1
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Dulin D. An Introduction to Magnetic Tweezers. Methods Mol Biol 2024; 2694:375-401. [PMID: 37824014 DOI: 10.1007/978-1-0716-3377-9_18] [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] [Indexed: 10/13/2023]
Abstract
Magnetic tweezers are a single-molecule force and torque spectroscopy technique that enable the mechanical interrogation in vitro of biomolecules, such as nucleic acids and proteins. They use a magnetic field originating from either permanent magnets or electromagnets to attract a magnetic particle, thus stretching the tethering biomolecule. They nicely complement other force spectroscopy techniques such as optical tweezers and atomic force microscopy (AFM) as they operate as a very stable force clamp, enabling long-duration experiments over a very broad range of forces spanning from 10 fN to 1 nN, with 1-10 milliseconds time and sub-nanometer spatial resolution. Their simplicity, robustness, and versatility have made magnetic tweezers a key technique within the field of single-molecule biophysics, being broadly applied to study the mechanical properties of, e.g., nucleic acids, genome processing molecular motors, protein folding, and nucleoprotein filaments. Furthermore, magnetic tweezers allow for high-throughput single-molecule measurements by tracking hundreds of biomolecules simultaneously both in real-time and at high spatiotemporal resolution. Magnetic tweezers naturally combine with surface-based fluorescence spectroscopy techniques, such as total internal reflection fluorescence microscopy, enabling correlative fluorescence and force/torque spectroscopy on biomolecules. This chapter presents an introduction to magnetic tweezers including a description of the hardware, the theory behind force calibration, its spatiotemporal resolution, combining it with other techniques, and a (non-exhaustive) overview of biological applications.
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Affiliation(s)
- David Dulin
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
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2
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Chang TR, Long X, Shastry S, Parks JW, Stone MD. Single-Molecule Mechanical Analysis of Strand Invasion in Human Telomere DNA. Biochemistry 2022; 61:1554-1560. [PMID: 35852986 PMCID: PMC9352315 DOI: 10.1021/acs.biochem.1c00448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Telomeres are essential
chromosome end capping structures that
safeguard the genome from dangerous DNA processing events. DNA strand
invasion occurs during vital transactions at telomeres, including
telomere length maintenance by the alternative lengthening of telomeres
(ALT) pathway. During telomeric strand invasion, a single-stranded
guanine-rich (G-rich) DNA invades at a complementary duplex telomere
repeat sequence, forming a displacement loop (D-loop) in which the
displaced DNA consists of the same G-rich sequence as the invading
single-stranded DNA. Single-stranded G-rich telomeric DNA readily
folds into stable, compact, structures called G-quadruplexes (GQs)
in vitro and is anticipated to form within the context of a D-loop;
however, evidence supporting this hypothesis is lacking. Here, we
report a magnetic tweezers assay that permits the controlled formation
of telomeric D-loops (TDLs) within uninterrupted duplex human telomere
DNA molecules of physiologically relevant lengths. Our results are
consistent with a model wherein the displaced single-stranded DNA
of a TDL fold into a GQ. This study provides new insight into telomere
structure and establishes a framework for the development of novel
therapeutics designed to target GQs at telomeres in cancer cells.
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Affiliation(s)
- Terren R. Chang
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
| | - Xi Long
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
| | - Shankar Shastry
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
- 10X Genomics, 6230 Stoneridge Mall Rd, Pleasanton, California 94588, United States
| | - Joseph W. Parks
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
- Invitae, 1400 16th St, San Francisco, California 94103, United States
| | - Michael D. Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High St, Santa Cruz, California 95064, United States
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3
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Maman N, Kumar P, Yadav A, Feingold M. Single Molecule Study of the Polymerization of RecA on dsDNA: The Dynamics of Individual Domains. Front Mol Biosci 2021; 8:609076. [PMID: 33842536 PMCID: PMC8025788 DOI: 10.3389/fmolb.2021.609076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
In the Escherichia coli, RecA plays a central role in the recombination and repair of the DNA. For homologous recombination, RecA binds to ssDNA forming a nucleoprotein filament. The RecA-ssDNA filament searches for a homologous sequence on a dsDNA and, subsequently, RecA mediates strand exchange between the ssDNA and the dsDNA. In vitro, RecA binds to both ssDNA and dsDNA. Despite a wide range of studies of the polymerization of RecA on dsDNA, both at the single molecule level and by means of biochemical methods, important aspects of this process are still awaiting a better understanding. Specifically, a detailed, quantitative description of the nucleation and growth dynamics of the RecA-dsDNA filaments is still lacking. Here, we use Optical Tweezers together with a single molecule analysis approach to measure the dynamics of the individual RecA domains on dsDNA and the corresponding growth rates for each of their fronts. We focus on the regime where the nucleation and growth rate constants, kn and kg, are comparable, leading to a coverage of the dsDNA molecule that consists of a small number of RecA domains. For the case of essentially irreversible binding (using ATPγS instead of ATP), we find that domain growth is highly asymmetric with a ratio of about 10:1 between the fast and slow fronts growth rates.
