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Dendooven T, Zhang Z, Yang J, McLaughlin SH, Schwab J, Scheres SHW, Yatskevich S, Barford D. Cryo-EM structure of the complete inner kinetochore of the budding yeast point centromere. SCIENCE ADVANCES 2023; 9:eadg7480. [PMID: 37506202 PMCID: PMC10381965 DOI: 10.1126/sciadv.adg7480] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023]
Abstract
The point centromere of budding yeast specifies assembly of the large kinetochore complex to mediate chromatid segregation. Kinetochores comprise the centromere-associated inner kinetochore (CCAN) complex and the microtubule-binding outer kinetochore KNL1-MIS12-NDC80 (KMN) network. The budding yeast inner kinetochore also contains the DNA binding centromere-binding factor 1 (CBF1) and CBF3 complexes. We determined the cryo-electron microscopy structure of the yeast inner kinetochore assembled onto the centromere-specific centromere protein A nucleosomes (CENP-ANuc). This revealed a central CENP-ANuc with extensively unwrapped DNA ends. These free DNA duplexes bind two CCAN protomers, one of which entraps DNA topologically, positioned on the centromere DNA element I (CDEI) motif by CBF1. The two CCAN protomers are linked through CBF3 forming an arch-like configuration. With a structural mechanism for how CENP-ANuc can also be linked to KMN involving only CENP-QU, we present a model for inner kinetochore assembly onto a point centromere and how it organizes the outer kinetochore for chromosome attachment to the mitotic spindle.
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Affiliation(s)
| | | | - Jing Yang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
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2
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Cieslinski K, Wu YL, Nechyporenko L, Hörner SJ, Conti D, Skruzny M, Ries J. Nanoscale structural organization and stoichiometry of the budding yeast kinetochore. J Cell Biol 2023; 222:213833. [PMID: 36705601 PMCID: PMC9929930 DOI: 10.1083/jcb.202209094] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/16/2022] [Accepted: 12/27/2022] [Indexed: 01/28/2023] Open
Abstract
Proper chromosome segregation is crucial for cell division. In eukaryotes, this is achieved by the kinetochore, an evolutionarily conserved multiprotein complex that physically links the DNA to spindle microtubules and takes an active role in monitoring and correcting erroneous spindle-chromosome attachments. Our mechanistic understanding of these functions and how they ensure an error-free outcome of mitosis is still limited, partly because we lack a complete understanding of the kinetochore structure in the cell. In this study, we use single-molecule localization microscopy to visualize individual kinetochore complexes in situ in budding yeast. For major kinetochore proteins, we measured their abundance and position within the metaphase kinetochore. Based on this comprehensive dataset, we propose a quantitative model of the budding yeast kinetochore. While confirming many aspects of previous reports based on bulk imaging, our results present a unifying nanoscale model of the kinetochore in budding yeast.
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Affiliation(s)
- Konstanty Cieslinski
- https://ror.org/03mstc592Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,Translational Radiation Oncology Unit, Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | - Yu-Le Wu
- https://ror.org/03mstc592Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,Faculty of Biosciences, Collaboration for Joint PhD Degree Between European Molecular Biology Laboratory and Heidelberg University, Heidelberg, Germany
| | - Lisa Nechyporenko
- https://ror.org/03mstc592Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Sarah Janice Hörner
- https://ror.org/03mstc592Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,https://ror.org/04p61dj41Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany,Interdisciplinary Center for Neuroscience, Heidelberg University, Heidelberg, Germany
| | - Duccio Conti
- https://ror.org/03vpj4s62Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Michal Skruzny
- https://ror.org/03mstc592Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jonas Ries
- https://ror.org/03mstc592Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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3
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Jaitly P, Legrand M, Das A, Patel T, Chauvel M, Maufrais C, d’Enfert C, Sanyal K. A phylogenetically-restricted essential cell cycle progression factor in the human pathogen Candida albicans. Nat Commun 2022; 13:4256. [PMID: 35869076 PMCID: PMC9307598 DOI: 10.1038/s41467-022-31980-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 07/13/2022] [Indexed: 12/14/2022] Open
Abstract
Chromosomal instability caused by cell division errors is associated with antifungal drug resistance in fungal pathogens. Here, we identify potential mechanisms underlying such instability by conducting an overexpression screen monitoring chromosomal stability in the human fungal pathogen Candida albicans. Analysis of ~1000 genes uncovers six chromosomal stability (CSA) genes, five of which are related to cell division genes of other organisms. The sixth gene, CSA6, appears to be present only in species belonging to the CUG-Ser clade, which includes C. albicans and other human fungal pathogens. The protein encoded by CSA6 localizes to the spindle pole bodies, is required for exit from mitosis, and induces a checkpoint-dependent metaphase arrest upon overexpression. Thus, Csa6 is an essential cell cycle progression factor that is restricted to the CUG-Ser fungal clade, and could therefore be explored as a potential antifungal target. Chromosomal instability caused by cell division errors is associated with antifungal drug resistance in fungal pathogens. Here, Jaitly et al. identify several genes involved in chromosomal stability in Candida albicans, including a phylogenetically restricted gene encoding an essential cell-cycle progression factor.
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Sreekumar L, Kumari K, Guin K, Bakshi A, Varshney N, Thimmappa BC, Narlikar L, Padinhateeri R, Siddharthan R, Sanyal K. Orc4 spatiotemporally stabilizes centromeric chromatin. Genome Res 2021; 31:607-621. [PMID: 33514624 PMCID: PMC8015856 DOI: 10.1101/gr.265900.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 01/27/2021] [Indexed: 11/24/2022]
Abstract
The establishment of centromeric chromatin and its propagation by the centromere-specific histone CENPA is mediated by epigenetic mechanisms in most eukaryotes. DNA replication origins, origin binding proteins, and replication timing of centromere DNA are important determinants of centromere function. The epigenetically regulated regional centromeres in the budding yeast Candida albicans have unique DNA sequences that replicate earliest in every chromosome and are clustered throughout the cell cycle. In this study, the genome-wide occupancy of the replication initiation protein Orc4 reveals its abundance at all centromeres in C. albicans Orc4 is associated with four different DNA sequence motifs, one of which coincides with tRNA genes (tDNA) that replicate early and cluster together in space. Hi-C combined with genome-wide replication timing analyses identify that early replicating Orc4-bound regions interact with themselves stronger than with late replicating Orc4-bound regions. We simulate a polymer model of chromosomes of C. albicans and propose that the early replicating and highly enriched Orc4-bound sites preferentially localize around the clustered kinetochores. We also observe that Orc4 is constitutively localized to centromeres, and both Orc4 and the helicase Mcm2 are essential for cell viability and CENPA stability in C. albicans Finally, we show that new molecules of CENPA are recruited to centromeres during late anaphase/telophase, which coincides with the stage at which the CENPA-specific chaperone Scm3 localizes to the kinetochore. We propose that the spatiotemporal localization of Orc4 within the nucleus, in collaboration with Mcm2 and Scm3, maintains centromeric chromatin stability and CENPA recruitment in C. albicans.
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Affiliation(s)
- Lakshmi Sreekumar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Kiran Kumari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Research Academy, Mumbai 400076, India
- Department of Chemical Engineering, Monash University, Melbourne 3800, Australia
| | - Krishnendu Guin
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Asif Bakshi
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Neha Varshney
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Bhagya C Thimmappa
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Leelavati Narlikar
- Department of Chemical Engineering, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Rahul Siddharthan
- The Institute of Mathematical Sciences/HBNI, Taramani, Chennai 600113, India
| | - Kaustuv Sanyal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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5
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Boopathi R, Danev R, Khoshouei M, Kale S, Nahata S, Ramos L, Angelov D, Dimitrov S, Hamiche A, Petosa C, Bednar J. Phase-plate cryo-EM structure of the Widom 601 CENP-A nucleosome core particle reveals differential flexibility of the DNA ends. Nucleic Acids Res 2020; 48:5735-5748. [PMID: 32313946 PMCID: PMC7261176 DOI: 10.1093/nar/gkaa246] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/11/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022] Open
Abstract
The histone H3 variant CENP-A marks centromeres epigenetically and is essential for mitotic fidelity. Previous crystallographic studies of the CENP-A nucleosome core particle (NCP) reconstituted with a human α-satellite DNA derivative revealed both DNA ends to be highly flexible, a feature important for CENP-A mitotic functions. However, recent cryo-EM studies of CENP-A NCP complexes comprising primarily Widom 601 DNA reported well-ordered DNA ends. Here, we report the cryo-EM structure of the CENP-A 601 NCP determined by Volta phase-plate imaging. The data reveal that one (‘left’) 601 DNA end is well ordered whereas the other (‘right’) end is flexible and partly detached from the histone core, suggesting sequence-dependent dynamics of the DNA termini. Indeed, a molecular dynamics simulation of the CENP-A 601 NCP confirmed the distinct dynamics of the two DNA extremities. Reprocessing the image data using two-fold symmetry yielded a cryo-EM map in which both DNA ends appeared well ordered, indicating that such an artefact may inadvertently arise if NCP asymmetry is lost during image processing. These findings enhance our understanding of the dynamic features that discriminate CENP-A from H3 nucleosomes by revealing that DNA end flexibility can be fine-tuned in a sequence-dependent manner.
