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Shiekh S, Feldt D, Jack A, Kodikara SG, Alfehaid J, Pasha S, Yildiz A, Balci H. Protection of the Telomeric Junction by the Shelterin Complex. J Am Chem Soc 2024. [PMID: 39207958 DOI: 10.1021/jacs.4c08649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Shelterin serves critical roles in suppressing superfluous DNA damage repair pathways on telomeres. The junction between double-stranded telomeric tracts (dsTEL) and single-stranded telomeric overhang (ssTEL) is the most accessible region of the telomeric DNA. The shelterin complex contains dsTEL and ssTEL binding proteins and can protect this junction by bridging the ssTEL and dsTEL tracts. To test this possibility, we monitored shelterin binding to telomeric DNA substrates with varying ssTEL and dsTEL lengths and quantified its impact on telomere accessibility using single-molecule fluorescence microscopy methods in vitro. We identified the first dsTEL repeat nearest the junction as the preferred binding site for creating the shelterin bridge. Shelterin requires at least two ssTEL repeats, while the POT1 subunit of shelterin that binds to ssTEL requires longer ssTEL tracts for stable binding to telomeres and effective protection of the junction region. The ability of POT1 to protect the junction is significantly enhanced by the 5'-phosphate at the junction. Collectively, our results show that shelterin enhances the binding stability of POT1 to ssTEL and provides more effective protection compared with POT1 alone by bridging single- and double-stranded telomeric tracts.
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Affiliation(s)
- Sajad Shiekh
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Darion Feldt
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Amanda Jack
- Biophysics Graduate Group, University of California, Berkeley, California 94720, United States
| | - Sineth G Kodikara
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Janan Alfehaid
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Sabaha Pasha
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Ahmet Yildiz
- Biophysics Graduate Group, University of California, Berkeley, California 94720, United States
- Physics Department, University of California, Berkeley, California 94720, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Hamza Balci
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
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2
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Shiekh S, Feldt D, Jack A, Kodikara SG, Alfehaid J, Pasha S, Yildiz A, Balci H. Protection of the Telomeric Junction by the Shelterin Complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.18.608453. [PMID: 39229120 PMCID: PMC11370466 DOI: 10.1101/2024.08.18.608453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Shelterin serves critical roles in suppressing superfluous DNA damage repair pathways on telomeres. The junction between double-stranded telomeric tracts (dsTEL) and single-stranded telomeric overhang (ssTEL) is the most accessible region of the telomeric DNA. The shelterin complex contains dsTEL and ssTEL binding proteins and can protect this junction by bridging between the ssTEL and dsTEL tracts. To test this possibility, we monitored shelterin binding to telomeric DNA substrates with varying ssTEL and dsTEL lengths and quantified its impact on telomere accessibility using single-molecule fluorescence microscopy methods in vitro . We identified the first dsTEL repeat nearest to the junction as the preferred binding site for creating the shelterin bridge. Shelterin requires at least two ssTEL repeats while the POT1 subunit of shelterin that binds to ssTEL requires longer ssTEL tracts for stable binding to telomeres and effective protection of the junction region. The ability of POT1 to protect the junction is significantly enhanced by the 5'-phosphate at the junction. Collectively, our results show that shelterin enhances the binding stability of POT1 to ssTEL and provides more effective protection compared to POT1 alone by bridging single- and double-stranded telomeric tracts. Table of Content Graphic
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Wang C, Xu G, Liu X, Jiang L, Zhou X, Liu M, Li C. 19F Nuclear Magnetic Resonance Fingerprinting Technique for Identifying and Quantifying G-Quadruplex Topology in Human Telomeric Overhangs. J Am Chem Soc 2024; 146:4741-4751. [PMID: 38346932 DOI: 10.1021/jacs.3c12247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
G-quadruplexes (G4s) are noncanonical nucleic acid secondary structures with diverse topological features and biological roles. Human telomeric (Htelo) overhangs consisting of TTAGGG repeats can fold into G4s that adopt different topologies under physiological conditions. These G4s are potential targets for anticancer drugs. Despite intensive research, the existence and topology of G4s at Htelo overhangs in vivo are still unclear because there is no method to distinguish and quantify the topology of Htelo overhangs with native lengths that can form more than three tandem G4s in living cells. Herein, we present a novel 19F chemical shift fingerprinting technique to identify and quantify the topology of the Htelo overhangs up to five G-quadruplexes (G4s) and 120 nucleotides long both in vitro and in living cells. Our results show that longer overhang sequences tend to form stable G4s at the 5'- and 3'-ends, while the interior G4s are dynamic and "sliding" along the sequence, with TTA or 1-3 TTAGGG repeats as a linker. Each G4 in the longer overhang is conformationally heterogeneous, but the predominant ones are hybrid-2, two- or three-tetrad antiparallel, and hybrid-1 at the 5'-terminal, interior, and 3'-terminal, respectively. Additionally, we observed a distinct behavior of different lengths of telomeric sequences in living cells, suggesting that the overhang length and protein accessibility are related to its function. This technique provides a powerful tool for quickly identifying the folding topology and relative population of long Htelo overhangs, which may provide valuable insights into telomere functionality and be beneficial for structure-based anticancer drug development targeting G4s.