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Affiliation(s)
- Nitzan Maman
- Department of Physics, Ben Gurion University of the Negev, Beer Sheva, Israel.,The Ilse Katz Center for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Pramod Kumar
- Department of Physics, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Amarjeet Yadav
- Department of Physics, Ben Gurion University of the Negev, Beer Sheva, Israel.,Department of Applied Physics, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Mario Feingold
- Department of Physics, Ben Gurion University of the Negev, Beer Sheva, Israel.,The Ilse Katz Center for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva, Israel
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4
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Alekseev A, Serdakov M, Pobegalov G, Yakimov A, Bakhlanova I, Baitin D, Khodorkovskii M. Single-molecule analysis reveals two distinct states of the compressed RecA filament on single-stranded DNA. FEBS Lett 2020; 594:3464-3476. [PMID: 32880917 DOI: 10.1002/1873-3468.13922] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/20/2020] [Accepted: 08/24/2020] [Indexed: 11/07/2022]
Abstract
The RecA protein plays a key role in bacterial homologous recombination (HR) and acts through assembly of long helical filaments around single-stranded DNA in the presence of ATP. Large-scale conformational changes induced by ATP hydrolysis result in transitions between stretched and compressed forms of the filament. Here, using a single-molecule approach, we show that compressed RecA nucleoprotein filaments can exist in two distinct interconvertible states depending on the presence of ADP in the monomer-monomer interface. Binding of ADP promotes cooperative conformational transitions and directly affects mechanical properties of the filament. Our findings reveal that RecA nucleoprotein filaments are able to continuously cycle between three mechanically distinct states that might have important implications for RecA-mediated processes of HR.
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Affiliation(s)
| | - Maksim Serdakov
- Peter the Great St Petersburg Polytechnic University, Russia
| | | | - Alexandr Yakimov
- Peter the Great St Petersburg Polytechnic University, Russia
- Department of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute (B.P. Konstantinov of National Research Centre 'Kurchatov Institute'), Gatchina, Russia
| | - Irina Bakhlanova
- Department of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute (B.P. Konstantinov of National Research Centre 'Kurchatov Institute'), Gatchina, Russia
| | - Dmitry Baitin
- Department of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute (B.P. Konstantinov of National Research Centre 'Kurchatov Institute'), Gatchina, Russia
| | - Mikhail Khodorkovskii
- Peter the Great St Petersburg Polytechnic University, Russia
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
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5
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Hogrel G, Lu Y, Alexandre N, Bossé A, Dulermo R, Ishino S, Ishino Y, Flament D. Role of RadA and DNA Polymerases in Recombination-Associated DNA Synthesis in Hyperthermophilic Archaea. Biomolecules 2020; 10:E1045. [PMID: 32674430 PMCID: PMC7407445 DOI: 10.3390/biom10071045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/03/2020] [Accepted: 07/09/2020] [Indexed: 01/20/2023] Open
Abstract
Among the three domains of life, the process of homologous recombination (HR) plays a central role in the repair of double-strand DNA breaks and the restart of stalled replication forks. Curiously, main protein actors involved in the HR process appear to be essential for hyperthermophilic Archaea raising interesting questions about the role of HR in replication and repair strategies of those Archaea living in extreme conditions. One key actor of this process is the recombinase RadA, which allows the homologous strand search and provides a DNA substrate required for following DNA synthesis and restoring genetic information. DNA polymerase operation after the strand exchange step is unclear in Archaea. Working with Pyrococcus abyssi proteins, here we show that both DNA polymerases, family-B polymerase (PolB) and family-D polymerase (PolD), can take charge of processing the RadA-mediated recombination intermediates. Our results also indicate that PolD is far less efficient, as compared with PolB, to extend the invaded DNA at the displacement-loop (D-loop) substrate. These observations coincide with previous genetic analyses obtained on Thermococcus species showing that PolB is mainly involved in DNA repair without being essential probably because PolD could take over combined with additional partners.
