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Ukraintsev AA, Kutuzov MM, Lavrik OI. Studying Structure and Functions of Nucleosomes with Atomic Force Microscopy. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:674-687. [PMID: 38831504 DOI: 10.1134/s0006297924040072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 06/05/2024]
Abstract
Chromatin is an epigenetic platform for implementation of DNA-dependent processes. Nucleosome, as a basic level of chromatin compaction, largely determines its properties and structure. In the study of nucleosomes structure and functions physicochemical tools are actively used, such as magnetic and optical "tweezers", "DNA curtains", nuclear magnetic resonance, X-ray crystallography, and cryogenic electron microscopy, as well as optical methods based on Förster resonance energy transfer. Despite the fact that these approaches make it possible to determine a wide range of structural and functional characteristics of chromatin and nucleosomes with high spatial and time resolution, atomic force microscopy (AFM) complements the capabilities of these methods. The results of structural studies of nucleosome focusing on the AFM method development are presented in this review. The possibilities of AFM are considered in the context of application of other physicochemical approaches.
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Affiliation(s)
- Alexander A Ukraintsev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Mikhail M Kutuzov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
- Novosibirsk State University, Novosibirsk, 630090, Russia
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2
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Irvin EM, Wang H. Single-molecule imaging of genome maintenance proteins encountering specific DNA sequences and structures. DNA Repair (Amst) 2023; 128:103528. [PMID: 37392578 PMCID: PMC10989508 DOI: 10.1016/j.dnarep.2023.103528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 06/08/2023] [Accepted: 06/21/2023] [Indexed: 07/03/2023]
Abstract
DNA repair pathways are tightly regulated processes that recognize specific hallmarks of DNA damage and coordinate lesion repair through discrete mechanisms, all within the context of a three-dimensional chromatin landscape. Dysregulation or malfunction of any one of the protein constituents in these pathways can contribute to aging and a variety of diseases. While the collective action of these many proteins is what drives DNA repair on the organismal scale, it is the interactions between individual proteins and DNA that facilitate each step of these pathways. In much the same way that ensemble biochemical techniques have characterized the various steps of DNA repair pathways, single-molecule imaging (SMI) approaches zoom in further, characterizing the individual protein-DNA interactions that compose each pathway step. SMI techniques offer the high resolving power needed to characterize the molecular structure and functional dynamics of individual biological interactions on the nanoscale. In this review, we highlight how our lab has used SMI techniques - traditional atomic force microscopy (AFM) imaging in air, high-speed AFM (HS-AFM) in liquids, and the DNA tightrope assay - over the past decade to study protein-nucleic acid interactions involved in DNA repair, mitochondrial DNA replication, and telomere maintenance. We discuss how DNA substrates containing specific DNA sequences or structures that emulate DNA repair intermediates or telomeres were generated and validated. For each highlighted project, we discuss novel findings made possible by the spatial and temporal resolution offered by these SMI techniques and unique DNA substrates.
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Affiliation(s)
| | - Hong Wang
- Toxicology Program, North Carolina State University, Raleigh, NC, USA; Physics Department, North Carolina State University, Raleigh, NC, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.
