building 206, Room B-840, Ramat Gan 52900, Israel
| | - Eyal Banin
- Division of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Erez Y. Levanon
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Building 206, Room B-840, Ramat Gan 52900, Israel
| | - Dror Sharon
- Division of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Shay Ben-Aroya
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Building 206, Room B-840, Ramat Gan 52900, Israel
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16
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Pacesa M, Pelea O, Jinek M. Past, present, and future of CRISPR genome editing technologies. Cell 2024; 187:1076-1100. [PMID: 38428389 DOI: 10.1016/j.cell.2024.01.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 03/03/2024]
Abstract
Genome editing has been a transformative force in the life sciences and human medicine, offering unprecedented opportunities to dissect complex biological processes and treat the underlying causes of many genetic diseases. CRISPR-based technologies, with their remarkable efficiency and easy programmability, stand at the forefront of this revolution. In this Review, we discuss the current state of CRISPR gene editing technologies in both research and therapy, highlighting limitations that constrain them and the technological innovations that have been developed in recent years to address them. Additionally, we examine and summarize the current landscape of gene editing applications in the context of human health and therapeutics. Finally, we outline potential future developments that could shape gene editing technologies and their applications in the coming years.
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Affiliation(s)
- Martin Pacesa
- Laboratory of Protein Design and Immunoengineering, École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, Station 19, CH-1015 Lausanne, Switzerland
| | - Oana Pelea
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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17
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Karki A, Campbell KB, Mozumder S, Fisher AJ, Beal PA. Impact of Disease-Associated Mutations on the Deaminase Activity of ADAR1. Biochemistry 2024; 63:282-293. [PMID: 38190734 PMCID: PMC10872254 DOI: 10.1021/acs.biochem.3c00405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
The innate immune system relies on molecular sensors to detect distinctive molecular patterns, including viral double-stranded RNA (dsRNA), which triggers responses resulting in apoptosis and immune infiltration. Adenosine Deaminases Acting on RNA (ADARs) catalyze the deamination of adenosine (A) to inosine (I), serving as a mechanism to distinguish self from non-self RNA and prevent aberrant immune activation. Loss-of-function mutations in the ADAR1 gene are one cause of Aicardi Goutières Syndrome (AGS), a severe autoimmune disorder in children. Although seven out of the eight AGS-associated mutations in ADAR1 occur within the catalytic domain of the ADAR1 protein, their specific effects on the catalysis of adenosine deamination remain poorly understood. In this study, we carried out a biochemical investigation of four AGS-causing mutations (G1007R, R892H, K999N, and Y1112F) in ADAR1 p110 and truncated variants. These studies included adenosine deamination rate measurements with two different RNA substrates derived from human transcripts known to be edited by ADAR1 p110 (glioma-associated oncogene homologue 1 (hGli1), 5-hydroxytryptamine receptor 2C (5-HT2cR)). Our results indicate that AGS-associated mutations at two amino acid positions directly involved in stabilizing the base-flipped conformation of the ADAR-RNA complex (G1007R and R892H) had the most detrimental impact on catalysis. The K999N mutation, positioned near the RNA binding interface, altered catalysis contextually. Finally, the Y1112F mutation had small effects in each of the assays described here. These findings shed light on the differential effects of disease-associated mutations on adenosine deamination by ADAR1, thereby advancing our structural and functional understanding of ADAR1-mediated RNA editing.
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Affiliation(s)
- Agya Karki
- Department of Chemistry, University of California, Davis, CA, USA 95616
| | | | - Sukanya Mozumder
- Department of Chemistry, University of California, Davis, CA, USA 95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA 95616
| | - Andrew J. Fisher
- Department of Chemistry, University of California, Davis, CA, USA 95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA 95616
| | - Peter A. Beal
- Department of Chemistry, University of California, Davis, CA, USA 95616
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18
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Cottrell KA, Andrews RJ, Bass BL. The competitive landscape of the dsRNA world. Mol Cell 2024; 84:107-119. [PMID: 38118451 PMCID: PMC10843539 DOI: 10.1016/j.molcel.2023.11.033] [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: 10/16/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/22/2023]
Abstract
The ability to sense and respond to infection is essential for life. Viral infection produces double-stranded RNAs (dsRNAs) that are sensed by proteins that recognize the structure of dsRNA. This structure-based recognition of viral dsRNA allows dsRNA sensors to recognize infection by many viruses, but it comes at a cost-the dsRNA sensors cannot always distinguish between "self" and "nonself" dsRNAs. "Self" RNAs often contain dsRNA regions, and not surprisingly, mechanisms have evolved to prevent aberrant activation of dsRNA sensors by "self" RNA. Here, we review current knowledge about the life of endogenous dsRNAs in mammals-the biosynthesis and processing of dsRNAs, the proteins they encounter, and their ultimate degradation. We highlight mechanisms that evolved to prevent aberrant dsRNA sensor activation and the importance of competition in the regulation of dsRNA sensors and other dsRNA-binding proteins.
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Affiliation(s)
- Kyle A Cottrell
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA.
| | - Ryan J Andrews
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
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19
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Zhang Y, Lei Y, Dong Y, Chen S, Sun S, Zhou F, Zhao Z, Chen B, Wei L, Chen J, Meng Z. Emerging roles of RNA ac4C modification and NAT10 in mammalian development and human diseases. Pharmacol Ther 2024; 253:108576. [PMID: 38065232 DOI: 10.1016/j.pharmthera.2023.108576] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 01/13/2024]
Abstract
RNA ac4C modification is a novel and rare chemical modification observed in mRNA. Traditional biochemical studies had primarily associated ac4C modification with tRNA and rRNA until in 2018, Arango D et al. first reported the presence of ac4C modification on mRNA and demonstrated its critical role in mRNA stability and translation regulation. Furthermore, they established that the ac4C modification on mRNA is mediated by the classical N-acetyltransferase NAT10. Subsequent studies have underscored the essential implications of NAT10 and mRNA ac4C modification across both physiological and pathological regulatory processes. In this review, we aimed to explore the discovery history of RNA ac4C modification, its detection methods, and its regulatory mechanisms in disease and physiological development. We offer a forward-looking examination and discourse concerning the employment of RNA ac4C modification as a prospective therapeutic strategy across diverse diseases. Furthermore, we comprehensively summarize the functions and mechanisms of NAT10 in gene expression regulation and pathogenesis independent of RNA ac4C modification.
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Affiliation(s)
- Yigan Zhang
- Institute of Biomedical Research, Department of Infectious Diseases, Regulatory Mechanism and Targeted Therapy for Liver Cancer Shiyan Key Laboratory, Hubei rovincial Clinical Research Center for Precise Diagnosis and Treatment of Liver Cancer, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China; Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China
| | - Yumei Lei
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
| | - Yanbin Dong
- Institute of Biophysics, Chinese Academy of Sciences, Key Laboratory of Nucleic Acid Biology, Chinese Academy of Sciences, Beijing, China
| | - Shuwen Chen
- School of Biomedical Engineering, Hubei University of Medicine, Shiyan, China
| | - Siyuan Sun
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
| | - Fange Zhou
- The First Clinical School of Hubei University of Medicine, Shiyan, China
| | - Zhiwen Zhao
- Department of Emergency Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Bonan Chen
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Lv Wei
- Institute of Biophysics, Chinese Academy of Sciences, Key Laboratory of Nucleic Acid Biology, Chinese Academy of Sciences, Beijing, China.
| | - Juan Chen
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China.
| | - Zhongji Meng
- Institute of Biomedical Research, Department of Infectious Diseases, Regulatory Mechanism and Targeted Therapy for Liver Cancer Shiyan Key Laboratory, Hubei rovincial Clinical Research Center for Precise Diagnosis and Treatment of Liver Cancer, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China; Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China.
