1
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Lin YY, Müller P, Karagianni E, Hepp N, Mueller-Planitz F, Vanderlinden W, Lipfert J. Epigenetic Histone Modifications H3K36me3 and H4K5/8/12/16ac Induce Open Polynucleosome Conformations via Different Mechanisms. J Mol Biol 2024; 436:168671. [PMID: 38908785 DOI: 10.1016/j.jmb.2024.168671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 05/28/2024] [Accepted: 06/16/2024] [Indexed: 06/24/2024]
Abstract
Nucleosomes are the basic compaction unit of chromatin and nucleosome structure and their higher-order assemblies regulate genome accessibility. Many post-translational modifications alter nucleosome dynamics, nucleosome-nucleosome interactions, and ultimately chromatin structure and gene expression. Here, we investigate the role of two post-translational modifications associated with actively transcribed regions, H3K36me3 and H4K5/8/12/16ac, in the contexts of tri-nucleosome arrays that provide a tractable model system for quantitative single-molecule analysis, while enabling us to probe nucleosome-nucleosome interactions. Direct visualization by AFM imaging reveals that H3K36me3 and H4K5/8/12/16ac nucleosomes adopt significantly more open and loose conformations than unmodified nucleosomes. Similarly, magnetic tweezers force spectroscopy shows a reduction in DNA outer turn wrapping and nucleosome-nucleosome interactions for the modified nucleosomes. The results suggest that for H3K36me3 the increased breathing and outer DNA turn unwrapping seen in mononucleosomes propagates to more open conformations in nucleosome arrays. In contrast, the even more open structures of H4K5/8/12/16ac nucleosome arrays do not appear to derive from the dynamics of the constituent mononucleosomes, but are driven by reduced nucleosome-nucleosome interactions, suggesting that stacking interactions can overrule DNA breathing of individual nucleosomes. We anticipate that our methodology will be broadly applicable to reveal the influence of other post-translational modifications and to observe the activity of nucleosome remodelers.
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Affiliation(s)
- Yi-Yun Lin
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands
| | - Peter Müller
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands
| | - Evdoxia Karagianni
- Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands
| | - Nicola Hepp
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany; Current address: Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Felix Mueller-Planitz
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Willem Vanderlinden
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands; School of Physics and Astronomy, University of Edinburg, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom.
| | - Jan Lipfert
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands.
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2
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Basov A, Dorohova A, Malyshko V, Moiseev A, Svidlov A, Bezhenar M, Nechipurenko Y, Dzhimak S. Influence of a Single Deuterium Substitution for Protium on the Frequency Generation of Different-Size Bubbles in IFNA17. Int J Mol Sci 2023; 24:12137. [PMID: 37569512 PMCID: PMC10418495 DOI: 10.3390/ijms241512137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/21/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
The influence of a single 2H/1H replacement on the frequency generation of different-size bubbles in the human interferon alpha-17 gene (IFNA17) under various energies was studied by a developed algorithm and mathematical modeling without simplifications or averaging. This new approach showed the efficacy of researching DNA bubbles and open states both when all hydrogen bonds in nitrogenous base pairs are protium and after an 2H-substitution. After a single deuterium substitution under specific energies, it was demonstrated that the non-coding region of IFNA17 had a more significant regulatory role in bubble generation in the whole gene than the promoter had. It was revealed that a single deuterium substitution for protium has an influence on the frequency generation of DNA bubbles, which also depends on their size and is always higher for the smaller bubbles under the largest number of the studied energies. Wherein, compared to the natural condition under the same critical value of energy, the bigger raises of the bubble frequency occurrence (maximums) were found for 11-30 base pair (bp) bubbles (higher by 319%), 2-4 bp bubbles (higher by 300%), and 31 bp and over ones (higher by 220%); whereas the most significant reductions of the indicators (minimums) were observed for 11-30 bp bubbles (lower by 43%) and bubbles size over 30 bp (lower by 82%). In this study, we also analyzed the impact of several circumstances on the AT/GC ratio in the formation of DNA bubbles, both under natural conditions and after a single hydrogen isotope exchange. Moreover, based on the obtained data, substantial positive and inverse correlations were revealed between the AT/GC ratio and some factors (energy values, size of DNA bubbles). So, this modeling and variant of the modified algorithm, adapted for researching DNA bubbles, can be useful to study the regulation of replication and transcription in the genes under different isotopic substitutions in the nucleobases.
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Affiliation(s)
- Alexandr Basov
- Department of Fundamental and Clinical Biochemistry, Kuban State Medical University, Krasnodar 350063, Russia; (A.B.); (V.M.)
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
| | - Anna Dorohova
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Vadim Malyshko
- Department of Fundamental and Clinical Biochemistry, Kuban State Medical University, Krasnodar 350063, Russia; (A.B.); (V.M.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Arkadii Moiseev
- Scientific Department, Kuban State Agrarian University, Krasnodar 350004, Russia;
| | - Alexandr Svidlov
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Maria Bezhenar
- Department of Function Theory, Kuban State University, Krasnodar 350040, Russia;
| | - Yury Nechipurenko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Stepan Dzhimak
- Department of Radiophysics and Nanotechnology, Kuban State University, Krasnodar 350040, Russia; (A.D.); (A.S.); (S.D.)
