1
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Shen G, Ma Y, Zhang H, Wang F, Yang F, Ye H, Li R, Wang C, Tang Y. Novel fluorescence strategy based on G-quadruplex structure-switching aptamer for enrofloxacin detection in food and environmental samples. Food Chem 2024; 441:138393. [PMID: 38199111 DOI: 10.1016/j.foodchem.2024.138393] [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: 09/24/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/12/2024]
Abstract
Enrofloxacin (ENR) is widely used in the prevention and treatment of animal infectious diseases, so it is necessary to strengthen the residue detection of this drug in animal-derived food and water environments. In this work, for the first time, we engineered assembly a split ENR aptamer into the G-quadruplex (G4) region to form a new aptamer (G4-ENRA) that provides a more sensitive signal-reporting function while retaining target-specific recognition ability of the aptamer. This rational design effectively overcomes the issue of difficulty in identification probe development. Under the optimized conditions, a response range of 0.05-20 µM and limit of detection of 26.7 nM were obtained by directly detecting fluorescence signals, displaying a comparative advantage over the previously reported methods. Moreover, this method demonstrated satisfactory performance for the ENR detection in various real food and environmental samples, with the detection recoveries ranging from 95.87 % to 104.36 %, illustrating promising applicability prospects.
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Affiliation(s)
- Gang Shen
- National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China
| | - Yingnan Ma
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Hong Zhang
- National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China.
| | - Fangfang Wang
- National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China
| | - Fengmin Yang
- National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China
| | - Huanfeng Ye
- National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China
| | - Runzhi Li
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Changzheng Wang
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
| | - Yalin Tang
- National Laboratory for Molecular Sciences, Center for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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2
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Sahayasheela VJ, Sugiyama H. RNA G-quadruplex in functional regulation of noncoding RNA: Challenges and emerging opportunities. Cell Chem Biol 2024; 31:53-70. [PMID: 37909035 DOI: 10.1016/j.chembiol.2023.08.010] [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: 04/18/2023] [Revised: 07/12/2023] [Accepted: 08/22/2023] [Indexed: 11/02/2023]
Abstract
G-quadruplexes (G4s) are stable, noncanonical structures formed in guanine (G)-rich sequences of DNA/RNA. G4 structures are reported to play a regulatory role in various cellular processes and, recently, a considerable number of studies have attributed new biological functions to these structures, especially in RNA. Noncoding RNA (ncRNA), which does not translate into a functional protein, is widely expressed and has been shown to play a key role in shaping cellular activity. There has been growing evidence of G4 formation in several ncRNA classes, and it has been identified as a key part for diverse biological functions and physio-pathological contexts in neurodegenerative diseases and cancer. This review discusses RNA G4s (rG4s) in ncRNA, focusing on the molecular mechanism underlying its function. This review also aims to highlight potential and emerging opportunities to identify and target the rG4s in ncRNA to understand its function and, ultimately, treat many diseases.
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Affiliation(s)
- Vinodh J Sahayasheela
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-Ushinomaecho, Sakyo-Ku, Kyoto 606-8501, Japan.
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3
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Gao C, Mohamed HI, Deng J, Umer M, Anwar N, Chen J, Wu Q, Wang Z, He Y. Effects of Molecular Crowding on the Structure, Stability, and Interaction with Ligands of G-quadruplexes. ACS OMEGA 2023; 8:14342-14348. [PMID: 37125118 PMCID: PMC10134454 DOI: 10.1021/acsomega.3c01169] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
G-quadruplexes (G4s) are widely found in cells and have significant biological functions, which makes them a target for screening antitumor and antiviral drugs. Most of the previous research on G4s has been conducted mainly in diluted solutions. However, cells are filled with organelles and many biomolecules, resulting in a constant state of a crowded molecular environment. The conformation and stability of some G4s were found to change significantly in the molecularly crowded environment, and interactions with ligands were disturbed to some extent. The structure of the G4s and their biological functions are correlated, and the effect of the molecularly crowded environment on G4 conformational transitions and interactions with ligands should be considered in drug design targeting G4s. This review discusses the changes in the conformation and stability of G4s in a physiological environment. Moreover, the mechanism of action of the molecularly crowded environment affecting the G4 has been further reviewed based on previous studies. Furthermore, current challenges and future research directions are put forward. This review has implications for the design of drugs targeting G4s.
