1
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Bhatt U, Cucchiarini A, Luo Y, Evans CW, Mergny JL, Iyer KS, Smith NM. Preferential formation of Z-RNA over intercalated motifs in long noncoding RNA. Genome Res 2024; 34:217-230. [PMID: 38355305 PMCID: PMC10984386 DOI: 10.1101/gr.278236.123] [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: 06/30/2023] [Accepted: 01/31/2024] [Indexed: 02/16/2024]
Abstract
Secondary structure is a principal determinant of lncRNA function, predominantly regarding scaffold formation and interfaces with target molecules. Noncanonical secondary structures that form in nucleic acids have known roles in regulating gene expression and include G-quadruplexes (G4s), intercalated motifs (iMs), and R-loops (RLs). In this paper, we used the computational tools G4-iM Grinder and QmRLFS-finder to predict the formation of each of these structures throughout the lncRNA transcriptome in comparison to protein-coding transcripts. The importance of the predicted structures in lncRNAs in biological contexts was assessed by combining our results with publicly available lncRNA tissue expression data followed by pathway analysis. The formation of predicted G4 (pG4) and iM (piM) structures in select lncRNA sequences was confirmed in vitro using biophysical experiments under near-physiological conditions. We find that the majority of the tested pG4s form highly stable G4 structures, and identify many previously unreported G4s in biologically important lncRNAs. In contrast, none of the piM sequences are able to form iM structures, consistent with the idea that RNA is unable to form stable iMs. Unexpectedly, these C-rich sequences instead form Z-RNA structures, which have not been previously observed in regions containing cytosine repeats and represent an interesting and underexplored target for protein-RNA interactions. Our results highlight the prevalence and potential structure-associated functions of noncanonical secondary structures in lncRNAs, and show G4 and Z-RNA structure formation in many lncRNA sequences for the first time, furthering the understanding of the structure-function relationship in lncRNAs.
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Affiliation(s)
- Uditi Bhatt
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Anne Cucchiarini
- Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Yu Luo
- Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Cameron W Evans
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jean-Louis Mergny
- Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - K Swaminathan Iyer
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Nicole M Smith
- School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia;
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2
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Nichols PJ, Welty R, Krall JB, Henen MA, Vicens Q, Vögeli B. Zα Domain of ADAR1 Binds to an A-Form-like Nucleic Acid Duplex with Low Micromolar Affinity. Biochemistry 2024; 63:777-787. [PMID: 38437710 PMCID: PMC11168418 DOI: 10.1021/acs.biochem.3c00636] [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: 03/06/2024]
Abstract
The left-handed Z-conformation of nucleic acids can be adopted by both DNA and RNA when bound by Zα domains found within a variety of viral and innate immune response proteins. While Z-form adoption is preferred by certain sequences, such as the commonly studied (CpG)n repeats, Zα has been reported to bind to a wide range of sequence contexts. Studying how Zα interacts with B-/A-form helices prior to their conversion to the Z-conformation is challenging as binding coincides with Z-form adoption. Here, we studied the binding of Zα fromHomo sapiens ADAR1 to a locked "A-type" version of the (CpG)3 construct (LNA (CpG)3) where the sugar pucker is locked into the C3'-endo/C2'-exo conformation, which prevents the duplex from adopting the alternating C2'/C3'-endo sugar puckers found in the Z-conformation. Using NMR and other biophysical techniques, we find that ZαADAR1 binds to the LNA (CpG)3 using a similar interface as for Z-form binding, with a dissociation constant (KD) of ∼4 μM. In contrast to Z-DNA/Z-RNA, where two ZαADAR1 bind to every 6 bp stretch, our data suggests that ZαADAR1 binds to multiple LNA molecules, indicating a completely different binding mode. Because ZαADAR1 binds relatively tightly to a non-Z-form model, its binding to B/A-form helices may need to be considered when experiments are carried out which attempt to identify the Z-form targets of Zα domains. The use of LNA constructs may be beneficial in experiments where negative controls for Z-form adoption are needed.