- Laboratory of Problems of Stable Isotope Spreading in Living Systems, Federal Research Center of the Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344006, Russia
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3
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Influence of Single Deuterium Replacement on Frequency of Hydrogen Bond Dissociation in IFNA17 under the Highest Critical Energy Range. Int J Mol Sci 2022; 23:ijms232415487. [PMID: 36555136 PMCID: PMC9778762 DOI: 10.3390/ijms232415487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/02/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
The effect of single substitutions of protium for deuterium in hydrogen bonds between pairs of nitrogenous bases on the open states occurrence probability at high critical breaking energies of these bonds has been studied. The study was carried out using numerical methods based on the angular mathematical model of DNA. The IFNA17 gene was divided into three approximately equal parts. A comparison of the open states occurrence probability in these parts of the gene was done. To improve the accuracy of the results, a special data processing algorithm was developed. The developed methods have shown their suitability for taking into account the occurrence of open states in the entire range of high critical energies. It has been established that single 2H/1H substitutions in certain nitrogenous bases can be a mechanism for maintaining the vital activity of IFNA17 under critical conditions. In general, the developed method of the mathematical modeling provide unprecedented insight into the DNA behavior under the highest critical energy range, which greatly expands scientific understanding of nucleobases interaction.
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4
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Bell NAW, Molloy JE. Efficient golden gate assembly of DNA constructs for single molecule force spectroscopy and imaging. Nucleic Acids Res 2022; 50:e77. [PMID: 35489063 PMCID: PMC9303394 DOI: 10.1093/nar/gkac300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 03/18/2022] [Accepted: 04/13/2022] [Indexed: 01/01/2023] Open
Abstract
Single-molecule techniques such as optical tweezers and fluorescence imaging are powerful tools for probing the biophysics of DNA and DNA-protein interactions. The application of these methods requires efficient approaches for creating designed DNA structures with labels for binding to a surface or microscopic beads. In this paper, we develop a simple and fast technique for making a diverse range of such DNA constructs by combining PCR amplicons and synthetic oligonucleotides using golden gate assembly rules. We demonstrate high yield fabrication of torsionally-constrained duplex DNA up to 10 kbp in length and a variety of DNA hairpin structures. We also show how tethering to a cross-linked antibody substrate significantly enhances measurement lifetime under high force. This rapid and adaptable fabrication method streamlines the assembly of DNA constructs for single molecule biophysics.
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5
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Konrad SF, Vanderlinden W, Lipfert J. Quantifying epigenetic modulation of nucleosome breathing by high-throughput AFM imaging. Biophys J 2022; 121:841-851. [PMID: 35065917 PMCID: PMC8943691 DOI: 10.1016/j.bpj.2022.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/30/2021] [Accepted: 01/19/2022] [Indexed: 11/30/2022] Open
Abstract
Nucleosomes are the basic units of chromatin and critical for storage and expression of eukaryotic genomes. Chromatin accessibility and gene readout are heavily regulated by epigenetic marks, in which post-translational modifications of histones play a key role. However, the mode of action and the structural implications at the single-molecule level of nucleosomes is still poorly understood. Here we apply a high-throughput atomic force microscopy imaging and analysis pipeline to investigate the conformational landscape of the nucleosome variants three additional methyl groups at lysine 36 of histone H3 (H3K36me3), phosphorylation of H3 histones at serine 10 (H3S10phos), and acetylation of H4 histones at lysines 5, 8, 12, and 16 (H4K5/8/12/16ac). Our data set of more than 25,000 nucleosomes reveals nucleosomal unwrapping steps corresponding to 5-bp DNA. We find that H3K36me3 nucleosomes unwrap significantly more than wild-type nucleosomes and additionally unwrap stochastically from both sides, similar to centromere protein A (CENP-A) nucleosomes and in contrast to the highly anticooperative unwrapping of wild-type nucleosomes. Nucleosomes with H3S10phos or H4K5/8/12/16ac modifications show unwrapping populations similar to wild-type nucleosomes and also retain the same level of anticooperativity. Our findings help to put the mode of action of these modifications into context. Although H3K36me3 likely acts partially by directly affecting nucleosome structure on the single-molecule level, H3S10phos and H4K5/8/12/16ac must predominantly act through higher-order processes. Our analysis pipeline is readily applicable to other nucleosome variants and will facilitate future high-resolution studies of the conformational landscape of nucleoprotein complexes.
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Affiliation(s)
- Sebastian F. Konrad
- Department of Physics and Center for NanoScience, LMU Munich, Munich, Germany
| | - Willem Vanderlinden
- Department of Physics and Center for NanoScience, LMU Munich, Munich, Germany
| | - Jan Lipfert
- Department of Physics and Center for NanoScience, LMU Munich, Munich, Germany.
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6
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Millar DP. Conformational Dynamics of DNA Polymerases Revealed at the Single-Molecule Level. Front Mol Biosci 2022; 9:826593. [PMID: 35281261 PMCID: PMC8913937 DOI: 10.3389/fmolb.2022.826593] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/20/2022] [Indexed: 12/25/2022] Open
Abstract
DNA polymerases are intrinsically dynamic macromolecular machines. The purpose of this review is to describe the single-molecule Förster resonance energy transfer (smFRET) methods that are used to probe the conformational dynamics of DNA polymerases, focusing on E. coli DNA polymerase I. The studies reviewed here reveal the conformational dynamics underpinning the nucleotide selection, proofreading and 5′ nuclease activities of Pol I. Moreover, the mechanisms revealed for Pol I are likely employed across the DNA polymerase family. smFRET methods have also been used to examine other aspects of DNA polymerase activity.