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3
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Dynamic human MutSα-MutLα complexes compact mismatched DNA. Proc Natl Acad Sci U S A 2020; 117:16302-16312. [PMID: 32586954 DOI: 10.1073/pnas.1918519117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
DNA mismatch repair (MMR) corrects errors that occur during DNA replication. In humans, mutations in the proteins MutSα and MutLα that initiate MMR cause Lynch syndrome, the most common hereditary cancer. MutSα surveilles the DNA, and upon recognition of a replication error it undergoes adenosine triphosphate-dependent conformational changes and recruits MutLα. Subsequently, proliferating cell nuclear antigen (PCNA) activates MutLα to nick the error-containing strand to allow excision and resynthesis. The structure-function properties of these obligate MutSα-MutLα complexes remain mostly unexplored in higher eukaryotes, and models are predominately based on studies of prokaryotic proteins. Here, we utilize atomic force microscopy (AFM) coupled with other methods to reveal time- and concentration-dependent stoichiometries and conformations of assembling human MutSα-MutLα-DNA complexes. We find that they assemble into multimeric complexes comprising three to eight proteins around a mismatch on DNA. On the timescale of a few minutes, these complexes rearrange, folding and compacting the DNA. These observations contrast with dominant models of MMR initiation that envision diffusive MutS-MutL complexes that move away from the mismatch. Our results suggest MutSα localizes MutLα near the mismatch and promotes DNA configurations that could enhance MMR efficiency by facilitating MutLα nicking the DNA at multiple sites around the mismatch. In addition, such complexes may also protect the mismatch region from nucleosome reassembly until repair occurs, and they could potentially remodel adjacent nucleosomes.
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4
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Cheong LZ, Zhao W, Song S, Shen C. Lab on a tip: Applications of functional atomic force microscopy for the study of electrical properties in biology. Acta Biomater 2019; 99:33-52. [PMID: 31425893 DOI: 10.1016/j.actbio.2019.08.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/17/2019] [Accepted: 08/13/2019] [Indexed: 12/11/2022]
Abstract
Electrical properties, such as charge propagation, dielectrics, surface potentials, conductivity, and piezoelectricity, play crucial roles in biomolecules, biomembranes, cells, tissues, and other biological samples. However, characterizing these electrical properties in delicate biosamples is challenging. Atomic Force Microscopy (AFM), the so called "Lab on a Tip" is a powerful and multifunctional approach to quantitatively study the electrical properties of biological samples at the nanometer level. Herein, the principles, theories, and achievements of various modes of AFM in this area have been reviewed and summarized. STATEMENT OF SIGNIFICANCE: Electrical properties such as dielectric and piezoelectric forces, charge propagation behaviors play important structural and functional roles in biosystems from the single molecule level, to cells and tissues. Atomic force microscopy (AFM) has emerged as an ideal toolkit to study electrical property of biology. Herein, the basic principles of AFM are described. We then discuss the multiple modes of AFM to study the electrical properties of biological samples, including Electrostatic Force Microscopy (EFM), Kelvin Probe Force Microscopy (KPFM), Conductive Atomic Force Microscopy (CAFM), Piezoresponse Force Microscopy (PFM) and Scanning ElectroChemical Microscopy (SECM). Finally, the outlook, prospects, and challenges of the various AFM modes when studying the electrical behaviour of the samples are discussed.
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5
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Kaur P, Longley MJ, Pan H, Wang H, Copeland WC. Single-molecule DREEM imaging reveals DNA wrapping around human mitochondrial single-stranded DNA binding protein. Nucleic Acids Res 2019; 46:11287-11302. [PMID: 30256971 PMCID: PMC6265486 DOI: 10.1093/nar/gky875] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/18/2018] [Indexed: 01/01/2023] Open
Abstract
Improper maintenance of the mitochondrial genome progressively disrupts cellular respiration and causes severe metabolic disorders commonly termed mitochondrial diseases. Mitochondrial single-stranded DNA binding protein (mtSSB) is an essential component of the mtDNA replication machinery. We utilized single-molecule methods to examine the modes by which human mtSSB binds DNA to help define protein interactions at the mtDNA replication fork. Direct visualization of individual mtSSB molecules by atomic force microscopy (AFM) revealed a random distribution of mtSSB tetramers bound to extended regions of single-stranded DNA (ssDNA), strongly suggesting non-cooperative binding by mtSSB. Selective binding to ssDNA was confirmed by AFM imaging of individual mtSSB tetramers bound to gapped plasmid DNA substrates bearing defined single-stranded regions. Shortening of the contour length of gapped DNA upon binding mtSSB was attributed to DNA wrapping around mtSSB. Tracing the DNA path in mtSSB–ssDNA complexes with Dual-Resonance-frequency-Enhanced Electrostatic force Microscopy established a predominant binding mode with one DNA strand winding once around each mtSSB tetramer at physiological salt conditions. Single-molecule imaging suggests mtSSB may not saturate or fully protect single-stranded replication intermediates during mtDNA synthesis, leaving the mitochondrial genome vulnerable to chemical mutagenesis, deletions driven by primer relocation or other actions consistent with clinically observed deletion biases.