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Affiliation(s)
- Chao Gao
- National
R&D Center for Se-rich Agricultural Products Processing, Hubei
Engineering Research Center for Deep Processing of Green Se-rich Agricultural
Products, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Hany I. Mohamed
- Chemistry
Department, Faculty of Science, Benha University, Benha 13518, Egypt
| | - Jieya Deng
- National
R&D Center for Se-rich Agricultural Products Processing, Hubei
Engineering Research Center for Deep Processing of Green Se-rich Agricultural
Products, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Muhammad Umer
- Institute
for Forest Resources and Environment of Guizhou and Forestry College,
Research Center of Forest Ecology, Guizhou
University, Guiyang 550025, China
| | - Naureen Anwar
- Department
of Zoology, University of Narowal, Narowal, Punjab 51600, Pakistan
| | - Jixin Chen
- National
R&D Center for Se-rich Agricultural Products Processing, Hubei
Engineering Research Center for Deep Processing of Green Se-rich Agricultural
Products, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Qiao Wu
- Wuhan
Botanical Garden, Chinese Academy of Science, Wuhan 430074, China
| | - Zhangqian Wang
- National
R&D Center for Se-rich Agricultural Products Processing, Hubei
Engineering Research Center for Deep Processing of Green Se-rich Agricultural
Products, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Yi He
- National
R&D Center for Se-rich Agricultural Products Processing, Hubei
Engineering Research Center for Deep Processing of Green Se-rich Agricultural
Products, School of Modern Industry for Selenium Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
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4
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Li F, Zhou J. G-quadruplexes from non-coding RNAs. J Mol Med (Berl) 2023:10.1007/s00109-023-02314-7. [PMID: 37069370 DOI: 10.1007/s00109-023-02314-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 03/22/2023] [Accepted: 03/30/2023] [Indexed: 04/19/2023]
Abstract
Non-coding RNAs (ncRNAs) are significant regulators of gene expression in a wide range of biological processes, such as transcription, RNA maturation, or translation. ncRNAs interplay with proteins or other RNAs through not only classical sequence-based mechanisms but also unique higher-order structures such as RNA G-quadruplexes (rG4s). rG4s are predictably formed in guanine-rich sequences and are closely related to various human diseases, such as tumors, neurodegenerative diseases, and infections. This review focuses on the vital role of rG4s in ncRNAs, particularly lncRNAs and miRNAs. We outline the dynamic balance between rG4s and RNA stem-loop/hairpin structures and the interplay between ncRNAs and interactors, thereby modulating gene expression and disease progression. A complete understanding of the biological regulatory role and mechanism of rG4s in ncRNAs affirms the critical importance of folding into the appropriate three-dimensional structure in maintaining or modulating the functions of ncRNAs. It makes them novel therapeutic targets for adjusting potential-G4-containing-ncRNAs-associated diseases.
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Affiliation(s)
- Fangyuan Li
- Department Medical Research Central, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Clinical Biobank, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Jiang Zhou
- Beijing National Laboratory for Molecular Sciences, Analytical Instrumentation Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
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5
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Li F, Guo D, Xie T, Zhang S, Wang A, Li Y, Zhou J. G-quadruplex from precursor miR-1587 modulated its maturation and function. Int J Biol Macromol 2023; 231:123279. [PMID: 36657549 DOI: 10.1016/j.ijbiomac.2023.123279] [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: 08/19/2022] [Revised: 11/15/2022] [Accepted: 01/05/2023] [Indexed: 01/18/2023]
Abstract
A certain proportion of pre-miRNAs, which contained potential G-quadruplex forming sequences, was found to act as a mediator to Dicer-mediated cleavage, and that the regulation of miRNA production and function may be achieved through the G-quadruplex structure. In this study, human precursor miR-1587 sequence was transfected after the incubation with different solution conditions (K+, TMPyP4, etc.). Firstly, the formation of G-quadruplex from precursor miR-1587 sequences was confirmed by CD and UV melting. The expression of miR-1587 level was then evaluated by Q-RT-PCR, and the results showed that the formation of G-quadruplex inhibited the miR-1587 maturation process, resulting in a reduced miR-1587 expression. Meanwhile the destabilization of G-quadruplex led to an increased miR-1587 expression by contrast. Then, the weakened inhibition of miR-1587 towards its target genes, such as TAGLN or NCOR1, was presented confirming by Q-RT-PCR and western blot. Molecular mechanism by dual-luciferase assays showed that the modulations of miR-1587 expression and function were due to the G-quadruplex structure transformation, but not the simple change of solution conditions. This study highlighted the importance of maintaining specific structures during miRNA biosynthesis and provided a way to alter the function of G-rich precursor miRNAs by modulating molecular conformation using ionic solutions or ligands.