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20
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Budzko L, Hoffa-Sobiech K, Jackowiak P, Figlerowicz M. Engineered deaminases as a key component of DNA and RNA editing tools. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 34:102062. [PMID: 38028200 PMCID: PMC10661471 DOI: 10.1016/j.omtn.2023.102062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Over recent years, zinc-dependent deaminases have attracted increasing interest as key components of nucleic acid editing tools that can generate point mutations at specific sites in either DNA or RNA by combining a targeting module (such as a catalytically impaired CRISPR-Cas component) and an effector module (most often a deaminase). Deaminase-based molecular tools are already being utilized in a wide spectrum of therapeutic and research applications; however, their medical and biotechnological potential seems to be much greater. Recent reports indicate that the further development of nucleic acid editing systems depends largely on our ability to engineer the substrate specificity and catalytic activity of the editors themselves. In this review, we summarize the current trends and achievements in deaminase engineering. The presented data indicate that the potential of these enzymes has not yet been fully revealed or understood. Several examples show that even relatively minor changes in the structure of deaminases can give them completely new and unique properties.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Karolina Hoffa-Sobiech
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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21
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Zhang B, Li Y, Zhang J, Wang Y, Liang C, Lu T, Zhang C, Liu L, Qin Y, He J, Zhao X, Yu J, Hao J, Yang J, Li MJ, Yao Z, Ma S, Cheng H, Cheng T, Shi L. ADAR1 links R-loop homeostasis to ATR activation in replication stress response. Nucleic Acids Res 2023; 51:11668-11687. [PMID: 37831098 PMCID: PMC10681745 DOI: 10.1093/nar/gkad839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/12/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023] Open
Abstract
Unscheduled R-loops are a major source of replication stress and DNA damage. R-loop-induced replication defects are sensed and suppressed by ATR kinase, whereas it is not known whether R-loop itself is actively involved in ATR activation and, if so, how this is achieved. Here, we report that the nuclear form of RNA-editing enzyme ADAR1 promotes ATR activation and resolves genome-wide R-loops, a process that requires its double-stranded RNA-binding domains. Mechanistically, ADAR1 interacts with TOPBP1 and facilitates its loading on perturbed replication forks by enhancing the association of TOPBP1 with RAD9 of the 9-1-1 complex. When replication is inhibited, DNA-RNA hybrid competes with TOPBP1 for ADAR1 binding to promote the translocation of ADAR1 from damaged fork to accumulate at R-loop region. There, ADAR1 recruits RNA helicases DHX9 and DDX21 to unwind R-loops, simultaneously allowing TOPBP1 to stimulate ATR more efficiently. Collectively, we propose that the tempo-spatially regulated assembly of ADAR1-nucleated protein complexes link R-loop clearance and ATR activation, while R-loops crosstalk with blocked replication forks by transposing ADAR1 to finetune ATR activity and safeguard the genome.
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Affiliation(s)
- Biao Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
| | - Yi Li
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Jieyou Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Yuejiao Wang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Can Liang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Ting Lu
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
| | - Chunyong Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Ling Liu
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Yan Qin
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Jiahuan He
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, 100006, Beijing, China
| | - Xiangnan Zhao
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
| | - Jia Yu
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, 100006, Beijing, China
| | - Jihui Hao
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Jie Yang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Mulin Jun Li
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Zhi Yao
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Shuai Ma
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Hui Cheng
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
| | - Tao Cheng
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
- Tianjin Institutes of Health Science, National Clinical Research Center for Blood Diseases, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
| | - Lei Shi
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin 300070, China
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22
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Pfeiffer LS, Stafforst T. Precision RNA base editing with engineered and endogenous effectors. Nat Biotechnol 2023; 41:1526-1542. [PMID: 37735261 DOI: 10.1038/s41587-023-01927-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/26/2023] [Indexed: 09/23/2023]
Abstract
RNA base editing refers to the rewriting of genetic information within an intact RNA molecule and serves various functions, such as evasion of the endogenous immune system and regulation of protein function. To achieve this, certain enzymes have been discovered in human cells that catalyze the conversion of one nucleobase into another. This natural process could be exploited to manipulate and recode any base in a target transcript. In contrast to DNA base editing, analogous changes introduced in RNA are not permanent or inheritable but rather allow reversible and doseable effects that appeal to various therapeutic applications. The current practice of RNA base editing involves the deamination of adenosines and cytidines, which are converted to inosines and uridines, respectively. In this Review, we summarize current site-directed RNA base-editing strategies and highlight recent achievements to improve editing efficiency, precision, codon-targeting scope and in vivo delivery into disease-relevant tissues. Besides engineered editing effectors, we focus on strategies to harness endogenous adenosine deaminases acting on RNA (ADAR) enzymes and discuss limitations and future perspectives to apply the tools in basic research and as a therapeutic modality. We expect the field to realize the first RNA base-editing drug soon, likely on a well-defined genetic disease. However, the long-term challenge will be to carve out the sweet spot of the technology where its unique ability is exploited to modulate signaling cues, metabolism or other clinically relevant processes in a safe and doseable manner.
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Affiliation(s)
- Laura S Pfeiffer
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Thorsten Stafforst
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany.
- Gene and RNA Therapy Center, Faculty of Medicine, University of Tübingen, Tübingen, Germany.
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23
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Jacobsen CS, Salvador P, Yung JF, Kragness S, Mendoza HG, Mandel G, Beal PA. Library Screening Reveals Sequence Motifs That Enable ADAR2 Editing at Recalcitrant Sites. ACS Chem Biol 2023; 18:2188-2199. [PMID: 37040436 PMCID: PMC10581013 DOI: 10.1021/acschembio.3c00107] [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] [Indexed: 04/13/2023]
Abstract
Adenosine deaminases acting on RNA (ADARs) catalyze the hydrolytic deamination of adenosine to inosine in duplex RNA. The inosine product preferentially base pairs with cytidine resulting in an effective A-to-G edit in RNA. ADAR editing can result in a recoding event alongside other alterations to RNA function. A consequence of ADARs' selective activity on duplex RNA is that guide RNAs (gRNAs) can be designed to target an adenosine of interest and promote a desired recoding event. One of ADAR's main limitations is its preference to edit adenosines with specific 5' and 3' nearest neighbor nucleotides (e.g., 5' U, 3' G). Current rational design approaches are well-suited for this ideal sequence context, but limited when applied to difficult-to-edit sites. Here we describe a strategy for the in vitro evaluation of very large libraries of ADAR substrates (En Masse Evaluation of RNA Guides, EMERGe). EMERGe allows for a comprehensive screening of ADAR substrate RNAs that complements current design approaches. We used this approach to identify sequence motifs for gRNAs that enable editing in otherwise difficult-to-edit target sites. A guide RNA bearing one of these sequence motifs enabled the cellular repair of a premature termination codon arising from mutation of the MECP2 gene associated with Rett Syndrome. EMERGe provides an advancement in screening that not only allows for novel gRNA design, but also furthers our understanding of ADARs' specific RNA-protein interactions.
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Affiliation(s)
- Casey S. Jacobsen
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
| | - Prince Salvador
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
| | - John F. Yung
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA, 97239
| | - Sabrina Kragness
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA, 97239
| | - Herra G. Mendoza
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
| | - Gail Mandel
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA, 97239
| | - Peter A. Beal
- Department of Chemistry, University of California, Davis, Davis, CA, USA, 95616
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24
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Mendoza HG, Beal PA. Chemical Modifications in RNA: Elucidating the Chemistry of dsRNA-Specific Adenosine Deaminases (ADARs). Acc Chem Res 2023; 56:2489-2499. [PMID: 37665999 PMCID: PMC10826463 DOI: 10.1021/acs.accounts.3c00390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The term RNA editing refers to any structural change in an RNA molecule (e.g. insertion, deletion, or base modification) that changes its coding properties and is not a result of splicing. An important class of enzymes involved in RNA editing is the ADAR family (adenosine deaminases acting on RNA), which facilitate the deamination of adenosine (A) to inosine (I) in double-stranded RNA (dsRNA). Inosines are decoded as guanosines (G) in most cellular processes; hence, A-to-I editing can be considered an A-to-G substitution. Among the RNA editing enzymes, ADARs are of particular interest because a large portion of RNA editing events are due to A-to-I editing by the two catalytically active human ADARs (ADAR1 and ADAR2). ADARs have diverse roles in RNA processing, gene expression regulation, and innate immunity; and mutations in the ADAR genes and dysregulated ADAR activity have been associated with cancer, autoimmune diseases, and neurological disorders. A-to-I editing is also currently being explored for correcting disease-causing mutations in the RNA, where therapeutic guide oligonucleotides complementary to the target transcript are used to form a dsRNA substrate and site-specifically direct ADAR editing. Knowledge of the mechanism of ADAR-catalyzed reaction and the origin of its substrate selectivity will allow understanding of ADAR’s role in disease biology and expedite the process of developing ADAR-targeted therapeutics. Chemically modified oligonucleotides provide a versatile platform for modulating the activity and interrogating the structure, function, and selectivity of nucleic acid binding or modifying proteins. In this account, we provide an overview of oligonucleotide modifications that have allowed us to gain deeper understanding of ADAR’s molecular mechanisms, which we utilize in the rational design and optimization of ADAR activity modulators. First, we describe the use of the nucleoside analog 8-azanebularine (8-azaN) to generate high-affinity ADAR-RNA complexes for biochemical and biophysical studies with ADARs, with particular emphasis on X-ray crystallography. We then discuss key observations derived from the crystal structures of ADAR bound to 8-azaN-modified RNA duplexes and describe how these findings provided insight into ADAR editing optimization by introducing nucleoside modifications at various positions in synthetic guide strands. We also present the informed design of 8-azaN-modified RNA duplexes that selectively bind and inhibit ADAR1 but not the closely-related ADAR2 enzyme. Finally, we conclude with some open questions on ADAR structure and substrate recognition and share our current endeavors in the development of ADAR guide oligonucleotides and inhibitors.
