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Portillo-Ledesma S, Chung S, Hoffman J, Schlick T. Regulation of chromatin architecture by transcription factor binding. eLife 2024; 12:RP91320. [PMID: 38241351 PMCID: PMC10945602 DOI: 10.7554/elife.91320] [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] [Indexed: 01/21/2024] Open
Abstract
Transcription factors (TF) bind to chromatin and regulate the expression of genes. The pair Myc:Max binds to E-box regulatory DNA elements throughout the genome to control the transcription of a large group of specific genes. We introduce an implicit modeling protocol for Myc:Max binding to mesoscale chromatin fibers at nucleosome resolution to determine TF effect on chromatin architecture and shed light into its mechanism of gene regulation. We first bind Myc:Max to different chromatin locations and show how it can direct fiber folding and formation of microdomains, and how this depends on the linker DNA length. Second, by simulating increasing concentrations of Myc:Max binding to fibers that differ in the DNA linker length, linker histone density, and acetylation levels, we assess the interplay between Myc:Max and other chromatin internal parameters. Third, we study the mechanism of gene silencing by Myc:Max binding to the Eed gene loci. Overall, our results show how chromatin architecture can be regulated by TF binding. The position of TF binding dictates the formation of microdomains that appear visible only at the ensemble level. At the same time, the level of linker histone and tail acetylation, or different linker DNA lengths, regulates the concentration-dependent effect of TF binding. Furthermore, we show how TF binding can repress gene expression by increasing fiber folding motifs that help compact and occlude the promoter region. Importantly, this effect can be reversed by increasing linker histone density. Overall, these results shed light on the epigenetic control of the genome dictated by TF binding.
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Affiliation(s)
- Stephanie Portillo-Ledesma
- Department of Chemistry, 100 Washington Square East, Silver Building, New York UniversityNew YorkUnited States
- Simons Center for Computational Physical Chemistry, 24 Waverly Place, Silver Building, New York UniversityNew YorkUnited States
| | - Suckwoo Chung
- Department of Chemistry, 100 Washington Square East, Silver Building, New York UniversityNew YorkUnited States
| | - Jill Hoffman
- Department of Chemistry, 100 Washington Square East, Silver Building, New York UniversityNew YorkUnited States
| | - Tamar Schlick
- Department of Chemistry, 100 Washington Square East, Silver Building, New York UniversityNew YorkUnited States
- Simons Center for Computational Physical Chemistry, 24 Waverly Place, Silver Building, New York UniversityNew YorkUnited States
- Courant Institute of Mathematical Sciences, New York UniversityNew YorkUnited States
- New York University-East China Normal University Center for Computational Chemistry, New York University ShanghaiShanghaiChina
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2
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Portillo-Ledesma S, Chung S, Hoffman J, Schlick T. Regulation of Chromatin Architecture by Transcription Factor Binding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.26.559535. [PMID: 37808867 PMCID: PMC10557667 DOI: 10.1101/2023.09.26.559535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Transcription factors (TF) bind to chromatin and regulate the expression of genes. The pair Myc:Max binds to E-box regulatory DNA elements throughout the genome, controlling transcription of a large group of specific genes. We introduce an implicit modeling protocol for Myc:Max binding to mesoscale chromatin fibers to determine TF effect on chromatin architecture and shed light on its mechanism of gene regulation. We first bind Myc:Max to different chromatin locations and show how it can direct fiber folding and formation of microdomains, and how this depends on the linker DNA length. Second, by simulating increasing concentrations of Myc:Max binding to fibers that differ in the DNA linker length, linker histone density, and acetylation levels, we assess the interplay between Myc:Max and other chromatin internal parameters. Third, we study the mechanism of gene silencing by Myc:Max binding to the Eed gene loci. Overall, our results show how chromatin architecture can be regulated by TF binding. The position of TF binding dictates the formation of microdomains that appear visible only at the ensemble level. On the other hand, the presence of linker histone, acetylations, or different linker DNA lengths regulates the concentration-dependent effect of TF binding. Furthermore, we show how TF binding can repress gene expression by increasing fiber folding motifs that help compact and occlude the promoter region. Importantly, this effect can be reversed by increasing linker histone density. Overall, these results shed light on the epigenetic control of the genome dictated by TF binding.
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Affiliation(s)
- Stephanie Portillo-Ledesma
- Department of Chemistry, 100 Washington Square East, Silver Building, New York University, New York, NY 10003 U.S.A
- Simons Center for Computational Physical Chemistry, 24 Waverly Place, Silver Building, New York University, New York, NY 10003 U.S.A
| | - Suckwoo Chung
- Department of Chemistry, 100 Washington Square East, Silver Building, New York University, New York, NY 10003 U.S.A
| | - Jill Hoffman
- Department of Chemistry, 100 Washington Square East, Silver Building, New York University, New York, NY 10003 U.S.A
| | - Tamar Schlick
- Department of Chemistry, 100 Washington Square East, Silver Building, New York University, New York, NY 10003 U.S.A
- Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012 U.S.A
- New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200122 China
- Simons Center for Computational Physical Chemistry, 24 Waverly Place, Silver Building, New York University, New York, NY 10003 U.S.A
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3
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Ide S, Tamura S, Maeshima K. Chromatin behavior in living cells: Lessons from single‐nucleosome imaging and tracking. Bioessays 2022; 44:e2200043. [DOI: 10.1002/bies.202200043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Satoru Ide
- Genome Dynamics Laboratory National Institute of Genetics, ROIS Mishima Shizuoka Japan
- Department of Genetics School of Life Science SOKENDAI Mishima Shizuoka Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory National Institute of Genetics, ROIS Mishima Shizuoka Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory National Institute of Genetics, ROIS Mishima Shizuoka Japan
- Department of Genetics School of Life Science SOKENDAI Mishima Shizuoka Japan
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4
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Chromatin, stacked at the centromere. Nat Struct Mol Biol 2022; 29:288-290. [PMID: 35422518 DOI: 10.1038/s41594-022-00759-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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5
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Swygert SG, Lin D, Portillo-Ledesma S, Lin PY, Hunt DR, Kao CF, Schlick T, Noble WS, Tsukiyama T. Local chromatin fiber folding represses transcription and loop extrusion in quiescent cells. eLife 2021; 10:e72062. [PMID: 34734806 PMCID: PMC8598167 DOI: 10.7554/elife.72062] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/03/2021] [Indexed: 12/16/2022] Open
Abstract
A longstanding hypothesis is that chromatin fiber folding mediated by interactions between nearby nucleosomes represses transcription. However, it has been difficult to determine the relationship between local chromatin fiber compaction and transcription in cells. Further, global changes in fiber diameters have not been observed, even between interphase and mitotic chromosomes. We show that an increase in the range of local inter-nucleosomal contacts in quiescent yeast drives the compaction of chromatin fibers genome-wide. Unlike actively dividing cells, inter-nucleosomal interactions in quiescent cells require a basic patch in the histone H4 tail. This quiescence-specific fiber folding globally represses transcription and inhibits chromatin loop extrusion by condensin. These results reveal that global changes in chromatin fiber compaction can occur during cell state transitions, and establish physiological roles for local chromatin fiber folding in regulating transcription and chromatin domain formation.
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Affiliation(s)
- Sarah G Swygert
- Basic Sciences Division, Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Dejun Lin
- Department of Genome Sciences, University of WashingtonSeattleUnited States
| | | | - Po-Yen Lin
- Institute of Cellular and Organismic Biology, Academia SinicaTaipeiTaiwan
| | - Dakota R Hunt
- Basic Sciences Division, Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Cheng-Fu Kao
- Institute of Cellular and Organismic Biology, Academia SinicaTaipeiTaiwan
| | - Tamar Schlick
- Department of Chemistry, New York UniversityNew YorkUnited States
- Courant Institute of Mathematical Sciences, New York UniversityNew YorkUnited States
- New York University-East China Normal University Center for Computational Chemistry at New York University ShanghaiShanghaiChina
| | - William S Noble
- Department of Genome Sciences, University of WashingtonSeattleUnited States
- Paul G. Allen School of Computer Science and Engineering, University of WashingtonSeattleUnited States
| | - Toshio Tsukiyama
- Basic Sciences Division, Fred Hutchinson Cancer Research CenterSeattleUnited States
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Hansen JC, Maeshima K, Hendzel MJ. The solid and liquid states of chromatin. Epigenetics Chromatin 2021; 14:50. [PMID: 34717733 PMCID: PMC8557566 DOI: 10.1186/s13072-021-00424-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022] Open
Abstract
The review begins with a concise description of the principles of phase separation. This is followed by a comprehensive section on phase separation of chromatin, in which we recount the 60 years history of chromatin aggregation studies, discuss the evidence that chromatin aggregation intrinsically is a physiologically relevant liquid-solid phase separation (LSPS) process driven by chromatin self-interaction, and highlight the recent findings that under specific solution conditions chromatin can undergo liquid-liquid phase separation (LLPS) rather than LSPS. In the next section of the review, we discuss how certain chromatin-associated proteins undergo LLPS in vitro and in vivo. Some chromatin-binding proteins undergo LLPS in purified form in near-physiological ionic strength buffers while others will do so only in the presence of DNA, nucleosomes, or chromatin. The final section of the review evaluates the solid and liquid states of chromatin in the nucleus. While chromatin behaves as an immobile solid on the mesoscale, nucleosomes are mobile on the nanoscale. We discuss how this dual nature of chromatin, which fits well the concept of viscoelasticity, contributes to genome structure, emphasizing the dominant role of chromatin self-interaction.