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Affiliation(s)
- Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Matthew J Longley
- Genome Integrity and Structural Biology Laboratory, NIEHS, NIH, Research Triangle Park, NC 27709, USA
| | - Hai Pan
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, NIEHS, NIH, Research Triangle Park, NC 27709, USA
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6
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Bower EKM, Cooper LP, Roberts GA, White JH, Luyten Y, Morgan RD, Dryden DTF. A model for the evolution of prokaryotic DNA restriction-modification systems based upon the structural malleability of Type I restriction-modification enzymes. Nucleic Acids Res 2019; 46:9067-9080. [PMID: 30165537 PMCID: PMC6158711 DOI: 10.1093/nar/gky760] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 08/21/2018] [Indexed: 12/28/2022] Open
Abstract
Restriction Modification (RM) systems prevent the invasion of foreign genetic material into bacterial cells by restriction and protect the host's genetic material by methylation. They are therefore important in maintaining the integrity of the host genome. RM systems are currently classified into four types (I to IV) on the basis of differences in composition, target recognition, cofactors and the manner in which they cleave DNA. Comparing the structures of the different types, similarities can be observed suggesting an evolutionary link between these different types. This work describes the ‘deconstruction’ of a large Type I RM enzyme into forms structurally similar to smaller Type II RM enzymes in an effort to elucidate the pathway taken by Nature to form these different RM enzymes. Based upon the ability to engineer new enzymes from the Type I ‘scaffold’, an evolutionary pathway and the evolutionary pressures required to move along the pathway from Type I RM systems to Type II RM systems are proposed. Experiments to test the evolutionary model are discussed.
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Affiliation(s)
- Edward K M Bower
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh EH9 3FJ, UK
| | - Laurie P Cooper
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh EH9 3FJ, UK
| | - Gareth A Roberts
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh EH9 3FJ, UK
| | - John H White
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh EH9 3FJ, UK
| | - Yvette Luyten
- New England Biolabs, 240 County Road, Ipswich, MA 01938-2723, USA
| | - Richard D Morgan
- New England Biolabs, 240 County Road, Ipswich, MA 01938-2723, USA
| | - David T F Dryden
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
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7
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Pisano S, Gilson E. Analysis of DNA-Protein Complexes by Atomic Force Microscopy Imaging: The Case of TRF2-Telomeric DNA Wrapping. Methods Mol Biol 2019; 1886:75-97. [PMID: 30374863 DOI: 10.1007/978-1-4939-8894-5_5] [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: 06/08/2023]
Abstract
Atomic force microscopy (AFM) is a non-optical microscopy that enables the acquisition at the nanoscale level of a 3D topographical image of the sample. For 30 years, AFM has been a valuable tool in life sciences to study biological samples in the field of tissue, cellular and molecular imaging, of mechanical properties and of force spectroscopy. Since the early beginnings of the technique, AFM has been extensively exploited as an imaging tool for structural studies of nucleic acids and nucleoprotein complexes. The morphometric analysis performed on the images can unveil specific structural and functional aspects of the sample, such as the multimerization state of proteins bound to DNA, or DNA conformational changes led by the DNA-binding proteins. Herein, a method for analyzing a complex formed by a telomeric DNA sequence wrapped around the TRF2 binding protein is presented. The described procedure could be applied to the study of any type of DNA-protein complex.