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Affiliation(s)
- Fangyuan Li
- Medical Research Central, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China; Clinical Biobank, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China.
| | - Dan Guo
- Medical Research Central, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China; Clinical Biobank, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China
| | - Ting Xie
- Medical Research Central, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China; Clinical Biobank, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China
| | - Sumei Zhang
- Medical Research Central, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China; Clinical Biobank, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China
| | - Anqi Wang
- Medical Research Central, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China; Clinical Biobank, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China
| | - YingXing Li
- Medical Research Central, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China
| | - Jiang Zhou
- College of Chemistry and Molecular Engineering, Peking University, China
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6
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Santos T, Miranda A, Imbert L, Monchaud D, Salgado GF, Cabrita EJ, Cruz C. Targeting a G-quadruplex from let-7e pre-miRNA with small molecules and nucleolin. J Pharm Biomed Anal 2022; 215:114757. [PMID: 35462282 DOI: 10.1016/j.jpba.2022.114757] [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: 12/12/2021] [Revised: 02/28/2022] [Accepted: 04/03/2022] [Indexed: 10/18/2022]
Abstract
Let-7e precursor microRNA has the potential to adopt a G-quadruplex (rG4) structure and recently, its roles in oncology have been the focus of much attention, as it is now known that let-7e pre-miRNA is frequently dysregulated in cancers. Therefore, it is crucial to unveil and fully characterize its ability to adopt a rG4 structure, which could be stabilized or destabilized by small molecules and proteins such as nucleolin, a protein that is deeply associated with miRNA biogenesis. Herein, by combining a set of different methods such as circular dichroism (CD), nuclear magnetic resonance (NMR), UV spectroscopy (thermal difference spectra (TDS) and isothermal difference spectra (IDS)) and polyacrylamide gel electrophoresis (PAGE), we demonstrate the formation of the rG4 structure found in let-7e pre-miRNA sequence in the presence of K+ (5'-GGGCUGAGGUAGGAGG-3'). The ability of eight small molecules (or ligands) to bind to and stabilize this rG4 structure was also fully assessed. The dissociation constants for each RNA G-quadruplex/ligand complex, determined by surface plasmon resonance (SPR), ranged in the 10-6 to 10-9 M range. Lastly, the binding of the rG4 structure to nucleolin in the presence and absence of ligands was evaluated via CD, SPR, PAGE and confocal microscopy. The small molecules 360 A and PDS demonstrated attractive properties to targetthe rG4 structure of let-7e pre-miRNA and control its biology. Our findings also highlighted that the interaction of TMPyP4 with the G-quadruplex of let-7e precursor miRNA could block the formation of the complex between the rG4 and nucleolin. Overall, this study introduces an approach to target the rG4 found in let-7e pre-miRNA which opens up a new opportunity to control the microRNA biogenesis.
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Affiliation(s)
- Tiago Santos
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, Covilhã 6200-506, Portugal
| | - André Miranda
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, Covilhã 6200-506, Portugal
| | - Lionel Imbert
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France; Univ. Grenoble Alpes, CNRS, CEA, EMBL Integrated Structural Biology Grenoble (ISBG), Grenoble, France
| | - David Monchaud
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), CNRS UMR 6302, UBFC Dijon, Dijon 21078, France
| | - Gilmar F Salgado
- ARNA Laboratory, Université de Bordeaux, Inserm U1212, CNRS UMR 5320, IECB, Pessac 33607, France
| | - Eurico J Cabrita
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica 2819-516, Portugal
| | - Carla Cruz
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, Covilhã 6200-506, Portugal.