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Affiliation(s)
- Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka, 411-8540, Japan.
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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7
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Molecular dynamics simulations reveal how H3K56 acetylation impacts nucleosome structure to promote DNA exposure for lesion sensing. DNA Repair (Amst) 2021; 107:103201. [PMID: 34399316 DOI: 10.1016/j.dnarep.2021.103201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/12/2021] [Accepted: 08/02/2021] [Indexed: 01/04/2023]
Abstract
The first order of DNA packaging is the nucleosome with the DNA wrapped around the histone octamer. This leaves the nucleosomal DNA with access restrictions, which impose a significant barrier to repair of damaged DNA. The efficiency of DNA repair has been related to nucleosome structure and chromatin status, which is modulated in part by post-translational modifications (PTMs) of histones. Numerous studies have suggested a role for acetylation of lysine at position 56 of the H3 histone (H3K56ac) in various DNA transactions, including the response to DNA damage and its association with human cancer. Biophysical studies have revealed that H3K56ac increases DNA accessibility by facilitating spontaneous and transient unwrapping motions of the DNA ends. However, how this acetylation mark modulates nucleosome structure and dynamics to promote accessibility to the damaged DNA for repair factors and other proteins is still poorly understood. Here, we utilize approximately 5-6 microseconds of atomistic molecular dynamics simulations to delineate the impact of H3K56 acetylation on the nucleosome structure and dynamics, and to elucidate how these nucleosome properties are further impacted when a bulky benzo[a]pyrene-derived DNA lesion is placed near the acetylation site. Our findings reveal that H3K56ac alone induces considerable disturbance to the histone-DNA/histone-histone interactions, and amplifies the distortions imposed by the presence of the lesion. Our work highlights the important role of H3K56 acetylation in response to DNA damage and depicts how access to DNA lesions by the repair machinery can be facilitated within the nucleosome via a key acetylation event.
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8
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Woods DC, Rodríguez-Ropero F, Wereszczynski J. The Dynamic Influence of Linker Histone Saturation within the Poly-Nucleosome Array. J Mol Biol 2021; 433:166902. [PMID: 33667509 DOI: 10.1016/j.jmb.2021.166902] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/15/2021] [Accepted: 02/20/2021] [Indexed: 02/08/2023]
Abstract
Linker histones bind to nucleosomes and modify chromatin structure and dynamics as a means of epigenetic regulation. Biophysical studies have shown that chromatin fibers can adopt a plethora of conformations with varying levels of compaction. Linker histone condensation, and its specific binding disposition, has been associated with directly tuning this ensemble of states. However, the atomistic dynamics and quantification of this mechanism remains poorly understood. Here, we present molecular dynamics simulations of octa-nucleosome arrays, based on a cryo-EM structure of the 30-nm chromatin fiber, with and without the globular domains of the H1 linker histone to determine how they influence fiber structures and dynamics. Results show that when bound, linker histones inhibit DNA flexibility and stabilize repeating tetra-nucleosomal units, giving rise to increased chromatin compaction. Furthermore, upon the removal of H1, there is a significant destabilization of this compact structure as the fiber adopts less strained and untwisted states. Interestingly, linker DNA sampling in the octa-nucleosome is exaggerated compared to its mono-nucleosome counterparts, suggesting that chromatin architecture plays a significant role in DNA strain even in the absence of linker histones. Moreover, H1-bound states are shown to have increased stiffness within tetra-nucleosomes, but not between them. This increased stiffness leads to stronger long-range correlations within the fiber, which may result in the propagation of epigenetic signals over longer spatial ranges. These simulations highlight the effects of linker histone binding on the internal dynamics and global structure of poly-nucleosome arrays, while providing physical insight into a mechanism of chromatin compaction.
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Affiliation(s)
- Dustin C Woods
- Department of Chemistry and the Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, IL 60616, United States
| | - Francisco Rodríguez-Ropero
- Department of Physics and the Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, IL 60616, United States
| | - Jeff Wereszczynski
- Department of Physics and the Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, IL 60616, United States.
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9
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Gómez-García PA, Portillo-Ledesma S, Neguembor MV, Pesaresi M, Oweis W, Rohrlich T, Wieser S, Meshorer E, Schlick T, Cosma MP, Lakadamyali M. Mesoscale Modeling and Single-Nucleosome Tracking Reveal Remodeling of Clutch Folding and Dynamics in Stem Cell Differentiation. Cell Rep 2021; 34:108614. [PMID: 33440158 PMCID: PMC7842188 DOI: 10.1016/j.celrep.2020.108614] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 10/29/2020] [Accepted: 12/16/2020] [Indexed: 01/01/2023] Open
Abstract
Nucleosomes form heterogeneous groups in vivo, named clutches. Clutches are smaller and less dense in mouse embryonic stem cells (ESCs) compared to neural progenitor cells (NPCs). Using coarse-grained modeling of the pluripotency Pou5f1 gene, we show that the genome-wide clutch differences between ESCs and NPCs can be reproduced at a single gene locus. Larger clutch formation in NPCs is associated with changes in the compaction and internucleosome contact probability of the Pou5f1 fiber. Using single-molecule tracking (SMT), we further show that the core histone protein H2B is dynamic, and its local mobility relates to the structural features of the chromatin fiber. H2B is less stable and explores larger areas in ESCs compared to NPCs. The amount of linker histone H1 critically affects local H2B dynamics. Our results have important implications for how nucleosome organization and H2B dynamics contribute to regulate gene activity and cell identity.
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Affiliation(s)
- Pablo Aurelio Gómez-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), 08003 Barcelona, Spain; Institute of Photonic Sciences (ICFO), The Barcelona Institute of Science and Technology (BIST), Castelldefels, 08860 Barcelona, Spain
| | - Stephanie Portillo-Ledesma
- Department of Chemistry, 1021 Silver Center, 100 Washington Square East, New York University, New York, NY 10003, USA
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), 08003 Barcelona, Spain
| | - Martina Pesaresi
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), 08003 Barcelona, Spain
| | - Walaa Oweis
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Talia Rohrlich
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Stefan Wieser
- Institute of Photonic Sciences (ICFO), The Barcelona Institute of Science and Technology (BIST), Castelldefels, 08860 Barcelona, Spain
| | - Eran Meshorer
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Tamar Schlick
- Department of Chemistry, 1021 Silver Center, 100 Washington Square East, New York University, New York, NY 10003, USA; Courant Institute of Mathematical Sciences, 251 Mercer Street, New York University, New York, NY 10012, USA; NYU-ECNU Center for Computational Chemistry at New York University Shanghai, 340 Geography Building, 3663 North Zhongshan Road, Shanghai 3663, China
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China; CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
| | - Melike Lakadamyali
- Perelman School of Medicine, Department of Physiology, University of Pennsylvania, Clinical Research Building, 415 Curie Boulevard, Philadelphia, PA 19104, USA; Perelman School of Medicine, Department of Cell and Developmental Biology, University of Pennsylvania, Biomedical Research Building, 421 Curie Boulevard, Philadelphia, PA 19104, USA.
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10
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le Paige UB, Xiang S, Hendrix MMRM, Zhang Y, Folkers GE, Weingarth M, Bonvin AMJJ, Kutateladze TG, Voets IK, Baldus M, van Ingen H. Characterization of nucleosome sediments for protein interaction studies by solid-state NMR spectroscopy. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:187-202. [PMID: 35647606 PMCID: PMC9135053 DOI: 10.5194/mr-2-187-2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Regulation of DNA-templated processes such as gene transcription and DNA repair depend on the interaction of a wide range of proteins with the nucleosome, the fundamental building block of chromatin. Both solution and solid-state NMR spectroscopy have become an attractive approach to study the dynamics and interactions of nucleosomes, despite their high molecular weight of ~ 200 kDa. For solid-state NMR (ssNMR) studies, dilute solutions of nucleosomes are converted to a dense phase by sedimentation or precipitation. Since nucleosomes are known to self-associate, these dense phases may induce extensive interactions between nucleosomes, which could interfere with protein-binding studies. Here, we characterized the packing of nucleosomes in the dense phase created by sedimentation using NMR and small-angle X-ray scattering (SAXS) experiments. We found that nucleosome sediments are gels with variable degrees of solidity, have nucleosome concentration close to that found in crystals, and are stable for weeks under high-speed magic angle spinning (MAS). Furthermore, SAXS data recorded on recovered sediments indicate that there is no pronounced long-range ordering of nucleosomes in the sediment. Finally, we show that the sedimentation approach can also be used to study low-affinity protein interactions with the nucleosome. Together, our results give new insights into the sample characteristics of nucleosome sediments for ssNMR studies and illustrate the broad applicability of sedimentation-based NMR studies.