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Affiliation(s)
- Sabrina Pisano
- Université Côte d'Azur, CNRS UMR 7284/INSERM U108, Institute for Research on Cancer and Aging, Nice (IRCAN), Medical School, Nice, France.
| | - Eric Gilson
- Université Côte d'Azur, CNRS UMR 7284/INSERM U108, Institute for Research on Cancer and Aging, Nice (IRCAN), Medical School, Nice, France
- International Laboratory in Hematology and Cancer, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Shanghai Ruijin Hospital, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Shanghai, China
- Department of Genetics, CHU Nice, Université Côte d'Azur, Nice, France
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8
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Dutta S, Rivetti C, Gassman NR, Young CG, Jones BT, Scarpinato K, Guthold M. Analysis of single, cisplatin-induced DNA bends by atomic force microscopy and simulations. J Mol Recognit 2018; 31:e2731. [PMID: 29862590 DOI: 10.1002/jmr.2731] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 12/20/2022]
Abstract
Bent DNA, or DNA that is locally more flexible, is a recognition motif for many DNA binding proteins. These DNA conformational properties can thus influence many cellular processes, such as replication, transcription, and DNA repair. The importance of these DNA conformational properties is juxtaposed to the experimental difficulty to accurately determine small bends, locally more flexible DNA, or a combination of both (bends with increased flexibility). In essence, many current bulk methods use average quantities, such as the average end-to-end distance, to extract DNA conformational properties; they cannot access the additional information that is contained in the end-to-end distance distributions. We developed a method that exploits this additional information to determine DNA conformational parameters. The method is based on matching end-to-end distance distributions obtained experimentally by atomic force microscopy imaging to distributions obtained from simulations. We applied this method to investigate cisplatin GG biadducts. We found that cisplatin induces a bend angle of 36° and softens the DNA locally around the bend.
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Affiliation(s)
- Samrat Dutta
- Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | - Claudio Rivetti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Natalie R Gassman
- USA Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - Carl G Young
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA
| | - Bradley T Jones
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA
| | - Karin Scarpinato
- Division of Research, Florida Atlantic University, Boca Raton, FL, USA
| | - Martin Guthold
- Department of Physics, Wake Forest University, Winston-Salem, NC, USA
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9
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Mohan Bangalore D, Tessmer I. Unique insight into protein-DNA interactions from single molecule atomic force microscopy. AIMS BIOPHYSICS 2018. [DOI: 10.3934/biophy.2018.3.194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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10
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Beckwitt EC, Kong M, Van Houten B. Studying protein-DNA interactions using atomic force microscopy. Semin Cell Dev Biol 2017; 73:220-230. [PMID: 28673677 DOI: 10.1016/j.semcdb.2017.06.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Abstract
Atomic force microscopy (AFM) has made significant contributions to the study of protein-DNA interactions by making it possible to topographically image biological samples. A single protein-DNA binding reaction imaged by AFM can reveal protein binding specificity and affinity, protein-induced DNA bending, and protein binding stoichiometry. Changes in DNA structure, complex conformation, and cooperativity, can also be analyzed. In this review we highlight some important examples in the literature and discuss the advantages and limitations of these measurements. We also discuss important advances in technology that will facilitate the progress of AFM in the future.