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7
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Ghafouri-Fard S, Abak A, Baniahmad A, Hussen BM, Taheri M, Jamali E, Dinger ME. Interaction between non-coding RNAs, mRNAs and G-quadruplexes. Cancer Cell Int 2022; 22:171. [PMID: 35488342 PMCID: PMC9052686 DOI: 10.1186/s12935-022-02601-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/19/2022] [Indexed: 12/01/2022] Open
Abstract
G-quadruplexes are secondary helical configurations established between guanine-rich nucleic acids. The structure is seen in the promoter regions of numerous genes under certain situations. Predicted G-quadruplex-forming sequences are distributed across the genome in a non-random way. These structures are formed in telomeric regions of the human genome and oncogenic promoter G-rich regions. Identification of mechanisms of regulation of stability of G-quadruplexes has practical significance for understanding the molecular basis of genetic diseases such as cancer. A number of non-coding RNAs such as H19, XIST, FLJ39051 (GSEC), BC200 (BCYRN1), TERRA, pre-miRNA-1229, pre-miRNA-149 and miR-1587 have been found to contain G-quadraplex-forming regions or affect configuration of these structures in target genes. In the current review, we outline the recent research on the interaction between G-quadruplexes and non-coding RNAs, other RNA transcripts and DNA molecules.
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Affiliation(s)
- Soudeh Ghafouri-Fard
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Atefe Abak
- Phytochemistry Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Aria Baniahmad
- Institute of Human Genetics, Jena University Hospital, 07740, Jena, Germany
| | - Bashdar Mahmud Hussen
- Department of Pharmacognosy, College of Pharmacy, Hawler Medical University, Erbil, Kurdistan Region, Iraq.,Center of Research and Strategic Studies, Lebanese French University, Erbil, Kurdistan Region, Iraq
| | - Mohammad Taheri
- Institute of Human Genetics, Jena University Hospital, 07740, Jena, Germany.
| | - Elena Jamali
- Skull Base Research Center, Loghman Hakin Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Marcel E Dinger
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
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8
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Figueiredo J, Santos T, Miranda A, Alexandre D, Teixeira B, Simões P, Lopes-Nunes J, Cruz C. Ligands as Stabilizers of G-Quadruplexes in Non-Coding RNAs. Molecules 2021; 26:6164. [PMID: 34684745 PMCID: PMC8540333 DOI: 10.3390/molecules26206164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/03/2021] [Accepted: 10/06/2021] [Indexed: 11/16/2022] Open
Abstract
The non-coding RNAs (ncRNA) are RNA transcripts with different sizes, structures and biological functions that do not encode functional proteins. RNA G-quadruplexes (rG4s) have been found in small and long ncRNAs. The existence of an equilibrium between rG4 and stem-loop structures in ncRNAs and its effect on biological processes remains unexplored. For example, deviation from the stem-loop leads to deregulated mature miRNA levels, demonstrating that miRNA biogenesis can be modulated by ions or small molecules. In light of this, we report several examples of rG4s in certain types of ncRNAs, and the implications of G4 stabilization using small molecules, also known as G4 ligands, in the regulation of gene expression, miRNA biogenesis, and miRNA-mRNA interactions. Until now, different G4 ligands scaffolds were synthesized for these targets. The regulatory role of the above-mentioned rG4s in ncRNAs can be used as novel therapeutic approaches for adjusting miRNA levels.
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Affiliation(s)
| | | | | | | | | | | | | | - Carla Cruz
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Hen-rique, 6200-506 Covilhã, Portugal; (J.F.); (T.S.); (A.M.); (D.A.); (B.T.); (P.S.); (J.L.-N.)
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9
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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10
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Bağda E, Bağda E, Kocak A, Durmuş M. Investigation of Binding behaviour of a water-soluble gallium (III) phthalocyanine with double-stranded and G-quadruplex DNA via experimental and computational methods. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130536] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Lyu K, Chow EYC, Mou X, Chan TF, Kwok CK. RNA G-quadruplexes (rG4s): genomics and biological functions. Nucleic Acids Res 2021; 49:5426-5450. [PMID: 33772593 PMCID: PMC8191793 DOI: 10.1093/nar/gkab187] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/02/2021] [Accepted: 03/24/2021] [Indexed: 02/07/2023] Open
Abstract
G-quadruplexes (G4s) are non-classical DNA or RNA secondary structures that have been first observed decades ago. Over the years, these four-stranded structural motifs have been demonstrated to have significant regulatory roles in diverse biological processes, but challenges remain in detecting them globally and reliably. Compared to DNA G4s (dG4s), the study of RNA G4s (rG4s) has received less attention until recently. In this review, we will summarize the innovative high-throughput methods recently developed to detect rG4s on a transcriptome-wide scale, highlight the many novel and important functions of rG4 being discovered in vivo across the tree of life, and discuss the key biological questions to be addressed in the near future.