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Affiliation(s)
- Ulric B. le Paige
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - ShengQi Xiang
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Marco M. R. M. Hendrix
- Laboratory of Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, the Netherlands
| | - Yi Zhang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Gert E. Folkers
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Markus Weingarth
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Alexandre M. J. J. Bonvin
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Tatiana G. Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Ilja K. Voets
- Laboratory of Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, the Netherlands
| | - Marc Baldus
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Hugo van Ingen
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
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11
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Portillo-Ledesma S, Tsao LH, Wagley M, Lakadamyali M, Cosma MP, Schlick T. Nucleosome Clutches are Regulated by Chromatin Internal Parameters. J Mol Biol 2020; 433:166701. [PMID: 33181171 DOI: 10.1016/j.jmb.2020.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/27/2020] [Accepted: 11/02/2020] [Indexed: 01/17/2023]
Abstract
Nucleosomes cluster together when chromatin folds in the cell to form heterogeneous groups termed "clutches". These structural units add another level of chromatin regulation, for example during cell differentiation. Yet, the mechanisms that regulate their size and compaction remain obscure. Here, using our chromatin mesoscale model, we dissect clutch patterns in fibers with different combinations of nucleosome positions, linker histone density, and acetylation levels to investigate their role in clutch regulation. First, we isolate the effect of each chromatin parameter by studying systems with regular nucleosome spacing; second, we design systems with naturally-occurring linker lengths that fold onto specific clutch patterns; third, we model gene-encoding fibers to understand how these combined factors contribute to gene structure. Our results show how these chromatin parameters act together to produce different-sized nucleosome clutches. The length of nucleosome free regions (NFRs) profoundly affects clutch size, while the length of linker DNA has a moderate effect. In general, higher linker histone densities produce larger clutches by a chromatin compaction mechanism, while higher acetylation levels produce smaller clutches by a chromatin unfolding mechanism. We also show that it is possible to design fibers with naturally-occurring DNA linkers and NFRs that fold onto specific clutch patterns. Finally, in gene-encoding systems, a complex combination of variables dictates a gene-specific clutch pattern. Together, these results shed light into the mechanisms that regulate nucleosome clutches and suggest a new epigenetic mechanism by which chromatin parameters regulate transcriptional activity via the three-dimensional folded state of the genome at a nucleosome level.
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Affiliation(s)
- Stephanie Portillo-Ledesma
- Department of Chemistry, New York University, 1021 Silver, 100 Washington Square East, New York, NY, 10003, USA
| | - Lucille H Tsao
- Department of Chemistry, New York University, 1021 Silver, 100 Washington Square East, New York, NY, 10003, USA
| | - Meghna Wagley
- Department of Chemistry, New York University, 1021 Silver, 100 Washington Square East, New York, NY, 10003, USA
| | - Melike Lakadamyali
- Perelman School of Medicine, Department of Physiology, University of Pennsylvania, Clinical Research Building, 415 Curie Boulevard, Philadelphia, PA 19104, USA; Perelman School of Medicine, Department of Cell and Developmental Biology, University of Pennsylvania, Clinical Research Building, 415 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China; CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Tamar Schlick
- Department of Chemistry, New York University, 1021 Silver, 100 Washington Square East, New York, NY, 10003, USA; New York University-East China Normal University Center for Computational Chemistry at New York University Shanghai, Room 340, Geography Building, 3663 North Zhongshan Road, Shanghai, 200062, China; Courant Institute of Mathematical Sciences, New York University, 251 Mercer St, New York, NY, 10012, USA.
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12
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Beads on a string-nucleosome array arrangements and folding of the chromatin fiber. Nat Struct Mol Biol 2020; 27:109-118. [PMID: 32042149 DOI: 10.1038/s41594-019-0368-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/20/2019] [Indexed: 12/21/2022]
Abstract
Understanding how the genome is structurally organized as chromatin is essential for understanding its function. Here, we review recent developments that allowed the readdressing of old questions regarding the primary level of chromatin structure, the arrangement of nucleosomes along the DNA and the folding of the nucleosome fiber in nuclear space. In contrast to earlier views of nucleosome arrays as uniformly regular and folded, recent findings reveal heterogeneous array organization and diverse modes of folding. Local structure variations reflect a continuum of functional states characterized by differences in post-translational histone modifications, associated chromatin-interacting proteins and nucleosome-remodeling enzymes.
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13
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Ohyama T. New Aspects of Magnesium Function: A Key Regulator in Nucleosome Self-Assembly, Chromatin Folding and Phase Separation. Int J Mol Sci 2019; 20:ijms20174232. [PMID: 31470631 PMCID: PMC6747271 DOI: 10.3390/ijms20174232] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 02/07/2023] Open
Abstract
Metal cations are associated with many biological processes. The effects of these cations on nucleic acids and chromatin were extensively studied in the early stages of nucleic acid and chromatin research. The results revealed that some monovalent and divalent metal cations, including Mg2+, profoundly affect the conformations and stabilities of nucleic acids, the folding of chromatin fibers, and the extent of chromosome condensation. Apart from these effects, there have only been a few reports on the functions of these cations. In 2007 and 2013, however, Mg2+-implicated novel phenomena were found: Mg2+ facilitates or enables both self-assembly of identical double-stranded (ds) DNA molecules and self-assembly of identical nucleosomes in vitro. These phenomena may be deeply implicated in the heterochromatin domain formation and chromatin-based phase separation. Furthermore, a recent study showed that elevation of the intranuclear Mg2+ concentration causes unusual differentiation of mouse ES (embryonic stem) cells. All of these phenomena seem to be closely related to one another. Mg2+ seems to be a key regulator of chromatin dynamics and chromatin-based biological processes.
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Affiliation(s)
- Takashi Ohyama
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
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Röder K, Wales DJ. Predicting Pathways between Distant Configurations for Biomolecules. J Chem Theory Comput 2018; 14:4271-4278. [DOI: 10.1021/acs.jctc.8b00370] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Konstantin Röder
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - David J. Wales
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
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15
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How does chromatin package DNA within nucleus and regulate gene expression? Int J Biol Macromol 2017; 101:862-881. [PMID: 28366861 DOI: 10.1016/j.ijbiomac.2017.03.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/26/2023]
Abstract
The human body is made up of 60 trillion cells, each cell containing 2 millions of genomic DNA in its nucleus. How is this genomic deoxyribonucleic acid [DNA] organised into nuclei? Around 1880, W. Flemming discovered a nuclear substance that was clearly visible on staining under primitive light microscopes and named it 'chromatin'; this is now thought to be the basic unit of genomic DNA organization. Since long before DNA was known to carry genetic information, chromatin has fascinated biologists. DNA has a negatively charged phosphate backbone that produces electrostatic repulsion between adjacent DNA regions, making it difficult for DNA to fold upon itself. In this article, we will try to shed light on how does chromatin package DNA within nucleus and regulate gene expression?
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16
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Luque A, Ozer G, Schlick T. Correlation among DNA Linker Length, Linker Histone Concentration, and Histone Tails in Chromatin. Biophys J 2016; 110:2309-2319. [PMID: 27276249 PMCID: PMC4906253 DOI: 10.1016/j.bpj.2016.04.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 04/12/2016] [Accepted: 04/19/2016] [Indexed: 01/08/2023] Open
Abstract
Eukaryotic cells condense their genetic material in the nucleus in the form of chromatin, a macromolecular complex made of DNA and multiple proteins. The structure of chromatin is intimately connected to the regulation of all eukaryotic organisms, from amoebas to humans, but its organization remains largely unknown. The nucleosome repeat length (NRL) and the concentration of linker histones (ρLH) are two structural parameters that vary among cell types and cell cycles; the NRL is the number of DNA basepairs wound around each nucleosome core plus the number of basepairs linking successive nucleosomes. Recent studies have found a linear empirical relationship between the variation of these two properties for different cells, but its underlying mechanism remains elusive. Here we apply our established mesoscale chromatin model to explore the mechanisms responsible for this relationship, by investigating chromatin fibers as a function of NRL and ρLH combinations. We find that a threshold of linker histone concentration triggers the compaction of chromatin into well-formed 30-nm fibers; this critical value increases linearly with NRL, except for long NRLs, where the fibers remain disorganized. Remarkably, the interaction patterns between core histone tails and chromatin elements are highly sensitive to the NRL and ρLH combination, suggesting a molecular mechanism that could have a key role in regulating the structural state of the fibers in the cell. An estimate of the minimized work and volume associated with storage of chromatin fibers in the nucleus further suggests factors that could spontaneously regulate the NRL as a function of linker histone concentration. Both the tail interaction map and DNA packing considerations support the empirical NRL/ρLH relationship and offer a framework to interpret experiments for different chromatin conditions in the cell.