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7
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Aicart-Ramos C, Hormeno S, Wilkinson OJ, Dillingham MS, Moreno-Herrero F. Long DNA constructs to study helicases and nucleic acid translocases using optical tweezers. Methods Enzymol 2022; 673:311-358. [DOI: 10.1016/bs.mie.2022.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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8
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Leicher R, Liu S. Probing the Interaction Between Chromatin and Chromatin-Associated Complexes with Optical Tweezers. Methods Mol Biol 2022; 2478:313-327. [PMID: 36063325 PMCID: PMC10751574 DOI: 10.1007/978-1-0716-2229-2_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Single-molecule force spectroscopy is a powerful tool to analyze the architecture and interaction of large macromolecular assemblies that are refractory to high-resolution structural interrogations. Here, we describe an optical tweezers-based platform for extracting the mechanical fingerprints of individual nucleosome arrays bound with chromatin-associated complexes, such as the Polycomb repressive complex 2 (PRC2). This platform comprehensively characterizes the diverse binding modes of PRC2 on chromatin, measures their mechanical strengths, and is broadly applicable to the studies of other epigenetic machineries.
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Affiliation(s)
- Rachel Leicher
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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9
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Wang Z, Deng W. Dynamic transcription regulation at the single-molecule level. Dev Biol 2021; 482:67-81. [PMID: 34896367 DOI: 10.1016/j.ydbio.2021.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 02/07/2023]
Abstract
Cell fate changes during development, differentiation, and reprogramming are largely controlled at the transcription level. The DNA-binding transcription factors (TFs) often act in a combinatorial fashion to alter chromatin states and drive cell type-specific gene expression. Recent advances in fluorescent microscopy technologies have enabled direct visualization of biomolecules involved in the process of transcription and its regulatory events at the single-molecule level in living cells. Remarkably, imaging and tracking individual TF molecules at high temporal and spatial resolution revealed that they are highly dynamic in searching and binding cognate targets, rather than static and binding constantly. In combination with investigation using techniques from biochemistry, structure biology, genetics, and genomics, a more well-rounded view of transcription regulation is emerging. In this review, we briefly cover the technical aspects of live-cell single-molecule imaging and focus on the biological relevance and interpretation of the single-molecule dynamic features of transcription regulatory events observed in the native chromatin environment of living eukaryotic cells. We also discuss how these dynamic features might shed light on mechanistic understanding of transcription regulation.
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Affiliation(s)
- Zuhui Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Beijing Advanced Innovation Center for Genomics (ICG), Peking University, Beijing, 100871, China; Peking-Tsinghua Center for Life Sciences (CLS), Peking University, Beijing, 100871, China; School of Life Sciences, Peking University, Beijing, 100871, China.
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10
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Wang L, Peng Q, Yin N, Xie Y, Xu J, Chen A, Yi J, Tang J, Xiang J. Chromatin accessibility regulates chemotherapy-induced dormancy and reactivation. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 26:269-279. [PMID: 34513309 PMCID: PMC8413835 DOI: 10.1016/j.omtn.2021.07.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/26/2021] [Indexed: 12/14/2022]
Abstract
Cisplatin-based chemotherapy remains the standard care for non-small cell lung cancer (NSCLC) patients. Relapse after chemotherapy-induced dormancy affects the overall survival of patients. The evolution of cancer cells under chemotherapy stress is regulated by transcription factors (TFs) with binding sites initially buried deep within inaccessible chromatin. The transcription machinery and dynamic epigenetic alterations during the process of dormancy-reactivation of lung cancer cells after chemotherapy need to be investigated. Here, we investigated the chromatin accessibility of lung cancer cells after cisplatin treatment, using an assay for transposase-accessible chromatin sequencing (ATAC-seq). We observed that global chromatin accessibility was extensively improved. Transcriptional Regulatory Relationships Unraveled by Sentence-based Text mining (TRRUST) v.2 was used to elucidate TF-target interaction during the process of dormancy and reactivation. Enhancer regions and motifs specific to key TFs including JUN, MYC, SMAD3, E2F1, SP1, CTCF, SMAD4, STAT3, NFKB1, and KLF4 were enriched in differential loci ATAC-seq peaks of dormant and reactivated cancer cells induced by chemotherapy. The findings suggest that these key TFs regulated gene expressions during the process of dormancy and reactivation of cancer cells through altering promoter accessibility of target genes. Our study helps advance understanding of how cancer cells adapt to the stress induced by chemotherapy through TF binding motif accessibility.
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Affiliation(s)
- Lujuan Wang
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Changsha, Hunan 410013, China
| | - Qiu Peng
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Changsha, Hunan 410013, China
| | - Na Yin
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Changsha, Hunan 410013, China
| | - Yaohuan Xie
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Changsha, Hunan 410013, China
| | - Jiaqi Xu
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Changsha, Hunan 410013, China
| | - Anqi Chen
- Department of Thoracic Surgery, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410013, China.,Hunan Key Laboratory of Early Diagnosis and Precise Treatment of Lung Cancer, Central South University, Changsha, Hunan, China
| | - Junqi Yi
- Department of Thoracic Surgery, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410013, China.,Hunan Key Laboratory of Early Diagnosis and Precise Treatment of Lung Cancer, Central South University, Changsha, Hunan, China
| | - Jingqun Tang
- Department of Thoracic Surgery, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410013, China.,Hunan Key Laboratory of Early Diagnosis and Precise Treatment of Lung Cancer, Central South University, Changsha, Hunan, China
| | - Juanjuan Xiang
- Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Changsha, Hunan 410013, China
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11
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Konrad SF, Vanderlinden W, Lipfert J. A High-throughput Pipeline to Determine DNA and Nucleosome Conformations by AFM Imaging. Bio Protoc 2021; 11:e4180. [PMID: 34722827 DOI: 10.21769/bioprotoc.4180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/30/2021] [Accepted: 07/28/2021] [Indexed: 11/02/2022] Open
Abstract
Atomic force microscopy (AFM) is a powerful tool to image macromolecular complexes with nanometer resolution and exquisite single-molecule sensitivity. While AFM imaging is well-established to investigate DNA and nucleoprotein complexes, AFM studies are often limited by small datasets and manual image analysis that is slow and prone to user bias. Recently, we have shown that a combination of large scale AFM imaging and automated image analysis of nucleosomes can overcome these previous limitations of AFM nucleoprotein studies. Using our high-throughput imaging and analysis pipeline, we have resolved nucleosome wrapping intermediates with five base pair resolution and revealed how distinct nucleosome variants and environmental conditions affect the unwrapping pathways of nucleosomal DNA. Here, we provide a detailed protocol of our workflow to analyze DNA and nucleosome conformations focusing on practical aspects and experimental parameters. We expect our protocol to drastically enhance AFM analyses of DNA and nucleosomes and to be readily adaptable to a wide variety of other protein and protein-nucleic acid complexes.