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Affiliation(s)
- Ramachandran Boopathi
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Radostin Danev
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Maryam Khoshouei
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Seyit Kale
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda MD 20894, USA
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Balcova, Izmir 35330, Turkey
| | - Sunil Nahata
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Lorrie Ramos
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Dimitar Angelov
- Laboratoire de Biologie et de Modélisation de la Cellule (LBMC), CNRS/ ENSL/UCBL, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Stefan Dimitrov
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Balcova, Izmir 35330, Turkey
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
- Correspondence may also be addressed to Stefan Dimitrov.
| | - Ali Hamiche
- Département de Génomique Fonctionnelle et Cancer, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC)/Université de Strasbourg/ CNRS/INSERM, 67404 Illkirch Cedex, France
- Correspondence may also be addressed to Ali Hamiche.
| | - Carlo Petosa
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
- Correspondence may also be addressed to Carlo Petosa.
| | - Jan Bednar
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
- Laboratory of the Biology and Pathology of the Eye, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General Teaching Hospital, 128 00 Prague, Czech Republic
- To whom correspondence should be addressed. Tel: +33 4 76 54 94 73;
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6
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Le TT, Gao X, Park SH, Lee J, Inman JT, Lee JH, Killian JL, Badman RP, Berger JM, Wang MD. Synergistic Coordination of Chromatin Torsional Mechanics and Topoisomerase Activity. Cell 2020; 179:619-631.e15. [PMID: 31626768 PMCID: PMC6899335 DOI: 10.1016/j.cell.2019.09.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/16/2019] [Accepted: 09/24/2019] [Indexed: 12/23/2022]
Abstract
DNA replication in eukaryotes generates DNA supercoiling, which may intertwine (braid) daughter chromatin fibers to form precatenanes, posing topological challenges during chromosome segregation. The mechanisms that limit precatenane formation remain unclear. By making direct torque measurements, we demonstrate that the intrinsic mechanical properties of chromatin play a fundamental role in dictating precatenane formation and regulating chromatin topology. Whereas a single chromatin fiber is torsionally soft, a braided fiber is torsionally stiff, indicating that supercoiling on chromatin substrates is preferentially directed in front of the fork during replication. We further show that topoisomerase II relaxation displays a strong preference for a single chromatin fiber over a braided fiber. These results suggest a synergistic coordination-the mechanical properties of chromatin inherently suppress precatenane formation during replication elongation by driving DNA supercoiling ahead of the fork, where supercoiling is more efficiently removed by topoisomerase II. VIDEO ABSTRACT.
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Affiliation(s)
- Tung T Le
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Xiang Gao
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Seong Ha Park
- Biophysics Program, Cornell University, Ithaca, NY 14853, USA
| | - Jaeyoon Lee
- Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - James T Inman
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Joyce H Lee
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica L Killian
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Ryan P Badman
- Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michelle D Wang
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA.
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7
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The ATAD2/ANCCA homolog Yta7 cooperates with Scm3 HJURP to deposit Cse4 CENP-A at the centromere in yeast. Proc Natl Acad Sci U S A 2020; 117:5386-5393. [PMID: 32079723 DOI: 10.1073/pnas.1917814117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The AAA+ ATPase and bromodomain factor ATAD2/ANCCA is overexpressed in many types of cancer, but how it contributes to tumorigenesis is not understood. Here, we report that the Saccharomyces cerevisiae homolog Yta7ATAD2 is a deposition factor for the centromeric histone H3 variant Cse4CENP-A at the centromere in yeast. Yta7ATAD2 regulates the levels of centromeric Cse4CENP-A in that yta7∆ causes reduced Cse4CENP-A deposition, whereas YTA7 overexpression causes increased Cse4CENP-A deposition. Yta7ATAD2 coimmunoprecipitates with Cse4CENP-A and is associated with the centromere, arguing for a direct role of Yta7ATAD2 in Cse4CENP-A deposition. Furthermore, increasing centromeric Cse4CENP-A levels by YTA7 overexpression requires the activity of Scm3HJURP, the centromeric nucleosome assembly factor. Importantly, Yta7ATAD2 interacts in vivo with Scm3HJURP, indicating that Yta7ATAD2 is a cochaperone for Scm3HJURP The absence of Yta7 causes defects in growth and chromosome segregation with mutations in components of the inner kinetochore (CTF19/CCAN, Mif2CENP-C, Cbf1). Since Yta7ATAD2 is an AAA+ ATPase and potential hexameric unfoldase, our results suggest that it may unfold the Cse4CENP-A histone and hand it over to Scm3HJURP for subsequent deposition in the centromeric nucleosome. Furthermore, our findings suggest that ATAD2 overexpression may enhance malignant transformation in humans by misregulating centromeric CENP-A levels, thus leading to defects in kinetochore assembly and chromosome segregation.
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8
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Dhatchinamoorthy K, Unruh JR, Lange JJ, Levy M, Slaughter BD, Gerton JL. The stoichiometry of the outer kinetochore is modulated by microtubule-proximal regulatory factors. J Cell Biol 2019; 218:2124-2135. [PMID: 31118239 PMCID: PMC6605801 DOI: 10.1083/jcb.201810070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 04/11/2019] [Accepted: 05/02/2019] [Indexed: 12/16/2022] Open
Abstract
Dhatchinamoorthy et al. suggest the stoichiometry of outer submodules of the budding yeast kinetochore is strongly influenced by factors at the kinetochore–microtubule interface such as Fin1 and Dam1. Outer kinetochore stoichiometry is remarkably plastic and responsive to microtubule-proximal regulation. The kinetochore is a large molecular machine that attaches chromosomes to microtubules and facilitates chromosome segregation. The kinetochore includes submodules that associate with the centromeric DNA and submodules that attach to microtubules. Additional copies of several submodules of the kinetochore are added during anaphase, including the microtubule binding module Ndc80. While the factors governing plasticity are not known, they could include regulation based on microtubule–kinetochore interactions. We report that Fin1 localizes to the microtubule-proximal edge of the kinetochore cluster during anaphase based on single-particle averaging of super-resolution images. Fin1 is required for the assembly of normal levels of Dam1 and Ndc80 submodules. Levels of Ndc80 further depend on the Dam1 microtubule binding complex. Our results suggest the stoichiometry of outer kinetochore submodules is strongly influenced by factors at the kinetochore–microtubule interface such as Fin1 and Dam1, and phosphorylation by cyclin-dependent kinase. Outer kinetochore stoichiometry is remarkably plastic and responsive to microtubule-proximal regulation.
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Affiliation(s)
- Karthik Dhatchinamoorthy
- Stowers Institute for Medical Research, Kansas City, MO.,Open University, Milton Keynes, England, UK
| | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO
| | | | | | | | - Jennifer L Gerton
- Stowers Institute for Medical Research, Kansas City, MO .,Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS
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9
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Hamilton G, Dimitrova Y, Davis TN. Seeing is believing: our evolving view of kinetochore structure, composition, and assembly. Curr Opin Cell Biol 2019; 60:44-52. [PMID: 31078123 DOI: 10.1016/j.ceb.2019.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/20/2019] [Accepted: 03/28/2019] [Indexed: 11/26/2022]
Abstract
This review highlights three recent trends in the field of kinetochore biology: the proliferation of structural data for kinetochore protein complexes (including CBF3, Dam1c, Mis12cMIND, and CENP-NLChl4/Iml3); the growing consensus that the kinetochore is a dynamic structure whose composition changes as the cell cycle progresses; and the mounting evidence of multiple pathways whereby the microtubule-binding elements of the outer kinetochore may be recruited by inner kinetochore proteins. Our focus is on the two best-studied systems in the field: human and budding yeast kinetochores. This review will demonstrate the remarkable similarity of these two systems, as well as their intriguing differences.
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Affiliation(s)
- Grace Hamilton
- Department of Biochemistry, University of Washington Box 357350, 1705 NE Pacific St., Seattle, WA 98195-7350, USA
| | - Yoana Dimitrova
- Genentech, Inc., 1 DNA Way, MS: 27, South San Francisco, CA 94080, USA
| | - Trisha N Davis
- Department of Biochemistry, University of Washington Box 357350, 1705 NE Pacific St., Seattle, WA 98195-7350, USA.