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Affiliation(s)
- Emily C Beckwitt
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA; The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Muwen Kong
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA; The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Bennett Van Houten
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA; The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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11
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LeBlanc S, Wilkins H, Li Z, Kaur P, Wang H, Erie DA. Using Atomic Force Microscopy to Characterize the Conformational Properties of Proteins and Protein-DNA Complexes That Carry Out DNA Repair. Methods Enzymol 2017; 592:187-212. [PMID: 28668121 PMCID: PMC5761736 DOI: 10.1016/bs.mie.2017.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Atomic force microscopy (AFM) is a scanning probe technique that allows visualization of single biomolecules and complexes deposited on a surface with nanometer resolution. AFM is a powerful tool for characterizing protein-protein and protein-DNA interactions. It can be used to capture snapshots of protein-DNA solution dynamics, which in turn, enables the characterization of the conformational properties of transient protein-protein and protein-DNA interactions. With AFM, it is possible to determine the stoichiometries and binding affinities of protein-protein and protein-DNA associations, the specificity of proteins binding to specific sites on DNA, and the conformations of the complexes. We describe methods to prepare and deposit samples, including surface treatments for optimal depositions, and how to quantitatively analyze images. We also discuss a new electrostatic force imaging technique called DREEM, which allows the visualization of the path of DNA within proteins in protein-DNA complexes. Collectively, these methods facilitate the development of comprehensive models of DNA repair and provide a broader understanding of all protein-protein and protein-nucleic acid interactions. The structural details gleaned from analysis of AFM images coupled with biochemistry provide vital information toward establishing the structure-function relationships that govern DNA repair processes.
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Affiliation(s)
- Sharonda LeBlanc
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Hunter Wilkins
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zimeng Li
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Parminder Kaur
- North Carolina State University, Raleigh, NC, United States
| | - Hong Wang
- North Carolina State University, Raleigh, NC, United States
| | - Dorothy A Erie
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
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12
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Abstract
Ubiquitous conserved processes that repair DNA damage are essential for the maintenance and propagation of genomes over generations. Then again, inaccuracies in DNA transactions and failures to remove mutagenic lesions cause heritable genome changes. Building on decades of research using genetics and biochemistry, unprecedented quantitative insight into DNA repair mechanisms has come from the new-found ability to measure single proteins in vitro and inside individual living cells. This has brought together biologists, chemists, engineers, physicists, and mathematicians to solve long-standing questions about the way in which repair enzymes search for DNA lesions and form protein complexes that act in DNA repair pathways. Furthermore, unexpected discoveries have resulted from capabilities to resolve molecular heterogeneity and cell subpopulations, provoking new questions about the role of stochastic processes in DNA repair and mutagenesis. These studies are leading to new technologies that will find widespread use in basic research, biotechnology, and medicine.
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Affiliation(s)
- Stephan Uphoff
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom; ,
| | - David J Sherratt
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom; ,
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13
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Adkins NL, Swygert SG, Kaur P, Niu H, Grigoryev SA, Sung P, Wang H, Peterson CL. Nucleosome-like, Single-stranded DNA (ssDNA)-Histone Octamer Complexes and the Implication for DNA Double Strand Break Repair. J Biol Chem 2017; 292:5271-5281. [PMID: 28202543 DOI: 10.1074/jbc.m117.776369] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/13/2017] [Indexed: 11/06/2022] Open
Abstract
Repair of DNA double strand breaks (DSBs) is key for maintenance of genome integrity. When DSBs are repaired by homologous recombination, DNA ends can undergo extensive processing, producing long stretches of single-stranded DNA (ssDNA). In vivo, DSB processing occurs in the context of chromatin, and studies indicate that histones may remain associated with processed DSBs. Here we demonstrate that histones are not evicted from ssDNA after in vitro chromatin resection. In addition, we reconstitute histone-ssDNA complexes (termed ssNucs) with ssDNA and recombinant histones and analyze these particles by a combination of native gel electrophoresis, sedimentation velocity, electron microscopy, and a recently developed electrostatic force microscopy technique, DREEM (dual-resonance frequency-enhanced electrostatic force microscopy). The reconstituted ssNucs are homogenous and relatively stable, and DREEM reveals ssDNA wrapping around histones. We also find that histone octamers are easily transferred in trans from ssNucs to either double-stranded DNA or ssDNA. Furthermore, the Fun30 remodeling enzyme, which has been implicated in DNA repair, binds ssNucs preferentially over nucleosomes, and ssNucs are effective at activating Fun30 ATPase activity. Our results indicate that ssNucs may be a hallmark of processes that generate ssDNA, and that posttranslational modification of ssNucs may generate novel signaling platforms involved in genome stability.