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Affiliation(s)
- Herra G. Mendoza
- Department of Chemistry, University of California, Davis, CA 95616 USA
| | - Peter A. Beal
- Department of Chemistry, University of California, Davis, CA 95616 USA
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25
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Chen X, McAndrew MJ, Lapinaite A. Unlocking the secrets of ABEs: the molecular mechanism behind their specificity. Biochem Soc Trans 2023; 51:1635-1646. [PMID: 37526140 PMCID: PMC10586758 DOI: 10.1042/bst20221508] [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: 04/13/2023] [Revised: 07/13/2023] [Accepted: 07/18/2023] [Indexed: 08/02/2023]
Abstract
CRISPR-Cas, the bacterial immune systems, have transformed the field of genome editing by providing efficient, easily programmable, and accessible tools for targeted genome editing. DNA base editors (BE) are state-of-the-art CRISPR-based technology, allowing for targeted modifications of individual nucleobases within the genome. Among the BEs, adenine base editors (ABEs) have shown great potential due to their ability to convert A-to-G with high efficiency. However, current ABEs have limitations in terms of their specificity and targeting range. In this review, we provide an overview of the molecular mechanism of ABEs, with a focus on the mechanism of deoxyadenosine deamination by evolved tRNA-specific adenosine deaminase (TadA). We discuss how mutations and adjustments introduced via both directed evolution as well as rational design have improved ABE efficiency and specificity. This review offers insights into the molecular mechanism of ABEs, providing a roadmap for future developments in the precision genome editing field.
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Affiliation(s)
- Xiaoyu Chen
- School of Molecular Sciences, Arizona State University, Tempe, AZ, U.S.A
| | | | - Audrone Lapinaite
- School of Molecular Sciences, Arizona State University, Tempe, AZ, U.S.A
- Arizona State University-Banner Neurodegenerative Disease Research Center at the Biodesign Institute, Arizona State University, Tempe, AZ, U.S.A
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, U.S.A
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26
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Latifi N, Mack AM, Tellioglu I, Di Giorgio S, Stafforst T. Precise and efficient C-to-U RNA base editing with SNAP-CDAR-S. Nucleic Acids Res 2023; 51:e84. [PMID: 37462074 PMCID: PMC10450179 DOI: 10.1093/nar/gkad598] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/08/2023] [Accepted: 07/05/2023] [Indexed: 08/26/2023] Open
Abstract
Site-directed RNA base editing enables the transient and dosable change of genetic information and represents a recent strategy to manipulate cellular processes, paving ways to novel therapeutic modalities. While tools to introduce adenosine-to-inosine changes have been explored quite intensively, the engineering of precise and programmable tools for cytidine-to-uridine editing is somewhat lacking behind. Here we demonstrate that the cytidine deaminase domain evolved from the ADAR2 adenosine deaminase, taken from the RESCUE-S tool, provides very efficient and highly programmable editing when changing the RNA targeting mechanism from Cas13-based to SNAP-tag-based. Optimization of the guide RNA chemistry further allowed to dramatically improve editing yields in the difficult-to-edit 5'-CCN sequence context thus improving the substrate scope of the tool. Regarding editing efficiency, SNAP-CDAR-S outcompeted the RESCUE-S tool clearly on all tested targets, and was highly superior in perturbing the β-catenin pathway. NGS analysis showed similar, moderate global off-target A-to-I and C-to-U editing for both tools.
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Affiliation(s)
- Ngadhnjim Latifi
- Interfaculty Institute of Biochemistry, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Aline Maria Mack
- Interfaculty Institute of Biochemistry, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Irem Tellioglu
- Division of Immune Diversity (D150), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Faculty of Engineering, University of Heidelberg, 69120 Heidelberg, Germany
| | - Salvatore Di Giorgio
- Division of Immune Diversity (D150), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Thorsten Stafforst
- Interfaculty Institute of Biochemistry, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
- Gene and RNA Therapy Center (GRTC), Faculty of Medicine University Tuebingen, Germany
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27
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Qiu L, Jing Q, Li Y, Han J. RNA modification: mechanisms and therapeutic targets. MOLECULAR BIOMEDICINE 2023; 4:25. [PMID: 37612540 PMCID: PMC10447785 DOI: 10.1186/s43556-023-00139-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 07/28/2023] [Indexed: 08/25/2023] Open
Abstract
RNA modifications are dynamic and reversible chemical modifications on substrate RNA that are regulated by specific modifying enzymes. They play important roles in the regulation of many biological processes in various diseases, such as the development of cancer and other diseases. With the help of advanced sequencing technologies, the role of RNA modifications has caught increasing attention in human diseases in scientific research. In this review, we briefly summarized the basic mechanisms of several common RNA modifications, including m6A, m5C, m1A, m7G, Ψ, A-to-I editing and ac4C. Importantly, we discussed their potential functions in human diseases, including cancer, neurological disorders, cardiovascular diseases, metabolic diseases, genetic and developmental diseases, as well as immune disorders. Through the "writing-erasing-reading" mechanisms, RNA modifications regulate the stability, translation, and localization of pivotal disease-related mRNAs to manipulate disease development. Moreover, we also highlighted in this review all currently available RNA-modifier-targeting small molecular inhibitors or activators, most of which are designed against m6A-related enzymes, such as METTL3, FTO and ALKBH5. This review provides clues for potential clinical therapy as well as future study directions in the RNA modification field. More in-depth studies on RNA modifications, their roles in human diseases and further development of their inhibitors or activators are needed for a thorough understanding of epitranscriptomics as well as diagnosis, treatment, and prognosis of human diseases.
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Affiliation(s)
- Lei Qiu
- State Key Laboratory of Biotherapy and Cancer Center, Research Laboratory of Tumor Epigenetics and Genomics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, P.R. China
| | - Qian Jing
- State Key Laboratory of Biotherapy and Cancer Center, Research Laboratory of Tumor Epigenetics and Genomics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, P.R. China
| | - Yanbo Li
- State Key Laboratory of Biotherapy and Cancer Center, Research Laboratory of Tumor Epigenetics and Genomics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, P.R. China
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Junhong Han
- State Key Laboratory of Biotherapy and Cancer Center, Research Laboratory of Tumor Epigenetics and Genomics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, P.R. China.
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28
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Broni E, Ashley C, Velazquez M, Khan S, Striegel A, Sakyi PO, Peracha S, Bebla K, Sodhi M, Kwofie SK, Ademokunwa A, Miller WA. In Silico Discovery of Potential Inhibitors Targeting the RNA Binding Loop of ADAR2 and 5-HT2CR from Traditional Chinese Natural Compounds. Int J Mol Sci 2023; 24:12612. [PMID: 37628792 PMCID: PMC10454645 DOI: 10.3390/ijms241612612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/02/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Adenosine deaminase acting on RNA 2 (ADAR2) is an important enzyme involved in RNA editing processes, particularly in the conversion of adenosine to inosine in RNA molecules. Dysregulation of ADAR2 activity has been implicated in various diseases, including neurological disorders (including schizophrenia), inflammatory disorders, viral infections, and cancers. Therefore, targeting ADAR2 with small molecules presents a promising therapeutic strategy for modulating RNA editing and potentially treating associated pathologies. However, there are limited compounds that effectively inhibit ADAR2 reactions. This study therefore employed computational approaches to virtually screen natural compounds from the traditional Chinese medicine (TCM) library. The shortlisted compounds demonstrated a stronger binding affinity to the ADAR2 (<-9.5 kcal/mol) than the known inhibitor, 8-azanebularine (-6.8 kcal/mol). The topmost compounds were also observed to possess high binding affinity towards 5-HT2CR with binding energies ranging from -7.8 to -12.9 kcal/mol. Further subjecting the top ADAR2-ligand complexes to molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) calculations revealed that five potential hit compounds comprising ZINC000014637370, ZINC000085593577, ZINC000042890265, ZINC000039183320, and ZINC000101100339 had favorable binding free energies of -174.911, -137.369, -117.236, -67.023, and -64.913 kJ/mol, respectively, with the human ADAR2 protein. Residues Lys350, Cys377, Glu396, Cys451, Arg455, Ser486, Gln488, and Arg510 were also predicted to be crucial in ligand recognition and binding. This finding will provide valuable insights into the molecular interactions between ADAR2 and small molecules, aiding in the design of future ADAR2 inhibitors with potential therapeutic applications. The potential lead compounds were also profiled to have insignificant toxicities. A structural similarity search via DrugBank revealed that ZINC000039183320 and ZINC000014637370 were similar to naringin and naringenin, which are known adenosine deaminase (ADA) inhibitors. These potential novel ADAR2 inhibitors identified herein may be beneficial in treating several neurological disorders, cancers, viral infections, and inflammatory disorders caused by ADAR2 after experimental validation.