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Affiliation(s)
- Chen Wang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Guohua Xu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Xiaoli Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Ling Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Xin Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
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4
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Shiekh S, Kodikara SG, Balci H. Structure, Topology, and Stability of Multiple G-quadruplexes in Long Telomeric Overhangs. J Mol Biol 2024; 436:168205. [PMID: 37481156 PMCID: PMC10799177 DOI: 10.1016/j.jmb.2023.168205] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/05/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023]
Abstract
Telomeres and their single stranded overhangs gradually shorten with successive cell divisions, as part of the natural aging process, but can be elongated by telomerase, a nucleoprotein complex which is activated in the majority of cancers. This prominent implication in cancer and aging has made the repetitive telomeric sequences (TTAGGG repeats) and the G-quadruplex structures that form in their overhangs the focus of intense research in the past several decades. However, until recently most in vitro efforts to understand the structure, stability, dynamics, and interactions of telomeric overhangs had been focused on short sequences that are not representative of longer sequences encountered in a physiological setting. In this review, we will provide a broad perspective about telomeres and associated factors, and introduce the agents and structural characteristics involved in organizing, maintaining, and protecting telomeric DNA. We will also present a summary of recent research performed on long telomeric sequences, nominally defined as those that can form two or more tandem G-quadruplexes, i.e., which contain eight or more TTAGGG repeats. Results of experimental studies using a broad array of experimental tools, in addition to recent computational efforts will be discussed, particularly in terms of their implications for the stability, folding topology, and compactness of the tandem G-quadruplexes that form in long telomeric overhangs.
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Affiliation(s)
- Sajad Shiekh
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | | | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH 44242, USA.
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Kodikara SG, Merkel KJ, Haas SJ, Shiekh S, Balci H. Detecting secondary structure formation with FRET-PAINT. Analyst 2023; 148:4655-4658. [PMID: 37671909 PMCID: PMC10561560 DOI: 10.1039/d3an01118f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
We present single molecule studies demonstrating the capabilities of the FRET-PAINT method to detect secondary structures that would be challenging to detect with alternative methods, particularly single molecule FRET (smFRET). Instead of relying on the change in end-to-end separation as in smFRET, we use the change in accessibility to a small probe as the criterion for secondary structure formation and relative stability. As a model system, we study G-triplex formation by human telomeric repeat sequences in different structural contexts.
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Affiliation(s)
| | - Kylie J Merkel
- Department of Physics, Kent State University, Kent, OH, 44242, USA.
| | - Simon J Haas
- Department of Physics, Kent State University, Kent, OH, 44242, USA.
| | - Sajad Shiekh
- Department of Physics, Kent State University, Kent, OH, 44242, USA.
| | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH, 44242, USA.
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6
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Abraham Punnoose J, Thomas KJ, Chandrasekaran AR, Vilcapoma J, Hayden A, Kilpatrick K, Vangaveti S, Chen A, Banco T, Halvorsen K. High-throughput single-molecule quantification of individual base stacking energies in nucleic acids. Nat Commun 2023; 14:631. [PMID: 36746949 PMCID: PMC9902561 DOI: 10.1038/s41467-023-36373-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/26/2023] [Indexed: 02/08/2023] Open
Abstract
Base stacking interactions between adjacent bases in DNA and RNA are important for many biological processes and in biotechnology applications. Previous work has estimated stacking energies between pairs of bases, but contributions of individual bases has remained unknown. Here, we use a Centrifuge Force Microscope for high-throughput single molecule experiments to measure stacking energies between adjacent bases. We found stacking energies strongest between purines (G|A at -2.3 ± 0.2 kcal/mol) and weakest between pyrimidines (C|T at -0.5 ± 0.1 kcal/mol). Hybrid stacking with phosphorylated, methylated, and RNA nucleotides had no measurable effect, but a fluorophore modification reduced stacking energy. We experimentally show that base stacking can influence stability of a DNA nanostructure, modulate kinetics of enzymatic ligation, and assess accuracy of force fields in molecular dynamics simulations. Our results provide insights into fundamental DNA interactions that are critical in biology and can inform design in biotechnology applications.
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Affiliation(s)
- Jibin Abraham Punnoose
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Kevin J Thomas
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | | | - Javier Vilcapoma
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Andrew Hayden
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Kacey Kilpatrick
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA.,Department of Chemistry, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Sweta Vangaveti
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Alan Chen
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA.,Department of Chemistry, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Thomas Banco
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Ken Halvorsen
- The RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA.
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7
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Kristoffersen E, Coletta A, Lund L, Schiøtt B, Birkedal V. Inhibited complete folding of consecutive human telomeric G-quadruplexes. Nucleic Acids Res 2023; 51:1571-1582. [PMID: 36715345 PMCID: PMC9976873 DOI: 10.1093/nar/gkad004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 12/24/2022] [Accepted: 01/04/2023] [Indexed: 01/31/2023] Open
Abstract
Noncanonical DNA structures, termed G-quadruplexes, are present in human genomic DNA and are important elements in many DNA metabolic processes. Multiple sites in the human genome have G-rich DNA stretches able to support formation of several consecutive G-quadruplexes. One of those sites is the telomeric overhang region that has multiple repeats of TTAGGG and is tightly associated with both cancer and aging. We investigated the folding of consecutive G-quadruplexes in both potassium- and sodium-containing solutions using single-molecule FRET spectroscopy, circular dichroism, thermal melting and molecular dynamics simulations. Our observations show coexistence of partially and fully folded DNA, the latter consisting of consecutive G-quadruplexes. Following the folding process over hours in sodium-containing buffers revealed fast G-quadruplex folding but slow establishment of thermodynamic equilibrium. We find that full consecutive G-quadruplex formation is inhibited by the many DNA structures randomly nucleating on the DNA, some of which are off-path conformations that need to unfold to allow full folding. Our study allows describing consecutive G-quadruplex formation in both nonequilibrium and equilibrium conditions by a unified picture, where, due to the many possible DNA conformations, full folding with consecutive G-quadruplexes as beads on a string is not necessarily achieved.