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Affiliation(s)
- Kaixin Lyu
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Eugene Yui-Ching Chow
- School of Life Sciences, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Xi Mou
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Ting-Fung Chan
- School of Life Sciences, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.,Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
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12
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Sanchez-Martin V, Soriano M, Garcia-Salcedo JA. Quadruplex Ligands in Cancer Therapy. Cancers (Basel) 2021; 13:3156. [PMID: 34202648 PMCID: PMC8267697 DOI: 10.3390/cancers13133156] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/18/2021] [Accepted: 06/20/2021] [Indexed: 02/07/2023] Open
Abstract
Nucleic acids can adopt alternative secondary conformations including four-stranded structures known as quadruplexes. To date, quadruplexes have been demonstrated to exist both in human chromatin DNA and RNA. In particular, quadruplexes are found in guanine-rich sequences constituting G-quadruplexes, and in cytosine-rich sequences forming i-Motifs as a counterpart. Quadruplexes are associated with key biological processes ranging from transcription and translation of several oncogenes and tumor suppressors to telomeres maintenance and genome instability. In this context, quadruplexes have prompted investigations on their possible role in cancer biology and the evaluation of small-molecule ligands as potential therapeutic agents. This review aims to provide an updated close-up view of the literature on quadruplex ligands in cancer therapy, by grouping together ligands for DNA and RNA G-quadruplexes and DNA i-Motifs.
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Affiliation(s)
- Victoria Sanchez-Martin
- Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain;
- Microbiology Unit, Biosanitary Research Institute IBS, University Hospital Virgen de las Nieves, 18014 Granada, Spain
- Department of Biochemistry, Molecular Biology III and Immunology, University of Granada, 18016 Granada, Spain
| | - Miguel Soriano
- Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain;
- Centre for Intensive Mediterranean Agrosystems and Agri-Food Biotechnology (CIAMBITAL), University of Almeria, 04001 Almeria, Spain
| | - Jose Antonio Garcia-Salcedo
- Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain;
- Microbiology Unit, Biosanitary Research Institute IBS, University Hospital Virgen de las Nieves, 18014 Granada, Spain
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13
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Tassinari M, Richter SN, Gandellini P. Biological relevance and therapeutic potential of G-quadruplex structures in the human noncoding transcriptome. Nucleic Acids Res 2021; 49:3617-3633. [PMID: 33721024 PMCID: PMC8053107 DOI: 10.1093/nar/gkab127] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 12/11/2022] Open
Abstract
Noncoding RNAs are functional transcripts that are not translated into proteins. They represent the largest portion of the human transcriptome and have been shown to regulate gene expression networks in both physiological and pathological cell conditions. Research in this field has made remarkable progress in the comprehension of how aberrations in noncoding RNA drive relevant disease-associated phenotypes; however, the biological role and mechanism of action of several noncoding RNAs still need full understanding. Besides fulfilling its function through sequence-based mechanisms, RNA can form complex secondary and tertiary structures which allow non-canonical interactions with proteins and/or other nucleic acids. In this context, the presence of G-quadruplexes in microRNAs and long noncoding RNAs is increasingly being reported. This evidence suggests a role for RNA G-quadruplexes in controlling microRNA biogenesis and mediating noncoding RNA interaction with biological partners, thus ultimately regulating gene expression. Here, we review the state of the art of G-quadruplexes in the noncoding transcriptome, with their structural and functional characterization. In light of the existence and further possible development of G-quadruplex binders that modulate G-quadruplex conformation and protein interactions, we also discuss the therapeutic potential of G-quadruplexes as targets to interfere with disease-associated noncoding RNAs.