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Affiliation(s)
- Sebastian F Konrad
- Department of Physics and Center for Nanoscience, LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Willem Vanderlinden
- Department of Physics and Center for Nanoscience, LMU Munich, Amalienstr. 54, 80799 Munich, Germany
| | - Jan Lipfert
- Department of Physics and Center for Nanoscience, LMU Munich, Amalienstr. 54, 80799 Munich, Germany
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12
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Morrison O, Thakur J. Molecular Complexes at Euchromatin, Heterochromatin and Centromeric Chromatin. Int J Mol Sci 2021; 22:6922. [PMID: 34203193 PMCID: PMC8268097 DOI: 10.3390/ijms22136922] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/19/2023] Open
Abstract
Chromatin consists of a complex of DNA and histone proteins as its core components and plays an important role in both packaging DNA and regulating DNA metabolic pathways such as DNA replication, transcription, recombination, and chromosome segregation. Proper functioning of chromatin further involves a network of interactions among molecular complexes that modify chromatin structure and organization to affect the accessibility of DNA to transcription factors leading to the activation or repression of the transcription of target DNA loci. Based on its structure and compaction state, chromatin is categorized into euchromatin, heterochromatin, and centromeric chromatin. In this review, we discuss distinct chromatin factors and molecular complexes that constitute euchromatin-open chromatin structure associated with active transcription; heterochromatin-less accessible chromatin associated with silencing; centromeric chromatin-the site of spindle binding in chromosome segregation.
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Affiliation(s)
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd #2006, Atlanta, GA 30322, USA;
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13
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Histone dynamics mediate DNA unwrapping and sliding in nucleosomes. Nat Commun 2021; 12:2387. [PMID: 33888707 PMCID: PMC8062685 DOI: 10.1038/s41467-021-22636-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/23/2021] [Indexed: 02/06/2023] Open
Abstract
Nucleosomes are elementary building blocks of chromatin in eukaryotes. They tightly wrap ∼147 DNA base pairs around an octamer of histone proteins. How nucleosome structural dynamics affect genome functioning is not completely clear. Here we report all-atom molecular dynamics simulations of nucleosome core particles at a timescale of 15 microseconds. At this timescale, functional modes of nucleosome dynamics such as spontaneous nucleosomal DNA breathing, unwrapping, twisting, and sliding were observed. We identified atomistic mechanisms of these processes by analyzing the accompanying structural rearrangements of the histone octamer and histone-DNA contacts. Octamer dynamics and plasticity were found to enable DNA unwrapping and sliding. Through multi-scale modeling, we showed that nucleosomal DNA dynamics contribute to significant conformational variability of the chromatin fiber at the supranucleosomal level. Our study further supports mechanistic coupling between fine details of histone dynamics and chromatin functioning, provides a framework for understanding the effects of various chromatin modifications.
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14
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Konrad SF, Vanderlinden W, Frederickx W, Brouns T, Menze BH, De Feyter S, Lipfert J. High-throughput AFM analysis reveals unwrapping pathways of H3 and CENP-A nucleosomes. NANOSCALE 2021; 13:5435-5447. [PMID: 33683227 DOI: 10.1039/d0nr08564b] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nucleosomes, the fundamental units of chromatin, regulate readout and expression of eukaryotic genomes. Single-molecule experiments have revealed force-induced nucleosome accessibility, but a high-resolution unwrapping landscape in the absence of external forces is currently lacking. Here, we introduce a high-throughput pipeline for the analysis of nucleosome conformations based on atomic force microscopy and automated, multi-parameter image analysis. Our data set of ∼10 000 nucleosomes reveals multiple unwrapping states corresponding to steps of 5 bp DNA. For canonical H3 nucleosomes, we observe that dissociation from one side impedes unwrapping from the other side, but in contrast to force-induced unwrapping, we find only a weak sequence-dependent asymmetry. Notably, centromeric CENP-A nucleosomes do not unwrap anti-cooperatively, in stark contrast to H3 nucleosomes. Finally, our results reconcile previous conflicting findings about the differences in height between H3 and CENP-A nucleosomes. We expect our approach to enable critical insights into epigenetic regulation of nucleosome structure and stability and to facilitate future high-throughput AFM studies that involve heterogeneous nucleoprotein complexes.
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Affiliation(s)
- Sebastian F Konrad
- Department of Physics and Center for Nanoscience, LMU Munich, Amalienstr. 54, 80799 Munich, Germany.
| | - Willem Vanderlinden
- Department of Physics and Center for Nanoscience, LMU Munich, Amalienstr. 54, 80799 Munich, Germany.
| | - Wout Frederickx
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Tine Brouns
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Björn H Menze
- Department of Informatics, Technical University of Munich, Boltzmannstr. 3, 85748 Garching, Germany
| | - Steven De Feyter
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Jan Lipfert
- Department of Physics and Center for Nanoscience, LMU Munich, Amalienstr. 54, 80799 Munich, Germany.