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Affiliation(s)
- Emil Laust Kristoffersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Andrea Coletta
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Line Mørkholt Lund
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Birgit Schiøtt
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark,Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
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8
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Craig JM, Mills M, Kim HC, Huang JR, Abell S, Mount J, Gundlach J, Neuman K, Laszlo A. Nanopore tweezers measurements of RecQ conformational changes reveal the energy landscape of helicase motion. Nucleic Acids Res 2022; 50:10601-10613. [PMID: 36165957 PMCID: PMC9561376 DOI: 10.1093/nar/gkac837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 09/02/2022] [Accepted: 09/19/2022] [Indexed: 11/13/2022] Open
Abstract
Helicases are essential for nearly all nucleic acid processes across the tree of life, yet detailed understanding of how they couple ATP hydrolysis to translocation and unwinding remains incomplete because their small (∼300 picometer), fast (∼1 ms) steps are difficult to resolve. Here, we use Nanopore Tweezers to observe single Escherichia coli RecQ helicases as they translocate on and unwind DNA at ultrahigh spatiotemporal resolution. Nanopore Tweezers simultaneously resolve individual steps of RecQ along the DNA and conformational changes of the helicase associated with stepping. Our data reveal the mechanochemical coupling between physical domain motions and chemical reactions that together produce directed motion of the helicase along DNA. Nanopore Tweezers measurements are performed under either assisting or opposing force applied directly on RecQ, shedding light on how RecQ responds to such forces in vivo. Determining the rates of translocation and physical conformational changes under a wide range of assisting and opposing forces reveals the underlying dynamic energy landscape that drives RecQ motion. We show that RecQ has a highly asymmetric energy landscape that enables RecQ to maintain velocity when encountering molecular roadblocks such as bound proteins and DNA secondary structures. This energy landscape also provides a mechanistic basis making RecQ an 'active helicase,' capable of unwinding dsDNA as fast as it translocates on ssDNA. Such an energy landscape may be a general strategy for molecular motors to maintain consistent velocity despite opposing loads or roadblocks.
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Affiliation(s)
- Jonathan M Craig
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
| | - Maria Mills
- Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Physics & Astronomy, University of Missouri, 701 S College Ave, Physics Building Rm 223, Columbia, MO 65211, USA
| | - Hwanhee C Kim
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
| | - Jesse R Huang
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
| | - Sarah J Abell
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
| | - Jonathan W Mount
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
| | - Jens H Gundlach
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
| | - Keir C Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew H Laszlo
- Department of Physics, University of Washington, 3910 15th Ave NE, Seattle, WA, USA
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9
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Sherazi SAM, Abbasi A, Jamil A, Uzair M, Ikram A, Qamar S, Olamide AA, Arshad M, Fried PJ, Ljubisavljevic M, Wang R, Bashir S. Molecular hallmarks of long non-coding RNAs in aging and its significant effect on aging-associated diseases. Neural Regen Res 2022; 18:959-968. [PMID: 36254975 PMCID: PMC9827784 DOI: 10.4103/1673-5374.355751] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aging is linked to the deterioration of many physical and cognitive abilities and is the leading risk factor for Alzheimer's disease. The growing aging population is a significant healthcare problem globally that researchers must investigate to better understand the underlying aging processes. Advances in microarrays and sequencing techniques have resulted in deeper analyses of diverse essential genomes (e.g., mouse, human, and rat) and their corresponding cell types, their organ-specific transcriptomes, and the tissue involved in aging. Traditional gene controllers such as DNA- and RNA-binding proteins significantly influence such programs, causing the need to sort out long non-coding RNAs, a new class of powerful gene regulatory elements. However, their functional significance in the aging process and senescence has yet to be investigated and identified. Several recent researchers have associated the initiation and development of senescence and aging in mammals with several well-reported and novel long non-coding RNAs. In this review article, we identified and analyzed the evolving functions of long non-coding RNAs in cellular processes, including cellular senescence, aging, and age-related pathogenesis, which are the major hallmarks of long non-coding RNAs in aging.
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Affiliation(s)
- Syed Aoun Mehmood Sherazi
- Department of Biological Sciences, Faculty of Basic & Applied Sciences, International Islamic University, Islamabad, Pakistan
| | - Asim Abbasi
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Abdullah Jamil
- Department of Pharmacology, Government College University, Faisalabad, Pakistan
| | - Mohammad Uzair
- Department of Biological Sciences, Faculty of Basic & Applied Sciences, International Islamic University, Islamabad, Pakistan
| | - Ayesha Ikram
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Shanzay Qamar
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | | | - Muhammad Arshad
- Department of Biological Sciences, Faculty of Basic & Applied Sciences, International Islamic University, Islamabad, Pakistan
| | - Peter J. Fried
- Department of Neurology, Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Beth Israel Deaconess Medical Center (KS 158), Harvard Medical School, Boston, MA, USA
| | - Milos Ljubisavljevic
- Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ran Wang
- Department of Psychiatry, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China,Mental Health Institute of Hebei Medical University, Shijiazhuang, Hebei Province, China
| | - Shahid Bashir
- Neuroscience Center, King Fahad Specialist Hospital, Dammam, Saudi Arabia,Correspondence to: Shahid Bashir, .