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Affiliation(s)
- Gaëlle Hogrel
- Laboratoire de Microbiologie des Environnements Extrêmes, Ifremer, CNRS, Univ Brest, 29280 Plouzané, France; (G.H.); (Y.L.); (N.A.); (A.B.); (R.D.)
- LIA1211 MICROBSEA, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Xiamen-Plouzané, France
| | - Yang Lu
- Laboratoire de Microbiologie des Environnements Extrêmes, Ifremer, CNRS, Univ Brest, 29280 Plouzané, France; (G.H.); (Y.L.); (N.A.); (A.B.); (R.D.)
- LIA1211 MICROBSEA, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Xiamen-Plouzané, France
| | - Nicolas Alexandre
- Laboratoire de Microbiologie des Environnements Extrêmes, Ifremer, CNRS, Univ Brest, 29280 Plouzané, France; (G.H.); (Y.L.); (N.A.); (A.B.); (R.D.)
- LIA1211 MICROBSEA, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Xiamen-Plouzané, France
| | - Audrey Bossé
- Laboratoire de Microbiologie des Environnements Extrêmes, Ifremer, CNRS, Univ Brest, 29280 Plouzané, France; (G.H.); (Y.L.); (N.A.); (A.B.); (R.D.)
- LIA1211 MICROBSEA, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Xiamen-Plouzané, France
| | - Rémi Dulermo
- Laboratoire de Microbiologie des Environnements Extrêmes, Ifremer, CNRS, Univ Brest, 29280 Plouzané, France; (G.H.); (Y.L.); (N.A.); (A.B.); (R.D.)
- LIA1211 MICROBSEA, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Xiamen-Plouzané, France
| | - Sonoko Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Fukuoka 819-0395, Japan; (S.I.); (Y.I.)
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Fukuoka 819-0395, Japan; (S.I.); (Y.I.)
| | - Didier Flament
- Laboratoire de Microbiologie des Environnements Extrêmes, Ifremer, CNRS, Univ Brest, 29280 Plouzané, France; (G.H.); (Y.L.); (N.A.); (A.B.); (R.D.)
- LIA1211 MICROBSEA, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Xiamen-Plouzané, France
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6
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Atwell SX, Migliozzi D, Dupont A, Viovy JL, Cappello G. Structural transitions and mechanochemical coupling in the nucleoprotein filament explain homology selectivity and Rad51 protein cooperativity in cellular DNA repair. Phys Rev E 2020; 101:032407. [PMID: 32289957 DOI: 10.1103/physreve.101.032407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/17/2020] [Indexed: 11/07/2022]
Abstract
The nucleoprotein filament (NPF) is the fundamental element of homologous recombination (HR), a major mechanism for the repair of double-strand DNA breaks in the cell. The NPF is made of the damaged DNA strand surrounded by recombinase proteins, and its sensitivity to base-pairing mismatches is a crucial feature that guarantees the fidelity of the repair. The concurrent recombinases are also essential for several steps of HR. In this work, we used torque-sensitive magnetic tweezers to probe and apply mechanical constraints to single nucleoprotein filaments (NPFs). We demonstrated that the NPF undergoes structural transitions from a stretched to a compact state, and we measured the corresponding mechanochemical signatures. Using an active two-state model, we proposed a free-energy landscape for the NPF transition. Using this quantitative model, we explained both how the sensitivity of the NPF to the homology length is regulated by its structural transition and how the cooperativity of Rad51 favors selectivity to relatively long homologous sequences.