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10
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Zhao H, Winogradoff D, Dalal Y, Papoian GA. The Oligomerization Landscape of Histones. Biophys J 2019; 116:1845-1855. [PMID: 31005236 DOI: 10.1016/j.bpj.2019.03.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/06/2019] [Accepted: 03/14/2019] [Indexed: 12/29/2022] Open
Abstract
In eukaryotes, DNA is packaged within nucleosomes. The DNA of each nucleosome is typically centered around an octameric histone protein core: one central tetramer plus two separate dimers. Studying the assembly mechanisms of histones is essential for understanding the dynamics of entire nucleosomes and higher-order DNA packaging. Here, we investigate canonical histone assembly and that of the centromere-specific histone variant, centromere protein A (CENP-A), using molecular dynamics simulations. We quantitatively characterize their thermodynamical and dynamical features, showing that two H3/H4 dimers form a structurally floppy, weakly bound complex, the latter exhibiting large instability around the central interface manifested via a swiveling motion of two halves. This finding is consistent with the recently observed DNA handedness flipping of the tetrasome. In contrast, the variant CENP-A encodes distinctive stability to its tetramer with a rigid but twisted interface compared to the crystal structure, implying diverse structural possibilities of the histone variant. Interestingly, the observed tetramer dynamics alter significantly and appear to reach a new balance when H2A/H2B dimers are present. Furthermore, we found that the preferred structure for the (CENP-A/H4)2 tetramer is incongruent with the octameric structure, explaining many of the unusual dynamical behaviors of the CENP-A nucleosome. In all, these data reveal key mechanistic insights and structural details for the assembly of canonical and variant histone tetramers and octamers, providing theoretical quantifications and physical interpretations for longstanding and recent experimental observations. Based on these findings, we propose different chaperone-assisted binding and nucleosome assembly mechanisms for the canonical and CENP-A histone oligomers.
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Affiliation(s)
- Haiqing Zhao
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, Maryland; Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - David Winogradoff
- Chemical Physics Program, Institute for Physical Science and Technology
| | - Yamini Dalal
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
| | - Garegin A Papoian
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, Maryland; Chemical Physics Program, Institute for Physical Science and Technology; Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland.
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11
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Khan T, Kandola TS, Wu J, Venkatesan S, Ketter E, Lange JJ, Rodríguez Gama A, Box A, Unruh JR, Cook M, Halfmann R. Quantifying Nucleation In Vivo Reveals the Physical Basis of Prion-like Phase Behavior. Mol Cell 2019; 71:155-168.e7. [PMID: 29979963 PMCID: PMC6086602 DOI: 10.1016/j.molcel.2018.06.016] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/26/2018] [Accepted: 06/07/2018] [Indexed: 01/29/2023]
Abstract
Protein self-assemblies modulate protein activities over biological timescales that can exceed the lifetimes of the proteins or even the cells that harbor them. We hypothesized that these timescales relate to kinetic barriers inherent to the nucleation of ordered phases. To investigate nucleation barriers in living cells, we developed distributed amphifluoric FRET (DAmFRET). DAmFRET exploits a photoconvertible fluorophore, heterogeneous expression, and large cell numbers to quantify via flow cytometry the extent of a protein's self-assembly as a function of cellular concentration. We show that kinetic barriers limit the nucleation of ordered self-assemblies and that the persistence of the barriers with respect to concentration relates to structure. Supersaturation resulting from sequence-encoded nucleation barriers gave rise to prion behavior and enabled a prion-forming protein, Sup35 PrD, to partition into dynamic intracellular condensates or to form toxic aggregates. Our results suggest that nucleation barriers govern cytoplasmic inheritance, subcellular organization, and proteotoxicity.
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Affiliation(s)
- Tarique Khan
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Tejbir S Kandola
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jianzheng Wu
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | | | - Ellen Ketter
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jeffrey J Lange
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | | | - Andrew Box
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Malcolm Cook
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Randal Halfmann
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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12
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Hoffmann G, Samel-Pommerencke A, Weber J, Cuomo A, Bonaldi T, Ehrenhofer-Murray AE. A role for CENP-A/Cse4 phosphorylation on serine 33 in deposition at the centromere. FEMS Yeast Res 2019; 18:4768140. [PMID: 29272409 DOI: 10.1093/femsyr/fox094] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/18/2017] [Indexed: 12/16/2022] Open
Abstract
Centromeres are the sites of assembly of the kinetochore, which connect the chromatids to the microtubules for sister chromatid segregation during cell division. Centromeres are characterized by the presence of the histone H3 variant CENP-A (termed Cse4 in Saccharomyces cerevisiae). Here, we investigated the function of serine 33 phosphorylation of Cse4 (Cse4-S33ph) in S. cerevisiae, which lies within the essential N-terminal domain (END) of the extended Cse4 N-terminus. Significantly, we identified histone H4-K5, 8, 12R to cause a temperature-sensitive growth defect with mutations in Cse4-S33 and sensitivity to nocodazole and hydroxyurea. Furthermore, the absence of Cse4-S33ph reduced the levels of Cse4 at centromeric sequences, suggesting that Cse4 deposition is defective in the absence of S33 phosphorylation. We furthermore identified synthetic genetic interactions with histone H2A-E57A and H2A-L66A, which both cause a reduced interaction with the histone chaperone FACT and reduced H2A/H2B levels in chromatin, again supporting the notion that a combined defect of H2A/H2B and Cse4 deposition causes centromeric defects. Altogether, our data highlight the importance of correct histone deposition in building a functional centromeric nucleosome and suggests a role for Cse4-S33ph in this process.
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Affiliation(s)
- Gesine Hoffmann
- Institut für Biologie, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | | | - Jan Weber
- Biozentrum Köln, Universität zu Köln, 50674 Köln, Germany
| | - Alessandro Cuomo
- Department of Experimental Oncology, European Institute of Oncology, 20139 Milano, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, European Institute of Oncology, 20139 Milano, Italy
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13
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Anedchenko EA, Samel-Pommerencke A, Tran Nguyen TM, Shahnejat-Bushehri S, Pöpsel J, Lauster D, Herrmann A, Rappsilber J, Cuomo A, Bonaldi T, Ehrenhofer-Murray AE. The kinetochore module Okp1 CENP-Q/Ame1 CENP-U is a reader for N-terminal modifications on the centromeric histone Cse4 CENP-A. EMBO J 2018; 38:embj.201898991. [PMID: 30389668 DOI: 10.15252/embj.201898991] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 11/09/2022] Open
Abstract
Kinetochores are supramolecular assemblies that link centromeres to microtubules for sister chromatid segregation in mitosis. For this, the inner kinetochore CCAN/Ctf19 complex binds to centromeric chromatin containing the histone variant CENP-A, but whether the interaction of kinetochore components to centromeric nucleosomes is regulated by posttranslational modifications is unknown. Here, we investigated how methylation of arginine 37 (R37Me) and acetylation of lysine 49 (K49Ac) on the CENP-A homolog Cse4 from Saccharomyces cerevisiae regulate molecular interactions at the inner kinetochore. Importantly, we found that the Cse4 N-terminus binds with high affinity to the Ctf19 complex subassembly Okp1/Ame1 (CENP-Q/CENP-U in higher eukaryotes), and that this interaction is inhibited by R37Me and K49Ac modification on Cse4. In vivo defects in cse4-R37A were suppressed by mutations in OKP1 and AME1, and biochemical analysis of a mutant version of Okp1 showed increased affinity for Cse4. Altogether, our results demonstrate that the Okp1/Ame1 heterodimer is a reader module for posttranslational modifications on Cse4, thereby targeting the yeast CCAN complex to centromeric chromatin.
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Affiliation(s)
- Ekaterina A Anedchenko
- Department of Molecular Cell Biology, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Anke Samel-Pommerencke
- Department of Molecular Cell Biology, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tra My Tran Nguyen
- Department of Molecular Cell Biology, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sara Shahnejat-Bushehri
- Department of Molecular Cell Biology, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Juliane Pöpsel
- Department of Molecular Cell Biology, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Daniel Lauster
- Department of Experimental Biophysics, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Andreas Herrmann
- Department of Experimental Biophysics, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Department of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Alessandro Cuomo
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Ann E Ehrenhofer-Murray
- Department of Molecular Cell Biology, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
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14
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Zhang W, Lukoyanova N, Miah S, Lucas J, Vaughan CK. Insights into Centromere DNA Bending Revealed by the Cryo-EM Structure of the Core Centromere Binding Factor 3 with Ndc10. Cell Rep 2018; 24:744-754. [PMID: 30021170 PMCID: PMC6077249 DOI: 10.1016/j.celrep.2018.06.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/06/2018] [Accepted: 06/15/2018] [Indexed: 12/21/2022] Open
Abstract
The centromere binding factor 3 (CBF3) complex binds the third centromere DNA element in organisms with point centromeres, such as S. cerevisiae. It is an essential complex for assembly of the kinetochore in these organisms, as it facilitates genetic centromere specification and allows association of all other kinetochore components. We determined high-resolution structures of the core complex of CBF3 alone and in association with a monomeric construct of Ndc10, using cryoelectron microscopy (cryo-EM). We identify the DNA-binding site of the complex and present a model in which CBF3 induces a tight bend in centromeric DNA, thus facilitating assembly of the centromeric nucleosome. Cryo-EM studies of CBF3 reveal the core complex has a deep asymmetric channel The size, conservation, and charge of the channel suggest that it binds centromere DNA Unique insertions in the Ctf13 F box provide the binding site for one Ndc10 monomer The Ndc10 DNA-binding site is in plane with and perpendicular to the CBF3 channel
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Affiliation(s)
- Wenjuan Zhang
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK; Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Natalya Lukoyanova
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Shomon Miah
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Jonathan Lucas
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Cara K Vaughan
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK; Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
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15
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Politi AZ, Cai Y, Walther N, Hossain MJ, Koch B, Wachsmuth M, Ellenberg J. Quantitative mapping of fluorescently tagged cellular proteins using FCS-calibrated four-dimensional imaging. Nat Protoc 2018; 13:1445-1464. [PMID: 29844523 PMCID: PMC6609853 DOI: 10.1038/nprot.2018.040] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability to tag a protein at its endogenous locus with a fluorescent protein (FP) enables quantitative understanding of protein dynamics at the physiological level. Genome-editing technology has now made this powerful approach routinely applicable to mammalian cells and many other model systems, thereby opening up the possibility to systematically and quantitatively map the cellular proteome in four dimensions. 3D time-lapse confocal microscopy (4D imaging) is an essential tool for investigating spatial and temporal protein dynamics; however, it lacks the required quantitative power to make the kind of absolute and comparable measurements required for systems analysis. In contrast, fluorescence correlation spectroscopy (FCS) provides quantitative proteomic and biophysical parameters such as protein concentration, hydrodynamic radius, and oligomerization but lacks the capability for high-throughput application in 4D spatial and temporal imaging. Here we present an automated experimental and computational workflow that integrates both methods and delivers quantitative 4D imaging data in high throughput. These data are processed to yield a calibration curve relating the fluorescence intensities (FIs) of image voxels to the absolute protein abundance. The calibration curve allows the conversion of the arbitrary FIs to protein amounts for all voxels of 4D imaging stacks. Using our workflow, users can acquire and analyze hundreds of FCS-calibrated image series to map their proteins of interest in four dimensions. Compared with other protocols, the current protocol does not require additional calibration standards and provides an automated acquisition pipeline for FCS and imaging data. The protocol can be completed in 1 d.