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10
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Pokhrel P, Sasaki S, Hu C, Karna D, Pandey S, Ma Y, Nagasawa K, Mao H. Single-molecule displacement assay reveals strong binding of polyvalent dendrimer ligands to telomeric G-quadruplex. Anal Biochem 2022; 649:114693. [PMID: 35500657 PMCID: PMC9133229 DOI: 10.1016/j.ab.2022.114693] [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: 02/22/2022] [Revised: 04/04/2022] [Accepted: 04/17/2022] [Indexed: 11/01/2022]
Abstract
Binding between a ligand and a receptor is a fundamental step in many natural or synthetic processes. In biosensing, a tight binding with a small dissociation constant (Kd) between the probe and analyte can lead to superior specificity and sensitivity. Owing to their capability of evaluating competitors, displacement assays have been used to estimate Kd at the ensemble average level. At the more sensitive single-molecule level, displacement assays are yet to be established. Here, we developed a single-molecule displacement assay (smDA) in an optical tweezers instrument and used this innovation to evaluate the binding of the L2H2-6OTD ligands to human telomeric DNA G-quadruplexes. After measuring Kd of linear and dendrimer L2H2-6OTD ligands, we found that dendrimer ligands have enhanced binding affinity to the G-quadruplexes due to their polyvalent geometry. This increased binding affinity enhanced inhibition of telomerase elongation on a telomere template in a Telomerase Repeated Amplification Protocol (TRAP). Our experiments demonstrate that the smDA approach can efficiently evaluate binding processes in chemical and biological processes.
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Affiliation(s)
- Pravin Pokhrel
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA
| | - Shogo Sasaki
- Department of Biotechnology and Life Science Faculty of Technology, Tokyo University of Agriculture and Technology (TUAT), 2-14-16 Naka-cho, Koganeishi, Tokyo, 184-8588, Japan
| | - Changpeng Hu
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA; Department of Pharmacy, The Second Affiliated Hospital, Army Medical University, Chongqing, 400037, China
| | - Deepak Karna
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA
| | - Shankar Pandey
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA
| | - Yue Ma
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology (TUAT), 2-14-16 Naka-cho, Koganeishi, Tokyo, 184-8588, Japan
| | - Kazuo Nagasawa
- Department of Biotechnology and Life Science Faculty of Technology, Tokyo University of Agriculture and Technology (TUAT), 2-14-16 Naka-cho, Koganeishi, Tokyo, 184-8588, Japan.
| | - Hanbin Mao
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA.
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11
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Marquevielle J, De Rache A, Vialet B, Morvan E, Mergny JL, Amrane S. G-quadruplex structure of the C. elegans telomeric repeat: a two tetrads basket type conformation stabilized by a non-canonical C-T base-pair. Nucleic Acids Res 2022; 50:7134-7146. [PMID: 35736226 PMCID: PMC9262591 DOI: 10.1093/nar/gkac523] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 05/07/2022] [Accepted: 06/01/2022] [Indexed: 12/24/2022] Open
Abstract
The Caenorhabditis elegans model has greatly contributed to the understanding of the role of G-quadruplexes in genomic instability. The GGCTTA repeats of the C. elegans telomeres resemble the GGGTTA repeats of the human telomeres. However, the comparison of telomeric sequences (Homo sapiens, Tetrahymena, Oxytricha, Bombyx mori and Giardia) revealed that small changes in these repeats can drastically change the topology of the folded G-quadruplex. In the present work we determined the structure adopted by the C. elegans telomeric sequence d[GG(CTTAGG)3]. The investigated C. elegans telomeric sequence is shown to fold into an intramolecular two G-tetrads basket type G-quadruplex structure that includes a C-T base pair in the diagonal loop. This work sheds light on the telomeric structure of the widely used C. elegans animal model.
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Affiliation(s)
- Julien Marquevielle
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, ARNA laboratory, 146 rue Léo Saignat F-33000 Bordeaux, France
- Institut Européen de Chimie et Biologie, UMS 3033 US001, CNRS-Université de Bordeaux, 2 rue Robert Escarpit, F-33600 Pessac, France
| | - Aurore De Rache
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, ARNA laboratory, 146 rue Léo Saignat F-33000 Bordeaux, France
- Institut Européen de Chimie et Biologie, UMS 3033 US001, CNRS-Université de Bordeaux, 2 rue Robert Escarpit, F-33600 Pessac, France
- Department of Chemistry, UNamur, 61 rue de Bruxelles, B-5000 Namur, Belgium
| | - Brune Vialet
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, ARNA laboratory, 146 rue Léo Saignat F-33000 Bordeaux, France
| | - Estelle Morvan
- Institut Européen de Chimie et Biologie, UMS 3033 US001, CNRS-Université de Bordeaux, 2 rue Robert Escarpit, F-33600 Pessac, France
| | - Jean-Louis Mergny
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, ARNA laboratory, 146 rue Léo Saignat F-33000 Bordeaux, France
- Institut Européen de Chimie et Biologie, UMS 3033 US001, CNRS-Université de Bordeaux, 2 rue Robert Escarpit, F-33600 Pessac, France
- Laboratoire d’Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Samir Amrane
- Univ. Bordeaux, Inserm U1212, CNRS UMR 5320, ARNA laboratory, 146 rue Léo Saignat F-33000 Bordeaux, France
- Institut Européen de Chimie et Biologie, UMS 3033 US001, CNRS-Université de Bordeaux, 2 rue Robert Escarpit, F-33600 Pessac, France
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12
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Liu L, Zhang W, Zhong MQ, Jia MH, Jiang F, Zhang Y, Xiao CD, Xiao X, Shen XC. Tetraphenylethene derivative that discriminates parallel G-quadruplexes. RSC Adv 2022; 12:14765-14775. [PMID: 35702216 PMCID: PMC9109478 DOI: 10.1039/d2ra01433e] [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: 03/04/2022] [Accepted: 04/26/2022] [Indexed: 11/29/2022] Open
Abstract