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Affiliation(s)
- Parker J. Nichols
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Robb Welty
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Jeffrey B. Krall
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Morkos A. Henen
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
- Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
- Present address: Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77204, USA
| | - Beat Vögeli
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
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3
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Nichols PJ, Krall JB, Henen MA, Welty R, Macfadden A, Vicens Q, Vögeli B. Z-Form Adoption of Nucleic Acid is a Multi-Step Process Which Proceeds through a Melted Intermediate. J Am Chem Soc 2024; 146:677-694. [PMID: 38131335 DOI: 10.1021/jacs.3c10406] [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: 12/23/2023]
Abstract
The left-handed Z-conformation of nucleic acids can be adopted by both DNA and RNA when bound by Zα domains found within a variety of innate immune response proteins. Zα domains stabilize this higher-energy conformation by making specific interactions with the unique geometry of Z-DNA/Z-RNA. However, the mechanism by which a right-handed helix contorts to become left-handed in the presence of proteins, including the intermediate steps involved, is poorly understood. Through a combination of nuclear magnetic resonance (NMR) and other biophysical measurements, we have determined that in the absence of Zα, under low salt conditions at room temperature, d(CpG) and r(CpG) constructs show no observable evidence of transient Z-conformations greater than 0.5% on either the intermediate or slow NMR time scales. At higher temperatures, we observed a transient unfolded intermediate. The ease of melting a nucleic acid duplex correlates with Z-form adoption rates in the presence of Zα. The largest contributing factor to the activation energies of Z-form adoption as calculated by Arrhenius plots is the ease of flipping the sugar pucker, as required for Z-DNA and Z-RNA. Together, these data validate the previously proposed "zipper model" for Z-form adoption in the presence of Zα. Overall, Z-conformations are more likely to be adopted by double-stranded DNA and RNA regions flanked by less stable regions and by RNAs experiencing torsional/mechanical stress.
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Affiliation(s)
- Parker J Nichols
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
| | - Jeffrey B Krall
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
| | - Morkos A Henen
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
- Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Robb Welty
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
| | - Andrea Macfadden
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
| | - Beat Vögeli
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, United States
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4
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Nichols PJ, Krall JB, Henen MA, Vögeli B, Vicens Q. Z-RNA biology: a central role in the innate immune response? RNA (NEW YORK, N.Y.) 2023; 29:273-281. [PMID: 36596670 PMCID: PMC9945438 DOI: 10.1261/rna.079429.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Z-RNA is a higher-energy, left-handed conformation of RNA, whose function has remained elusive. A growing body of work alludes to regulatory roles for Z-RNA in the immune response. Here, we review how Z-RNA features present in cellular RNAs-especially containing retroelements-could be recognized by a family of winged helix proteins, with an impact on host defense. We also discuss how mutations to specific Z-contacting amino acids disrupt their ability to stabilize Z-RNA, resulting in functional losses. We end by highlighting knowledge gaps in the field, which, if addressed, would significantly advance this active area of research.
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Affiliation(s)
- Parker J Nichols
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jeffrey B Krall
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Morkos A Henen
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Beat Vögeli
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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5
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NMR Titration Studies in Z-DNA Dynamics. Methods Mol Biol 2023; 2651:69-83. [PMID: 36892760 DOI: 10.1007/978-1-0716-3084-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
Chemical shift perturbation (CSP) is a simple NMR technique for studying the DNA binding of proteins. Titration of the unlabeled DNA into the 15N-labeled protein is monitored by acquiring a two-dimensional (2D) heteronuclear single-quantum correlation (HSQC) spectrum at each step of the titration. CSP can also provide information on the DNA-binding dynamics of proteins, as well as protein-induced conformational changes in DNA. Here, we describe the titration of DNA for the 15N-labeled Z-DNA-binding protein, monitored via 2D HSQC spectra. NMR titration data can be analyzed with the active B-Z transition model to provide the protein-induced B-Z transition dynamics of DNA.
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6
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Thermodynamic analysis of Zα domain-nucleic acid interactions. Biochem J 2022; 479:1727-1741. [PMID: 35969150 DOI: 10.1042/bcj20220200] [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: 04/25/2022] [Revised: 08/08/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022]
Abstract
DNA/RNA molecules adopting the left-handed conformation (Z-form) have been attributed with immunogenic properties. However, their biological role and importance has been a topic of debate for many years. The discovery of Z-DNA/RNA binding domains (Zα domains) in varied proteins that are involved in the innate immune response, such as the interferon inducible form of the RNA editing enzyme ADAR1 (p150), Z-DNA binding protein 1 (ZBP1), the fish kinase PKZ and the poxvirus inhibitor of interferon response E3L, indicates important roles of Z-DNA/RNA in immunity and self/non-self-discrimination. Such Zα domain-containing proteins recognise left-handed Z-DNA/RNA in a conformation-specific manner. Recent studies have implicated these domains in virus recognition. Given these important emerging roles for the Zα domains, it is pivotal to understand the mechanism of recognition of the Z-DNA/Z-RNA by these domains. To this end, we assessed the binding thermodynamics of Zα domain from ORF112 and ADAR1 on T(CG)3 and T(CG)6 oligonucleotides which have high propensity to adopt the Z-conformation. Our study highlights important differences in the mode of oligonucleotide binding by the two Zα domains originating from different proteins. Site-directed mutagenesis was employed together with isothermal titration calorimetry to tease apart finer details of the binding thermodynamics. Our work advances the understanding on binding thermodynamics of Zα domains to their cognate nucleic acid substrates and paves the ground for future efforts to gain a complete appreciation of this process.