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Affiliation(s)
- Scott X Atwell
- Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, Sorbonne Universités, UPMC Univ Paris 06, Unité Mixte de Recherche 168, 75005 Paris, France
| | - Daniel Migliozzi
- Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, Sorbonne Universités, UPMC Univ Paris 06, Unité Mixte de Recherche 168, 75005 Paris, France.,Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - Aurélie Dupont
- Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, Sorbonne Universités, UPMC Univ Paris 06, Unité Mixte de Recherche 168, 75005 Paris, France.,Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, CNRS, F-38000 Grenoble, France
| | - Jean-Louis Viovy
- Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, Sorbonne Universités, UPMC Univ Paris 06, Unité Mixte de Recherche 168, Institut Pierre Gilles de Gennes, MMBM Group, 75005 Paris, France
| | - Giovanni Cappello
- Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, Sorbonne Universités, UPMC Univ Paris 06, Unité Mixte de Recherche 168, 75005 Paris, France.,Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, CNRS, F-38000 Grenoble, France
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7
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Yang YJ, Song L, Zhao XC, Zhang C, Wu WQ, You HJ, Fu H, Zhou EC, Zhang XH. A Universal Assay for Making DNA, RNA, and RNA-DNA Hybrid Configurations for Single-Molecule Manipulation in Two or Three Steps without Ligation. ACS Synth Biol 2019; 8:1663-1672. [PMID: 31264849 DOI: 10.1021/acssynbio.9b00241] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite having a great variety of topologies, most DNA, RNA, and RNA-DNA hybrid (RDH) configurations for single-molecule manipulation are composed of several single-stranded (ss) DNA and ssRNA strands, with functional labels at the two ends for surface tethering. On this basis, we developed a simple, robust, and universal amplification-annealing (AA) assay for making all these configurations in two or three steps without inefficient digestion and ligation reactions. As examples, we made ssDNA, short ssDNA with double-stranded (ds) DNA handles, dsDNA with ssDNA handles, replication-fork shaped DNA/RDH/RNA, DNA holiday junction, three-site multiple-labeled and nicked DNA, torsion-constrained RNA/RDH, and short ssRNA with RDH handles. In addition to single-molecule manipulation techniques including optical tweezers, magnetic tweezers, and atomic force microscopy, these configurations can be applied in other surface-tethering techniques as well.
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Affiliation(s)
- Ya-Jun Yang
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Lun Song
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Xiao-Cong Zhao
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Chen Zhang
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Wen-Qiang Wu
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Hui-Juan You
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hang Fu
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Er-Chi Zhou
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Xing-Hua Zhang
- College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
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8
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Kriegel F, Vanderlinden W, Nicolaus T, Kardinal A, Lipfert J. Measuring Single-Molecule Twist and Torque in Multiplexed Magnetic Tweezers. Methods Mol Biol 2018; 1814:75-98. [PMID: 29956228 DOI: 10.1007/978-1-4939-8591-3_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Magnetic tweezers permit application of precisely calibrated stretching forces to nucleic acid molecules tethered between a surface and superparamagnetic beads. In addition, magnetic tweezers can control the tethers' twist. Here, we focus on recent extensions of the technique that expand the capabilities of conventional magnetic tweezers by enabling direct measurements of single-molecule torque and twist. Magnetic torque tweezers (MTT) still control the DNA or RNA tether's twist, but directly measure molecular torque by monitoring changes in the equilibrium rotation angle upon overwinding and underwinding of the tether. In freely orbiting magnetic tweezers (FOMT), one end of the tether is allowed to rotate freely, while still applying stretching forces and monitoring rotation angle. Both MTT and FOMT have provided unique insights into the mechanical properties, structural transitions, and interactions of DNA and RNA. Here, we provide step-by-step protocols to carry out FOMT and MTT measurements. In particular, we focus on multiplexed measurements, i.e., measurements that record data for multiple nucleic acid tethers at the same time, to improve statistics and to facilitate the observation of rare events.
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Affiliation(s)
- Franziska Kriegel
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
| | - Willem Vanderlinden
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany.,Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven-University of Leuven, Leuven, Belgium
| | - Thomas Nicolaus
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
| | - Angelika Kardinal
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, LMU Munich, Munich, Germany.