G-Quadruplex (G4), as a non-canonical nucleic acid secondary structure, has been proved to be prevalent in genomes and plays important roles in many biological processes. Ligands targeting G4, especially small-molecular fluorescent light-up probes with selectivity for special conformations, are essential for studying the relationship between G4 folding and the cellular response. However, their development still remains challenging but is attracting massive attention. Here, we synthesized a new tetraphenylethene derivative, namely TPE-B, as a parallel G4 probe. Fluorescence experiments showed that TPE-B could give out a strong fluorescence response to the G4 structure. Moreover, it gave a much higher fluorescence intensity response to parallel G4s than anti-parallel ones, which indicated that TPE-B could serve as a special tool for probing parallel G4s. The circular dichroism (CD) spectra and melting curves showed that TPE-B could selectively bind and stabilize parallel G4s without changing their topology. ESI-MS studies showed that TPE-B could bind to parallel G4 with a 1 : 1 stoichiometry. The gel staining results showed that TPE-B was a good candidate for probing parallel G4s. Altogether, the TPE-B molecule may serve as a promising new probe that can discriminate parallel G4s. A tetraphenylethene derivative: 1,1′,1′′,1′′′-(((ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl)) tetrakis(oxy)) tetrakis(butane-4,1-diyl)) tetrakis(4-(dimethylamino) pyridin-1-ium) bromide (TPE-B) has been designed as a fluorescent light-up probe with high selectivity for parallel G-quadruplexes![]()
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Affiliation(s)
- Lei Liu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China
| | - Wei Zhang
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University Guiyang 550025 P. R. China
| | - Ming-Qing Zhong
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China
| | - Meng-Hao Jia
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China
| | - Fei Jiang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China
| | - Yan Zhang
- Department of Radiology, Affiliated Hospital of Guizhou Medical University Guiyang Guizhou 550001 P. R. China
| | - Chao-Da Xiao
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China .,The Key Laboratory of Optimal Utilization of Natural Medicine Resources, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China
| | - Xin Xiao
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University Guiyang 550025 P. R. China
| | - Xiang-Chun Shen
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China .,The Key Laboratory of Optimal Utilization of Natural Medicine Resources, Guizhou Medical University, University Town Guian New District Guizhou 550025 P. R. China
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13
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Frasson I, Pirota V, Richter SN, Doria F. Multimeric G-quadruplexes: A review on their biological roles and targeting. Int J Biol Macromol 2022; 204:89-102. [PMID: 35124022 DOI: 10.1016/j.ijbiomac.2022.01.197] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/20/2022] [Accepted: 01/31/2022] [Indexed: 12/12/2022]
Abstract
In human cells, nucleic acids adopt several non-canonical structures that regulate key cellular processes. Among them, G-quadruplexes (G4s) are stable structures that form in guanine-rich regions in vitro and in cells. G4 folded/unfolded state shapes numerous cellular processes, including genome replication, transcription, and translation. Moreover, G4 folding is involved in genomic instability. G4s have been described to multimerize, forming high-order structures in both DNA and/or RNA strands. Multimeric G4s can be formed by adjacent intramolecular G4s joined by stacking interactions or connected by short loops. Multimeric G4s can also originate from the assembly of guanines embedded on independent DNA or RNA strands. Notably, crucial regions of the human genome, such as the 3'-terminal overhang of the telomeric DNA as well as the open reading frame of genes involved in the preservation of neuron viability in the human central and peripheral nervous system are prone to form multimeric G4s. The biological importance of such structures has been recently described, with multimeric G4s playing potentially protective or deleterious effects in the pathogenic cascade of various diseases. Here, we portray the multifaceted scenario of multimeric G4s, in terms of structural properties, biological roles, and targeting strategies.
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Affiliation(s)
- Ilaria Frasson
- Department of Molecular Medicine, University of Padova, via A. Gabelli 63, 35121 Padova, Italy
| | - Valentina Pirota
- Department of Chemistry, University of Pavia, v. le Taramelli 10, 27100 Pavia, Italy; G4-INTERACT, USERN, v. le Taramelli 10, 27100 Pavia, Italy
| | - Sara N Richter
- Department of Molecular Medicine, University of Padova, via A. Gabelli 63, 35121 Padova, Italy.
| | - Filippo Doria
- Department of Chemistry, University of Pavia, v. le Taramelli 10, 27100 Pavia, Italy.
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14
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Hu XX, Wang SQ, Gan SQ, Liu L, Zhong MQ, Jia MH, Jiang F, Xu Y, Xiao CD, Shen XC. A Small Ligand That Selectively Binds to the G-quadruplex at the Human Vascular Endothelial Growth Factor Internal Ribosomal Entry Site and Represses the Translation. Front Chem 2021; 9:781198. [PMID: 34858949 PMCID: PMC8630693 DOI: 10.3389/fchem.2021.781198] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
G-quadruplexes are believed to have important biological functions, so many small molecules have been screened or developed for targeting G-quadruplexes. However, it is still a major challenge to find molecules that recognize specific G-quadruplexes. Here, by using a combination of surface plasmon resonance, electrospray ionization mass spectrometry, circular dichroism, Western blot, luciferase assay, and reverse transcriptase stop assay, we observed a small molecule, namely, oxymatrine (OMT) that could selectively bind to the RNA G-quadruplex in 5′-untranslated regions (UTRs) of human vascular endothelial growth factor (hVEGF), but could not bind to other G-quadruplexes. OMT could selectively repress the translation of VEGF in cervical cancer cells. Furthermore, it could recognize VEGF RNA G-quadruplexes in special conformations. The results indicate that OMT may serve as a potentially special tool for studying the VEGF RNA G-quadruplex in cells and as a valuable scaffold for the design of ligands that recognize different G-quadruplexes.