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Affiliation(s)
- Martina Tassinari
- Department of Biosciences, University of Milan, via G. Celoria 26, 20133 Milano, Italy
| | - Sara N Richter
- Department of Molecular Medicine, University of Padua, via A. Gabelli 63, 35121 Padova, Italy
| | - Paolo Gandellini
- Department of Biosciences, University of Milan, via G. Celoria 26, 20133 Milano, Italy
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14
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Tu D, Dou J, Wang M, Zhuang H, Zhang X. M2 macrophages contribute to cell proliferation and migration of breast cancer. Cell Biol Int 2021; 45:831-838. [PMID: 33325089 DOI: 10.1002/cbin.11528] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/20/2020] [Accepted: 12/13/2020] [Indexed: 12/24/2022]
Abstract
Breast cancer is a kind of malignant tumor that severely threatens women's lives and health worldwide. Tumor-associated macrophages (TAMs) have been reported to mediate tumor progression, while the mechanism still needs further identification. In this study, we found that M2 macrophages promoted increased cell proliferation and migration as well as reduced expression of interferon regulatory factor 7 (IRF7) and increased the expression of miR-1587 in breast cancer cells. Overexpression of IRF7 or miR-1587 knockdown reversed M2 macrophage-induced cell proliferation and migration as well as tumor growth in vivo. Mechanistically, miR-1587 targeted the 3'-untranslated region (3'-UTR) of IRF7 mRNA to regulate its protein expression leading to tumor progression. Collectively, this study revealed that the miR-1587/IRF7 axis mediates M2 macrophage-induced breast cancer progression, and this sheds light on further clinical therapy for breast cancer by targeting TAMs as well as the miR-1587/IRF7 axis.
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Affiliation(s)
- Daoyuan Tu
- Department of General Surgery, Huai'an Second People's Hospital and The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, P.R. China
| | - Jin Dou
- Department of General Surgery, Huai'an Second People's Hospital and The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, P.R. China
| | - Mingkao Wang
- Department of General Surgery, Huai'an Second People's Hospital and The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, P.R. China
| | - Haiwen Zhuang
- Department of General Surgery, Huai'an Second People's Hospital and The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, P.R. China
| | - Xiaoyu Zhang
- Department of General Surgery, Huai'an Second People's Hospital and The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, P.R. China
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15
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Sanchez-Martin V, Lopez-Pujante C, Soriano-Rodriguez M, Garcia-Salcedo JA. An Updated Focus on Quadruplex Structures as Potential Therapeutic Targets in Cancer. Int J Mol Sci 2020; 21:ijms21238900. [PMID: 33255335 PMCID: PMC7734589 DOI: 10.3390/ijms21238900] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023] Open
Abstract
Non-canonical, four-stranded nucleic acids secondary structures are present within regulatory regions in the human genome and transcriptome. To date, these quadruplex structures include both DNA and RNA G-quadruplexes, formed in guanine-rich sequences, and i-Motifs, found in cytosine-rich sequences, as their counterparts. Quadruplexes have been extensively associated with cancer, playing an important role in telomere maintenance and control of genetic expression of several oncogenes and tumor suppressors. Therefore, quadruplex structures are considered attractive molecular targets for cancer therapeutics with novel mechanisms of action. In this review, we provide a general overview about recent research on the implications of quadruplex structures in cancer, firstly gathering together DNA G-quadruplexes, RNA G-quadruplexes as well as DNA i-Motifs.
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Affiliation(s)
- Victoria Sanchez-Martin
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Microbiology Unit, University Hospital Virgen de las Nieves, Biosanitary Research Institute IBS, Granada, 18014 Granada, Spain
- Department of Biochemistry, Molecular Biology III and Immunology, University of Granada, 18016 Granada, Spain
| | - Carmen Lopez-Pujante
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
| | - Miguel Soriano-Rodriguez
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Centre for Intensive Mediterranean Agrosystems and Agri-food Biotechnology (CIAMBITAL), University of Almeria, 04001 Almeria, Spain
- Correspondence: (M.S.-R.); (J.A.G.-S.); Tel.: +34-958715500 (M.S.-R.); +34-958715500 (J.A.G.-S.)
| | - Jose A. Garcia-Salcedo
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Microbiology Unit, University Hospital Virgen de las Nieves, Biosanitary Research Institute IBS, Granada, 18014 Granada, Spain
- Correspondence: (M.S.-R.); (J.A.G.-S.); Tel.: +34-958715500 (M.S.-R.); +34-958715500 (J.A.G.-S.)