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7
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Go Y, Ahn HB, Kim BS, Lee AR, Oh KI, Lee JH. Conformational exchange of the Zα domain of human RNA editing enzyme ADAR1 studied by NMR spectroscopy. Biochem Biophys Res Commun 2021; 580:63-66. [PMID: 34624571 DOI: 10.1016/j.bbrc.2021.09.084] [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: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/26/2022]
Abstract
Z-DNA binding proteins (ZBPs) play important roles in RNA editing, innate immune responses, and viral infections. Numerous studies have implicated a role for conformational motions during ZBPs binding upon DNA, but the quantitative intrinsic conformational exchanges of ZBP have not been elucidated. To understand the correlation between the biological function and dynamic feature of the Zα domains of human ADAR1 (hZαADAR1), we have performed the 15N backbone amide Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments on the free hZαADAR1 at two different magnetic fields at 35 °C. The robust inter-dependence of parameters in the global fitting process using multi-magnetic field CPMG profiles allows us characterizing the dynamic properties of conformational changes in hZαADAR1. This study found that free hZαADAR1 exhibited the conformational exchange with a kex of 5784 s-1 between the states "A" (89% population) and "B" (11% population). The different hydrophobic interactions among helices α1, α2, and α3 between these two states might correlate with efficient Z-DNA binding achieved by the hydrogen bonding interactions between its side-chains and the phosphate backbone of Z-DNA.
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Affiliation(s)
- Youyeon Go
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Hye-Bin Ahn
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Byeong-Seon Kim
- Department of Chemistry Education and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Ae-Ree Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Kwang-Im Oh
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea.
| | - Joon-Hwa Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea.
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8
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Pandya N, Bhagwat SR, Kumar A. Regulatory role of Non-canonical DNA Polymorphisms in human genome and their relevance in Cancer. Biochim Biophys Acta Rev Cancer 2021; 1876:188594. [PMID: 34303788 DOI: 10.1016/j.bbcan.2021.188594] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 12/17/2022]
Abstract
DNA has the ability to form polymorphic structures like canonical duplex DNA and non-canonical triplex DNA, Cruciform, Z-DNA, G-quadruplex (G4), i-motifs, and hairpin structures. The alteration in the form of DNA polymorphism in the response to environmental changes influences the gene expression. Non-canonical structures are engaged in various biological functions, including chromatin epigenetic and gene expression regulation via transcription and translation, as well as DNA repair and recombination. The presence of non-canonical structures in the regulatory region of the gene alters the gene expression and affects the cellular machinery. Formation of non-canonical structure in the regulatory site of cancer-related genes either inhibits or dysregulate the gene function and promote tumour formation. In the current article, we review the influence of non-canonical structure on the regulatory mechanisms in human genome. Moreover, we have also discussed the relevance of non-canonical structures in cancer and provided information on the drugs used for their treatment by targeting these structures.
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Affiliation(s)
- Nirali Pandya
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Sonali R Bhagwat
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India.