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Affiliation(s)
- Emmanuel Broni
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Carolyn Ashley
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Miriam Velazquez
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Sufia Khan
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Andrew Striegel
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Chemical and Biochemistry, College of Science, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Patrick O. Sakyi
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG 56, Ghana
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Sunyani P.O. Box 214, Ghana
| | - Saqib Peracha
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Kristeen Bebla
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Monsheel Sodhi
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Samuel K. Kwofie
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG 77, Ghana
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra P.O. Box LG 54, Ghana
| | - Adesanya Ademokunwa
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Cognitive and Behavioral Neuroscience, Loyola University Chicago, Chicago, IL 60660, USA
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
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29
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Yin L, Shi K, Aihara H. Structural basis of sequence-specific cytosine deamination by double-stranded DNA deaminase toxin DddA. Nat Struct Mol Biol 2023; 30:1153-1159. [PMID: 37460895 PMCID: PMC10442228 DOI: 10.1038/s41594-023-01034-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 06/12/2023] [Indexed: 07/21/2023]
Abstract
The interbacterial deaminase toxin DddA catalyzes cytosine-to-uracil conversion in double-stranded (ds) DNA and enables CRISPR-free mitochondrial base editing, but the molecular mechanisms underlying its unique substrate selectivity have remained elusive. Here, we report crystal structures of DddA bound to a dsDNA substrate containing the 5'-TC target motif. These structures show that DddA binds to the minor groove of a sharply bent dsDNA and engages the target cytosine extruded from the double helix. DddA Phe1375 intercalates in dsDNA and displaces the 5' (-1) thymine, which in turn replaces the target (0) cytosine and forms a noncanonical T-G base pair with the juxtaposed guanine. This tandem displacement mechanism allows DddA to locate a target cytosine without flipping it into the active site. Biochemical experiments demonstrate that DNA base mismatches enhance the DddA deaminase activity and relax its sequence selectivity. On the basis of the structural information, we further identified DddA mutants that exhibit attenuated activity or altered substrate preference. Our studies may help design new tools useful in genome editing or other applications.
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Affiliation(s)
- Lulu Yin
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Ke Shi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA.
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.
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30
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Booth BJ, Nourreddine S, Katrekar D, Savva Y, Bose D, Long TJ, Huss DJ, Mali P. RNA editing: Expanding the potential of RNA therapeutics. Mol Ther 2023; 31:1533-1549. [PMID: 36620962 PMCID: PMC9824937 DOI: 10.1016/j.ymthe.2023.01.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/06/2022] [Accepted: 01/04/2023] [Indexed: 01/09/2023] Open
Abstract
RNA therapeutics have had a tremendous impact on medicine, recently exemplified by the rapid development and deployment of mRNA vaccines to combat the COVID-19 pandemic. In addition, RNA-targeting drugs have been developed for diseases with significant unmet medical needs through selective mRNA knockdown or modulation of pre-mRNA splicing. Recently, RNA editing, particularly antisense RNA-guided adenosine deaminase acting on RNA (ADAR)-based programmable A-to-I editing, has emerged as a powerful tool to manipulate RNA to enable correction of disease-causing mutations and modulate gene expression and protein function. Beyond correcting pathogenic mutations, the technology is particularly well suited for therapeutic applications that require a transient pharmacodynamic effect, such as the treatment of acute pain, obesity, viral infection, and inflammation, where it would be undesirable to introduce permanent alterations to the genome. Furthermore, transient modulation of protein function, such as altering the active sites of enzymes or the interface of protein-protein interactions, opens the door to therapeutic avenues ranging from regenerative medicine to oncology. These emerging RNA-editing-based toolsets are poised to broadly impact biotechnology and therapeutic applications. Here, we review the emerging field of therapeutic RNA editing, highlight recent laboratory advancements, and discuss the key challenges on the path to clinical development.
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Affiliation(s)
| | - Sami Nourreddine
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | | | | | | | | | | | - Prashant Mali
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA.
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31
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Ruan X, Hu K, Zhang X. PIE-seq: identifying RNA-binding protein targets by dual RNA-deaminase editing and sequencing. Nat Commun 2023; 14:3275. [PMID: 37280234 DOI: 10.1038/s41467-023-39054-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023] Open
Abstract
RNA-binding proteins (RBPs) are essential for gene regulation, but it remains a challenge to identify their RNA targets across cell types. Here we present PIE-Seq to investigate Protein-RNA Interaction with dual-deaminase Editing and Sequencing by conjugating C-to-U and A-to-I base editors to RBPs. We benchmark PIE-Seq and demonstrate its sensitivity in single cells, its application in the developing brain, and its scalability with 25 human RBPs. Bulk PIE-Seq identifies canonical binding features for RBPs such as PUM2 and NOVA1, and nominates additional target genes for most tested RBPs such as SRSF1 and TDP-43/TARDBP. Homologous RBPs frequently edit similar sequences and gene sets in PIE-Seq while different RBP families show distinct targets. Single-cell PIE-PUM2 uncovers comparable targets to bulk samples and applying PIE-PUM2 to the developing mouse neocortex identifies neural-progenitor- and neuron-specific target genes such as App. In summary, PIE-Seq provides an orthogonal approach and resource to uncover RBP targets in mice and human cells.
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Affiliation(s)
- Xiangbin Ruan
- Department of Human Genetics and The Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Kaining Hu
- Department of Human Genetics and The Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Xiaochang Zhang
- Department of Human Genetics and The Neuroscience Institute, University of Chicago, Chicago, IL, USA.
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Vallecillo-Viejo IC, Voss G, Albertin CB, Liscovitch-Brauer N, Eisenberg E, Rosenthal JJC. Squid express conserved ADAR orthologs that possess novel features. Front Genome Ed 2023; 5:1181713. [PMID: 37342458 PMCID: PMC10278661 DOI: 10.3389/fgeed.2023.1181713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/15/2023] [Indexed: 06/23/2023] Open
Abstract
The coleoid cephalopods display unusually extensive mRNA recoding by adenosine deamination, yet the underlying mechanisms are not well understood. Because the adenosine deaminases that act on RNA (ADAR) enzymes catalyze this form of RNA editing, the structure and function of the cephalopod orthologs may provide clues. Recent genome sequencing projects have provided blueprints for the full complement of coleoid cephalopod ADARs. Previous results from our laboratory have shown that squid express an ADAR2 homolog, with two splice variants named sqADAR2a and sqADAR2b and that these messages are extensively edited. Based on octopus and squid genomes, transcriptomes, and cDNA cloning, we discovered that two additional ADAR homologs are expressed in coleoids. The first is orthologous to vertebrate ADAR1. Unlike other ADAR1s, however, it contains a novel N-terminal domain of 641 aa that is predicted to be disordered, contains 67 phosphorylation motifs, and has an amino acid composition that is unusually high in serines and basic amino acids. mRNAs encoding sqADAR1 are themselves extensively edited. A third ADAR-like enzyme, sqADAR/D-like, which is not orthologous to any of the vertebrate isoforms, is also present. Messages encoding sqADAR/D-like are not edited. Studies using recombinant sqADARs suggest that only sqADAR1 and sqADAR2 are active adenosine deaminases, both on perfect duplex dsRNA and on a squid potassium channel mRNA substrate known to be edited in vivo. sqADAR/D-like shows no activity on these substrates. Overall, these results reveal some unique features in sqADARs that may contribute to the high-level RNA recoding observed in cephalopods.