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Affiliation(s)
- Antoni Luque
- Department of Mathematics and Statistics, Viral Information Institute and Computational Science Research Center, San Diego State University, San Diego, California
| | - Gungor Ozer
- Department of Chemistry, New York University, New York, New York
| | - Tamar Schlick
- Department of Chemistry, New York University, New York, New York; Courant Institute of Mathematical Sciences, New York University, New York, New York; New York University-East China Normal University Center for Computational Chemistry at New York University Shanghai, Shanghai, China.
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17
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Krajewski WA. On the role of inter-nucleosomal interactions and intrinsic nucleosome dynamics in chromatin function. Biochem Biophys Rep 2016; 5:492-501. [PMID: 28955857 PMCID: PMC5600426 DOI: 10.1016/j.bbrep.2016.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/05/2016] [Accepted: 02/15/2016] [Indexed: 01/10/2023] Open
Abstract
Evidence is emerging that many diseases result from defects in gene functions, which, in turn, depend on the local chromatin environment of a gene. However, it still remains not fully clear how chromatin activity code is 'translated' to the particular 'activating' or 'repressing' chromatin structural transition. Commonly, chromatin remodeling in vitro was studied using mononucleosomes as a model. However, recent data suggest that structural reorganization of a single mononucleosome is not equal to remodeling of a nucleosome particle under multinucleosomal content - such as, interaction of nucleosomes via flexible histone termini could significantly alter the mode (and the resulting products) of nucleosome structural transitions. It is becoming evident that a nucleosome array does not constitute just a 'polymer' of individual 'canonical' nucleosomes due to multiple inter-nucleosomal interactions which affect nucleosome dynamics and structure. It could be hypothesized, that inter-nucleosomal interactions could act in cooperation with nucleosome inherent dynamics to orchestrate DNA-based processes and promote formation and stabilization of highly-dynamic, accessible structure of a nucleosome array. In the proposed paper we would like to discuss the nucleosome dynamics within the chromatin fiber mainly as it pertains to the roles of the structural changes mediated by inter-nucleosomal interactions.
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Affiliation(s)
- Wladyslaw A Krajewski
- Institute of Developmental Biology of Russian Academy of Sciences, ul. Vavilova 26, Moscow, 119334 Russia
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18
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Collepardo-Guevara R, Portella G, Vendruscolo M, Frenkel D, Schlick T, Orozco M. Chromatin Unfolding by Epigenetic Modifications Explained by Dramatic Impairment of Internucleosome Interactions: A Multiscale Computational Study. J Am Chem Soc 2015; 137:10205-15. [PMID: 26192632 PMCID: PMC6251407 DOI: 10.1021/jacs.5b04086] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Histone tails and their epigenetic modifications play crucial roles in gene expression regulation by altering the architecture of chromatin. However, the structural mechanisms by which histone tails influence the interconversion between active and inactive chromatin remain unknown. Given the technical challenges in obtaining detailed experimental characterizations of the structure of chromatin, multiscale computations offer a promising alternative to model the effect of histone tails on chromatin folding. Here we combine multimicrosecond atomistic molecular dynamics simulations of dinucleosomes and histone tails in explicit solvent and ions, performed with three different state-of-the-art force fields and validated by experimental NMR measurements, with coarse-grained Monte Carlo simulations of 24-nucleosome arrays to describe the conformational landscape of histone tails, their roles in chromatin compaction, and the impact of lysine acetylation, a widespread epigenetic change, on both. We find that while the wild-type tails are highly flexible and disordered, the dramatic increase of secondary-structure order by lysine acetylation unfolds chromatin by decreasing tail availability for crucial fiber-compacting internucleosome interactions. This molecular level description of the effect of histone tails and their charge modifications on chromatin folding explains the sequence sensitivity and underscores the delicate connection between local and global structural and functional effects. Our approach also opens new avenues for multiscale processes of biomolecular complexes.
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Affiliation(s)
- Rosana Collepardo-Guevara
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
- Joint BSC-CRG-IRB Pro-gramme on Computational Biology. Institute for Research in Biomedicine. Baldiri i Reixac 19. 08028, Barcelona, Spain
| | - Guillem Portella
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
- Joint BSC-CRG-IRB Pro-gramme on Computational Biology. Institute for Research in Biomedicine. Baldiri i Reixac 19. 08028, Barcelona, Spain
| | - Michele Vendruscolo
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Daan Frenkel
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Tamar Schlick
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003, USA
- Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012, USA
| | - Modesto Orozco
- Joint BSC-CRG-IRB Pro-gramme on Computational Biology. Institute for Research in Biomedicine. Baldiri i Reixac 19. 08028, Barcelona, Spain
- Departament de Bioquímica i Biologia Molecular. Facultat de Biologia. Universitat de Barcelona. Avgda Diagonal 643, 08028, Barcelona, Spain
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Winogradoff D, Echeverria I, Potoyan DA, Papoian GA. The Acetylation Landscape of the H4 Histone Tail: Disentangling the Interplay between the Specific and Cumulative Effects. J Am Chem Soc 2015; 137:6245-53. [DOI: 10.1021/jacs.5b00235] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- David Winogradoff
- Chemical
Physics Program and ‡Department of Chemistry and Biochemistry and
Institute for Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
| | - Ignacia Echeverria
- Chemical
Physics Program and ‡Department of Chemistry and Biochemistry and
Institute for Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
| | - Davit A. Potoyan
- Chemical
Physics Program and ‡Department of Chemistry and Biochemistry and
Institute for Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
| | - Garegin A. Papoian
- Chemical
Physics Program and ‡Department of Chemistry and Biochemistry and
Institute for Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
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20
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Interaction of chromatin with a histone H1 containing swapped N- and C-terminal domains. Biosci Rep 2015; 35:BSR20150087. [PMID: 26182371 PMCID: PMC4613717 DOI: 10.1042/bsr20150087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 04/27/2015] [Indexed: 12/12/2022] Open
Abstract
The present study was to understand whether the globular or C-terminal linker histone domain is more important for its binding to chromatin. Using histone H1, with swapped domain orientation,
we found that both domains are equally important for nucleosome binding. Although the details of the structural involvement of histone H1 in the organization of the nucleosome are quite well understood, the sequential events involved in the recognition of its binding site are not as well known. We have used a recombinant human histone H1 (H1.1) in which the N- and C-terminal domains (NTD/CTD) have been swapped and we have reconstituted it on to a 208-bp nucleosome. We have shown that the swapped version of the protein is still able to bind to nucleosomes through its structurally folded wing helix domain (WHD); however, analytical ultracentrifuge analysis demonstrates its ability to properly fold the chromatin fibre is impaired. Furthermore, FRAP analysis shows that the highly dynamic binding association of histone H1 with the chromatin fibre is altered, with a severely decreased half time of residence. All of this suggests that proper binding of histone H1 to chromatin is determined by the simultaneous and synergistic binding of its WHD–CTD to the nucleosome.
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21
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Li G, Zhu P. Structure and organization of chromatin fiber in the nucleus. FEBS Lett 2015; 589:2893-904. [PMID: 25913782 DOI: 10.1016/j.febslet.2015.04.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 12/30/2022]
Abstract
Eukaryotic genomes are organized hierarchically into chromatin structures by histones. Despite extensive research for over 30 years, not only the fundamental structure of the 30-nm chromatin fiber is being debated, but the actual existence of such fiber remains hotly contested. In this review, we focus on the most recent progress in elucidating the structure of the 30-nm fiber upon in vitro reconstitution, and its possible organization inside the nucleus. In addition, we discuss the roles of linker histone H1 as well as the importance of specific nucleosome-nucleosome interactions in the formation of the 30-nm fiber. Finally, we discuss the involvement of structural variations and epigenetic mechanisms available for the regulation of this chromatin form.