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Affiliation(s)
- Nicholas L Adkins
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Sarah G Swygert
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Parminder Kaur
- the Department of Physics.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695
| | - Hengyao Niu
- the Department Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, and
| | - Sergei A Grigoryev
- the Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Patrick Sung
- the Department Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, and
| | - Hong Wang
- the Department of Physics.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695
| | - Craig L Peterson
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605,
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14
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Skibbens RV. Of Rings and Rods: Regulating Cohesin Entrapment of DNA to Generate Intra- and Intermolecular Tethers. PLoS Genet 2016; 12:e1006337. [PMID: 27788133 PMCID: PMC5082857 DOI: 10.1371/journal.pgen.1006337] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The clinical relevance of cohesin in DNA repair, tumorigenesis, and severe birth defects continues to fuel efforts in understanding cohesin structure, regulation, and enzymology. Early models depicting huge cohesin rings that entrap two DNA segments within a single lumen are fading into obscurity based on contradictory findings, but elucidating cohesin structure amid a myriad of functions remains challenging. Due in large part to integrated uses of a wide range of methodologies, recent advances are beginning to cast light into the depths that previously cloaked cohesin structure. Additional efforts similarly provide new insights into cohesin enzymology: specifically, the discoveries of ATP-dependent transitions that promote cohesin binding and release from DNA. In combination, these efforts posit a new model that cohesin exists primarily as a relatively flattened structure that entraps only a single DNA molecule and that subsequent ATP hydrolysis, acetylation, and oligomeric assembly tether together individual DNA segments.
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Affiliation(s)
- Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
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15
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Laptenko O, Tong DR, Manfredi J, Prives C. The Tail That Wags the Dog: How the Disordered C-Terminal Domain Controls the Transcriptional Activities of the p53 Tumor-Suppressor Protein. Trends Biochem Sci 2016; 41:1022-1034. [PMID: 27669647 DOI: 10.1016/j.tibs.2016.08.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 01/22/2023]
Abstract
The p53 tumor suppressor is a transcription factor (TF) that exerts antitumor functions through its ability to regulate the expression of multiple genes. Within the p53 protein resides a relatively short unstructured C-terminal domain (CTD) that remarkably participates in virtually every aspect of p53 performance as a TF. Because these aspects are often interdependent and it is not always possible to dissect them experimentally, there has been a great deal of controversy about the CTD. In this review we evaluate the significance and key features of this interesting region of p53 and its impact on the many aspects of p53 function in light of previous and more recent findings.
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Affiliation(s)
- Oleg Laptenko
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - David R Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - James Manfredi
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Carol Prives
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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16
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Kaur P, Wu D, Lin J, Countryman P, Bradford KC, Erie DA, Riehn R, Opresko PL, Wang H. Enhanced electrostatic force microscopy reveals higher-order DNA looping mediated by the telomeric protein TRF2. Sci Rep 2016; 6:20513. [PMID: 26856421 PMCID: PMC4746636 DOI: 10.1038/srep20513] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 01/04/2016] [Indexed: 12/19/2022] Open
Abstract
Shelterin protein TRF2 modulates telomere structures by promoting dsDNA compaction and T-loop formation. Advancement of our understanding of the mechanism underlying TRF2-mediated DNA compaction requires additional information regarding DNA paths in TRF2-DNA complexes. To uncover the location of DNA inside protein-DNA complexes, we recently developed the Dual-Resonance-frequency-Enhanced Electrostatic force Microscopy (DREEM) imaging technique. DREEM imaging shows that in contrast to chromatin with DNA wrapping around histones, large TRF2-DNA complexes (with volumes larger than TRF2 tetramers) compact DNA inside TRF2 with portions of folded DNA appearing at the edge of these complexes. Supporting coarse-grained molecular dynamics simulations uncover the structural requirement and sequential steps during TRF2-mediated DNA compaction and result in folded DNA structures with protruding DNA loops as seen in DREEM imaging. Revealing DNA paths in TRF2 complexes provides new mechanistic insights into structure-function relationships underlying telomere maintenance pathways.