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Affiliation(s)
- Xiao-Xia Hu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.,Department of Physiology, College of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
| | - Sheng-Quan Wang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China
| | - Shi-Quan Gan
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China
| | - Lei Liu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China
| | - Ming-Qing Zhong
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China
| | - Meng-Hao Jia
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China
| | - Fei Jiang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China
| | - Yan Xu
- Division of Chemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Chao-Da Xiao
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.,The Key Laboratory of Optimal Utilization of Natural Medicine Resources, Guizhou Medical University, Guiyang, China
| | - Xiang-Chun Shen
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.,The Key Laboratory of Optimal Utilization of Natural Medicine Resources, Guizhou Medical University, Guiyang, China
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15
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Grün JT, Schwalbe H. Folding dynamics of polymorphic G-quadruplex structures. Biopolymers 2021; 113:e23477. [PMID: 34664713 DOI: 10.1002/bip.23477] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 12/14/2022]
Abstract
G-quadruplexes (G4), found in numerous places within the human genome, are involved in essential processes of cell regulation. Chromosomal DNA G4s are involved for example, in replication and transcription as first steps of gene expression. Hence, they influence a plethora of downstream processes. G4s possess an intricate structure that differs from canonical B-form DNA. Identical DNA G4 sequences can adopt multiple long-lived conformations, a phenomenon known as G4 polymorphism. A detailed understanding of the molecular mechanisms that drive G4 folding is essential to understand their ambivalent regulatory roles. Disentangling the inherent dynamic and polymorphic nature of G4 structures thus is key to unravel their biological functions and make them amenable as molecular targets in novel therapeutic approaches. We here review recent experimental approaches to monitor G4 folding and discuss structural aspects for possible folding pathways. Substantial progress in the understanding of G4 folding within the recent years now allows drawing comprehensive models of the complex folding energy landscape of G4s that we herein evaluate based on computational and experimental evidence.
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Affiliation(s)
- J Tassilo Grün
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University, Frankfurt/M, Germany.,Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/M, Germany
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16
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Hoque ME, Mustafa G, Basu S, Balci H. Encounters between Cas9/dCas9 and G-Quadruplexes: Implications for Transcription Regulation and Cas9-Mediated DNA Cleavage. ACS Synth Biol 2021; 10:972-978. [PMID: 33970608 DOI: 10.1021/acssynbio.1c00067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Using the nuclease-dead Cas9 (dCas9), we targeted in cellulo a G-rich sequence, which contains multiple potentially G-quadruplex (GQ) forming sites, within the human tyrosine hydroxylase (TH) promoter. We demonstrate that transcription can be up or down regulated by targeting different parts of this G-rich sequence. Our results suggest that TH transcription levels correlate with stability of different GQs formed by this sequence and targeting them with dCas9 can modulate their stability. Unlike alternative approaches, regulating TH expression by targeting the promoter GQs with dCas9 enables a specific and potentially transient control and does not require mutations in the sequence. We also investigated whether the presence of GQs in target sequences impacts DNA cleavage activity of Cas9. We discovered significant reduction in cleavage activity when the vicinity of a high-stability GQ was targeted. Furthermore, this reduction is significantly more prominent for the G-rich strand compared to the complementary C-rich strand.
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Affiliation(s)
- Mohammed Enamul Hoque
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Golam Mustafa
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Soumitra Basu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Hamza Balci
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
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17
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Carrino S, Hennecker CD, Murrieta AC, Mittermaier A. Frustrated folding of guanine quadruplexes in telomeric DNA. Nucleic Acids Res 2021; 49:3063-3076. [PMID: 33693924 PMCID: PMC8034632 DOI: 10.1093/nar/gkab140] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 01/22/2021] [Accepted: 02/19/2021] [Indexed: 11/23/2022] Open
Abstract
Human chromosomes terminate in long, single-stranded, DNA overhangs of the repetitive sequence (TTAGGG)n. Sets of four adjacent TTAGGG repeats can fold into guanine quadruplexes (GQ), four-stranded structures that are implicated in telomere maintenance and cell immortalization and are targets in cancer therapy. Isolated GQs have been studied in detail, however much less is known about folding in long repeat sequences. Such chains adopt an enormous number of configurations containing various arrangements of GQs and unfolded gaps, leading to a highly frustrated energy landscape. To better understand this phenomenon, we used mutagenesis, thermal melting, and global analysis to determine stability, kinetic, and cooperativity parameters for GQ folding within chains containing 8–12 TTAGGG repeats. We then used these parameters to simulate the folding of 32-repeat chains, more representative of intact telomeres. We found that a combination of folding frustration and negative cooperativity between adjacent GQs increases TTAGGG unfolding by up to 40-fold, providing an abundance of unfolded gaps that are potential binding sites for telomeric proteins. This effect was most pronounced at the chain termini, which could promote telomere extension by telomerase. We conclude that folding frustration is an important and largely overlooked factor controlling the structure of telomeric DNA.
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Affiliation(s)
- Simone Carrino
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Christopher D Hennecker
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Ana C Murrieta
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada.,School of Engineering and Sciences, Instituto Tecnológico y de Estudios Superiores De Monterrey, Av. Eugenio Garza Sada 2501 Sur Col. Tecnológico C.P. 64849, Monterrey, Nuevo León, México
| | - Anthony Mittermaier
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
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18
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Mustafa G, Shiekh S, Gc K, Abeysirigunawardena S, Balci H. Interrogating accessibility of telomeric sequences with FRET-PAINT: evidence for length-dependent telomere compaction. Nucleic Acids Res 2021; 49:3371-3380. [PMID: 33693934 PMCID: PMC8034622 DOI: 10.1093/nar/gkab067] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/23/2021] [Accepted: 03/08/2021] [Indexed: 12/25/2022] Open
Abstract
Single-stranded telomeric overhangs are ∼200 nucleotides long and can form tandem G-quadruplex (GQ) structures, which reduce their accessibility to nucleases and proteins that activate DNA damage response. Whether these tandem GQs further stack to form compact superstructures, which may provide better protection for longer telomeres, is not known. We report single-molecule measurements where the accessibility of 24-144 nucleotide long human telomeric DNA molecules is interrogated by a short PNA molecule that is complementary to a single GGGTTA repeat, as implemented in the FRET-PAINT method. Binding of the PNA strand to available GGGTTA sequences results in discrete FRET bursts which were analyzed in terms of their dwell times, binding frequencies, and topographic distributions. The binding frequencies were greater for binding to intermediate regions of telomeric DNA compared to 3'- or 5'-ends, suggesting these regions are more accessible. Significantly, the binding frequency per telomeric repeat monotonically decreased with increasing telomere length. These results are consistent with telomeres forming more compact structures at longer lengths, reducing accessibility of these critical genomic sites.