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15
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Leicher R, Ge EJ, Lin X, Reynolds MJ, Xie W, Walz T, Zhang B, Muir TW, Liu S. Single-molecule and in silico dissection of the interaction between Polycomb repressive complex 2 and chromatin. Proc Natl Acad Sci U S A 2020; 117:30465-30475. [PMID: 33208532 PMCID: PMC7720148 DOI: 10.1073/pnas.2003395117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) installs and spreads repressive histone methylation marks on eukaryotic chromosomes. Because of the key roles that PRC2 plays in development and disease, how this epigenetic machinery interacts with DNA and nucleosomes is of major interest. Nonetheless, the mechanism by which PRC2 engages with native-like chromatin remains incompletely understood. In this work, we employ single-molecule force spectroscopy and molecular dynamics simulations to dissect the behavior of PRC2 on polynucleosome arrays. Our results reveal an unexpectedly diverse repertoire of PRC2 binding configurations on chromatin. Besides reproducing known binding modes in which PRC2 interacts with bare DNA, mononucleosomes, and adjacent nucleosome pairs, our data also provide direct evidence that PRC2 can bridge pairs of distal nucleosomes. In particular, the "1-3" bridging mode, in which PRC2 engages two nucleosomes separated by one spacer nucleosome, is a preferred low-energy configuration. Moreover, we show that the distribution and stability of different PRC2-chromatin interaction modes are modulated by accessory subunits, oncogenic histone mutations, and the methylation state of chromatin. Overall, these findings have implications for the mechanism by which PRC2 spreads histone modifications and compacts chromatin. The experimental and computational platforms developed here provide a framework for understanding the molecular basis of epigenetic maintenance mediated by Polycomb-group proteins.
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Affiliation(s)
- Rachel Leicher
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY 10065
- Tri-Institutional PhD Program in Chemical Biology, New York, NY 10065
| | - Eva J Ge
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - Xingcheng Lin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Matthew J Reynolds
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, NY 10065
| | - Wenjun Xie
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065
| | - Bin Zhang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;
| | - Tom W Muir
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY 10065;
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16
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Spakman D, King GA, Peterman EJG, Wuite GJL. Constructing arrays of nucleosome positioning sequences using Gibson Assembly for single-molecule studies. Sci Rep 2020; 10:9903. [PMID: 32555215 PMCID: PMC7303147 DOI: 10.1038/s41598-020-66259-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/24/2020] [Indexed: 01/08/2023] Open
Abstract
As the basic building blocks of chromatin, nucleosomes play a key role in dictating the accessibility of the eukaryotic genome. Consequently, nucleosomes are involved in essential genomic transactions such as DNA transcription, replication and repair. In order to unravel the mechanisms by which nucleosomes can influence, or be altered by, DNA-binding proteins, single-molecule techniques are increasingly employed. To this end, DNA molecules containing a defined series of nucleosome positioning sequences are often used to reconstitute arrays of nucleosomes in vitro. Here, we describe a novel method to prepare DNA molecules containing defined arrays of the ‘601’ nucleosome positioning sequence by exploiting Gibson Assembly cloning. The approaches presented here provide a more accessible and efficient means to generate arrays of nucleosome positioning motifs, and facilitate a high degree of control over the linker sequences between these motifs. Nucleosomes reconstituted on such arrays are ideal for interrogation with single-molecule techniques. To demonstrate this, we use dual-trap optical tweezers, in combination with fluorescence microscopy, to monitor nucleosome unwrapping and histone localisation as a function of tension. We reveal that, although nucleosomes unwrap at ~20 pN, histones (at least histone H3) remain bound to the DNA, even at tensions beyond 60 pN.
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Affiliation(s)
- Dian Spakman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Graeme A King
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands. .,Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Erwin J G Peterman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
| | - Gijs J L Wuite
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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17
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Öztürk MA, De M, Cojocaru V, Wade RC. Chromatosome Structure and Dynamics from Molecular Simulations. Annu Rev Phys Chem 2020; 71:101-119. [PMID: 32017651 DOI: 10.1146/annurev-physchem-071119-040043] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromatosomes are fundamental units of chromatin structure that are formed when a linker histone protein binds to a nucleosome. The positioning of the linker histone on the nucleosome influences the packing of chromatin. Recent simulations and experiments have shown that chromatosomes adopt an ensemble of structures that differ in the geometry of the linker histone-nucleosome interaction. In this article we review the application of Brownian, Monte Carlo, and molecular dynamics simulations to predict the structure of linker histone-nucleosome complexes, to study the binding mechanisms involved, and to predict how this binding affects chromatin fiber structure. These simulations have revealed the sensitivityof the chromatosome structure to variations in DNA and linker histone sequence, as well as to posttranslational modifications, thereby explaining the structural variability observed in experiments. We propose that a concerted application of experimental and computational approaches will reveal the determinants of chromatosome structural variability and how it impacts chromatin packing.