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9
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Oh KI, Lee AR, Choi SR, Go Y, Ryu KS, Kim EH, Lee JH. Systematic Approach to Find the Global Minimum of Relaxation Dispersion Data for Protein-Induced B-Z Transition of DNA. Int J Mol Sci 2021; 22:3517. [PMID: 33805331 PMCID: PMC8037647 DOI: 10.3390/ijms22073517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 11/17/2022] Open
Abstract
Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion spectroscopy is commonly used for quantifying conformational changes of protein in μs-to-ms timescale transitions. To elucidate the dynamics and mechanism of protein binding, parameters implementing CPMG relaxation dispersion results must be appropriately determined. Building an analytical model for multi-state transitions is particularly complex. In this study, we developed a new global search algorithm that incorporates a random search approach combined with a field-dependent global parameterization method. The robust inter-dependence of the parameters carrying out the global search for individual residues (GSIR) or the global search for total residues (GSTR) provides information on the global minimum of the conformational transition process of the Zα domain of human ADAR1 (hZαADAR1)-DNA complex. The global search results indicated that a α-helical segment of hZαADAR1 provided the main contribution to the three-state conformational changes of a hZαADAR1-DNA complex with a slow B-Z exchange process. The two global exchange rate constants, kex and kZB, were found to be 844 and 9.8 s-1, respectively, in agreement with two regimes of residue-dependent chemical shift differences-the "dominant oscillatory regime" and "semi-oscillatory regime". We anticipate that our global search approach will lead to the development of quantification methods for conformational changes not only in Z-DNA binding protein (ZBP) binding interactions but also in various protein binding processes.
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Affiliation(s)
- Kwang-Im Oh
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea; (K.-I.O.); (A.-R.L.); (S.-R.C.); (Y.G.)
| | - Ae-Ree Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea; (K.-I.O.); (A.-R.L.); (S.-R.C.); (Y.G.)
| | - Seo-Ree Choi
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea; (K.-I.O.); (A.-R.L.); (S.-R.C.); (Y.G.)
| | - Youyeon Go
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea; (K.-I.O.); (A.-R.L.); (S.-R.C.); (Y.G.)
| | - Kyoung-Seok Ryu
- Division of Magnetic Resonance, Korea Basic Science Institute, Ochang, Chungbuk 28119, Korea;
| | - Eun-Hee Kim
- Center for Research Equipment, Korea Basic Science Institute, Ochang, Chungbuk 28119, Korea;
| | - Joon-Hwa Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea; (K.-I.O.); (A.-R.L.); (S.-R.C.); (Y.G.)
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10
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Recognition of non-CpG repeats in Alu and ribosomal RNAs by the Z-RNA binding domain of ADAR1 induces A-Z junctions. Nat Commun 2021; 12:793. [PMID: 33542240 PMCID: PMC7862695 DOI: 10.1038/s41467-021-21039-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/07/2021] [Indexed: 12/11/2022] Open
Abstract
Adenosine-to-inosine (A-to-I) editing of eukaryotic cellular RNAs is essential for protection against auto-immune disorders. Editing is carried out by ADAR1, whose innate immune response-specific cytoplasmic isoform possesses a Z-DNA binding domain (Zα) of unknown function. Zα also binds to CpG repeats in RNA, which are a hallmark of Z-RNA formation. Unexpectedly, Zα has been predicted — and in some cases even shown — to bind to specific regions within mRNA and rRNA devoid of such repeats. Here, we use NMR, circular dichroism, and other biophysical approaches to demonstrate and characterize the binding of Zα to mRNA and rRNA fragments. Our results reveal a broad range of RNA sequences that bind to Zα and adopt Z-RNA conformations. Binding is accompanied by destabilization of neighboring A-form regions which is similar in character to what has been observed for B-Z-DNA junctions. The binding of Zα to non-CpG sequences is specific, cooperative and occurs with an affinity in the low micromolar range. This work allows us to propose a model for how Zα could influence the RNA binding specificity of ADAR1. ADAR1 is an interferon-induced enzyme that catalyzes editing of adenine to inosine across the transcriptome as part of the immune response. Here the authors establish how ADAR1 recognizes non-CpG RNA sequences to facilitate the formation of A-Z junctions.
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11
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Chiang DC, Li Y, Ng SK. The Role of the Z-DNA Binding Domain in Innate Immunity and Stress Granules. Front Immunol 2021; 11:625504. [PMID: 33613567 PMCID: PMC7886975 DOI: 10.3389/fimmu.2020.625504] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
Both DNA and RNA can maintain left-handed double helical Z-conformation under physiological condition, but only when stabilized by Z-DNA binding domain (ZDBD). After initial discovery in RNA editing enzyme ADAR1, ZDBD has also been described in pathogen-sensing proteins ZBP1 and PKZ in host, as well as virulence proteins E3L and ORF112 in viruses. The host-virus antagonism immediately highlights the importance of ZDBD in antiviral innate immunity. Furthermore, Z-RNA binding has been shown to be responsible for the localization of these ZDBD-containing proteins to cytoplasmic stress granules that play central role in coordinating cellular response to stresses. This review sought to consolidate current understanding of Z-RNA sensing in innate immunity and implore possible roles of Z-RNA binding within cytoplasmic stress granules.