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Affiliation(s)
- Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Dong Wu
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Jiangguo Lin
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA.,School of Bioscience and Engineering, South China University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Preston Countryman
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Kira C Bradford
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599.,Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599
| | - Robert Riehn
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania 15219, USA
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
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17
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Benarroch-Popivker D, Pisano S, Mendez-Bermudez A, Lototska L, Kaur P, Bauwens S, Djerbi N, Latrick CM, Fraisier V, Pei B, Gay A, Jaune E, Foucher K, Cherfils-Vicini J, Aeby E, Miron S, Londoño-Vallejo A, Ye J, Le Du MH, Wang H, Gilson E, Giraud-Panis MJ. TRF2-Mediated Control of Telomere DNA Topology as a Mechanism for Chromosome-End Protection. Mol Cell 2016; 61:274-86. [PMID: 26774283 DOI: 10.1016/j.molcel.2015.12.009] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/14/2015] [Accepted: 11/30/2015] [Indexed: 02/07/2023]
Abstract
The shelterin proteins protect telomeres against activation of the DNA damage checkpoints and recombinational repair. We show here that a dimer of the shelterin subunit TRF2 wraps ∼ 90 bp of DNA through several lysine and arginine residues localized around its homodimerization domain. The expression of a wrapping-deficient TRF2 mutant, named Top-less, alters telomeric DNA topology, decreases the number of terminal loops (t-loops), and triggers the ATM checkpoint, while still protecting telomeres against non-homologous end joining (NHEJ). In Top-less cells, the protection against NHEJ is alleviated if the expression of the TRF2-interacting protein RAP1 is reduced. We conclude that a distinctive topological state of telomeric DNA, controlled by the TRF2-dependent DNA wrapping and linked to t-loop formation, inhibits both ATM activation and NHEJ. The presence of RAP1 at telomeres appears as a backup mechanism to prevent NHEJ when topology-mediated telomere protection is impaired.
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Affiliation(s)
- Delphine Benarroch-Popivker
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Sabrina Pisano
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Aaron Mendez-Bermudez
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France; International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Shanghai Ruijin Hospital, Huangpu, Shanghai 200025, P.R. China
| | - Liudmyla Lototska
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Parminder Kaur
- Physics Department, North Carolina State University at Raleigh, Raleigh, NC 27695, USA
| | - Serge Bauwens
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Nadir Djerbi
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Chrysa M Latrick
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Vincent Fraisier
- Cell and Tissue Imaging Platform (PICT-IBiSA), Nikon Imaging Centre, UMR 144 CNRS Institut Curie, 75248 Paris Cedex 05, France
| | - Bei Pei
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Alexandre Gay
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Emilie Jaune
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Kevin Foucher
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Julien Cherfils-Vicini
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Eric Aeby
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 144, CEA Saclay, Gif-sur-Yvette F-91191, France
| | | | - Jing Ye
- International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Shanghai Ruijin Hospital, Huangpu, Shanghai 200025, P.R. China
| | - Marie-Hélène Le Du
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Bâtiment 144, CEA Saclay, Gif-sur-Yvette F-91191, France
| | - Hong Wang
- Physics Department, North Carolina State University at Raleigh, Raleigh, NC 27695, USA
| | - Eric Gilson
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France; International Laboratory in Hematology and Cancer, Shanghai Jiao Tong University School of Medicine/Ruijin Hospital/CNRS/INSERM/Nice University, Pôle Sino-Français de Recherche en Sciences du Vivant et Génomique, Shanghai Ruijin Hospital, Huangpu, Shanghai 200025, P.R. China; Department of Genetics, CHU Nice, Nice 06202, France.
| | - Marie-Josèphe Giraud-Panis
- Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France.
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