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Affiliation(s)
| | - Yin Cai
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Current address: Roche Diagnostics, Waiblingen, Germany
| | - Nike Walther
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
| | | | - Birgit Koch
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Current address: Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Malte Wachsmuth
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Current address: Luxendo GmbH, Heidelberg, Germany
| | - Jan Ellenberg
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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16
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Abstract
Despite the central role of Nuclear Pore Complexes (NPCs) as gatekeepers of RNA and protein transport between the cytoplasm and nucleoplasm, their large size and dynamic nature have impeded a full structural and functional elucidation. Here, we have determined a subnanometer precision structure for the entire 552-protein yeast NPC by satisfying diverse data including stoichiometry, a cryo-electron tomography map, and chemical cross-links. The structure reveals the NPC’s functional elements in unprecedented detail. The NPC is built of sturdy diagonal columns to which are attached connector cables, imbuing both strength and flexibility, while tying together all other elements of the NPC, including membrane-interacting regions and RNA processing platforms. Inwardly-directed anchors create a high density of transport factor-docking Phe-Gly repeats in the central channel, organized in distinct functional units. Taken together, this integrative structure allows us to rationalize the architecture, transport mechanism, and evolutionary origins of the NPC.
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17
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Dhatchinamoorthy K, Shivaraju M, Lange JJ, Rubinstein B, Unruh JR, Slaughter BD, Gerton JL. Structural plasticity of the living kinetochore. J Cell Biol 2017; 216:3551-3570. [PMID: 28939613 PMCID: PMC5674893 DOI: 10.1083/jcb.201703152] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/17/2017] [Accepted: 08/21/2017] [Indexed: 11/30/2022] Open
Abstract
The kinetochore is a large, evolutionarily conserved protein structure that connects chromosomes with microtubules. During chromosome segregation, outer kinetochore components track depolymerizing ends of microtubules to facilitate the separation of chromosomes into two cells. In budding yeast, each chromosome has a point centromere upon which a single kinetochore is built, which attaches to a single microtubule. This defined architecture facilitates quantitative examination of kinetochores during the cell cycle. Using three independent measures-calibrated imaging, FRAP, and photoconversion-we find that the Dam1 submodule is unchanged during anaphase, whereas MIND and Ndc80 submodules add copies to form an "anaphase configuration" kinetochore. Microtubule depolymerization and kinesin-related motors contribute to copy addition. Mathematical simulations indicate that the addition of microtubule attachments could facilitate tracking during rapid microtubule depolymerization. We speculate that the minimal kinetochore configuration, which exists from G1 through metaphase, allows for correction of misattachments. Our study provides insight into dynamics and plasticity of the kinetochore structure during chromosome segregation in living cells.
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Affiliation(s)
- Karthik Dhatchinamoorthy
- Stowers Institute for Medical Research, Kansas City, MO
- The Open University, Milton Keynes, England, UK
| | | | | | | | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO
| | | | - Jennifer L Gerton
- Stowers Institute for Medical Research, Kansas City, MO
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS
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18
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Nechemia-Arbely Y, Fachinetti D, Miga KH, Sekulic N, Soni GV, Kim DH, Wong AK, Lee AY, Nguyen K, Dekker C, Ren B, Black BE, Cleveland DW. Human centromeric CENP-A chromatin is a homotypic, octameric nucleosome at all cell cycle points. J Cell Biol 2017; 216:607-621. [PMID: 28235947 PMCID: PMC5350519 DOI: 10.1083/jcb.201608083] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/18/2016] [Accepted: 01/17/2017] [Indexed: 12/11/2022] Open
Abstract
In this study, the authors use new reference models for 23 human centromeres and find that at all cell cycle phases centromeric CENP-A chromatin complexes are octameric nucleosomes with two molecules of CENP-A. This finding refutes previous models that have suggested that hemisomes may briefly transition to octameric nucleosomes. Chromatin assembled with centromere protein A (CENP-A) is the epigenetic mark of centromere identity. Using new reference models, we now identify sites of CENP-A and histone H3.1 binding within the megabase, α-satellite repeat–containing centromeres of 23 human chromosomes. The overwhelming majority (97%) of α-satellite DNA is found to be assembled with histone H3.1–containing nucleosomes with wrapped DNA termini. In both G1 and G2 cell cycle phases, the 2–4% of α-satellite assembled with CENP-A protects DNA lengths centered on 133 bp, consistent with octameric nucleosomes with DNA unwrapping at entry and exit. CENP-A chromatin is shown to contain equimolar amounts of CENP-A and histones H2A, H2B, and H4, with no H3. Solid-state nanopore analyses show it to be nucleosomal in size. Thus, in contrast to models for hemisomes that briefly transition to octameric nucleosomes at specific cell cycle points or heterotypic nucleosomes containing both CENP-A and histone H3, human CENP-A chromatin complexes are octameric nucleosomes with two molecules of CENP-A at all cell cycle phases.
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Affiliation(s)
- Yael Nechemia-Arbely
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Daniele Fachinetti
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Karen H Miga
- Center for Biomolecular Science and Engineering, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Nikolina Sekulic
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gautam V Soni
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - Dong Hyun Kim
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Adeline K Wong
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Ah Young Lee
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Kristen Nguyen
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - Bing Ren
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
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19
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Chattoraj S, Saha S, Halder D, Jana SS, Bhattacharyya K. Structural Oscillations of Non-muscle Myosin II-C2: Time Resolved Confocal Microscopy. ChemistrySelect 2017. [DOI: 10.1002/slct.201601963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shyamtanu Chattoraj
- Department of Physical Chemistry; Indian Association for the Cultivation of Science; Jadavpur; Kolkata-32 INDIA
| | - Shekhar Saha
- Department of Biological Chemistry; Indian Association for the Cultivation of Science; Jadavpur; Kolkata-32 INDIA
- Department of Biochemistry and Molecular Genetics; University of Virginia; Charlottesville, VA USA
| | - Debdatta Halder
- Department of Biological Chemistry; Indian Association for the Cultivation of Science; Jadavpur; Kolkata-32 INDIA
| | - Siddhartha S. Jana
- Department of Biological Chemistry; Indian Association for the Cultivation of Science; Jadavpur; Kolkata-32 INDIA
| | - Kankan Bhattacharyya
- Department of Physical Chemistry; Indian Association for the Cultivation of Science; Jadavpur; Kolkata-32 INDIA
- Department of Chemistry; Indian Institute of Science Education and Research (IISER); Bhopal, Madhya Pradesh 462030 INDIA
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20
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Skene PJ, Henikoff S. An efficient targeted nuclease strategy for high-resolution mapping of DNA binding sites. eLife 2017; 6. [PMID: 28079019 PMCID: PMC5310842 DOI: 10.7554/elife.21856] [Citation(s) in RCA: 958] [Impact Index Per Article: 136.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/06/2017] [Indexed: 12/31/2022] Open
Abstract
We describe Cleavage Under Targets and Release Using Nuclease (CUT&RUN), a chromatin profiling strategy in which antibody-targeted controlled cleavage by micrococcal nuclease releases specific protein-DNA complexes into the supernatant for paired-end DNA sequencing. Unlike Chromatin Immunoprecipitation (ChIP), which fragments and solubilizes total chromatin, CUT&RUN is performed in situ, allowing for both quantitative high-resolution chromatin mapping and probing of the local chromatin environment. When applied to yeast and human nuclei, CUT&RUN yielded precise transcription factor profiles while avoiding crosslinking and solubilization issues. CUT&RUN is simple to perform and is inherently robust, with extremely low backgrounds requiring only ~1/10th the sequencing depth as ChIP, making CUT&RUN especially cost-effective for transcription factor and chromatin profiling. When used in conjunction with native ChIP-seq and applied to human CTCF, CUT&RUN mapped directional long range contact sites at high resolution. We conclude that in situ mapping of protein-DNA interactions by CUT&RUN is an attractive alternative to ChIP-seq. DOI:http://dx.doi.org/10.7554/eLife.21856.001 The DNA in a person’s skin cell will contain the same genes as the DNA in their muscle or brain cells. However, these cells have different identities because different genes are active in skin, muscle and brain cells. Proteins called transcription factors dictate the patterns of gene activation in the different kinds of cells by binding to DNA and switching nearby genes on or off. Transcription factors interact with other proteins such as histones that help to package DNA into a structure known as chromatin. Together, transcription factors, histones and other chromatin-associated