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9
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Miné-Hattab J, Recamier V, Izeddin I, Rothstein R, Darzacq X. Multi-scale tracking reveals scale-dependent chromatin dynamics after DNA damage. Mol Biol Cell 2017; 28:mbc.E17-05-0317. [PMID: 28794266 PMCID: PMC5687033 DOI: 10.1091/mbc.e17-05-0317] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/21/2017] [Accepted: 08/02/2017] [Indexed: 12/19/2022] Open
Abstract
The dynamic organization of genes inside the nucleus is an important determinant for their function. Using fast DNA tracking microscopy in S. cerevisiae cells and improved analysis of mean square displacements, we quantified DNA motion at time scales ranging from 10 milliseconds to minute and found that following DNA damage, DNA exhibits distinct sub-diffusive regimes. In response to double-strand breaks, chromatin is more mobile at large time scales but, surprisingly, its mobility is reduced at short time scales. This effect is even more pronounced at the site of damage. Such a pattern of dynamics is consistent with a global increase in chromatin persistence length in response to DNA damage. Scale-dependent nuclear exploration is regulated by the Rad51 repair protein, both at the break and throughout the genome. We propose a model in which stiffening of the damaged ends by the repair complex, combined with global increased stiffness, act like a "needle in a ball of yarn", enhancing the ability of the break to traverse the chromatin meshwork.
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Affiliation(s)
- Judith Miné-Hattab
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Paris 75005, France
- Department of Genetics & Development, Columbia University Medical Center, New York, NY 10032, USA
- Nuclear Dynamics, CNRS UMR 3664, Institut Curie, Paris 75005, France
| | - Vincent Recamier
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Paris 75005, France
| | - Ignacio Izeddin
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Paris 75005, France
- Institut Langevin, CNRS, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Rodney Rothstein
- Department of Genetics & Development, Columbia University Medical Center, New York, NY 10032, USA
| | - Xavier Darzacq
- Division of Genetics, Genomics & Development, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Paris 75005, France
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10
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Vlijm R, Kim SH, De Zwart PL, Dalal Y, Dekker C. The supercoiling state of DNA determines the handedness of both H3 and CENP-A nucleosomes. NANOSCALE 2017; 9:1862-1870. [PMID: 28094382 PMCID: PMC7959483 DOI: 10.1039/c6nr06245h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nucleosomes form the unit structure of the genome in eukaryotes, thereby constituting a fundamental tenet of chromatin biology. In canonical nucleosomes, DNA wraps around the histone octamer in a left-handed toroidal ramp. Here, in single-molecule magnetic tweezers studies of chaperone-assisted nucleosome assembly, we show that the handedness of the DNA wrapping around the nucleosome core is intrinsically ambidextrous, and depends on the pre-assembly supercoiling state of the DNA, i.e., it is not uniquely determined by the octameric histone core. Nucleosomes assembled onto negatively supercoiled DNA are found to exhibit a left-handed conformation, whereas assembly onto positively supercoiled DNA results in right-handed nucleosomes. This intrinsic flexibility to adopt both chiralities is observed both for canonical H3 nucleosomes, and for centromere-specific variant CENP-A nucleosomes. These data support recent advances suggesting an intrinsic adaptability of the nucleosome, and provide insights into how nucleosomes might rapidly re-assemble after cellular processes that generate positive supercoiling in vivo.