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Affiliation(s)
| | - Gjendine Voss
- The Eugene Bell Center, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Caroline B. Albertin
- The Eugene Bell Center, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Noa Liscovitch-Brauer
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - Eli Eisenberg
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
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Bellingrath JS, McClements ME, Fischer MD, MacLaren RE. Programmable RNA editing with endogenous ADAR enzymes - a feasible option for the treatment of inherited retinal disease? Front Mol Neurosci 2023; 16:1092913. [PMID: 37293541 PMCID: PMC10244592 DOI: 10.3389/fnmol.2023.1092913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 04/27/2023] [Indexed: 06/10/2023] Open
Abstract
RNA editing holds great promise for the therapeutic correction of pathogenic, single nucleotide variants (SNV) in the human transcriptome since it does not risk creating permanent off-targets edits in the genome and has the potential for innovative delivery options. Adenine deaminases acting on RNA (ADAR) enzymes catalyse the most widespread form of posttranscriptional RNA editing in humans and their ability to hydrolytically deaminate adenosine to inosine in double stranded RNA (dsRNA) has been harnessed to change pathogenic single nucleotide variants (SNVs) in the human genome on a transcriptional level. Until now, the most promising target editing rates have been achieved by exogenous delivery of the catalytically active ADAR deaminase domain (ADARDD) fused to an RNA binding protein. While it has been shown that endogenous ADARs can be recruited to a defined target site with the sole help of an ADAR-recruiting guide RNA, thus freeing up packaging space, decreasing the chance of an immune response against a foreign protein, and decreasing transcriptome-wide off-target effects, this approach has been limited by a low editing efficiency. Through the recent development of novel circular ADAR-recruiting guide RNAs as well as the optimisation of ADAR-recruiting antisense oligonucleotides, RNA editing with endogenous ADAR is now showing promising target editing efficiency in vitro and in vivo. A target editing efficiency comparable to RNA editing with exogenous ADAR was shown both in wild-type and disease mouse models as well as in wild-type non-human primates (NHP) immediately following and up to 6 weeks after application. With these encouraging results, RNA editing with endogenous ADAR has the potential to present an attractive option for the treatment of inherited retinal diseases (IRDs), a field where gene replacement therapy has been established as safe and efficacious, but where an unmet need still exists for genes that exceed the packaging capacity of an adeno associated virus (AAV) or are expressed in more than one retinal isoform. This review aims to give an overview of the recent developments in the field of RNA editing with endogenous ADAR and assess its applicability for the field of treatment of IRD.
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Affiliation(s)
- Julia-Sophia Bellingrath
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Michelle E. McClements
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - M. Dominik Fischer
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
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Diaz Quiroz JF, Ojha N, Shayhidin EE, De Silva D, Dabney J, Lancaster A, Coull J, Milstein S, Fraley AW, Brown CR, Rosenthal JJC. Development of a selection assay for small guide RNAs that drive efficient site-directed RNA editing. Nucleic Acids Res 2023; 51:e41. [PMID: 36840708 PMCID: PMC10123091 DOI: 10.1093/nar/gkad098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/10/2023] [Accepted: 02/20/2023] [Indexed: 02/26/2023] Open
Abstract
A major challenge confronting the clinical application of site-directed RNA editing (SDRE) is the design of small guide RNAs (gRNAs) that can drive efficient editing. Although many gRNA designs have effectively recruited endogenous Adenosine Deaminases that Act on RNA (ADARs), most of them exceed the size of currently FDA-approved antisense oligos. We developed an unbiased in vitro selection assay to identify short gRNAs that promote superior RNA editing of a premature termination codon. The selection assay relies on hairpin substrates in which the target sequence is linked to partially randomized gRNAs in the same molecule, so that gRNA sequences that promote editing can be identified by sequencing. These RNA substrates were incubated in vitro with ADAR2 and the edited products were selected using amplification refractory mutation system PCR and used to regenerate the substrates for a new round of selection. After nine repetitions, hairpins which drove superior editing were identified. When gRNAs of these hairpins were delivered in trans, eight of the top ten short gRNAs drove superior editing both in vitro and in cellula. These results show that efficient small gRNAs can be selected using our approach, an important advancement for the clinical application of SDRE.
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Affiliation(s)
- Juan Felipe Diaz Quiroz
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, The Marine Biological Laboratory, Woods Hole, MA, USA
| | - Namrata Ojha
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, The Marine Biological Laboratory, Woods Hole, MA, USA
| | | | | | | | | | | | | | | | | | - Joshua J C Rosenthal
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, The Marine Biological Laboratory, Woods Hole, MA, USA
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Mendoza HG, Matos VJ, Park S, Pham KM, Beal PA. Selective Inhibition of ADAR1 Using 8-Azanebularine-Modified RNA Duplexes. Biochemistry 2023; 62:1376-1387. [PMID: 36972568 PMCID: PMC10804918 DOI: 10.1021/acs.biochem.2c00686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Adenosine deaminases acting on RNA (ADARs) are RNA editing enzymes that catalyze the hydrolytic deamination of adenosine (A) to inosine (I) in dsRNA. In humans, two catalytically active ADARs, ADAR1 and ADAR2, perform this A-to-I editing event. The growing field of nucleotide base editing has highlighted ADARs as promising therapeutic agents while multiple studies have also identified ADAR1's role in cancer progression. However, the potential for site-directed RNA editing as well as the rational design of inhibitors is being hindered by the lack of detailed molecular understanding of RNA recognition by ADAR1. Here, we designed short RNA duplexes containing the nucleoside analog, 8-azanebularine (8-azaN), to gain insight into molecular recognition by the human ADAR1 catalytic domain. From gel shift and in vitro deamination experiments, we validate ADAR1 catalytic domain's duplex secondary structure requirement and present a minimum duplex length for binding (14 bp, with 5 bp 5' and 8 bp 3' to editing site). These findings concur with predicted RNA-binding contacts from a previous structural model of the ADAR1 catalytic domain. Finally, we establish that neither 8-azaN as a free nucleoside nor a ssRNA bearing 8-azaN inhibits ADAR1 and demonstrate that the 8-azaN-modified RNA duplexes selectively inhibit ADAR1 and not the closely related ADAR2 enzyme.
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Affiliation(s)
- Herra G. Mendoza
- Department of Chemistry, University of California, Davis, CA 95616 USA
| | | | - SeHee Park
- Department of Chemistry, University of California, Davis, CA 95616 USA
| | - Kevin M. Pham
- Department of Chemistry, University of California, Davis, CA 95616 USA
| | - Peter A. Beal
- Department of Chemistry, University of California, Davis, CA 95616 USA
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Broni E, Striegel A, Ashley C, Sakyi PO, Peracha S, Velazquez M, Bebla K, Sodhi M, Kwofie SK, Ademokunwa A, Khan S, Miller WA. Molecular Docking and Dynamics Simulation Studies Predict Potential Anti-ADAR2 Inhibitors: Implications for the Treatment of Cancer, Neurological, Immunological and Infectious Diseases. Int J Mol Sci 2023; 24:ijms24076795. [PMID: 37047766 PMCID: PMC10095294 DOI: 10.3390/ijms24076795] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/01/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023] Open
Abstract
Altered RNA editing has been linked to several neurodevelopmental disorders, including autism spectrum disorder (ASD) and intellectual disability, in addition to depression, schizophrenia, some cancers, viral infections and autoimmune disorders. The human ADAR2 is a potential therapeutic target for managing these various disorders due to its crucial role in adenosine to inosine editing. This study applied consensus scoring to rank potential ADAR2 inhibitors after performing molecular docking with AutoDock Vina and Glide (Maestro), using a library of 35,161 compounds obtained from traditional Chinese medicine. A total of 47 compounds were predicted to be good binders of the human ADAR2 and had insignificant toxicity concerns. Molecular dynamics (MD) simulations, including the molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) procedure, also emphasized the binding of the shortlisted compounds. The potential compounds had plausible binding free energies ranging from −81.304 to −1068.26 kJ/mol from the MM/PBSA calculations. ZINC000085511995, a naphthoquinone had more negative binding free energy (−1068.26 kJ/mol) than inositol hexakisphosphate (IHP) [−873.873 kJ/mol], an agonist and a strong binder of ADAR2. The potential displacement of IHP by ZINC000085511995 in the IHP binding site of ADAR2 could be explored for possible deactivation of ADAR2. Bayesian-based biological activity prediction corroborates the neuropharmacological, antineoplastic and antiviral activity of the potential lead compounds. All the potential lead compounds, except ZINC000014612330 and ZINC000013462928, were predicted to be inhibitors of various deaminases. The potential lead compounds also had probability of activity (Pa) > 0.442 and probability of inactivity (Pi) < 0.116 values for treating acute neurologic disorders, except for ZINC000085996580 and ZINC000013462928. Pursuing these compounds for their anti-ADAR2 activities holds a promising future, especially against neurological disorders, some cancers and viral infections caused by RNA viruses. Molecular interaction, hydrogen bond and per-residue decomposition analyses predicted Arg400, Arg401, Lys519, Trp687, Glu689, and Lys690 as hot-spot residues in the ADAR2 IHP binding site. Most of the top compounds were observed to have naphthoquinone, indole, furanocoumarin or benzofuran moieties. Serotonin and tryptophan, which are beneficial in digestive regulation, improving sleep cycle and mood, are indole derivatives. These chemical series may have the potential to treat neurological disorders, prion diseases, some cancers, specific viral infections, metabolic disorders and eating disorders through the disruption of ADAR2 pathways. A total of nine potential lead compounds were shortlisted as plausible modulators of ADAR2.