proteins determine whether or not nearby genes are active. Sometimes transcription factors and other chromatin-associated proteins bind to the wrong sites on DNA; this situation can lead to diseases in humans, such as cancer. This is one of the many reasons why researchers are interested in working out where specific DNA-binding proteins are located in different situations. A technique called chromatin immunoprecipitation (or ChIP for short) can be used to achieve this goal, yet despite being one of the most widely used techniques in molecular biology, ChIP is hampered by numerous problems. As such, many researchers are keen to find alternative approaches. Skene and Henikoff have now developed a new method, called CUT&RUN (which is short for “Cleavage Under Targets & Release Using Nuclease”) to map specific interactions between protein and DNA in a way that overcomes some of the problems with ChIP. In CUT&RUN, unlike in ChIP, the DNA in the starting cells does not need to be broken up first; this means that protein-DNA interactions are more likely to be maintained in their natural state. With CUT&RUN, as in ChIP, a specific antibody identifies the protein of interest. But in CUT&RUN, this antibody binds to the target protein in intact cells and cuts out the DNA that the protein is bound to, releasing the DNA fragment from the cell. This new strategy allows the DNA fragments to be sequenced and identified more efficiently than is currently possible with ChIP. Skene and Henikoff showed that their new method could more accurately identify where transcription factors bind to DNA from yeast and human cells. CUT&RUN also identified a specific histone that is rarely found in yeast chromatin and the technique can be used with a small number of starting cells. Given the advantages that CUT&RUN offers over ChIP, Skene and Henikoff anticipate that the method will be viewed as a cost-effective and versatile alternative to ChIP. In future, the method could be automated so that multiple analyses can be performed at once. DOI:http://dx.doi.org/10.7554/eLife.21856.002
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Affiliation(s)
- Peter J Skene
- Howard Hughes Medical Institute, Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Steven Henikoff
- Howard Hughes Medical Institute, Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States
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21
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Bloom K, Costanzo V. Centromere Structure and Function. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:515-539. [PMID: 28840251 DOI: 10.1007/978-3-319-58592-5_21] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The centromere is the genetic locus that specifies the site of kinetochore assembly, where the chromosome will attach to the kinetochore microtubule. The pericentromere is the physical region responsible for the geometry of bi-oriented sister kinetochores in metaphase. In budding yeast the 125 bp point centromere is sufficient to specify kinetochore assembly. The flanking region is enriched (3X) in cohesin and condensin relative to the remaining chromosome arms. The enrichment spans about 30-50 kb around each centromere. We refer to the flanking chromatin as the pericentromere in yeast. In mammals, a 5-10 Mb region dictates where the kinetochore is built. The kinetochore interacts with a very small fraction of DNA on the surface of the centromeric region. The remainder of the centromere lies between the sister kinetochores. This is typically called centromere chromatin. The chromatin sites that directly interface to microtubules cannot be identified due to the repeated sequence within the mammalian centromere. However in both yeast and mammals, the total amount of DNA between the sites of microtubule attachment in metaphase is highly conserved. In yeast the 16 chromosomes are clustered into a 250 nm diameter region, and 800 kb (16 × 50 kb) or ~1 Mb of DNA lies between sister kinetochores. In mammals, 5-10 Mb lies between sister kinetochores. In both organisms the sister kinetochores are separated by about 1 μm. Thus, centromeres of different organisms differ in how they specify kinetochore assembly, but there may be important centromere chromatin functions that are conserved throughout phylogeny. Recently, centromeric chromatin has been reconstituted in vitro using alpha satellite DNA revealing unexpected features of centromeric DNA organization, replication, and response to stress. We will focus on the conserved features of centromere in this review.
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Affiliation(s)
- Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, 623 Fordham Hall CB#3280, Chapel Hill, NC, 27599-3280, USA.
| | - Vincenzo Costanzo
- DNA Metabolism Laboratory, IFOM, The FIRC Institute of Molecular Oncology, Vai Adamello 16, 21139, Milan, Italy
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22
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Stankovic A, Jansen LET. Quantitative Microscopy Reveals Centromeric Chromatin Stability, Size, and Cell Cycle Mechanisms to Maintain Centromere Homeostasis. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:139-162. [PMID: 28840236 DOI: 10.1007/978-3-319-58592-5_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Centromeres are chromatin domains specified by nucleosomes containing the histone H3 variant, CENP-A. This unique centromeric structure is at the heart of a strong self-templating epigenetic mechanism that renders centromeres heritable. We review how specific quantitative microscopy approaches have contributed to the determination of the copy number, architecture, size, and dynamics of centromeric chromatin and its associated centromere complex and kinetochore. These efforts revealed that the key to long-term centromere maintenance is the slow turnover of CENP-A nucleosomes, a critical size of the chromatin domain and its cell cycle-coupled replication. These features come together to maintain homeostasis of a chromatin locus that directs its own epigenetic inheritance and facilitates the assembly of the mitotic kinetochore.
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Affiliation(s)
- Ana Stankovic
- Instituto Gulbenkian de Ciência, 2780-156, Oeiras, Portugal
| | - Lars E T Jansen
- Instituto Gulbenkian de Ciência, 2780-156, Oeiras, Portugal.
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23
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Zhao H, Winogradoff D, Bui M, Dalal Y, Papoian GA. Promiscuous Histone Mis-Assembly Is Actively Prevented by Chaperones. J Am Chem Soc 2016; 138:13207-13218. [PMID: 27454815 PMCID: PMC7757119 DOI: 10.1021/jacs.6b05355] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Histone proteins are essential for the organization, expression, and inheritance of genetic material for eukaryotic cells. A centromere-specific H3 histone variant, centromere protein A (CENP-A), shares about 50% amino acid sequence identity with H3. CENP-A is required for packaging the centromere and for the proper separation of chromosomes during mitosis. Despite their distinct biological functions, previously reported crystal structures of the CENP-A/H4 and H3/H4 dimers reveal a high degree of similarity. In this work, we characterize the structural dynamics of CENP-A/H4 and H3/H4 dimers based on a dual-resolution approach, using both microsecond-scale explicit-solvent all-atom and coarse-grained (CG) molecular dynamics (MD) simulations. Our data show that the H4 histone is significantly more rigid compared with the H3 histone and its variant CENP-A, hence, serving as a reinforcing structural element within the histone core. We report that the CENP-A/H4 dimer is significantly more dynamic than its canonical counterpart H3/H4, and our results provide a physical explanation for this flexibility. Further, we observe that the centromere-specific chaperone Holliday Junction Recognition Protein (HJURP) stabilizes the CENP-A/H4 dimer by forming a specific electrostatic interaction network. Finally, replacing CENP-A S68 with E68 disrupts the binding interface between CENP-A and HJURP in all-atom MD simulation, and consistently, in vivo experiments demonstrate that replacing CENP-A S68 with E68 disrupts CENP-A's localization to the centromere. Based on all our results, we propose that, during the CENP-A/H4 deposition process, the chaperone HJURP protects various substructures of the dimer, serving both as a folding and binding chaperone.
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Affiliation(s)
- Haiqing Zhao
- Biophysics Program, University of Maryland, College Park, Maryland 20742, United States
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - David Winogradoff
- Chemical Physics Program, University of Maryland, College Park, Maryland 20742, United States
| | - Minh Bui
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yamini Dalal
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Garegin A. Papoian
- Biophysics Program, University of Maryland, College Park, Maryland 20742, United States
- Chemical Physics Program, University of Maryland, College Park, Maryland 20742, United States
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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24
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Yu RR, Mahto SK, Justus K, Alexander MM, Howard CJ, Ottesen JJ. Hybrid phase ligation for efficient synthesis of histone proteins. Org Biomol Chem 2016; 14:2603-7. [PMID: 26821702 PMCID: PMC4767651 DOI: 10.1039/c5ob02195b] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We introduce a hybrid solid-solution phase ligation approach that combines the efficiency of solid phase ligation with solution phase ligation in the total synthesis of modified histone proteins. A two linker strategy allows analysis throughout work on the solid phase and maximizes yields through cleavage at an external Rink, while an internal HMBA linker allows the native carboxyl terminus for any protein sequence. We demonstrate this approach for two histone proteins: triple-acetylated H4-K5ac, K12ac, K91ac and CENP-A-K124ac.