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Affiliation(s)
- Golam Mustafa
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | - Sajad Shiekh
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | - Keshav Gc
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | | | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH 44242, USA
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19
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Onizuka K, Ganbold E, Ma Y, Sasaki S, Hazemi ME, Chen Y, Sato N, Ozawa M, Nagasawa K, Nagatsugi F. Selective alkylation of parallel G-quadruplex structure. Org Biomol Chem 2021; 19:2891-2894. [PMID: 33570069 DOI: 10.1039/d0ob02365e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The selective alkylation of nucleic acids is important for a medicinal approach and biological study. We now report a novel selective alkylation of the parallel G-quadruplex structure using the conjugate of the macrocyclic hexaoxazole L2G2-6OTD-1M1PA and vinyl-quinazolinone-S(O)Me (6OTD-VQ-S(O)Me).
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Affiliation(s)
- Kazumitsu Onizuka
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
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20
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Monsen RC, Chakravarthy S, Dean WL, Chaires JB, Trent JO. The solution structures of higher-order human telomere G-quadruplex multimers. Nucleic Acids Res 2021; 49:1749-1768. [PMID: 33469644 PMCID: PMC7897503 DOI: 10.1093/nar/gkaa1285] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/21/2020] [Accepted: 01/13/2021] [Indexed: 12/17/2022] Open
Abstract
Human telomeres contain the repeat DNA sequence 5′-d(TTAGGG), with duplex regions that are several kilobases long terminating in a 3′ single-stranded overhang. The structure of the single-stranded overhang is not known with certainty, with disparate models proposed in the literature. We report here the results of an integrated structural biology approach that combines small-angle X-ray scattering, circular dichroism (CD), analytical ultracentrifugation, size-exclusion column chromatography and molecular dynamics simulations that provide the most detailed characterization to date of the structure of the telomeric overhang. We find that the single-stranded sequences 5′-d(TTAGGG)n, with n = 8, 12 and 16, fold into multimeric structures containing the maximal number (2, 3 and 4, respectively) of contiguous G4 units with no long gaps between units. The G4 units are a mixture of hybrid-1 and hybrid-2 conformers. In the multimeric structures, G4 units interact, at least transiently, at the interfaces between units to produce distinctive CD signatures. Global fitting of our hydrodynamic and scattering data to a worm-like chain (WLC) model indicates that these multimeric G4 structures are semi-flexible, with a persistence length of ∼34 Å. Investigations of its flexibility using MD simulations reveal stacking, unstacking, and coiling movements, which yield unique sites for drug targeting.
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Affiliation(s)
- Robert C Monsen
- Department of Biochemistry & Molecular Genetics, University of Louisville Medical School, Louisville, KY 40202, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - William L Dean
- James Graham Brown Cancer Center, University of Louisville Medical School, Louisville, KY 40202, USA
| | - Jonathan B Chaires
- Department of Biochemistry & Molecular Genetics, University of Louisville Medical School, Louisville, KY 40202, USA.,James Graham Brown Cancer Center, University of Louisville Medical School, Louisville, KY 40202, USA.,Department of Medicine, University of Louisville Medical School, Louisville, KY 40202, USA
| | - John O Trent
- Department of Biochemistry & Molecular Genetics, University of Louisville Medical School, Louisville, KY 40202, USA.,James Graham Brown Cancer Center, University of Louisville Medical School, Louisville, KY 40202, USA.,Department of Medicine, University of Louisville Medical School, Louisville, KY 40202, USA
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21
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Hao X, Wang C, Wang Y, Li C, Hou J, Zhang F, Kang C, Gao L. Topological conversion of human telomeric G-quadruplexes from hybrid to parallel form induced by naphthalene diimide ligands. Int J Biol Macromol 2020; 167:1048-1058. [PMID: 33188810 DOI: 10.1016/j.ijbiomac.2020.11.059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
G-quadruplexes (GQs) have become promising anti-cancer therapeutic targets, which are formed by the folding of a guanine-rich repeat DNA/RNA sequence at human telomeres or oncogene promoters. Polymorphism has been observed for the folding topologies of intramolecular GQs. Here we report the topological conversion of human telomeric GQ induced by naphthalene diimide (NDI) ligands in K+ solution. The ligands selectively induce metastable hybrid-type GQs to highly stable parallel-type GQ at physiological temperature (37 °C) in dilute aqueous solutions and under crowding conditions that mimic cellular bioenvironment. According to spectroscopic analyses, the topological conversion is speculated to undergo stepwise unfolding of hybrid-type GQ through intermediate states to parallel-type GQ. The results will prompt further studies on the designs of ligands with GQ conformation regulation functions and nanotechnological systems based on nucleic acids with dynamic regulation of GQ conformation.