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Affiliation(s)
- Emmanuel Broni
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Andrew Striegel
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Chemical and Biochemistry, College of Science, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Carolyn Ashley
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Patrick O. Sakyi
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG 56, Ghana
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Sunyani P.O. Box 214, Ghana
| | - Saqib Peracha
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Miriam Velazquez
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Kristeen Bebla
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Monsheel Sodhi
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Samuel K. Kwofie
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG 77, Ghana
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra P.O. Box LG 54, Ghana
| | - Adesanya Ademokunwa
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Cognitive and Behavioral Neuroscience, Loyola University Chicago, Chicago, IL 60660, USA
| | - Sufia Khan
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
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Diaz Quiroz JF, Siskel LD, Rosenthal JJC. Site-directed A → I RNA editing as a therapeutic tool: moving beyond genetic mutations. RNA (NEW YORK, N.Y.) 2023; 29:498-505. [PMID: 36669890 PMCID: PMC10019371 DOI: 10.1261/rna.079518.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Adenosine deamination by the ADAR family of enzymes is a natural process that edits genetic information as it passes through messenger RNA. Adenosine is converted to inosine in mRNAs, and this base is interpreted as guanosine during translation. Realizing the potential of this activity for therapeutics, a number of researchers have developed systems that redirect ADAR activity to new targets, ones that are not normally edited. These site-directed RNA editing (SDRE) systems can be broadly classified into two categories: ones that deliver an antisense RNA oligonucleotide to bind opposite a target adenosine, creating an editable structure that endogenously expressed ADARs recognize, and ones that tether the catalytic domain of recombinant ADAR to an antisense RNA oligonucleotide that serves as a targeting mechanism, much like with CRISPR-Cas or RNAi. To date, SDRE has been used mostly to try and correct genetic mutations. Here we argue that these applications are not ideal SDRE, mostly because RNA edits are transient and genetic mutations are not. Instead, we suggest that SDRE could be used to tune cell physiology to achieve temporary outcomes that are therapeutically advantageous, particularly in the nervous system. These include manipulating excitability in nociceptive neural circuits, abolishing specific phosphorylation events to reduce protein aggregation related to neurodegeneration or reduce the glial scarring that inhibits nerve regeneration, or enhancing G protein-coupled receptor signaling to increase nerve proliferation for the treatment of sensory disorders like blindness and deafness.
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Affiliation(s)
- Juan F Diaz Quiroz
- Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
| | - Louise D Siskel
- Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
| | - Joshua J C Rosenthal
- Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
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Zhu T, Niu G, Zhang Y, Chen M, Li CY, Hao L, Zhang Z. Host-mediated RNA editing in viruses. Biol Direct 2023; 18:12. [PMID: 36978112 PMCID: PMC10043548 DOI: 10.1186/s13062-023-00366-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Viruses rely on hosts for life and reproduction, cause a variety of symptoms from common cold to AIDS to COVID-19 and provoke public health threats claiming millions of lives around the globe. RNA editing, as a crucial co-/post-transcriptional modification inducing nucleotide alterations on both endogenous and exogenous RNA sequences, exerts significant influences on virus replication, protein synthesis, infectivity and toxicity. Hitherto, a number of host-mediated RNA editing sites have been identified in diverse viruses, yet lacking a full picture of RNA editing-associated mechanisms and effects in different classes of viruses. Here we synthesize the current knowledge of host-mediated RNA editing in a variety of viruses by considering two enzyme families, viz., ADARs and APOBECs, thereby presenting a landscape of diverse editing mechanisms and effects between viruses and hosts. In the ongoing pandemic, our study promises to provide potentially valuable insights for better understanding host-mediated RNA editing on ever-reported and newly-emerging viruses.
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Affiliation(s)
- Tongtong Zhu
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangyi Niu
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuansheng Zhang
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Chen
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuan-Yun Li
- Laboratory of Bioinformatics and Genomic Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Lili Hao
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
| | - Zhang Zhang
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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39
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Brinkman HF, Jauregui Matos V, Mendoza HG, Doherty EE, Beal PA. Nucleoside analogs in ADAR guide strands targeting 5'-UA̲ sites. RSC Chem Biol 2023; 4:74-83. [PMID: 36685257 PMCID: PMC9811522 DOI: 10.1039/d2cb00165a] [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: 07/11/2022] [Accepted: 10/30/2022] [Indexed: 11/07/2022] Open
Abstract
Adenosine deaminases that act on RNA (ADARs) can be directed to predetermined sites in transcriptomes by forming duplex structures with exogenously delivered guide RNAs (gRNAs). They can then catalyze the hydrolytic deamination of adenosine to inosine in double stranded RNA, which is read as guanosine during translation. High resolution structures of ADAR2-RNA complexes revealed a unique conformation for the nucleotide in the guide strand base paired to the editing site's 5' nearest neighbor (-1 position). Here we describe the effect of 16 different nucleoside analogs at this position in a gRNA that targets a 5'-UA̲-3' site. We found that several analogs increase editing efficiency for both catalytically active human ADARs. In particular, 2'-deoxynebularine (dN) increased the ADAR1 and ADAR2 in vitro deamination rates when at the -1 position of gRNAs targeting the human MECP2 W104X site, the mouse IDUA W392X site, and a site in the 3'-UTR of human ACTB. Furthermore, a locked nucleic acid (LNA) modification at the -1 position was found to eliminate editing. When placed -1 to a bystander editing site in the MECP2 W104X sequence, bystander editing was eliminated while maintaining on-target editing. In vitro trends for four -1 nucleoside analogs were validated by directed editing of the MECP2 W104X site expressed on a reporter transcript in human cells. This work demonstrates the importance of the -1 position of the gRNA to ADAR editing and discloses nucleoside analogs for this site that modulate ADAR editing efficiency.
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Affiliation(s)
- Hannah F. Brinkman
- Department of Chemistry, University of California, One Shields AvenueDavisCA 95616USA
| | | | - Herra G. Mendoza
- Department of Chemistry, University of California, One Shields AvenueDavisCA 95616USA
| | - Erin E. Doherty
- Department of Chemistry, University of California, One Shields AvenueDavisCA 95616USA
| | - Peter A. Beal
- Department of Chemistry, University of California, One Shields AvenueDavisCA 95616USA
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Gao Q, Lu S, Wang Y, He L, Wang M, Jia R, Chen S, Zhu D, Liu M, Zhao X, Yang Q, Wu Y, Zhang S, Huang J, Mao S, Ou X, Sun D, Tian B, Cheng A. Bacterial DNA methyltransferase: A key to the epigenetic world with lessons learned from proteobacteria. Front Microbiol 2023; 14:1129437. [PMID: 37032876 PMCID: PMC10073500 DOI: 10.3389/fmicb.2023.1129437] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/27/2023] [Indexed: 04/11/2023] Open
Abstract
Epigenetics modulates expression levels of various important genes in both prokaryotes and eukaryotes. These epigenetic traits are heritable without any change in genetic DNA sequences. DNA methylation is a universal mechanism of epigenetic regulation in all kingdoms of life. In bacteria, DNA methylation is the main form of epigenetic regulation and plays important roles in affecting clinically relevant phenotypes, such as virulence, host colonization, sporulation, biofilm formation et al. In this review, we survey bacterial epigenomic studies and focus on the recent developments in the structure, function, and mechanism of several highly conserved bacterial DNA methylases. These methyltransferases are relatively common in bacteria and participate in the regulation of gene expression and chromosomal DNA replication and repair control. Recent advances in sequencing techniques capable of detecting methylation signals have enabled the characterization of genome-wide epigenetic regulation. With their involvement in critical cellular processes, these highly conserved DNA methyltransferases may emerge as promising targets for developing novel epigenetic inhibitors for biomedical applications.