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Affiliation(s)
- Ruixuan R Yu
- Department of Chemistry & Biochemistry, The Ohio State University, USA and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
| | - Santosh K Mahto
- Department of Chemistry & Biochemistry, The Ohio State University, USA
| | - Kurt Justus
- Department of Chemistry & Biochemistry, The Ohio State University, USA and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
| | | | - Cecil J Howard
- Department of Chemistry & Biochemistry, The Ohio State University, USA and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
| | - Jennifer J Ottesen
- Department of Chemistry & Biochemistry, The Ohio State University, USA and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
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25
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Shearing of the CENP-A dimerization interface mediates plasticity in the octameric centromeric nucleosome. Sci Rep 2015; 5:17038. [PMID: 26602160 PMCID: PMC4658507 DOI: 10.1038/srep17038] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/07/2015] [Indexed: 01/01/2023] Open
Abstract
The centromeric nucleosome is a key epigenetic determinant of centromere identity and function. Consequently, deciphering how CENP-A containing nucleosomes contribute structurally to centromere function is a fundamental question in chromosome biology. Here, we performed microsecond timescale all-atom molecular dynamics (MD) simulations of CENP-A and H3 nucleosomes, and report that the octameric CENP-A core particles and nucleosomes display different dynamics from their canonical H3-containing counterparts. The most significant motion observed is within key interactions at the heart of the CENP-A octameric core, wherein shearing of contacts within the CENP-A:CENP-A' dimerization interface results in a weaker four helix bundle, and an extrusion of 10-30 bp of DNA near the pseudo-dyad. Coupled to other local and global fluctuations, the CENP-A nucleosome occupies a more rugged free energy landscape than the canonical H3 nucleosome. Taken together, our data suggest that CENP-A encodes enhanced distortability to the octameric nucleosome, which may allow for enhanced flexing of the histone core in vivo.
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26
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Zhao H, Zhu X, Wang K, Gent JI, Zhang W, Dawe RK, Jiang J. Gene Expression and Chromatin Modifications Associated with Maize Centromeres. G3 (BETHESDA, MD.) 2015; 6:183-92. [PMID: 26564952 PMCID: PMC4704717 DOI: 10.1534/g3.115.022764] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/09/2015] [Indexed: 12/23/2022]
Abstract
Centromeres are defined by the presence of CENH3, a variant of histone H3. Centromeres in most plant species contain exclusively highly repetitive DNA sequences, which has hindered research on structure and function of centromeric chromatin. Several maize centromeres have been nearly completely sequenced, providing a sequence-based platform for genomic and epigenomic research of plant centromeres. Here we report a high resolution map of CENH3 nucleosomes in the maize genome. Although CENH3 nucleosomes are spaced ∼190 bp on average, CENH3 nucleosomes that occupied CentC, a 156-bp centromeric satellite repeat, showed clear positioning aligning with CentC monomers. Maize centromeres contain alternating CENH3-enriched and CENH3-depleted subdomains, which account for 87% and 13% of the centromeres, respectively. A number of annotated genes were identified in the centromeres, including 11 active genes that were located exclusively in CENH3-depleted subdomains. The euchromatic histone modification marks, including H3K4me3, H3K36me3 and H3K9ac, detected in maize centromeres were associated mainly with the active genes. Interestingly, maize centromeres also have lower levels of the heterochromatin histone modification mark H3K27me2 relative to pericentromeric regions. We conclude that neither H3K27me2 nor the three euchromatic histone modifications are likely to serve as functionally important epigenetic marks of centromere identity in maize.
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Affiliation(s)
- Hainan Zhao
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - Xiaobiao Zhu
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - Kai Wang
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602
| | - Wenli Zhang
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602
| | - Jiming Jiang
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
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27
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Mattiroli F, D'Arcy S, Luger K. The right place at the right time: chaperoning core histone variants. EMBO Rep 2015; 16:1454-66. [PMID: 26459557 DOI: 10.15252/embr.201540840] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/17/2015] [Indexed: 12/13/2022] Open
Abstract
Histone proteins dynamically regulate chromatin structure and epigenetic signaling to maintain cell homeostasis. These processes require controlled spatial and temporal deposition and eviction of histones by their dedicated chaperones. With the evolution of histone variants, a network of functionally specific histone chaperones has emerged. Molecular details of the determinants of chaperone specificity for different histone variants are only slowly being resolved. A complete understanding of these processes is essential to shed light on the genuine biological roles of histone variants, their chaperones, and their impact on chromatin dynamics.
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Affiliation(s)
- Francesca Mattiroli
- Department of Molecular and Radiobiological Sciences, Howard Hughes Medical Institute, Colorado State University, Fort Collins, CO, USA
| | - Sheena D'Arcy
- Department of Molecular and Radiobiological Sciences, Howard Hughes Medical Institute, Colorado State University, Fort Collins, CO, USA
| | - Karolin Luger
- Department of Molecular and Radiobiological Sciences, Howard Hughes Medical Institute, Colorado State University, Fort Collins, CO, USA
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28
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Scott KC, Bloom KS. Lessons learned from counting molecules: how to lure CENP-A into the kinetochore. Open Biol 2015; 4:rsob.140191. [PMID: 25500356 PMCID: PMC4281711 DOI: 10.1098/rsob.140191] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Kristin C Scott
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Kerry S Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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29
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Steiner FA, Henikoff S. Diversity in the organization of centromeric chromatin. Curr Opin Genet Dev 2015; 31:28-35. [PMID: 25956076 DOI: 10.1016/j.gde.2015.03.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 03/26/2015] [Accepted: 03/28/2015] [Indexed: 01/15/2023]
Abstract
Centromeric chromatin is distinguished primarily by nucleosomes containing the histone variant cenH3, which organizes the kinetochore that links the chromosome to the spindle apparatus. Whereas budding yeast have simple 'point' centromeres with single cenH3 nucleosomes, and fission yeast have 'regional' centromeres without obvious sequence specificity, the centromeres of most organisms are embedded in highly repetitive 'satellite' DNA. Recent studies have revealed a remarkable diversity in centromere chromatin organization among different lineages, including some that have lost cenH3 altogether. We review recent progress in understanding point, regional and satellite centromeres, as well as less well-studied centromere types, such as holocentromeres. We also discuss the formation of neocentromeres, the role of pericentric heterochromatin, and the structure and composition of the cenH3 nucleosome.
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Affiliation(s)
- Florian A Steiner
- Basic Sciences Division and Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Steven Henikoff
- Basic Sciences Division and Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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30
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Fujita R, Otake K, Arimura Y, Horikoshi N, Miya Y, Shiga T, Osakabe A, Tachiwana H, Ohzeki JI, Larionov V, Masumoto H, Kurumizaka H. Stable complex formation of CENP-B with the CENP-A nucleosome. Nucleic Acids Res 2015; 43:4909-22. [PMID: 25916850 PMCID: PMC4446444 DOI: 10.1093/nar/gkv405] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 04/15/2015] [Indexed: 01/16/2023] Open
Abstract
CENP-A and CENP-B are major components of centromeric chromatin. CENP-A is the histone H3 variant, which forms the centromere-specific nucleosome. CENP-B specifically binds to the CENP-B box DNA sequence on the centromere-specific repetitive DNA. In the present study, we found that the CENP-A nucleosome more stably retains human CENP-B than the H3.1 nucleosome in vitro. Specifically, CENP-B forms a stable complex with the CENP-A nucleosome, when the CENP-B box sequence is located at the proximal edge of the nucleosome. Surprisingly, the CENP-B binding was weaker when the CENP-B box sequence was located in the distal linker region of the nucleosome. This difference in CENP-B binding, depending on the CENP-B box location, was not observed with the H3.1 nucleosome. Consistently, we found that the DNA-binding domain of CENP-B specifically interacted with the CENP-A-H4 complex, but not with the H3.1-H4 complex, in vitro. These results suggested that CENP-B forms a more stable complex with the CENP-A nucleosome through specific interactions with CENP-A, if the CENP-B box is located proximal to the CENP-A nucleosome. Our in vivo assay also revealed that CENP-B binding in the vicinity of the CENP-A nucleosome substantially stabilizes the CENP-A nucleosome on alphoid DNA in human cells.
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Affiliation(s)
- Risa Fujita
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Koichiro Otake
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan
| | - Yasuhiro Arimura
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Naoki Horikoshi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Yuta Miya
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Tatsuya Shiga
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Akihisa Osakabe
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hiroaki Tachiwana
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Jun-ichirou Ohzeki
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan
| | - Vladimir Larionov
- Development Therapeutic Branch, National Cancer Institute, National Institutes of Health, Building 37, Room 5040, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Hiroshi Masumoto
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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31
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Coffman VC, Wu JQ. Every laboratory with a fluorescence microscope should consider counting molecules. Mol Biol Cell 2015; 25:1545-8. [PMID: 24825827 PMCID: PMC4019486 DOI: 10.1091/mbc.e13-05-0249] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Protein numbers in cells determine rates of biological processes, influence the architecture of cellular structures, reveal the stoichiometries of protein complexes, guide in vitro biochemical reconstitutions, and provide parameter values for mathematical modeling. The purpose of this essay is to increase awareness of methods for counting protein molecules using fluorescence microscopy and encourage more cell biologists to report these numbers. We address the state of the field in terms of utility and accuracy of the numbers reported and point readers to references for details of specific techniques and applications.