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Affiliation(s)
- R Vlijm
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, 2628CJ, The Netherlands
| | - S H Kim
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, 2628CJ, The Netherlands
| | - P L De Zwart
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, 2628CJ, The Netherlands
| | - Y Dalal
- Chromatin Structure and Epigenetic Mechanisms Unit, Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
| | - C Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, 2628CJ, The Netherlands
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11
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Finzi L, Dunlap D. Supercoiling biases the formation of loops involved in gene regulation. Biophys Rev 2016; 8:65-74. [PMID: 28510212 DOI: 10.1007/s12551-016-0211-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/17/2016] [Indexed: 11/25/2022] Open
Abstract
The function of DNA as a repository of genetic information is well-known. The post-genomic effort is to understand how this information-containing filament is chaperoned to manage its compaction and topological states. Indeed, the activities of enzymes that transcribe, replicate, or repair DNA are regulated to a large degree by access. Proteins that act at a distance along the filament by binding at one site and contacting another site, perhaps as part of a bigger complex, create loops that constitute topological domains and influence regulation. DNA loops and plectonemes are not necessarily spontaneous, especially large loops under tension for which high energy is required to bring their ends together, or small loops that require accessory proteins to facilitate DNA bending. However, the torsion in stiff filaments such as DNA dramatically modulates the topology, driving it from extended and genetically accessible to more looped and compact, genetically secured forms. Furthermore, there are accessory factors that bias the response of the DNA filament to supercoiling. For example, small molecules like polyamines, which neutralize the negative charge repulsions along the phosphate backbone, enhance flexibility and promote writhe over twist in response to torsion. Such increased flexibility likely pushes the topological equilibrium from twist toward writhe at tensions thought to exist in vivo. A predictable corollary is that stiffening DNA antagonizes looping and bending. Certain sequences are known to be more or less flexible or to exhibit curvature, and this may affect interactions with binding proteins. In vivo all of these factors operate simultaneously on DNA that is generally negatively supercoiled to some degree. Therefore, in order to better understand gene regulation that involves protein-mediated DNA loops, it is critical to understand the thermodynamics and kinetics of looping in DNA that is under tension, negatively supercoiled, and perhaps exposed to molecules that alter elasticity. Recent experiments quantitatively reveal how much negatively supercoiling DNA lowers the free energy of looping, possibly biasing the operation of genetic switches.
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Affiliation(s)
- Laura Finzi
- Department of Physics, Emory University, 400 Dowman Dr. N.E., Atlanta, GA, 30322, USA
| | - David Dunlap
- Department of Physics, Emory University, 400 Dowman Dr. N.E., Atlanta, GA, 30322, USA.
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12
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Probing the mechanical properties, conformational changes, and interactions of nucleic acids with magnetic tweezers. J Struct Biol 2016; 197:26-36. [PMID: 27368129 DOI: 10.1016/j.jsb.2016.06.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/06/2016] [Accepted: 06/28/2016] [Indexed: 11/21/2022]
Abstract
Nucleic acids are central to the storage and transmission of genetic information. Mechanical properties, along with their sequence, both enable and fundamentally constrain the biological functions of DNA and RNA. For small deformations from the equilibrium conformations, nucleic acids are well described by an isotropic elastic rod model. However, external forces and torsional strains can induce conformational changes, giving rise to a complex force-torque phase diagram. This review focuses on magnetic tweezers as a powerful tool to precisely determine both the elastic parameters and conformational transitions of nucleic acids under external forces and torques at the single-molecule level. We review several variations of magnetic tweezers, in particular conventional magnetic tweezers, freely orbiting magnetic tweezers and magnetic torque tweezers, and discuss their characteristic capabilities. We then describe the elastic rod model for DNA and RNA and discuss conformational changes induced by mechanical stress. The focus lies on the responses to torque and twist, which are crucial in the mechanics and interactions of nucleic acids and can directly be measured using magnetic tweezers. We conclude by highlighting several recent studies of nucleic acid-protein and nucleic acid-small-molecule interactions as further applications of magnetic tweezers and give an outlook of some exciting developments to come.