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Affiliation(s)
- Qun Gao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Shuwei Lu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Yuwei Wang
- Key Laboratory of Livestock and Poultry Provenance Disease Research in Mianyang, Sichuan, China
| | - Longgui He
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Mingshu Wang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Renyong Jia
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Shun Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Dekang Zhu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Mafeng Liu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Xinxin Zhao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Qiao Yang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Ying Wu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Shaqiu Zhang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Juan Huang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Sai Mao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Xumin Ou
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Di Sun
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Bin Tian
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Anchun Cheng
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
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41
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Li M, Yan C, Jiao Y, Xu Y, Bai C, Miao R, Jiang J, Liu J. Site-directed RNA editing by harnessing ADARs: advances and challenges. Funct Integr Genomics 2022; 22:1089-1103. [DOI: 10.1007/s10142-022-00910-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 11/04/2022]
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42
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Doherty EE, Karki A, Wilcox XE, Mendoza HG, Manjunath A, Matos VJ, Fisher AJ, Beal PA. ADAR activation by inducing a syn conformation at guanosine adjacent to an editing site. Nucleic Acids Res 2022; 50:10857-10868. [PMID: 36243986 PMCID: PMC9638939 DOI: 10.1093/nar/gkac897] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 11/27/2022] Open
Abstract
ADARs (adenosine deaminases acting on RNA) can be directed to sites in the transcriptome by complementary guide strands allowing for the correction of disease-causing mutations at the RNA level. However, ADARs show bias against editing adenosines with a guanosine 5′ nearest neighbor (5′-GA sites), limiting the scope of this approach. Earlier studies suggested this effect arises from a clash in the RNA minor groove involving the 2-amino group of the guanosine adjacent to an editing site. Here we show that nucleosides capable of pairing with guanosine in a syn conformation enhance editing for 5′-GA sites. We describe the crystal structure of a fragment of human ADAR2 bound to RNA bearing a G:G pair adjacent to an editing site. The two guanosines form a Gsyn:Ganti pair solving the steric problem by flipping the 2-amino group of the guanosine adjacent to the editing site into the major groove. Also, duplexes with 2′-deoxyadenosine and 3-deaza-2′-deoxyadenosine displayed increased editing efficiency, suggesting the formation of a Gsyn:AH+anti pair. This was supported by X-ray crystallography of an ADAR complex with RNA bearing a G:3-deaza dA pair. This study shows how non-Watson–Crick pairing in duplex RNA can facilitate ADAR editing enabling the design of next generation guide strands for therapeutic RNA editing.
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Affiliation(s)
- Erin E Doherty
- Department of Chemistry, University of California, Davis, CA, USA
| | - Agya Karki
- Department of Chemistry, University of California, Davis, CA, USA
| | - Xander E Wilcox
- Department of Chemistry, University of California, Davis, CA, USA
| | - Herra G Mendoza
- Department of Chemistry, University of California, Davis, CA, USA
| | | | | | - Andrew J Fisher
- Department of Chemistry, University of California, Davis, CA, USA.,Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Peter A Beal
- Department of Chemistry, University of California, Davis, CA, USA
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43
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Hajji K, Sedmík J, Cherian A, Amoruso D, Keegan LP, O'Connell MA. ADAR2 enzymes: efficient site-specific RNA editors with gene therapy aspirations. RNA (NEW YORK, N.Y.) 2022; 28:1281-1297. [PMID: 35863867 PMCID: PMC9479739 DOI: 10.1261/rna.079266.122] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The adenosine deaminase acting on RNA (ADAR) enzymes are essential for neuronal function and innate immune control. ADAR1 RNA editing prevents aberrant activation of antiviral dsRNA sensors through editing of long, double-stranded RNAs (dsRNAs). In this review, we focus on the ADAR2 proteins involved in the efficient, highly site-specific RNA editing to recode open reading frames first discovered in the GRIA2 transcript encoding the key GLUA2 subunit of AMPA receptors; ADAR1 proteins also edit many of these sites. We summarize the history of ADAR2 protein research and give an up-to-date review of ADAR2 structural studies, human ADARBI (ADAR2) mutants causing severe infant seizures, and mouse disease models. Structural studies on ADARs and their RNA substrates facilitate current efforts to develop ADAR RNA editing gene therapy to edit disease-causing single nucleotide polymorphisms (SNPs). Artificial ADAR guide RNAs are being developed to retarget ADAR RNA editing to new target transcripts in order to correct SNP mutations in them at the RNA level. Site-specific RNA editing has been expanded to recode hundreds of sites in CNS transcripts in Drosophila and cephalopods. In Drosophila and C. elegans, ADAR RNA editing also suppresses responses to self dsRNA.
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Affiliation(s)
- Khadija Hajji
- CEITEC Masaryk University, Brno 62500, Czech Republic
| | - Jiří Sedmík
- CEITEC Masaryk University, Brno 62500, Czech Republic
| | - Anna Cherian
- CEITEC Masaryk University, Brno 62500, Czech Republic
| | | | - Liam P Keegan
- CEITEC Masaryk University, Brno 62500, Czech Republic
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44
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Han W, Huang W, Wei T, Ye Y, Mao M, Wang Z. Programmable RNA base editing with a single gRNA-free enzyme. Nucleic Acids Res 2022; 50:9580-9595. [PMID: 36029126 PMCID: PMC9458445 DOI: 10.1093/nar/gkac713] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 07/02/2022] [Accepted: 08/09/2022] [Indexed: 12/24/2022] Open
Abstract
Programmable RNA editing enables rewriting gene expression without changing genome sequences. Current tools for specific RNA editing dependent on the assembly of guide RNA into an RNA/protein complex, causing delivery barrier and low editing efficiency. We report a new gRNA-free system, RNA editing with individual RNA-binding enzyme (REWIRE), to perform precise base editing with a single engineered protein. This artificial enzyme contains a human-originated programmable PUF domain to specifically recognize RNAs and different deaminase domains to achieve efficient A-to-I or C-to-U editing, which achieved 60-80% editing rate in human cells, with a few non-specific editing sites in the targeted region and a low level off-target effect globally. The RNA-binding domain in REWIREs was further optimized to improve editing efficiency and minimize off-target effects. We applied the REWIREs to correct disease-associated mutations and achieve both types of base editing in mice. As a single-component system originated from human proteins, REWIRE presents a precise and efficient RNA editing platform with broad applicability.
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Affiliation(s)
- Wenjian Han
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wendi Huang
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tong Wei
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanwen Ye
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Miaowei Mao
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zefeng Wang
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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45
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Grimm NB, Lee JT. Selective Xi reactivation and alternative methods to restore MECP2 function in Rett syndrome. Trends Genet 2022; 38:920-943. [PMID: 35248405 PMCID: PMC9915138 DOI: 10.1016/j.tig.2022.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
The human X-chromosome harbors only 4% of our genome but carries over 20% of genes associated with intellectual disability. Given that they inherit only one X-chromosome, males are more frequently affected by X-linked neurodevelopmental genetic disorders than females. However, despite inheriting two X-chromosomes, females can also be affected because X-chromosome inactivation enables only one of two X-chromosomes to be expressed per cell. For Rett syndrome and similar X-linked disorders affecting females, disease-specific treatments have remained elusive. However, a cure may be found within their own cells because every sick cell carries a healthy copy of the affected gene on the inactive X (Xi). Therefore, selective Xi reactivation may be a viable approach that would address the root cause of various X-linked disorders. Here, we discuss Rett syndrome and compare current approaches in the pharmaceutical pipeline to restore MECP2 function. We then focus on Xi reactivation and review available methods, lessons learned, and future directions.
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Affiliation(s)
- Niklas-Benedikt Grimm
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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46
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Xiang Y, Katrekar D, Mali P. Methods for recruiting endogenous and exogenous ADAR enzymes for site-specific RNA editing. Methods 2022; 205:158-166. [PMID: 35779766 DOI: 10.1016/j.ymeth.2022.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/08/2022] [Accepted: 06/27/2022] [Indexed: 12/01/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) can be repurposed to achieve site-specific A-to-I RNA editing by recruiting them to a target of interest via an ADAR-recruiting guide RNA (adRNA). In this chapter, we present details towards experimental methods to enable this via two orthogonal strategies: one, via recruitment of endogenous ADARs (i.e. ADARs already natively expressed in cells); and two, via recruitment of exogenous ADARs (i.e. ADARs delivered into cells). Towards the former, we describe the use of circular adRNAs to recruit endogenous ADARs to a desired mRNA target. This results in robust, persistent and highly transcript specific editing both in vitro and in vivo. Towards the latter, we describe the use of a split-ADAR2 system, which allows for overexpression of ADAR2 variants that can be utilized to edit adenosines with high specificity, including at challenging to edit adenosines in non-preferred motifs such as those flanked by a 5' guanosine. We anticipate the described methods should facilitate RNA editing applications across research and biotechnology settings.