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Affiliation(s)
- Valerie C Coffman
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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32
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Westhorpe FG, Straight AF. The centromere: epigenetic control of chromosome segregation during mitosis. Cold Spring Harb Perspect Biol 2014; 7:a015818. [PMID: 25414369 DOI: 10.1101/cshperspect.a015818] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A fundamental challenge for the survival of all organisms is maintaining the integrity of the genome in all cells. Cells must therefore segregate their replicated genome equally during each cell division. Eukaryotic organisms package their genome into a number of physically distinct chromosomes, which replicate during S phase and condense during prophase of mitosis to form paired sister chromatids. During mitosis, cells form a physical connection between each sister chromatid and microtubules of the mitotic spindle, which segregate one copy of each chromatid to each new daughter cell. The centromere is the DNA locus on each chromosome that creates the site of this connection. In this review, we present a brief history of centromere research and discuss our current knowledge of centromere establishment, maintenance, composition, structure, and function in mitosis.
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Affiliation(s)
- Frederick G Westhorpe
- Department of Biochemistry, Stanford University Medical School, Stanford, California 94305
| | - Aaron F Straight
- Department of Biochemistry, Stanford University Medical School, Stanford, California 94305
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33
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Abstract
Since discovery of the centromere-specific histone H3 variant CENP-A, centromeres have come to be defined as chromatin structures that establish the assembly site for the complex kinetochore machinery. In most organisms, centromere activity is defined epigenetically, rather than by specific DNA sequences. In this review, we describe selected classic work and recent progress in studies of centromeric chromatin with a focus on vertebrates. We consider possible roles for repetitive DNA sequences found at most centromeres, chromatin factors and modifications that assemble and activate CENP-A chromatin for kinetochore assembly, plus the use of artificial chromosomes and kinetochores to study centromere function.
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Affiliation(s)
- Tatsuo Fukagawa
- Department of Molecular Genetics, National Institute of Genetics and Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan.
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JR, UK.
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34
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Abstract
Systems biology has recently achieved significant success in the understanding of complex interconnected phenomena such as cell polarity and migration. In this context, the definition of systems biology has come to encompass the integration of quantitative measurements with sophisticated modeling approaches. This article will review recent progress in live cell imaging technologies that have expanded the possibilities of quantitative in vivo measurements, particularly in regards to molecule counting and quantitative measurements of protein concentration and dynamics. These methods have gained and continue to gain popularity with the biological community. In general, we will discuss three broad categories: protein interactions, protein quantitation, and protein dynamics.
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Affiliation(s)
- Sarah E Smith
- a Stowers Institute for Medical Research ; Kansas City , MO USA
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35
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Wisniewski J, Hajj B, Chen J, Mizuguchi G, Xiao H, Wei D, Dahan M, Wu C. Imaging the fate of histone Cse4 reveals de novo replacement in S phase and subsequent stable residence at centromeres. eLife 2014; 3:e02203. [PMID: 24844245 PMCID: PMC4067749 DOI: 10.7554/elife.02203] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The budding yeast centromere contains Cse4, a specialized histone H3 variant. Fluorescence pulse-chase analysis of an internally tagged Cse4 reveals that it is replaced with newly synthesized molecules in S phase, remaining stably associated with centromeres thereafter. In contrast, C-terminally-tagged Cse4 is functionally impaired, showing slow cell growth, cell lethality at elevated temperatures, and extra-centromeric nuclear accumulation. Recent studies using such strains gave conflicting findings regarding the centromeric abundance and cell cycle dynamics of Cse4. Our findings indicate that internally tagged Cse4 is a better reporter of the biology of this histone variant. Furthermore, the size of centromeric Cse4 clusters was precisely mapped with a new 3D-PALM method, revealing substantial compaction during anaphase. Cse4-specific chaperone Scm3 displays steady-state, stoichiometric co-localization with Cse4 at centromeres throughout the cell cycle, while undergoing exchange with a nuclear pool. These findings suggest that a stable Cse4 nucleosome is maintained by dynamic chaperone-in-residence Scm3.DOI: http://dx.doi.org/10.7554/eLife.02203.001.
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Affiliation(s)
- Jan Wisniewski
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, United States
| | - Bassam Hajj
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jiji Chen
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Gaku Mizuguchi
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, United States
| | - Hua Xiao
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, United States
| | - Debbie Wei
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, United States
| | - Maxime Dahan
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Carl Wu
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, United States
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36
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Abstract
Localization of the histone H3 variant Cse4 (CENP-A) at the ~125 base pair point centromere in budding yeast directs assembly of a kinetochore that binds one microtubule. Recent work suggests there is more Cse4 at point centromeres than originally thought.
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Affiliation(s)
- Thomas J Maresca
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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37
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Cieśliński K, Ries J. The yeast kinetochore - structural insights from optical microscopy. Curr Opin Chem Biol 2014; 20:1-8. [PMID: 24763395 DOI: 10.1016/j.cbpa.2014.03.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/26/2014] [Indexed: 11/19/2022]
Abstract
In eukaryotic organisms each chromosome is captured by spindle microtubules. This interaction is mediated by an evolutionarily conserved, multi-protein complex called kinetochore. The main function of the kinetochore is to maintain correct chromosome segregation during cell division by transporting each sister chromatid to the spindle pole bodies localized at the opposite sites of the yeast nucleus. The kinetochore of budding yeast (Saccharomyces cerevisiae) is often used as a model system due to its simple composition compared to higher eukaryotes. This review highlights results obtained using optical imaging that revealed relative positions and stoichiometry of the major components of the budding yeast kinetochore.
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Affiliation(s)
- Konstanty Cieśliński
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jonas Ries
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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38
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Henikoff S, Ramachandran S, Krassovsky K, Bryson TD, Codomo CA, Brogaard K, Widom J, Wang JP, Henikoff JG. The budding yeast Centromere DNA Element II wraps a stable Cse4 hemisome in either orientation in vivo. eLife 2014; 3:e01861. [PMID: 24737863 PMCID: PMC3983907 DOI: 10.7554/elife.01861] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In budding yeast, a single cenH3 (Cse4) nucleosome occupies the ∼120-bp functional centromere, however conflicting structural models for the particle have been proposed. To resolve this controversy, we have applied H4S47C-anchored cleavage mapping, which reveals the precise position of histone H4 in every nucleosome in the genome. We find that cleavage patterns at centromeres are unique within the genome and are incompatible with symmetrical structures, including octameric nucleosomes and (Cse4/H4)2 tetrasomes. Centromere cleavage patterns are compatible with a precisely positioned core structure, one in which each of the 16 yeast centromeres is occupied by oppositely oriented Cse4/H4/H2A/H2B hemisomes in two rotational phases within the population. Centromere-specific hemisomes are also inferred from distances observed between closely-spaced H4 cleavages, as predicted from structural modeling. Our results indicate that the orientation and rotational position of the stable hemisome at each yeast centromere is not specified by the functional centromere sequence. DOI:http://dx.doi.org/10.7554/eLife.01861.001 DNA is tightly packaged in cells for a variety of reasons—to allow it to fit inside the nucleus, to protect it from damage, and to help control the production of proteins from genes. The basic unit of packaged DNA is called a nucleosome, which consists of DNA wrapped around a structure formed by two pairs of four different proteins. These proteins, which are called histones, have a role that extends beyond providing structural support for DNA. When cells divide, for example, pairs of ‘sister chromosomes’ are pulled apart to ensure that the two daughter cells both have the same chromosomes as the original cell. The sister chromosomes are pulled apart from a single position called a centromere, and the nucleosomes at this position contain a histone that is different from the histones found everywhere else in the cell. However, until recently it was not clear if the nucleosomes that contained these special cenH3 histones had the same structure as other nucleosomes. Now Henikoff et al. have used a method called H4S47C-anchored cleavage mapping to study every nucleosome in the genome of the yeast S. cerevisiae. This mapping technique uses DNA sequencing to measure the precise distances between fixed points on the DNA in the nucleosome. Knowing these distances tells researchers a great deal about the number and position of the histones within each nucleosome in the genome. Using this approach, Henikoff et al. found that nucleosomes at centromeres are different from other nucleosomes in histone number and arrangement. In particular, the nucleosome at each yeast centromere contains only one each of the four different histones in an asymmetrical orientation, in contrast to all other yeast nucleosomes, which contain two sets of four histones in a symmetrical arrangement. Furthermore, each nucleosome at a centromere can adopt one of two orientations: these orientations are mirror images of each other, and they occur with equal probability. It should also be possible to use the mapping technique developed by Henikoff et al. to study the larger and more complex centromeres found in other organisms, including humans. DOI:http://dx.doi.org/10.7554/eLife.01861.002
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Affiliation(s)
- Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States
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39
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Recent applications of fluorescence correlation spectroscopy in live systems. FEBS Lett 2014; 588:3571-84. [PMID: 24726724 DOI: 10.1016/j.febslet.2014.03.056] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 03/29/2014] [Accepted: 03/31/2014] [Indexed: 11/20/2022]
Abstract
Fluorescence correlation spectroscopy (FCS) is a widely used technique in biophysics and has helped address many questions in the life sciences. It provides important advantages compared to other fluorescence and biophysical methods. Its single molecule sensitivity allows measuring proteins within biological samples at physiological concentrations without the need of overexpression. It provides quantitative data on concentrations, diffusion coefficients, molecular transport and interactions even in live organisms. And its reliance on simple fluorescence intensity and its fluctuations makes it widely applicable. In this review we focus on applications of FCS in live samples, with an emphasis on work in the last 5 years, in the hope to provide an overview of the present capabilities of FCS to address biologically relevant questions.