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13
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Pobegalov G, Cherevatenko G, Alekseev A, Sabantsev A, Kovaleva O, Vedyaykin A, Morozova N, Baitin D, Khodorkovskii M. Deinococcus radiodurans RecA nucleoprotein filaments characterized at the single-molecule level with optical tweezers. Biochem Biophys Res Commun 2015; 466:426-30. [DOI: 10.1016/j.bbrc.2015.09.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/08/2015] [Indexed: 01/08/2023]
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Lipfert J, van Oene MM, Lee M, Pedaci F, Dekker NH. Torque spectroscopy for the study of rotary motion in biological systems. Chem Rev 2014; 115:1449-74. [PMID: 25541648 DOI: 10.1021/cr500119k] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for NanoScience (CeNS), Ludwig-Maximilian-University Munich , Amalienstrasse 54, 80799 Munich, Germany
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Argudo D, Purohit PK. Equilibrium and kinetics of DNA overstretching modeled with a quartic energy landscape. Biophys J 2014; 107:2151-63. [PMID: 25418100 DOI: 10.1016/j.bpj.2014.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/22/2014] [Accepted: 09/16/2014] [Indexed: 11/18/2022] Open
Abstract
It is well known that the dsDNA molecule undergoes a phase transition from B-DNA into an overstretched state at high forces. For some time, the structure of the overstretched state remained unknown and highly debated, but recent advances in experimental techniques have presented evidence of more than one possible phase (or even a mixed phase) depending on ionic conditions, temperature, and basepair sequence. Here, we present a theoretical model to study the overstretching transition with the possibility that the overstretched state is a mixture of two phases: a structure with portions of inner strand separation (melted or M-DNA), and an extended phase that retains the basepair structure (S-DNA). We model the double-stranded DNA as a chain composed of n segments of length l, where the transition is studied by means of a Landau quartic potential with statistical fluctuations. The length l is a measure of cooperativity of the transition and is key to characterizing the overstretched phase. By analyzing the different values of l corresponding to a wide spectrum of experiments, we find that for a range of temperatures and ionic conditions, the overstretched form is likely to be a mix of M-DNA and S-DNA. For a transition close to a pure S-DNA state, where the change in extension is close to 1.7 times the original B-DNA length, we find l ? 25 basepairs regardless of temperature and ionic concentration. Our model is fully analytical, yet it accurately reproduces the force-extension curves, as well as the transient kinetic behavior, seen in DNA overstretching experiments.
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Affiliation(s)
- David Argudo
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Prashant K Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania.
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16
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He WL, Li YH, Hou WJ, Ke ZF, Chen XL, Lu LY, Cai SR, Song W, Zhang CH, He YL. RAD51 potentiates synergistic effects of chemotherapy with PCI-24781 and cis-diamminedichloroplatinum on gastric cancer. World J Gastroenterol 2014; 20:10094-10107. [PMID: 25110436 PMCID: PMC4123338 DOI: 10.3748/wjg.v20.i29.10094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 01/20/2014] [Accepted: 03/06/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the efficacy of PCI-24781, a broad-spectrum, hydroxamic acid-derived histone deacetylase inhibitor, in the treatment of gastric cancer (GC).
METHODS: With or without treatment of PCI-24781 and/or cis-diamminedichloroplatinum (CDDP), GC cell lines were subjected to functional analysis, including cell growth, apoptosis and clonogenic assays. Chromatin immunoprecipitation and luciferase reporter assays were used to determine the interacting molecules and the activity of the enzyme. An in vivo study was carried out in GC xenograft mice. Cell culture-based assays were represented as mean ± SD. ANOVA tests were used to assess differences across groups. All pairwise comparisons between tumor weights among treatment groups were made using the Tukey-Kramer method for multiple comparison adjustment to control experimental-wise type I error rates. Significance was set at P < 0.05.
RESULTS: PCI-24781 significantly reduced the growth of the GC cells, enhanced cell apoptosis and suppressed clonogenicity, and these effects synergized with the effects of CDDP. PCI-24781 modulated the cell cycle and significantly reduced the expression of RAD51, which is related to homologous recombination. Depletion of RAD51 augmented the biological functions of PCI-24781, CDDP and the combination treatment, whereas overexpressing RAD51 had the opposite effects. Increased binding of the transcription suppressor E2F4 on the RAD51 promoter appeared to play a major role in these processes. Furthermore, significant suppression of tumor growth and weight in vivo was obtained following PCI-24781 treatment, which synergized with the anticancer effect of CDDP.
CONCLUSION: These data suggest that RAD51 potentiates the synergistic effects of chemotherapy with PCI-24781 and CDDP on GC.