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16
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BTXA regulates the epithelial-mesenchymal transition and autophagy of keloid fibroblasts via modulating miR-1587/miR-2392 targeted ZEB2. Biosci Rep 2020; 39:220731. [PMID: 31652445 PMCID: PMC6822502 DOI: 10.1042/bsr20190679] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 09/10/2019] [Accepted: 09/30/2019] [Indexed: 12/23/2022] Open
Abstract
Keloids are very resistant to treatment in dermatology and plastic surgical practice. The present study aimed to explore the underlying mechanism of botulinum toxin A (BTXA) treated human skin keloid fibroblasts (HSFBs) proving some new insights into keloids treatment. Expression of miR-1587 and miR-2392 were significantly down-regulated in keloid tissues and HSFBs, while the ZEB2 was a target of both and up-regulated in keloid tissues and HSFBs compared with the normal controls. BTXA could significantly increase the expression of miR-1587 and miR-2392 but decrease the expression of ZEB2. BTXA could significantly inhibit the proliferation, cell cycle, and migration and promote apoptosis and autophagy of HSFBs; however, miR-1587 and miR-2392 inhibitors could reverse these effects of BTXA on HSFBs. Silencing ZEB2 could significantly attenuate the effects of miR-1587 and miR-2392 inhibitors in promoting cell proliferation and migration and suppressing apoptosis and autophagy of HSFBs after treating with BTXA. BTXA could suppress the proliferation and migration and promote apoptosis and autophagy of HSFBs via modulating miR-1587/miR-2392 targeted ZEB2.
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17
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Xi M, Li Y, Zhou J. Exploration of the formation and structure characteristics of a miR-92a promoter G-quadruplex by ESI-MS and CD. Talanta 2020; 211:120708. [PMID: 32070614 DOI: 10.1016/j.talanta.2019.120708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 10/25/2022]
Abstract
Combining electrospray ionization mass spectrometry (ESI-MS) with circular dichroism (CD) spectroscopy, a G-rich sequence from miR-92a promoter region was discovered to form a parallel G-quadruplex structures in KCl or NH4OAc solution. In case of high concentration of NH4OAc, the ESI mass spectra showed peaks of a dimeric G-quadruplex structure with 4 ammonium ions. Meanwhile, palmatine, a natural alkaloid, was screened by ESI-MS to bind with the miR-92a G-quadruplex affinitively. The variable temperature experiment of CD also proved that high concentration of NH4OAc or palmatine could promote the stability of the dimeric G-quadruplex structure. To get the specific characteristics of the miR-92a G-quadruplex structure, systematic mutations of guanine were tested. Based on the number of NH4+ or ligands, the important guanines involved in the G-quadruplex could be determined. Considering the importance of involved guanines and the number of G-quartets, we speculated an interlocked dimeric parallel G-quadruplex as a possible conformation of the miR-92a promoter G-quadruplex. All results obtained from ESI-MS and CD illustrate structure characteristics of the miR-92a G-quadruplex, which is a promising method for preliminary structural analysis of G-quadruplexes. Besides, this study also provides a strategy for regulating the functions of microRNA by exploring and targeting higher-order structures of miRNAs.
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Affiliation(s)
- Min Xi
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China; Beijing National Laboratory for Molecular Sciences, Analytical Instrumentation Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Yizhou Li
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China.
| | - Jiang Zhou
- Beijing National Laboratory for Molecular Sciences, Analytical Instrumentation Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
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18
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Chan KL, Peng B, Umar MI, Chan CY, Sahakyan AB, Le MTN, Kwok CK. Structural analysis reveals the formation and role of RNA G-quadruplex structures in human mature microRNAs. Chem Commun (Camb) 2018; 54:10878-10881. [PMID: 30204160 DOI: 10.1039/c8cc04635b] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Here we identify hundreds of RNA G-quadruplex (rG4) candidates in microRNAs (miRNAs), characterize the miRNA structure and miRNA-mRNA interactions on several mammalian-conserved miRNAs, and reveal the formation of rG4s in miRNAs. Notably, we study the effect of these rG4s in cells and uncover the role of rG4s in miRNA-mediated post-transcriptional regulation.