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Affiliation(s)
- Guohong Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Ping Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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22
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Pepenella S, Murphy KJ, Hayes JJ. A distinct switch in interactions of the histone H4 tail domain upon salt-dependent folding of nucleosome arrays. J Biol Chem 2014; 289:27342-27351. [PMID: 25122771 DOI: 10.1074/jbc.m114.595140] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The core histone tail domains mediate inter-nucleosomal interactions that direct folding and condensation of nucleosome arrays into higher-order chromatin structures. The histone H4 tail domain facilitates inter-array interactions by contacting both the H2A/H2B acidic patch and DNA of neighboring nucleosomes. Likewise, H4 tail-H2A contacts stabilize array folding. However, whether the H4 tail domains stabilize array folding via inter-nucleosomal interactions with the DNA of neighboring nucleosomes remains unclear. We utilized defined oligonucleosome arrays containing a single specialized nucleosome with a photo-inducible cross-linker in the N terminus of the H4 tail to characterize these interactions. We observed that the H4 tail participates exclusively in intra-array interactions with DNA in unfolded arrays. These interactions are diminished during array folding, yet no inter-nucleosome, intra-array H4 tail-DNA contacts are observed in condensed chromatin. However, we document contacts between the N terminus of the H4 tail and H2A. Installation of acetylation mimics known to disrupt H4-H2A surface interactions did not increase observance of H4-DNA inter-nucleosomal interactions. These results suggest the multiple functions of the H4 tail require targeted distinct interactions within condensed chromatin.
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Affiliation(s)
- Sharon Pepenella
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
| | - Kevin J Murphy
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
| | - Jeffrey J Hayes
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642.
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23
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Core Histone Charge and Linker Histone H1 Effects on the Chromatin Structure ofSchizosaccharomyces pombe. Biosci Biotechnol Biochem 2014; 76:2261-6. [DOI: 10.1271/bbb.120548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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24
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Intra- and inter-nucleosome interactions of the core histone tail domains in higher-order chromatin structure. Chromosoma 2013; 123:3-13. [PMID: 23996014 DOI: 10.1007/s00412-013-0435-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/17/2013] [Accepted: 08/19/2013] [Indexed: 10/26/2022]
Abstract
Eukaryotic chromatin is a hierarchical collection of nucleoprotein structures that package DNA to form chromosomes. The initial levels of packaging include folding of long strings of nucleosomes into secondary structures and array-array association into higher-order tertiary chromatin structures. The core histone tail domains are required for the assembly of higher-order structures and mediate short- and long-range intra- and inter-nucleosome interactions with both DNA and protein targets to direct their assembly. However, important details of these interactions remain unclear and are a subject of much interest and recent investigations. Here, we review work defining the interactions of the histone N-terminal tails with DNA and protein targets relevant to chromatin higher-order structures, with a specific emphasis on the contributions of H3 and H4 tails to oligonucleosome folding and stabilization. We evaluate both classic and recent experiments determining tail structures, effect of tail cleavage/loss, and posttranslational modifications of the tails on nucleosomes and nucleosome arrays, as well as inter-nucleosomal and inter-array interactions of the H3 and H4 N-terminal tails.
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25
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Histone chaperone FACT action during transcription through chromatin by RNA polymerase II. Proc Natl Acad Sci U S A 2013; 110:7654-9. [PMID: 23610384 DOI: 10.1073/pnas.1222198110] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
FACT (facilitates chromatin transcription) is a histone chaperone that promotes chromatin recovery during transcription, with additional roles in cell differentiation. Although several models of the action of FACT during transcription have been proposed, they remain to be experimentally evaluated. Here we show that human FACT (hFACT) facilitates transcription through chromatin and promotes nucleosome recovery in vitro. FACT action depends on the presence of histone H2A/H2B dimers in the nucleosome. Kinetic analysis suggests that hFACT decreases the lifetime of nonproductive RNA polymerase II (Pol II)-nucleosome complexes and facilitates the formation of productive complexes containing nucleosomal DNA partially uncoiled from the octamer. Taken together, our data suggest that hFACT interacts with DNA-binding surfaces of H2A/H2B dimers, facilitating uncoiling of DNA from the histone octamer. Thus, hFACT-H2A/H2B interactions play a key role in overcoming the nucleosomal barrier by Pol II and promoting nucleosome survival during transcription.
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26
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Yang Z, Hayes JJ. The divalent cations Ca2+ and Mg2+ play specific roles in stabilizing histone-DNA interactions within nucleosomes that are partially redundant with the core histone tail domains. Biochemistry 2011; 50:9973-81. [PMID: 22007636 DOI: 10.1021/bi201377x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We previously reported that reconstituted nucleosomes undergo sequence-dependent translational repositioning upon removal of the core histone tail domains under physiological conditions, indicating that the tails influence the choice of position. We report here that removal of the core histone tail domains increases the exposure of the DNA backbone in nucleosomes to hydroxyl radicals, a nonbiased chemical cleavage reagent, indicative of an increase in the motility of the DNA on the histone surface. Moreover, we demonstrate that the divalent cations Mg(2+) and Ca(2+) can replace the role of the tail domains with regard to stabilization of histone-DNA interactions within the nucleosome core and restrict repositioning of nucleosomes upon tail removal. However, when nucleosomes were incubated with Mg(2+) after tail removal, the original distribution of translational positions was not re-established, indicating that divalent cations increase the energy barrier between translational positions rather than altering the free energy differences between positions. Interestingly, other divalent cations such as Zn(2+), Fe(2+), Co(2+), and Mn(2+) had little or no effect on the stability of histone-DNA interactions within tailless nucleosomes. These results support the idea that specific binding sites for Mg(2+) and Ca(2+) ions exist within the nucleosome and play a critical role in nucleosome stability that is partially redundant with the core histone tail domains.
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Affiliation(s)
- Zungyoon Yang
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA
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27
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Structure and dynamics of dinucleosomes assessed by atomic force microscopy. JOURNAL OF AMINO ACIDS 2011; 2012:650840. [PMID: 22312477 PMCID: PMC3268019 DOI: 10.1155/2012/650840] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 08/13/2011] [Indexed: 12/01/2022]
Abstract
Dynamics of nucleosomes and their interactions are important for understanding the mechanism of chromatin assembly. Internucleosomal interaction is required for the formation of higher-order chromatin structures. Although H1 histone is critically involved in the process of chromatin assembly, direct internucleosomal interactions contribute to this process as well. To characterize the interactions of nucleosomes within the nucleosome array, we designed a dinucleosome and performed direct AFM imaging. The analysis of the AFM data showed dinucleosomes are very dynamic systems, enabling the nucleosomes to move in a broad range along the DNA template. Di-nucleosomes in close proximity were observed, but their population was low. The use of the zwitterionic detergent, CHAPS, increased the dynamic range of the di-nucleosome, facilitating the formation of tight di-nucleosomes. The role of CHAPS and similar natural products in chromatin structure and dynamics is also discussed.
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Abstract
Alterations of chromatin structure have been shown to be crucial for response to cell signaling and for programmed gene expression in development. Posttranslational histone modifications influence changes in chromatin structure both directly and by targeting or activating chromatin-remodeling complexes. Histone modifications intersect with cell signaling pathways to control gene expression and can act combinatorially to enforce or reverse epigenetic marks in chromatin. Through their recognition by protein complexes with enzymatic activities cross talk is established between different modifications and with other epigenetic pathways, including noncoding RNAs (ncRNAs) and DNA methylation. Here, we review the functions of histone modifications and their exploitation in the programming of gene expression during several events in development.
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Affiliation(s)
- Tamaki Suganuma
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.
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29
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Kowalski A, Pałyga J. Chromatin compaction in terminally differentiated avian blood cells: the role of linker histone H5 and non-histone protein MENT. Chromosome Res 2011; 19:579-90. [PMID: 21656257 PMCID: PMC3139888 DOI: 10.1007/s10577-011-9218-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 05/04/2011] [Accepted: 05/06/2011] [Indexed: 10/28/2022]
Abstract
Chromatin has a tendency to shift from a relatively decondensed (active) to condensed (inactive) state during cell differentiation due to interactions of specific architectural and/or regulatory proteins with DNA. A promotion of chromatin folding in terminally differentiated avian blood cells requires the presence of either histone H5 in erythrocytes or non-histone protein, myeloid and erythroid nuclear termination stage-specific protein (MENT), in white blood cells (lymphocytes and granulocytes). These highly abundant proteins assist in folding of nucleosome arrays and self-association of chromatin fibers into compacted chromatin structures. Here, we briefly review structural aspects and molecular mode of action by which these unrelated proteins can spread condensed chromatin to form inactivated regions in the genome.
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Affiliation(s)
- Andrzej Kowalski
- Department of Biochemistry and Genetics, Institute of Biology, Jan Kochanowski University, ul. Świętokrzyska 15, 25-406 Kielce, Poland.