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Daumke O, Roux A, Haucke V. BAR domain scaffolds in dynamin-mediated membrane fission. Cell 2014; 156:882-92. [PMID: 24581490 DOI: 10.1016/j.cell.2014.02.017] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Indexed: 10/25/2022]
Abstract
Biological membranes undergo constant remodeling by membrane fission and fusion to change their shape and to exchange material between subcellular compartments. During clathrin-mediated endocytosis, the dynamic assembly and disassembly of protein scaffolds comprising members of the bin-amphiphysin-rvs (BAR) domain protein superfamily constrain the membrane into distinct shapes as the pathway progresses toward fission by the GTPase dynamin. In this Review, we discuss how BAR domain protein assembly and disassembly are controlled in space and time and which structural and biochemical features allow the tight regulation of their shape and function to enable dynamin-mediated membrane fission.
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Affiliation(s)
- Oliver Daumke
- Max-Delbrück Centrum für Molekulare Medizin, Robert-Rössle-Strasse 10, 13125 Berlin, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany.
| | - Aurélien Roux
- University of Geneva, Department of Biochemistry, 30 quai Ernest Ansermet, 1211 Geneva 4, Switzerland, and Swiss National Centre for Competence in Research Programme Chemical Biology, 1211 Geneva, Switzerland.
| | - Volker Haucke
- Leibniz Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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Sanchez H, Reuter M, Yokokawa M, Takeyasu K, Wyman C. Taking it one step at a time in homologous recombination repair. DNA Repair (Amst) 2014; 20:110-118. [PMID: 24636751 DOI: 10.1016/j.dnarep.2014.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 01/10/2023]
Abstract
The individual steps in the process of homologous recombination are particularly amenable to analysis by single-molecule imaging and manipulation experiments. Over the past 20 years these have provided a wealth of new information on the DNA transactions that make up this vital process. Exciting progress in developing new tools and techniques to analyze more complex components, dynamic reaction steps and molecular coordination continues at a rapid pace. Here we highlight recent results and indicate some emerging techniques likely to produce the next stage of advanced insight into homologous recombination. In this and related fields the future is bright.
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Affiliation(s)
- Humberto Sanchez
- Department of Genetics, Cancer Genomics Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marcel Reuter
- Department of Genetics, Cancer Genomics Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Masatoshi Yokokawa
- Graduate School of Pure and Applied Science, University of Tsukuba, Japan
| | | | - Claire Wyman
- Department of Genetics, Cancer Genomics Center, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Radiation Oncology, Erasmus University Medical Center, Rotterdam, The Netherlands.
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Gold rotor bead tracking for high-speed measurements of DNA twist, torque and extension. Nat Methods 2014; 11:456-62. [PMID: 24562422 PMCID: PMC4211898 DOI: 10.1038/nmeth.2854] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 01/06/2014] [Indexed: 11/08/2022]
Abstract
Simultaneous measurements of DNA twist and extension have been used to measure physical properties of the double helix and to characterize structural dynamics and mechanochemistry in nucleoprotein complexes. However, the spatiotemporal resolution of twist measurements has been limited by the use of angular probes with large rotational drags, preventing the detection of short-lived intermediates or small angular steps. Here we introduce AuRBT, demonstrating a >100X improvement in time resolution over previous techniques. AuRBT employs gold nanoparticles as bright low-drag rotational and extensional probes, relying on instrumentation that combines magnetic tweezers with objective-side evanescent darkfield microscopy. In an initial application to molecular motor mechanism, we have examined the high-speed structural dynamics of DNA gyrase, revealing an unanticipated transient intermediate. AuRBT also enables direct measurements of DNA torque with >50X shorter integration times than previous techniques; here we demonstrate high-resolution torque spectroscopy by mapping the conformational landscape of a Z-forming DNA sequence.
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Alonso-Sarduy L, Longo G, Dietler G, Kasas S. Time-lapse AFM imaging of DNA conformational changes induced by daunorubicin. NANO LETTERS 2013; 13:5679-5684. [PMID: 24125039 DOI: 10.1021/nl403361f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cancer is a major health issue that absorbs the attention of a large part of the biomedical research. Intercalating agents bind to DNA molecules and can inhibit their synthesis and transcription; thus, they are increasingly used as drugs to fight cancer. In this work, we show how atomic force microscopy in liquid can characterize, through time-lapse imaging, the dynamical influence of intercalating agents on the supercoiling of DNA, improving our understanding of the drug's effect.
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Affiliation(s)
- Livan Alonso-Sarduy
- Laboratoire de Physique de la Matière Vivante, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
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