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Affiliation(s)
- Ka Lung Chan
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.
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19
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Li F, Tan W, Chen H, Zhou J, Xu M, Yuan G. Up- and downregulation of mature miR-1587 function by modulating its G-quadruplex structure and using small molecules. Int J Biol Macromol 2018; 121:127-134. [PMID: 30290263 DOI: 10.1016/j.ijbiomac.2018.10.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/02/2018] [Accepted: 10/02/2018] [Indexed: 12/13/2022]
Abstract
Using bioinformatics analysis, we found some mature human miRNAs containing G-rich sequences with four G-tracts that had a high probability of forming G-quadruplex structures. Here, we chose G-rich miR-1587 as a model to characterize the function and regulation of miRNAs. Using electrospray ionization mass spectrometry, magnetic resonance imaging, circular dichroism spectrometry, we had confirmed that miR-1587 folded into a stable parallel G-quadruplex structure. By microarray, Q-RT-PCR and 3'UTR luciferase assay, TAGLN, an early marker of smooth muscle differentiation and tumor suppressor, was identified as a target gene of miR-1587, thus providing a direct target to study miR-1587 functions. We identified three aspects of miR-1587 regulation: 1) KCl induced miR-1587 G-quadruplex formation, reducing the interaction between miR-1587 and the target gene, and inhibiting miR-1587 function; 2) pseudopalmatine ligand further inhibited miR-1587 binding to TAGLN mRNA, which disrupted its function and increased the TAGLN expression; 3) the addition of TMPyP4 ligand interfered G-quadruplex formation, and significantly enhanced miR-1587 regulation of TAGLN expression. This study has revealed the possibility of using the G-quadruplex structure as a strategy to regulate miR-1587 function, showing potential for the development of up- and downregulation of mature G-rich microRNA function by modulating its G-quadruplex and using small molecules.
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Affiliation(s)
- Fangyuan Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wei Tan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Han Chen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jiang Zhou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Ming Xu
- Institute of Vascular Medicine, Department of Cardiology, Peking University Third Hospital, Key Laboratory of Molecular Cardiovascular Sciences of Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health Beijing, 100191, China
| | - Gu Yuan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
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20
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Kumar M, Kaushik M, Kukreti S. A topological transition from bimolecular quadruplex to G-triplex/tri-G-quadruplex exhibited by truncated double repeats of human telomere. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:903-915. [PMID: 29934676 DOI: 10.1007/s00249-018-1312-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 04/11/2018] [Accepted: 05/21/2018] [Indexed: 12/12/2022]
Abstract
Human telomeric G-rich sequences can fold back into various conformations depending upon the salt (Na+ or K+) at physiological pH. On the basis of results obtained by native PAGE electrophoresis, circular dichroism, and UV-melting experiments, we report here that truncated sequences of human telomere (d-GGGTTAGGG; GM9, d-AGGGTTAGGG; GM10, d-TAGGGTTAGGG; GM11) adopt a varied range of quadruplex conformations as a function of the cation present. By correlating CD and gel electrophoresis experiments; it was concluded that the GM9 oligonucleotide can self-associate to form a tetramer quadruplex (antiparallel; AP) in Na+ solution and a mixture of G-triplex (AP) or tri-G-quadruplex (parallel; P) along with a tetramer G-quadruplex structure (AP) in K+. The GM10 oligonucleotide formed a bimolecular G-quadruplex in both Na+ and K+ solutions, while GM11 associated to form a bimolecular G-quadruplex (AP) structure in Na+ solution and a mixture of bimolecular G-quadruplex (AP) and bimolecular G-quadruplex (P) along with parallel G-triplex or antiparallel tri-G-quadruplex in K+. All the UV-melting profiles, thermal difference spectra, and CD melting curves suggested the formation of a variety of G-quadruplex conformations by the DNA sequences studied in Na+ and K+ ions. Hypothetical models for different conformations adopted by these DNA molecules have also been proposed, which may further enhance our knowledge about the divergent topologies of guanine quadruplexes.
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Affiliation(s)
- Mohan Kumar
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India
| | - Mahima Kaushik
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India.,Cluster Innovation Centre, University of Delhi, Delhi, India
| | - Shrikant Kukreti
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India.
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