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Affiliation(s)
- Mehmet Ali Öztürk
- Centre for Biological Signalling Studies (BIOSS) and Centre for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg, Germany;
| | - Madhura De
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), 69118 Heidelberg, Germany; .,Department of Biophysics of Macromolecules, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; .,Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Vlad Cojocaru
- In Silico Biomolecular Structure and Dynamics, Hubrecht Institute, 3584 CT Utrecht, The Netherlands; .,Computational Structural Biology Group, Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany
| | - Rebecca C Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), 69118 Heidelberg, Germany; .,Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany.,Center for Molecular Biology (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing (IWR), 69120 Heidelberg, Germany
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18
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Kaczmarczyk A, Meng H, Ordu O, Noort JV, Dekker NH. Chromatin fibers stabilize nucleosomes under torsional stress. Nat Commun 2020; 11:126. [PMID: 31913285 PMCID: PMC6949304 DOI: 10.1038/s41467-019-13891-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 11/25/2019] [Indexed: 01/11/2023] Open
Abstract
Torsional stress generated during DNA replication and transcription has been suggested to facilitate nucleosome unwrapping and thereby the progression of polymerases. However, the propagation of twist in condensed chromatin remains yet unresolved. Here, we measure how force and torque impact chromatin fibers with a nucleosome repeat length of 167 and 197. We find that both types of fibers fold into a left-handed superhelix that can be stabilized by positive torsion. We observe that the structural changes induced by twist were reversible, indicating that chromatin has a large degree of elasticity. Our direct measurements of torque confirmed the hypothesis of chromatin fibers as a twist buffer. Using a statistical mechanics-based torsional spring model, we extracted values of the chromatin twist modulus and the linking number per stacked nucleosome that were in good agreement with values measured here experimentally. Overall, our findings indicate that the supercoiling generated by DNA-processing enzymes, predicted by the twin-supercoiled domain model, can be largely accommodated by the higher-order structure of chromatin.
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Affiliation(s)
- Artur Kaczmarczyk
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, The Netherlands
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
- Faculty of Medicine, Imperial College London, Du Cane Road, W12 0NN, London, United Kingdom
| | - He Meng
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, The Netherlands
| | - Orkide Ordu
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - John van Noort
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, The Netherlands.
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
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19
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Ordu O, Lusser A, Dekker NH. DNA Sequence Is a Major Determinant of Tetrasome Dynamics. Biophys J 2019; 117:2217-2227. [PMID: 31521330 PMCID: PMC6895708 DOI: 10.1016/j.bpj.2019.07.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/13/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022] Open
Abstract
Eukaryotic genomes are hierarchically organized into protein-DNA assemblies for compaction into the nucleus. Nucleosomes, with the (H3-H4)2 tetrasome as a likely intermediate, are highly dynamic in nature by way of several different mechanisms. We have recently shown that tetrasomes spontaneously change the direction of their DNA wrapping between left- and right-handed conformations, which may prevent torque buildup in chromatin during active transcription or replication. DNA sequence has been shown to strongly affect nucleosome positioning throughout chromatin. It is not known, however, whether DNA sequence also impacts the dynamic properties of tetrasomes. To address this question, we examined tetrasomes assembled on a high-affinity DNA sequence using freely orbiting magnetic tweezers. In this context, we also studied the effects of mono- and divalent salts on the flipping dynamics. We found that neither DNA sequence nor altered buffer conditions affect overall tetrasome structure. In contrast, tetrasomes bound to high-affinity DNA sequences showed significantly altered flipping kinetics, predominantly via a reduction in the lifetime of the canonical state of left-handed wrapping. Increased mono- and divalent salt concentrations counteracted this behavior. Thus, our study indicates that high-affinity DNA sequences impact not only the positioning of the nucleosome but that they also endow the subnucleosomal tetrasome with enhanced conformational plasticity. This may provide a means to prevent histone loss upon exposure to torsional stress, thereby contributing to the integrity of chromatin at high-affinity sites.
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Affiliation(s)
- Orkide Ordu
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alexandra Lusser
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands.
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20
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Eltsov M, Grewe D, Lemercier N, Frangakis A, Livolant F, Leforestier A. Nucleosome conformational variability in solution and in interphase nuclei evidenced by cryo-electron microscopy of vitreous sections. Nucleic Acids Res 2019; 46:9189-9200. [PMID: 30053160 PMCID: PMC6158616 DOI: 10.1093/nar/gky670] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/13/2018] [Indexed: 01/04/2023] Open
Abstract
In Eukaryotes, DNA is wound around the histone octamer forming the basic chromatin unit, the nucleosome. Atomic structures have been obtained from crystallography and single particle cryo-electron microscopy (cryoEM) of identical engineered particles. But native nucleosomes are dynamical entities with diverse DNA sequence and histone content, and little is known about their conformational variability, especially in the cellular context. Using cryoEM and tomography of vitreous sections we analyse native nucleosomes, both in vitro, using purified particles solubilized at physiologically relevant concentrations (25–50%), and in situ, within interphase nuclei. We visualize individual nucleosomes at a level of detail that allows us to measure the distance between the DNA gyres wrapped around. In concentrated solutions, we demonstrate a salt-dependent transition, with a high salt compact conformation resembling the canonical nucleosome and an open low salt one, closer to nuclear nucleosomes. Although further particle characterization and cartography are needed to understand the relationship between this conformational variability and chromatin functional states, this work opens a route to chromatin exploration in situ.