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30
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31
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Szerlong HJ, Prenni JE, Nyborg JK, Hansen JC. Activator-dependent p300 acetylation of chromatin in vitro: enhancement of transcription by disruption of repressive nucleosome-nucleosome interactions. J Biol Chem 2010; 285:31954-64. [PMID: 20720004 DOI: 10.1074/jbc.m110.148718] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Condensation of chromatin into higher order structures is mediated by intra- and interfiber nucleosome-nucleosome interactions. Our goals in this study were to determine the impact specific activator-dependent histone acetylation had on chromatin condensation and to ascertain whether acetylation-induced changes in chromatin condensation were related to changes in RNA polymerase II (RNAPII) activity. To accomplish this, an in vitro model system was constructed in which the purified transcriptional activators, Tax and phosphorylated CREB (cAMP-response element-binding protein), recruited the p300 histone acetyltransferase to nucleosomal templates containing the human T-cell leukemia virus type-1 promoter sequences. We find that activator-dependent p300 histone acetylation disrupted both inter- and intrafiber nucleosome-nucleosome interactions and simultaneously led to enhanced RNAPII transcription from the decondensed model chromatin. p300 histone acetyltransferase activity had two distinct components: non-targeted, ubiquitous activity in the absence of activators and activator-dependent activity targeted primarily to promoter-proximal nucleosomes. Mass spectrometry identified several unique p300 acetylation sites on nucleosomal histone H3 (H3K9, H3K27, H3K36, and H3K37). Collectively, our data have important implications for understanding both the mechanism of RNAPII transcriptional regulation by chromatin and the molecular determinants of higher order chromatin structure.
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Affiliation(s)
- Heather J Szerlong
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870, USA
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32
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Perišić O, Collepardo-Guevara R, Schlick T. Modeling studies of chromatin fiber structure as a function of DNA linker length. J Mol Biol 2010; 403:777-802. [PMID: 20709077 DOI: 10.1016/j.jmb.2010.07.057] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 07/24/2010] [Accepted: 07/29/2010] [Indexed: 01/22/2023]
Abstract
Chromatin fibers encountered in various species and tissues are characterized by different nucleosome repeat lengths (NRLs) of the linker DNA connecting the nucleosomes. While single cellular organisms and rapidly growing cells with high protein production have short NRL ranging from 160 to 189 bp, mature cells usually have longer NRLs ranging between 190 and 220 bp. Recently, various experimental studies have examined the effect of NRL on the internal organization of chromatin fiber. Here, we investigate by mesoscale modeling of oligonucleosomes the folding patterns for different NRL, with and without linker histone (LH), under typical monovalent salt conditions using both one-start solenoid and two-start zigzag starting configurations. We find that short to medium NRL chromatin fibers (173 to 209 bp) with LH condense into zigzag structures and that solenoid-like features are viable only for longer NRLs (226 bp). We suggest that medium NRLs are more advantageous for packing and various levels of chromatin compaction throughout the cell cycle than their shortest and longest brethren; the former (short NRLs) fold into narrow fibers, while the latter (long NRLs) arrays do not easily lead to high packing ratios due to possible linker DNA bending. Moreover, we show that the LH has a small effect on the condensation of short-NRL arrays but has an important condensation effect on medium-NRL arrays, which have linker lengths similar to the LH lengths. Finally, we suggest that the medium-NRL species, with densely packed fiber arrangements, may be advantageous for epigenetic control because their histone tail modifications can have a greater effect compared to other fibers due to their more extensive nucleosome interaction network.
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Affiliation(s)
- Ognjen Perišić
- Department of Chemistry, New York University, New York, NY 10003, USA
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Ghosh S, Majumder P, Pradhan SK, Dasgupta D. Mechanism of interaction of small transcription inhibitors with DNA in the context of chromatin and telomere. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:795-809. [PMID: 20638489 DOI: 10.1016/j.bbagrm.2010.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/23/2010] [Accepted: 06/30/2010] [Indexed: 01/13/2023]
Abstract
Small molecules from natural and synthetic sources have long been employed as human drugs. The transcription inhibitory potential of one class of these molecules has paved their use as anticancer drugs. The principal mode of action of these molecules is via reversible interaction with genomic DNA, double and multiple stranded. In this article we have revisited the mechanism of the interaction in the context of chromatin and telomere. The established modes of association of these molecules with double helical DNA provide a preliminary mechanism of their transcription inhibitory potential, but the scenario assumes a different dimension when the genomic DNA is associated with proteins in the transcription apparatus of both prokaryotic and eukaryotic organisms. We have discussed this altered scenario as a prelude to understand the chemical biology of their action in the cell. For the telomeric quadruplex DNA, we have reviewed the mechanism of their association with the quadruplex and resultant cellular consequence.
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Affiliation(s)
- Saptaparni Ghosh
- Biophysics Division, Saha Institute of Nuclear Physics, Sector-I, Block-AF, Bidhan Nagar, Kolkata Pin, 700064, India
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Abstract
The interactive chromatin modeling web server (ICM Web) is an interactive tool that allows users to rapidly assess nucleosome stability and fold sequences of DNA into putative chromatin templates. ICM Web takes a sequence composed of As, Cs, Gs, and Ts as input and generates (i) a nucleosome energy level diagram, (ii) coarse-grained representations of free DNA and chromatin and (iii) plots of the helical parameters (Tilt, Roll, Twist, Shift, Slide and Rise) as a function of position. The user can select from several different energy models, nucleosome structures and methods for placing nucleosomes in the energy landscape. Alternatively, if nucleosome footprints are known from experiment, ICM Web can use these positions to create a nucleosome array. The default energy model achieves a correlation coefficient of 0.7 with 100 experimentally determined values of stability and properly predicts the location of six positioned nucleosomes in the mouse mammary tumor virus (MMTV) promoter. ICM Web is suitable for interactively investigating nucleosome stability and chromatin folding for sequences up to tens of kilobases in length. No login is required to use ICM Web.
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Affiliation(s)
- Richard C Stolz
- Department of Biostatistics, Tulane University, 1440 Canal Street, Suite 2001, New Orleans, LA 70112, USA
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35
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Multifunctionality of the linker histones: an emerging role for protein-protein interactions. Cell Res 2010; 20:519-28. [PMID: 20309017 DOI: 10.1038/cr.2010.35] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Linker histones, e.g., H1, are best known for their ability to bind to nucleosomes and stabilize both nucleosome structure and condensed higher-order chromatin structures. However, over the years many investigators have reported specific interactions between linker histones and proteins involved in important cellular processes. The purpose of this review is to highlight evidence indicating an important alternative mode of action for H1, namely protein-protein interactions. We first review key aspects of the traditional view of linker histone action, including the importance of the H1 C-terminal domain. We then discuss the current state of knowledge of linker histone interactions with other proteins, and, where possible, highlight the mechanism of linker histone-mediated protein-protein interactions. Taken together, the data suggest a combinatorial role for the linker histones, functioning both as primary chromatin architectural proteins and simultaneously as recruitment hubs for proteins involved in accessing and modifying the chromatin fiber.
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36
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Abstract
Chromatin is a highly regulated nucleoprotein complex through which genetic material is structured and maneuvered to elicit cellular processes, including transcription, cell division, differentiation, and DNA repair. In eukaryotes, the core of this structure is composed of nucleosomes, or repetitive histone octamer units typically enfolded by 147 base pairs of DNA. DNA is arranged and indexed through these nucleosomal structures to adjust local chromatin compaction and accessibility. Histones are subject to multiple covalent posttranslational modifications, some of which alter intrinsic chromatin properties, others of which present or hinder binding modules for non-histone, chromatin-modifying complexes. Although certain histone marks correlate with different biological outputs, we have yet to fully appreciate their effects on transcription and other cellular processes. Tremendous advancements over the past years have uncovered intriguing histone-related matters and raised important related questions. This review revisits past breakthroughs and discusses novel developments that pertain to histone posttranslational modifications and the affects they have on transcription and DNA packaging.
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Affiliation(s)
- Eric I Campos
- Department of Biochemistry, Howard Hughes Medical Institute, NYU School of Medicine, New York, New York 10016, USA
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37
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Schlick T, Perisić O. Mesoscale simulations of two nucleosome-repeat length oligonucleosomes. Phys Chem Chem Phys 2009; 11:10729-37. [PMID: 20145817 DOI: 10.1039/b918629h] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The compaction of chromatin, accessed through coarse-grained modeling and simulation, reveals different folding patterns as a function of the nucleosome repeat length (NRL), the presence of the linker histone, and the ionic strength. Our results indicate that the linker histone has negligible influence on short NRL fibers, whereas for longer NRL fibers it works like, and in tandem with, concentrated positive counterions to condense the chromatin fiber. Longer NRL fibers also exhibit structural heterogeneity, with solenoid-like conformations viable in addition to irregular zigzags. These features of chromatin and associated internucleosomal patterns presented here help interpret structural dependencies of the chromatin fiber on internal and external factors. In particular, we suggest that longer-NRL are more advantageous for packing and achieving various levels of fiber compaction throughout the cell cycle.
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Affiliation(s)
- Tamar Schlick
- Department of Chemistry and Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, New York 10012, USA.