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Affiliation(s)
- De Chen Chiang
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
| | - Yan Li
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Siew Kit Ng
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
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12
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Jin HS, Kim NH, Choi SR, Oh KI, Lee JH. Protein-induced B-Z transition of DNA duplex containing a 2'-OMe guanosine. Biochem Biophys Res Commun 2020; 533:417-423. [PMID: 32972754 DOI: 10.1016/j.bbrc.2020.09.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/07/2020] [Accepted: 09/07/2020] [Indexed: 02/06/2023]
Abstract
Structural transformation of the canonical right-handed helix, B-DNA, to the non-canonical left-handed helix, Z-DNA, can be induced by the Zα domain of the human RNA editing enzyme ADAR1 (hZαADAR1). To characterize the site-specific preferences of binding and structural changes in DNA containing the 2'-O-methyl guanosine derivative (mG), titration of the imino proton spectra and chemical shift perturbations were performed on hZαADAR1 upon binding to Z-DNA. The structural transition between B-Z conformation as the changing ratio between DNA and protein showed a binding affinity of the modified DNA onto the Z-DNA binding protein similar to wild-type DNA or RNA. The chemical shift perturbation results showed that the overall structure and environment of the modified DNA revealed DNA-like properties rather than RNA-like characteristics. Moreover, we found evidence for two distinct regimes, "Z-DNA Sensing" and "Modification Sensing", based on the site-specific chemical shift perturbation between the DNA (or RNA) binding complex and the modified DNA-hZαADAR1 complex. Thus, we propose that modification of the sugar backbone of DNA with 2'-O-methyl guanosine promotes the changes in the surrounding α3 helical structural segment as well as the non-perturbed feature of the β-hairpin region.
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Affiliation(s)
- Ho-Seong Jin
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Na-Hyun Kim
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Seo-Ree Choi
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea
| | - Kwang-Im Oh
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea.
| | - Joon-Hwa Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, 52828, South Korea.
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13
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Dynamic regulation of Z-DNA in the mouse prefrontal cortex by the RNA-editing enzyme Adar1 is required for fear extinction. Nat Neurosci 2020; 23:718-729. [PMID: 32367065 PMCID: PMC7269834 DOI: 10.1038/s41593-020-0627-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 03/19/2020] [Indexed: 01/06/2023]
Abstract
DNA forms conformational states beyond the right-handed double-helix; however, the functional relevance of these non-canonical structures in the brain remains unknown. We show that, in the prefrontal cortex of mice, the formation of one such structure, Z-DNA, is involved in the regulation of extinction memory. Z-DNA is formed during fear learning, and reduced during extinction learning, which is mediated, in part, by a direct interaction between Z-DNA and the RNA editing enzyme Adar1. Adar1 binds to Z-DNA during fear extinction learning which leads to a reduction in Z-DNA at sites where Adar1 is recruited. Knockdown of Adar1 leads to an inability to modify a previously acquired fear memory and blocks activity-dependent changes in DNA structure and RNA state; effects that are fully rescued by the introduction of full-length Adar1. These findings suggest a novel mechanism of learning-induced gene regulation dependent on both proteins which recognize DNA structure, and the state.
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Oh KI, Kim J, Park CJ, Lee JH. Dynamics Studies of DNA with Non-canonical Structure Using NMR Spectroscopy. Int J Mol Sci 2020; 21:E2673. [PMID: 32290457 PMCID: PMC7216225 DOI: 10.3390/ijms21082673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 12/11/2022] Open
Abstract
The non-canonical structures of nucleic acids are essential for their diverse functions during various biological processes. These non-canonical structures can undergo conformational exchange among multiple structural states. Data on their dynamics can illustrate conformational transitions that play important roles in folding, stability, and biological function. Here, we discuss several examples of the non-canonical structures of DNA focusing on their dynamic characterization by NMR spectroscopy: (1) G-quadruplex structures and their complexes with target proteins; (2) i-motif structures and their complexes with proteins; (3) triplex structures; (4) left-handed Z-DNAs and their complexes with various Z-DNA binding proteins. This review provides insight into how the dynamic features of non-canonical DNA structures contribute to essential biological processes.
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Affiliation(s)
- Kwang-Im Oh
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea;
| | - Jinwoo Kim
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea;
| | - Chin-Ju Park
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea;
| | - Joon-Hwa Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea;
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