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Affiliation(s)
- Yichen Xiang
- Department of Bioengineering, University of California San Diego, USA
| | | | - Prashant Mali
- Department of Bioengineering, University of California San Diego, USA.
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47
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Fu T, Chan TW, Bahn JH, Kim TH, Rowat AC, Xiao X. Multifaceted role of RNA editing in promoting loss-of-function of PODXL in cancer. iScience 2022; 25:104836. [PMID: 35992085 PMCID: PMC9382340 DOI: 10.1016/j.isci.2022.104836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/16/2022] [Accepted: 07/20/2022] [Indexed: 12/03/2022] Open
Abstract
PODXL, a protein that is dysregulated in multiple cancers, plays an important role in promoting cancer metastasis. In this study, we report that RNA editing promotes the inclusion of a PODXL alternative exon. The resulting edited PODXL long isoform is more prone to protease digestion and has the strongest effects on reducing cell migration and cisplatin chemoresistance among the three PODXL isoforms (short, unedited long, and edited long isoforms). Importantly, the editing level of the PODXL recoding site and the inclusion level of the PODXL alternative exon are strongly associated with overall patient survival in Kidney Renal Clear Cell Carcinoma (KIRC). Supported by significant enrichment of exonic RNA editing sites in alternatively spliced exons, we hypothesize that exonic RNA editing sites may enhance proteomic diversity through alternative splicing, in addition to amino acid changes, a previously under-appreciated aspect of RNA editing function.
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Affiliation(s)
- Ting Fu
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tracey W. Chan
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jae Hoon Bahn
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tae-Hyung Kim
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Amy C. Rowat
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xinshu Xiao
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
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48
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Han RC, MacLaren RE. RNA gene editing in the eye and beyond: The neglected tool of the gene editing armatorium? INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2022; 372:175-205. [PMID: 36064264 DOI: 10.1016/bs.ircmb.2022.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RNA editing allows correction of pathological point mutations without permanently altering genomic DNA. Theoretically targetable to any RNA type and site, its flexibility and reversibility makes it a potentially powerful gene editing tool. RNA editing offers a host of potential advantages in specific niches when compared to currently available alternative gene manipulation techniques. Unlike DNA editors, which are currently too large to be delivered in vivo using a viral vector, smaller RNA editors fit easily within the capabilities of an adeno-associated virus (AAV). Unlike gene augmentation, which is limited by gene size and viral packaging constraints, RNA editing may correct transcripts too long to fit within a viral vector. In this article we examine the development of RNA editing and discuss potential applications and pitfalls. We argue that, although in its infancy, an RNA editing approach can offer unique advantages for selected retinal diseases.
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Affiliation(s)
- Ruofan Connie Han
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom; Oxford Eye Hospital, John Radcliffe, Oxford, United Kingdom
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49
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Li Q, Gloudemans MJ, Geisinger JM, Fan B, Aguet F, Sun T, Ramaswami G, Li YI, Ma JB, Pritchard JK, Montgomery SB, Li JB. RNA editing underlies genetic risk of common inflammatory diseases. Nature 2022; 608:569-577. [PMID: 35922514 PMCID: PMC9790998 DOI: 10.1038/s41586-022-05052-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/29/2022] [Indexed: 12/12/2022]
Abstract
A major challenge in human genetics is to identify the molecular mechanisms of trait-associated and disease-associated variants. To achieve this, quantitative trait locus (QTL) mapping of genetic variants with intermediate molecular phenotypes such as gene expression and splicing have been widely adopted1,2. However, despite successes, the molecular basis for a considerable fraction of trait-associated and disease-associated variants remains unclear3,4. Here we show that ADAR-mediated adenosine-to-inosine RNA editing, a post-transcriptional event vital for suppressing cellular double-stranded RNA (dsRNA)-mediated innate immune interferon responses5-11, is an important potential mechanism underlying genetic variants associated with common inflammatory diseases. We identified and characterized 30,319 cis-RNA editing QTLs (edQTLs) across 49 human tissues. These edQTLs were significantly enriched in genome-wide association study signals for autoimmune and immune-mediated diseases. Colocalization analysis of edQTLs with disease risk loci further pinpointed key, putatively immunogenic dsRNAs formed by expected inverted repeat Alu elements as well as unexpected, highly over-represented cis-natural antisense transcripts. Furthermore, inflammatory disease risk variants, in aggregate, were associated with reduced editing of nearby dsRNAs and induced interferon responses in inflammatory diseases. This unique directional effect agrees with the established mechanism that lack of RNA editing by ADAR1 leads to the specific activation of the dsRNA sensor MDA5 and subsequent interferon responses and inflammation7-9. Our findings implicate cellular dsRNA editing and sensing as a previously underappreciated mechanism of common inflammatory diseases.
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Affiliation(s)
- Qin Li
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Michael J. Gloudemans
- Department of Pathology, Stanford University, Stanford, CA, USA.,Biomedical Informatics Training Program, Stanford University, Stanford, CA, USA
| | | | - Boming Fan
- State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | | | - Tao Sun
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Gokul Ramaswami
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Yang I. Li
- Department of Genetics, Stanford University, Stanford, CA, USA.,Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Jin-Biao Ma
- State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | - Jonathan K. Pritchard
- Department of Genetics, Stanford University, Stanford, CA, USA.,Department of Biology, Stanford University, Stanford, CA, USA
| | - Stephen B. Montgomery
- Department of Genetics, Stanford University, Stanford, CA, USA.,Department of Pathology, Stanford University, Stanford, CA, USA.,These authors contributed equally: Stephen B. Montgomery, Jin Billy Li
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA, USA.
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50
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Raghava Kurup R, Oakes EK, Manning AC, Mukherjee P, Vadlamani P, Hundley HA. RNA binding by ADAR3 inhibits adenosine-to-inosine editing and promotes expression of immune response protein MAVS. J Biol Chem 2022; 298:102267. [PMID: 35850307 PMCID: PMC9418441 DOI: 10.1016/j.jbc.2022.102267] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 12/13/2022] Open
Abstract
Members of the ADAR family of double-stranded RNA–binding proteins regulate one of the most abundant RNA modifications in humans, the deamination of adenosine to inosine. Several transcriptome-wide studies have been carried out to identify RNA targets of the active deaminases ADAR1 and ADAR2. However, our understanding of ADAR3, the brain-specific deaminase-deficient ADAR family member, is limited to a few transcripts. In this study, we identified over 3300 transcripts bound by ADAR3 and observed that binding of ADAR3 correlated with reduced editing of over 400 sites in the glioblastoma transcriptome. We further investigated the impact of ADAR3 on gene regulation of the transcript that encodes MAVS, an essential protein in the innate immune response pathway. We observed reduced editing in the MAVS 3′ UTR in cells expressing increased ADAR3 or reduced ADAR1 suggesting ADAR3 acts as a negative regulator of ADAR1-mediated editing. While neither ADAR1 knockdown or ADAR3 overexpression affected MAVS mRNA expression, we demonstrate increased ADAR3 expression resulted in upregulation of MAVS protein expression. In addition, we created a novel genetic mutant of ADAR3 that exhibited enhanced RNA binding and MAVS upregulation compared with wildtype ADAR3. Interestingly, this ADAR3 mutant no longer repressed RNA editing, suggesting ADAR3 has a unique regulatory role beyond altering editing levels. Altogether, this study provides the first global view of ADAR3-bound RNAs in glioblastoma cells and identifies both a role for ADAR3 in repressing ADAR1-mediated editing and an RNA-binding dependent function of ADAR3 in regulating MAVS expression.
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Affiliation(s)
| | - Eimile K Oakes
- Department of Biology, Indiana University, Bloomington IN 47405, USA
| | - Aidan C Manning
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Bloomington IN 47405, USA
| | - Priyanka Mukherjee
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Bloomington IN 47405, USA
| | - Pranathi Vadlamani
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Bloomington IN 47405, USA
| | - Heather A Hundley
- Department of Biology, Indiana University, Bloomington IN 47405, USA.
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