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Emanuel M, Radja NH, Henriksson A, Schiessel H. The physics behind the larger scale organization of DNA in eukaryotes. Phys Biol 2009; 6:025008. [DOI: 10.1088/1478-3975/6/2/025008] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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39
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McBryant SJ, Klonoski J, Sorensen TC, Norskog SS, Williams S, Resch MG, Toombs JA, Hobdey SE, Hansen JC. Determinants of histone H4 N-terminal domain function during nucleosomal array oligomerization: roles of amino acid sequence, domain length, and charge density. J Biol Chem 2009; 284:16716-16722. [PMID: 19395382 DOI: 10.1074/jbc.m109.011288] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mg(2+)-dependent oligomerization of nucleosomal arrays is correlated with higher order folding transitions that stabilize chromosome structure beyond the 30-nm diameter fiber. In the present studies, we have employed a novel mutagenesis-based approach to identify the macromolecular determinants that control H4 N-terminal domain (NTD) function during oligomerization. Core histones were engineered in which 1) the H2A, H2B, and H3 NTDs were swapped onto the H4 histone fold; 2) the length of the H4 NTD and the H2A NTD on the H4 histone fold, were increased; 3) the charge density of the NTDs on the H4 histone fold was increased or decreased; and 4) the H4 NTD was placed on the H2B histone fold. Model nucleosomal arrays were assembled from wild type and mutant core histone octamers, and Mg(2+)-dependent oligomerization was characterized. The results demonstrated that the H2B and H3 NTDs could replace the H4 NTD, as could the H2A NTD if it was duplicated to the length of the native H4 NTD. Arrays oligomerized at lower salt concentrations as the length of the NTD on the H4 histone fold was increased. Mutations that decreased the NTD charge density required more Mg(2+) to oligomerize, whereas mutants that increased the charge density required less salt. Finally, the H4 NTD functioned differently when attached to the H2B histone fold than the H4 histone fold. These studies have revealed new insights into the biochemical basis for H4 NTD effects on genome architecture as well as the protein chemistry that underlies the function of the intrinsically disordered H4 NTD.
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Affiliation(s)
- Steven J McBryant
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Joshua Klonoski
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Troy C Sorensen
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Sarah S Norskog
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Sere Williams
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Michael G Resch
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - James A Toombs
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Sarah E Hobdey
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Jeffrey C Hansen
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870.
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Hizume K, Nakai T, Araki S, Prieto E, Yoshikawa K, Takeyasu K. Removal of histone tails from nucleosome dissects the physical mechanisms of salt-induced aggregation, linker histone H1-induced compaction, and 30-nm fiber formation of the nucleosome array. Ultramicroscopy 2009; 109:868-73. [PMID: 19328628 DOI: 10.1016/j.ultramic.2009.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In order to reveal the roles of histone tails in the formation of higher-order chromatin structures, we employed atomic force microscopy (AFM), and an in vitro reconstitution system to examine the properties of reconstituted chromatin composed of tail-less histones and a long DNA (106-kb plasmid) template. The tail-less nucleosomes did not aggregate at high salt concentrations or with an excess amount of core histones, in contrast with the behavior of nucleosomal arrays composed of nucleosomes containing normal, N-terminal tails. Analysis of our nucleosome distributions reveals that the attractive interaction between tail-less nucleosomes is weakened. Addition of linker histone H1 into the tail-less nucleosomal array failed to promote the formation of 30nm chromatin fibers that are usually formed in the normal nucleosomal array. These results demonstrate that the attractive interaction between nucleosomes via histone tails plays a critical role in the formation of the uniform 30-nm chromatin fiber.
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Affiliation(s)
- Kohji Hizume
- Laboratory of Plasma Membrane and Nuclear Signaling, Graduate School of Biostudies, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
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41
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The H4 tail domain participates in intra- and internucleosome interactions with protein and DNA during folding and oligomerization of nucleosome arrays. Mol Cell Biol 2008; 29:538-46. [PMID: 19001093 DOI: 10.1128/mcb.01343-08] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The condensation of nucleosome arrays into higher-order secondary and tertiary chromatin structures likely involves long-range internucleosomal interactions mediated by the core histone tail domains. We have characterized interarray interactions mediated by the H4 tail domain, known to play a predominant role in the formation of such structures. We find that the N-terminal end of the H4 tail mediates interarray contacts with DNA during self-association of oligonucleosome arrays similar to that found previously for the H3 tail domain. However, a site near the histone fold domain of H4 participates in a distinct set of interactions, contacting both DNA and H2A in condensed structures. Moreover, we also find that H4-H2A interactions occur via an intra- as well as an internucleosomal fashion, supporting an additional intranucleosomal function for the tail. Interestingly, acetylation of the H4 tail has little effect on interarray interactions by itself but overrides the strong stimulation of interarray interactions induced by linker histones. Our results indicate that the H4 tail facilitates secondary and tertiary chromatin structure formation via a complex array of potentially exclusive interactions that are distinct from those of the H3 tail domain.
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42
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Ujvári A, Hsieh FK, Luse SW, Studitsky VM, Luse DS. Histone N-terminal tails interfere with nucleosome traversal by RNA polymerase II. J Biol Chem 2008; 283:32236-43. [PMID: 18815126 DOI: 10.1074/jbc.m806636200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We determined the effect of the N-terminal histone tails on nucleosome traversal by yeast and human RNA polymerase II (pol II). Removal of H2A/H2B tails, H3/H4 tails, or all tails increased complete traversal of the nucleosome by human pol II, although the increase varied considerably depending on the template and on which tails were removed. Human pol II achieved >80% traversal of one nucleosomal template lacking the H2A/H2B tails, but even in those reactions, the transcript elongation rate was lower than the rate on pure DNA templates. For yeast pol II, transcription proceeded much farther into the nucleosome in the absence of tails, but complete read-through was not substantially increased by tail removal. Transcription factor IIS provided roughly the same level of read-through stimulation for transcript elongation in the presence or absence of tails. FACT also stimulated elongation on nucleosomal templates, and this effect was similar regardless of the presence of tails. For both polymerases, removal of the H2A/H2B tails reduced pausing throughout the nucleosome, suggesting that histone tails affect a common step at most points during nucleosome traversal. We conclude that histone tails provide a significant part of the nucleosomal barrier to pol II transcript elongation.
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Affiliation(s)
- Andrea Ujvári
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
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43
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Acetylation of Rsc4p by Gcn5p is essential in the absence of histone H3 acetylation. Mol Cell Biol 2008; 28:6967-72. [PMID: 18809572 DOI: 10.1128/mcb.00570-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rsc4p, a subunit of the RSC chromatin-remodeling complex, is acetylated at lysine 25 by Gcn5p, a well-characterized histone acetyltransferase (HAT). Mutation of lysine 25 does not result in a significant growth defect, and therefore whether this modification is important for the function of the essential RSC complex was unknown. In a search to uncover the molecular basis for the lethality resulting from loss of multiple histone H3-specific HATs, we determined that loss of Rsc4p acetylation is lethal in strains lacking histone H3 acetylation. Phenotype comparison of mutants with arginine and glutamine substitutions of acetylatable lysines within the histone H3 tail suggests that it is a failure to neutralize the charge of the H3 tail that is lethal in strains lacking Rsc4p acetylation. We also demonstrate that Rsc4p acetylation does not require any of the known Gcn5p-dependent HAT complexes and thus represents a truly novel function for Gcn5p. These results demonstrate for the first time the vital and yet redundant functions of histone H3 and Rsc4p acetylation in maintaining cell viability.
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44
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Lindner HH. Analysis of histones, histone variants, and their post-translationally modified forms. Electrophoresis 2008; 29:2516-32. [PMID: 18494025 DOI: 10.1002/elps.200800094] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
For many years, histones were considered passive structural components of eukaryotic chromatin. Meanwhile it has been proven that histones also participate in gene regulation and repression via post-translational modification. The multitude of these post-translational modifications and the existence of numerous histone variants require particular separation strategies for their analysis, a prerequisite for studying biological processes. The most widely utilized techniques for the separation of histones, namely PAGE, HPCE, RP-HPLC, and hydrophilic Interaction LC, are reviewed here. Problems inherent to the analysis of histones owing to their unique physical and chemical properties along with advantages and shortcomings of particular methods are discussed.
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Affiliation(s)
- Herbert H Lindner
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria.
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45
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sNASP, a histone H1-specific eukaryotic chaperone dimer that facilitates chromatin assembly. Biophys J 2008; 95:1314-25. [PMID: 18456819 DOI: 10.1529/biophysj.108.130021] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
NASP has been described as a histone H1 chaperone in mammals. However, the molecular mechanisms involved have not yet been characterized. Here, we show that this protein is not only present in mammals but is widely distributed throughout eukaryotes both in its somatic and testicular forms. The secondary structure of the human somatic version consists mainly of clusters of alpha-helices and exists as a homodimer in solution. The protein binds nonspecifically to core histone H2A-H2B dimers and H3-H4 tetramers but only forms specific complexes with histone H1. The formation of the NASP-H1 complexes is mediated by the N- and C-terminal domains of histone H1 and does not involve the winged helix domain that is characteristic of linker histones. In vitro chromatin reconstitution experiments show that this protein facilitates the incorporation of linker histones onto nucleosome arrays and hence is a bona fide linker histone chaperone.