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Affiliation(s)
- Mikhail Eltsov
- Buchmann Institute for Molecular Life Sciences, Goethe University, 60438 Frankfurt am Main, Germany
| | - Diana Grewe
- Buchmann Institute for Molecular Life Sciences, Goethe University, 60438 Frankfurt am Main, Germany
| | - Nicolas Lemercier
- Laboratoire de Physique des Solides, UMR 8502 CNRS, Université Paris-Sud, Université Paris-Saclay, Bat 510, 91405 Orsay Cedex, France
| | - Achilleas Frangakis
- Buchmann Institute for Molecular Life Sciences, Goethe University, 60438 Frankfurt am Main, Germany
| | - Françoise Livolant
- Laboratoire de Physique des Solides, UMR 8502 CNRS, Université Paris-Sud, Université Paris-Saclay, Bat 510, 91405 Orsay Cedex, France
| | - Amélie Leforestier
- Laboratoire de Physique des Solides, UMR 8502 CNRS, Université Paris-Sud, Université Paris-Saclay, Bat 510, 91405 Orsay Cedex, France
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21
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Hsu KW, Chow SY, Su BY, Lu YH, Chen CJ, Chen WL, Cheng MY, Fan HF. The synergy between RSC, Nap1 and adjacent nucleosome in nucleosome remodeling. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:129-140. [PMID: 30593928 DOI: 10.1016/j.bbagrm.2018.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/23/2018] [Accepted: 11/30/2018] [Indexed: 12/29/2022]
Abstract
Eukaryotes have evolved a specific strategy to package DNA. The nucleosome is a 147-base-pair DNA segment wrapped around histone core proteins that plays important roles regulating DNA-dependent biosynthesis and gene expression. Chromatin remodeling complexes (RSC, Remodel the Structure of Chromatin) hydrolyze ATP to perturb DNA-histone contacts, leading to nucleosome sliding and ejection. Here, we utilized tethered particle motion (TPM) experiments to investigate the mechanism of RSC-mediated nucleosome remodeling in detail. We observed ATP-dependent RSC-mediated DNA looping and nucleosome ejection along individual mononucleosomes and dinucleosomes. We found that nucleosome assembly protein 1 (Nap1) enhanced RSC-mediated nucleosome ejection in a two-step disassembly manner from dinucleosomes but not from mononucleosomes. Based on this work, we provide an entire reaction scheme for the RSC-mediated nucleosome remodeling process that includes DNA looping, nucleosome ejection, the influence of adjacent nucleosomes, and the coordinated action between Nap1 and RSC.
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Affiliation(s)
- Kuan-Wei Hsu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Sih-Yao Chow
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Bo-Yu Su
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Yi-Han Lu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Cyuan-Ji Chen
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Wen-Ling Chen
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Ming-Yuan Cheng
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Hsiu-Fang Fan
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan.
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22
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Zhou K, Gaullier G, Luger K. Nucleosome structure and dynamics are coming of age. Nat Struct Mol Biol 2018; 26:3-13. [PMID: 30532059 DOI: 10.1038/s41594-018-0166-x] [Citation(s) in RCA: 190] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/07/2018] [Indexed: 11/09/2022]
Abstract
Since the first high-resolution structure of the nucleosome was reported in 1997, the available information on chromatin structure has increased very rapidly. Here, we review insights derived from cutting-edge biophysical and structural approaches applied to the study of nucleosome dynamics and nucleosome-binding factors, with a focus on the experimental advances driving the research. In addition, we highlight emerging challenges in nucleosome structural biology.
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Affiliation(s)
- Keda Zhou
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Guillaume Gaullier
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Karolin Luger
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
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23
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Ordu O, Kremser L, Lusser A, Dekker NH. Modification of the histone tetramer at the H3-H3 interface impacts tetrasome conformations and dynamics. J Chem Phys 2018; 148:123323. [PMID: 29604863 DOI: 10.1063/1.5009100] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nucleosomes consisting of a short piece of deoxyribonucleic acid (DNA) wrapped around an octamer of histone proteins form the fundamental unit of chromatin in eukaryotes. Their role in DNA compaction comes with regulatory functions that impact essential genomic processes such as replication, transcription, and repair. The assembly of nucleosomes obeys a precise pathway in which tetramers of histones H3 and H4 bind to the DNA first to form tetrasomes, and two dimers of histones H2A and H2B are subsequently incorporated to complete the complex. As viable intermediates, we previously showed that tetrasomes can spontaneously flip between a left-handed and right-handed conformation of DNA-wrapping. To pinpoint the underlying mechanism, here we investigated the role of the H3-H3 interface for tetramer flexibility in the flipping process at the single-molecule level. Using freely orbiting magnetic tweezers, we studied the assembly and structural dynamics of individual tetrasomes modified at the cysteines close to this interaction interface by iodoacetamide (IA) in real time. While such modification did not affect the structural properties of the tetrasomes, it caused a 3-fold change in their flipping kinetics. The results indicate that the IA-modification enhances the conformational plasticity of tetrasomes. Our findings suggest that subnucleosomal dynamics may be employed by chromatin as an intrinsic and adjustable mechanism to regulate DNA supercoiling.
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Affiliation(s)
- Orkide Ordu
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Leopold Kremser
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innrain 80, 6020 Innsbruck, Austria
| | - Alexandra Lusser
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Nynke H Dekker
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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24
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Abstract
Magnetic tweezers form a unique tool to study the topology and mechanical properties of chromatin fibers. Chromatin is a complex of DNA and proteins that folds the DNA in such a way that meter-long stretches of DNA fit into the micron-sized cell nucleus. Moreover, it regulates accessibility of the genome to the cellular replication, transcription, and repair machinery. However, the structure and mechanisms that govern chromatin folding remain poorly understood, despite recent spectacular improvements in high-resolution imaging techniques. Single-molecule force spectroscopy techniques can directly measure both the extension of individual chromatin fragments with nanometer accuracy and the forces involved in the (un)folding of single chromatin fibers. Here, we report detailed methods that allow one to successfully prepare in vitro reconstituted chromatin fibers for use in magnetic tweezers-based force spectroscopy. The higher-order structure of different chromatin fibers can be inferred from fitting a statistical mechanics model to the force-extension data. These methods for quantifying chromatin folding can be extended to study many other processes involving chromatin, such as the epigenetic regulation of transcription.