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Affiliation(s)
- Xueyu Hao
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China
| | - Chunyu Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Yu Wang
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China
| | - Chunjie Li
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Jingwei Hou
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Feng Zhang
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Chuanqing Kang
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China.
| | - Lianxun Gao
- Laboratory of Polymer Composite and Engineering, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
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22
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Yasuda M, Ma Y, Okabe S, Wakabayashi Y, Su D, Chang YT, Seimiya H, Tera M, Nagasawa K. Target identification of a macrocyclic hexaoxazole G-quadruplex ligand using post-target-binding visualization. Chem Commun (Camb) 2020; 56:12905-12908. [PMID: 33030187 DOI: 10.1039/d0cc04957c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Macrocyclic hexaoxazoles (6OTDs) are G-quadruplex (G4) ligands, and some derivatives, such as L2H2-6OTD (1a) bearing two aminobutyl side chains, show cytotoxicity towards cancer cells. To identify the cellular target of 1a, we employed a post-target-binding strategy utilizing click reaction (Huisgen cyclization) between the azide-conjugated ligand L2H2-6OTD-Az (1b) and the cell-permeable dye CO-1 bearing a strained alkyne moiety and the BODIPY fluorophore under Cu-free conditions. We confirmed that introduction of the small azide group did not alter the physical or biological properties, including anti-cancer activity, of 1a, and we also demonstrated bias-free localization of CO-1. The post-binding visualization strategy suggested that L2H2-6OTD (1a) colocalized with RNA G4 in living cells.
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Affiliation(s)
- Mizuho Yasuda
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
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23
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Xiao CD, He ZY, Guo CX, Shen XC, Xu Y. Conformation of G-quadruplex Controlled by Click Reaction. Molecules 2020; 25:molecules25184339. [PMID: 32971833 PMCID: PMC7570587 DOI: 10.3390/molecules25184339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 11/16/2022] Open
Abstract
G-quadruplexes are non-canonical four stranded secondary structures possessing great biological importance. Controlling G-quadruplex conformation for further regulating biological processes is both exciting and challenging. In this study, we described a method for regulating G-quadruplex conformation by click chemistry for the first time. 8-ethynyl-2'-deoxyguanosine was synthesized and incorporated into a 12-nt telomere DNA sequence. Such a sequence, at first, formed mixed parallel/anti-parallel G-quadruplexes, while it changed to anti-parallel after reaction with azidobenzene. Meanwhile, the click reaction can give the sequence intense fluorescence.
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Affiliation(s)
- Chao-Da Xiao
- State Key Laboratory of Functions and Applications of Medicinal Plants, School of Pharmaceutical Sciences, Guizhou Medical University, University Town, Guian New District, Guiyang 550025, China;
- Correspondence: (C.-D.X.); (Y.X.); Tel.: +86-0851-88416160 (C.-D.X.); +81-985-85-0993 (Y.X.)
| | - Zhi-Yong He
- Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyo-take, Miyazaki 889-1692, Japan;
| | - Chuan-Xin Guo
- Nucleic Acid Division, Shanghai Cell Therapy Group Co. Ltd., Jiading, Shanghai 201805, China;
| | - Xiang-Chun Shen
- State Key Laboratory of Functions and Applications of Medicinal Plants, School of Pharmaceutical Sciences, Guizhou Medical University, University Town, Guian New District, Guiyang 550025, China;
| | - Yan Xu
- Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyo-take, Miyazaki 889-1692, Japan;
- Correspondence: (C.-D.X.); (Y.X.); Tel.: +86-0851-88416160 (C.-D.X.); +81-985-85-0993 (Y.X.)
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Bryan TM. G-Quadruplexes at Telomeres: Friend or Foe? Molecules 2020; 25:molecules25163686. [PMID: 32823549 PMCID: PMC7464828 DOI: 10.3390/molecules25163686] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 12/28/2022] Open
Abstract
Telomeres are DNA-protein complexes that cap and protect the ends of linear chromosomes. In almost all species, telomeric DNA has a G/C strand bias, and the short tandem repeats of the G-rich strand have the capacity to form into secondary structures in vitro, such as four-stranded G-quadruplexes. This has long prompted speculation that G-quadruplexes play a positive role in telomere biology, resulting in selection for G-rich tandem telomere repeats during evolution. There is some evidence that G-quadruplexes at telomeres may play a protective capping role, at least in yeast, and that they may positively affect telomere maintenance by either the enzyme telomerase or by recombination-based mechanisms. On the other hand, G-quadruplex formation in telomeric DNA, as elsewhere in the genome, can form an impediment to DNA replication and a source of genome instability. This review summarizes recent evidence for the in vivo existence of G-quadruplexes at telomeres, with a focus on human telomeres, and highlights some of the many unanswered questions regarding the location, form, and functions of these structures.
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Affiliation(s)
- Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
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Patrick EM, Slivka JD, Payne B, Comstock MJ, Schmidt JC. Observation of processive telomerase catalysis using high-resolution optical tweezers. Nat Chem Biol 2020; 16:801-809. [PMID: 32066968 PMCID: PMC7311264 DOI: 10.1038/s41589-020-0478-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/14/2020] [Indexed: 02/07/2023]
Abstract
Telomere maintenance by telomerase is essential for continuous proliferation of human cells and is vital for the survival of stem cells and 90% of cancer cells. To compensate for telomeric DNA lost during DNA replication, telomerase processively adds GGTTAG repeats to chromosome ends by copying the template region within its RNA subunit. Between repeat additions, the RNA template must be recycled. How telomerase remains associated with substrate DNA during this critical translocation step remains unknown. Using a newly developed single-molecule telomerase activity assay utilizing high-resolution optical tweezers, we demonstrate that stable substrate DNA binding at an anchor site within telomerase facilitates the processive synthesis of telomeric repeats. The product DNA synthesized by telomerase can be recaptured by the anchor site or fold into G-quadruplex structures. Our results provide detailed mechanistic insights into telomerase catalysis, a process of critical importance in aging and cancer.
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Affiliation(s)
- Eric M Patrick
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Joseph D Slivka
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
| | - Bramyn Payne
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
| | - Matthew J Comstock
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA.
| | - Jens C Schmidt
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA. .,Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University, East Lansing, MI, USA.
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