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46
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Rodríguez-Campos A, Azorín F. RNA is an integral component of chromatin that contributes to its structural organization. PLoS One 2007; 2:e1182. [PMID: 18000552 PMCID: PMC2063516 DOI: 10.1371/journal.pone.0001182] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Accepted: 10/25/2007] [Indexed: 11/19/2022] Open
Abstract
Chromatin structure is influenced by multiples factors, such as pH, temperature, nature and concentration of counterions, post-translational modifications of histones and binding of structural non-histone proteins. RNA is also known to contribute to the regulation of chromatin structure as chromatin-induced gene silencing was shown to depend on the RNAi machinery in S. pombe, plants and Drosophila. Moreover, both in Drosophila and mammals, dosage compensation requires the contribution of specific non-coding RNAs. However, whether RNA itself plays a direct structural role in chromatin is not known. Here, we report results that indicate a general structural role for RNA in eukaryotic chromatin. RNA is found associated to purified chromatin prepared from chicken liver, or cultured Drosophila S2 cells, and treatment with RNase A alters the structural properties of chromatin. Our results indicate that chromatin-associated RNAs, which account for 2%–5% of total chromatin-associated nucleic acids, are polyA− and show a size similar to that of the DNA contained in the corresponding chromatin fragments. Chromatin-associated RNA(s) are not likely to correspond to nascent transcripts as they are also found bound to chromatin when cells are treated with α-amanitin. After treatment with RNase A, chromatin fragments of molecular weight >3.000 bp of DNA showed reduced sedimentation through sucrose gradients and increased sensitivity to micrococcal nuclease digestion. This structural transition, which is observed both at euchromatic and heterochromatic regions, proceeds without loss of histone H1 or any significant change in core-histone composition and integrity.
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Affiliation(s)
- Antonio Rodríguez-Campos
- Institute of Molecular Biology of Barcelona (IBMB), CSIC, and Institute for Research in Biomedicine (IRB), Parc Científic de Barcelona, Barcelona, Spain.
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47
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Acetylation mimics within individual core histone tail domains indicate distinct roles in regulating the stability of higher-order chromatin structure. Mol Cell Biol 2007; 28:227-36. [PMID: 17938198 DOI: 10.1128/mcb.01245-07] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Nucleosome arrays undergo salt-dependent self-association into large oligomers in a process thought to recapitulate essential aspects of higher-order tertiary chromatin structure formation. Lysine acetylation within the core histone tail domains inhibits self-association, an effect likely related to its role in facilitating transcription. As acetylation of specific tail domains may encode distinct functions, we investigated biochemical and self-association properties of model nucleosome arrays containing combinations of native and mutant core histones with lysine-to-glutamine substitutions to mimic acetylation. Acetylation mimics within the tail domains of H2B and H4 caused the largest inhibition of array self-association, while modification of the H3 tail uniquely affected the stability of DNA wrapping within individual nucleosomes. In addition, the effect of acetylation mimics on array self-association is inconsistent with a simple charge neutralization mechanism. For example, acetylation mimics within the H2A tail can have either a positive or negative effect on self-association, dependent upon the acetylation state of the other tails and nucleosomal repeat length. Finally, we demonstrate that glutamine substitutions and lysine acetylation within the H4 tail domain have identical effects on nucleosome array self-association. Our results indicate that acetylation of specific tail domains plays distinct roles in the regulation of chromatin structure.
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Bertin A, Durand D, Renouard M, Livolant F, Mangenot S. H2A and H2B tails are essential to properly reconstitute nucleosome core particles. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:1083-94. [PMID: 17882413 DOI: 10.1007/s00249-007-0212-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 06/25/2007] [Accepted: 07/24/2007] [Indexed: 02/05/2023]
Abstract
The conformation of recombinant Nucleosome Core Particles (NCPs) lacking H2A and H2B histone tails (gH2AgH2B) are studied. The migration of these particles in acrylamide native gels is slowed down compared to intact reconstituted NCPs. gH2AgH2B NCPs are also much more sensitive to nuclease digestion than intact NCPs. Small angle X-ray scattering (SAXS) experiments point out that the absence of H2A and H2B tails produces small but significant conformational changes of the octamers conformation (without wrapped DNA), whereas gH2AgH2B NCP conformations are significantly altered. A separation of about 25-30 bp from the core could account for the experimental curves, but other types of DNA superhelix deformation cannot be excluded. The distorted gH2AgH2B octamer may not allow the correct winding of DNA around the core. The absence of the H2A and H2B tails would further prevent the secondary sliding of the DNA around the core and therefore impedes the stabilisation of the particle. Cryo-electron microscopy on the same particles also shows a detachment of DNA portions from the particle core. The effect is even stronger because the vitrification of the samples worsens the instability of gH2AgH2B NCPs.
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Affiliation(s)
- Aurélie Bertin
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud, 91405, Orsay Cedex, France.
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49
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Peterson S, Danowit R, Wunsch A, Jackson V. NAP1 catalyzes the formation of either positive or negative supercoils on DNA on basis of the dimer-tetramer equilibrium of histones H3/H4. Biochemistry 2007; 46:8634-46. [PMID: 17595058 DOI: 10.1021/bi6025215] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have studied the tetramer-dimer equilibrium of histones H3/H4 and its effect on DNA supercoiling. Two approaches were found to shift the equilibrium toward dimer. In both instances, when deposited on DNA, the dimers formed positively coiled DNA. The first approach was to modify cysteine 110 of H3 with 5,5'-dithio-bis(2-nitrobenzoic acid (DTNB) and to directly add the histones to DNA at physiological ionic strength. The second approach involved adding an excess of the histone chaperone, nucleosome assembly protein 1 (NAP1) to the H3/H4 prior to deposition on the DNA. It was also observed that when H3/H4 were deposited in the tetrameric state, negatively coiled DNA was formed. The topological state of the DNA prior to deposition was also found to influence the final conformational state of H3/H4. It is proposed that in the tetrameric state, the H3-H3 interface has a left-handed pitch prior to binding DNA. In the dimeric state, the H3-H3 interface is not established until bound to DNA, at which point either the left or right-handed pitch will form on the basis of the initial topology of the DNA. Formaldehyde cross-linking and reversal were applied to identify the histone-histone interactions that facilitate the formation of positive stress. Higher-order interactions between multiple H3/H4 dimers were required to propagate this specific conformation. Changes in the conformational state of H3/H4 were also observed when the histones were bound to DNA prior to treatment with NAP1. It is proposed that these conformational changes in H3/H4 are involved in promoter activation and transcription elongation through nucleosomes.
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Affiliation(s)
- Sharon Peterson
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, USA
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50
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Yang Z, Zheng C, Hayes JJ. The Core Histone Tail Domains Contribute to Sequence-dependent Nucleosome Positioning. J Biol Chem 2007; 282:7930-8. [PMID: 17234628 DOI: 10.1074/jbc.m610584200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The precise positioning of nucleosomes plays a critical role in the regulation of gene expression by modulating the DNA binding activity of trans-acting factors. However, molecular determinants responsible for positioning are not well understood. We examined whether the removal of the core histone tail domains from nucleosomes reconstituted with specific DNA fragments led to alteration of translational positions. Remarkably, we find that removal of tail domains from a nucleosome assembled on a DNA fragment containing a Xenopus borealis somatic-type 5S RNA gene results in repositioning of nucleosomes along the DNA, including two related major translational positions that move about 20 bp further upstream with respect to the 5S gene. In a nucleosome reconstituted with a DNA fragment containing the promoter of a Drosophila alcohol dehydrogenase gene, several translational positions shifted by about 10 bp along the DNA upon tail removal. However, the positions of nucleosomes assembled with a DNA fragment known to have one of the highest binding affinities for core histone proteins in the mouse genome were not altered by removal of core histone tail domains. Our data support the notion that the basic tail domains bind to nucleosomal DNA and influence the selection of the translational position of nucleosomes and that once tails are removed movement between translational positions occurs in a facile manner on some sequences. However, the effect of the N-terminal tails on the positioning and movement of a nucleosome appears to be dependent on the DNA sequence such that the contribution of the tails can be masked by very high affinity DNA sequences. Our results suggest a mechanism whereby sequence-dependent nucleosome positioning can be specifically altered by regulated changes in histone tail-DNA interactions in chromatin.
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Affiliation(s)
- Zungyoon Yang
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642, USA
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