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25
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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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26
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Balakrishnan L, Milavetz B. Epigenetic Regulation of Viral Biological Processes. Viruses 2017; 9:v9110346. [PMID: 29149060 PMCID: PMC5707553 DOI: 10.3390/v9110346] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/13/2017] [Accepted: 11/15/2017] [Indexed: 12/21/2022] Open
Abstract
It is increasingly clear that DNA viruses exploit cellular epigenetic processes to control their life cycles during infection. This review will address epigenetic regulation in members of the polyomaviruses, adenoviruses, human papillomaviruses, hepatitis B, and herpes viruses. For each type of virus, what is known about the roles of DNA methylation, histone modifications, nucleosome positioning, and regulatory RNA in epigenetic regulation of the virus infection will be discussed. The mechanisms used by certain viruses to dysregulate the host cell through manipulation of epigenetic processes and the role of cellular cofactors such as BRD4 that are known to be involved in epigenetic regulation of host cell pathways will also be covered. Specifically, this review will focus on the role of epigenetic regulation in maintaining viral episomes through the generation of chromatin, temporally controlling transcription from viral genes during the course of an infection, regulating latency and the switch to a lytic infection, and global dysregulation of cellular function.
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Affiliation(s)
- Lata Balakrishnan
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA.
| | - Barry Milavetz
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
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27
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Lauschke VM, Barragan I, Ingelman-Sundberg M. Pharmacoepigenetics and Toxicoepigenetics: Novel Mechanistic Insights and Therapeutic Opportunities. Annu Rev Pharmacol Toxicol 2017; 58:161-185. [PMID: 29029592 DOI: 10.1146/annurev-pharmtox-010617-053021] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pharmacological treatment and exposure to xenobiotics can cause substantial changes in epigenetic signatures. The majority of these epigenetic changes, caused by the compounds in question, occur downstream of transcriptional activation mechanisms, whereby the epigenetic alterations can create a transcriptional memory and stably modulate cell function. The increasing understanding of epigenetic mechanisms and their importance in disease has prompted the development of therapeutic interventions that target epigenetic modulatory mechanisms, particularly in oncology where inhibitors of epigenetic-modifying proteins (epidrugs) have been successfully used in treatment, mostly in combination with standard-of-care chemotherapy, either provoking direct cytotoxicity or inhibiting resistance to anticancer drugs. In addition, emerging methods for detecting epigenetically modified DNA in bodily fluids may provide information about tumor phenotype or drug treatment success. However, it is important to note that many technical pitfalls, such as the nondeconvolution of methylcytosine and hydroxymethylcytosine, compromise epigenetic analyses and the interpretation of results. In this review, we provide an update on the field, with an emphasis on the novel therapeutic opportunities made possible by epidrugs.
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Affiliation(s)
- Volker M Lauschke
- Pharmacogenetics Section, Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden;
| | - Isabel Barragan
- Pharmacoepigenetics Group, Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Magnus Ingelman-Sundberg
- Pharmacogenetics Section, Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden;
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28
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Imre L, Simándi Z, Horváth A, Fenyőfalvi G, Nánási P, Niaki EF, Hegedüs É, Bacsó Z, Weyemi U, Mauser R, Ausio J, Jeltsch A, Bonner W, Nagy L, Kimura H, Szabó G. Nucleosome stability measured in situ by automated quantitative imaging. Sci Rep 2017; 7:12734. [PMID: 28986581 PMCID: PMC5630628 DOI: 10.1038/s41598-017-12608-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 09/06/2017] [Indexed: 02/07/2023] Open
Abstract
Current approaches have limitations in providing insight into the functional properties of particular nucleosomes in their native molecular environment. Here we describe a simple and powerful method involving elution of histones using intercalators or salt, to assess stability features dependent on DNA superhelicity and relying mainly on electrostatic interactions, respectively, and measurement of the fraction of histones remaining chromatin-bound in the individual nuclei using histone type- or posttranslational modification- (PTM-) specific antibodies and automated, quantitative imaging. The method has been validated in H3K4me3 ChIP-seq experiments, by the quantitative assessment of chromatin loop relaxation required for nucleosomal destabilization, and by comparative analyses of the intercalator and salt induced release from the nucleosomes of different histones. The accuracy of the assay allowed us to observe examples of strict association between nucleosome stability and PTMs across cell types, differentiation state and throughout the cell-cycle in close to native chromatin context, and resolve ambiguities regarding the destabilizing effect of H2A.X phosphorylation. The advantages of the in situ measuring scenario are demonstrated via the marked effect of DNA nicking on histone eviction that underscores the powerful potential of topological relaxation in the epigenetic regulation of DNA accessibility.
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Affiliation(s)
- László Imre
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Zoltán Simándi
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4032, Hungary.,Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Attila Horváth
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - György Fenyőfalvi
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Péter Nánási
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Erfaneh Firouzi Niaki
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Éva Hegedüs
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Zsolt Bacsó
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Urbain Weyemi
- Center for Cancer Research National Cancer Institute, Bethesda, Maryland, 20892, USA
| | - Rebekka Mauser
- Institute of Biochemistry, Stuttgart University, Stuttgart, Germany
| | - Juan Ausio
- University of Victoria, Department of Biochemistry, Victoria, BC, V8W 3P6, Canada
| | - Albert Jeltsch
- Institute of Biochemistry, Stuttgart University, Stuttgart, Germany
| | - William Bonner
- Center for Cancer Research National Cancer Institute, Bethesda, Maryland, 20892, USA
| | - László Nagy
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4032, Hungary.,Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA.,MTA-DE "Lendulet" Immunogenomics Research Group, University of Debrecen, Debrecen, Hungary
| | - Hiroshi Kimura
- Cell Biology Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4032, Hungary.
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29
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Dos Remedios C. A review and summary of the contents of biophysical reviews volume 8, 2016. Biophys Rev 2017; 9:1-4. [PMID: 28510044 DOI: 10.1007/s12551-017-0249-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 01/16/2017] [Indexed: 12/12/2022] Open
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