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40
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McCormick CD, Akamatsu MS, Ti SC, Pollard TD. Measuring affinities of fission yeast spindle pole body proteins in live cells across the cell cycle. Biophys J 2014; 105:1324-35. [PMID: 24047983 DOI: 10.1016/j.bpj.2013.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 08/12/2013] [Accepted: 08/14/2013] [Indexed: 12/22/2022] Open
Abstract
Characterizing protein-protein interactions is essential for understanding molecular mechanisms, although reproducing cellular conditions in vitro is challenging and some proteins are difficult to purify. We developed a method to measure binding to cellular structures using fission yeast cells as reaction vessels. We varied the concentrations of Sid2p and Mob1p (proteins of the septation initiation network) and measured their binding to spindle pole bodies (SPBs), the centrosome equivalent of yeast. From our measurements we infer that Sid2p and Mob1p both exist as monomeric, heterodimeric, and homodimeric species throughout the cell cycle. During interphase these species have widely different affinities for their common receptor Cdc11p on the SPB. The data support a model with a subset of Cdc11p binding the heterodimeric species with a Kd < 0.1 μM when Sid2p binds Mob1p-Cdc11p and Kd in the micromolar range when Mob1p binds Sid2p-Cdc11p. During mitosis an additional species presumed to be the phosphorylated Sid2p-Mob1p heterodimer binds SPBs with a lower affinity. Homodimers of Sid2p or Mob1p bind to the rest of Cdc11p at SPBs with lower affinity: Kds > 10 μM during interphase and somewhat stronger during mitosis. These measurements allowed us to account for the fluctuations in Sid2p binding to SPBs throughout the cell cycle.
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Affiliation(s)
- Chad D McCormick
- Departments of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
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DNA replication components as regulators of epigenetic inheritance--lesson from fission yeast centromere. Protein Cell 2014; 5:411-9. [PMID: 24691906 PMCID: PMC4026425 DOI: 10.1007/s13238-014-0049-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/24/2014] [Indexed: 01/30/2023] Open
Abstract
Genetic information stored in DNA is accurately copied and transferred to subsequent generations through DNA replication. This process is accomplished through the concerted actions of highly conserved DNA replication components. Epigenetic information stored in the form of histone modifications and DNA methylation, constitutes a second layer of regulatory information important for many cellular processes, such as gene expression regulation, chromatin organization, and genome stability. During DNA replication, epigenetic information must also be faithfully transmitted to subsequent generations. How this monumental task is achieved remains poorly understood. In this review, we will discuss recent advances on the role of DNA replication components in the inheritance of epigenetic marks, with a particular focus on epigenetic regulation in fission yeast. Based on these findings, we propose that specific DNA replication components function as key regulators in the replication of epigenetic information across the genome.
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42
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Dechassa ML, Wyns K, Luger K. Scm3 deposits a (Cse4-H4)2 tetramer onto DNA through a Cse4-H4 dimer intermediate. Nucleic Acids Res 2014; 42:5532-42. [PMID: 24623811 PMCID: PMC4027189 DOI: 10.1093/nar/gku205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The assembly of centromeric nucleosomes is mediated by histone variant-specific chaperones. In budding yeast, the centromere-specific histone H3 variant is Cse4, and the histone chaperone Scm3 functions as a Cse4-specific nucleosome assembly factor. Here, we show that Scm3 exhibits specificity for Cse4-H4, but also interacts with major-type H3-H4 and H2A-H2B. Previously published structures of the Scm3 histone complex demonstrate that Scm3 binds only one copy of Cse4-H4. Consistent with this, we show that Scm3 deposits Cse4-H4 through a dimer intermediate onto deoxyribonucleic acid (DNA) to form a (Cse4-H4)2-DNA complex (tetrasome). Scm3-bound Cse4-H4 does not form a tetramer in the absence of DNA. Moreover, we demonstrate that Cse4 and H3 are structurally compatible to be incorporated in the same nucleosome to form heterotypic particles. Our data shed light on the mechanism of Scm3-mediated nucleosome assembly at the centromere.
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Affiliation(s)
- Mekonnen Lemma Dechassa
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
| | - Katharina Wyns
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Karolin Luger
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
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A network of players in H3 histone variant deposition and maintenance at centromeres. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:241-50. [DOI: 10.1016/j.bbagrm.2013.11.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 11/14/2013] [Accepted: 11/19/2013] [Indexed: 11/21/2022]
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44
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Biomolecular dynamics and binding studies in the living cell. Phys Life Rev 2014; 11:1-30. [DOI: 10.1016/j.plrev.2013.11.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 11/20/2013] [Indexed: 11/22/2022]
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Abstract
The propagation of all organisms depends on the accurate and orderly segregation of chromosomes in mitosis and meiosis. Budding yeast has long served as an outstanding model organism to identify the components and underlying mechanisms that regulate chromosome segregation. This review focuses on the kinetochore, the macromolecular protein complex that assembles on centromeric chromatin and maintains persistent load-bearing attachments to the dynamic tips of spindle microtubules. The kinetochore also serves as a regulatory hub for the spindle checkpoint, ensuring that cell cycle progression is coupled to the achievement of proper microtubule-kinetochore attachments. Progress in understanding the composition and overall architecture of the kinetochore, as well as its properties in making and regulating microtubule attachments and the spindle checkpoint, is discussed.
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46
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Verdaasdonk JS, Stephens AD, Haase J, Bloom K. Bending the rules: widefield microscopy and the Abbe limit of resolution. J Cell Physiol 2014; 229:132-8. [PMID: 23893718 PMCID: PMC4076117 DOI: 10.1002/jcp.24439] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 07/18/2013] [Indexed: 02/04/2023]
Abstract
One of the most fundamental concepts of microscopy is that of resolution-the ability to clearly distinguish two objects as separate. Recent advances such as structured illumination microscopy (SIM) and point localization techniques including photoactivated localization microscopy (PALM), and stochastic optical reconstruction microscopy (STORM) strive to overcome the inherent limits of resolution of the modern light microscope. These techniques, however, are not always feasible or optimal for live cell imaging. Thus, in this review, we explore three techniques for extracting high resolution data from images acquired on a widefield microscope-deconvolution, model convolution, and Gaussian fitting. Deconvolution is a powerful tool for restoring a blurred image using knowledge of the point spread function (PSF) describing the blurring of light by the microscope, although care must be taken to ensure accuracy of subsequent quantitative analysis. The process of model convolution also requires knowledge of the PSF to blur a simulated image which can then be compared to the experimentally acquired data to reach conclusions regarding its geometry and fluorophore distribution. Gaussian fitting is the basis for point localization microscopy, and can also be applied to tracking spot motion over time or measuring spot shape and size. All together, these three methods serve as powerful tools for high-resolution imaging using widefield microscopy.
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Affiliation(s)
- Jolien S. Verdaasdonk
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Andrew D. Stephens
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Julian Haase
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kerry Bloom
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Doherty K, Meere M, Piiroinen PT. A mathematical model of CENP-A incorporation in mammalian centromeres. Math Biosci 2014; 249:27-43. [PMID: 24472234 DOI: 10.1016/j.mbs.2014.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 12/21/2013] [Accepted: 01/16/2014] [Indexed: 12/01/2022]
Abstract
Centromere Protein A (CENP-A) is a histone H3 variant found at mammalian centromeres. Unlike canonical histones which are incorporated at centromeres in S phase, CENP-A is deposited at centromeric chromatin in G1. Although recent studies have elucidated many of the molecular details associated with the CENP-A incorporation pathway, some aspects of the process are still not fully understood. CENP-A incorporation in G1 requires multiple assembly factors for its recruitment and maintenance. In this study, the first mathematical model of the CENP-A incorporation pathway is developed. The model is based on what is currently known about the pathway and is calibrated by comparing numerical simulations with experimental observations taken from the literature. The model succinctly collates a large body of knowledge accumulated in recent decades concerning the pathway and produces results that are consistent with experimental findings. It identifies possible gaps in what is currently known about the pathway and suggests possible directions for future research. It is envisaged that the model will be expanded upon and improved as more information concerning the pathway comes to light.
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Affiliation(s)
- Kevin Doherty
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland, Galway, University Road, Galway, Ireland.
| | - Martin Meere
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland, Galway, University Road, Galway, Ireland.
| | - Petri T Piiroinen
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland, Galway, University Road, Galway, Ireland.
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Abstract
Biological questions are increasingly being addressed using a wide range of quantitative analytical tools to examine protein complex composition. Knowledge of the absolute number of proteins present provides insights into organization, function, and maintenance and is used in mathematical modeling of complex cellular dynamics. In this chapter, we outline and describe three microscopy-based methods for determining absolute protein numbers--fluorescence correlation spectroscopy, stepwise photobleaching, and ratiometric comparison of fluorescence intensity to known standards. In addition, we discuss the various fluorescently labeled proteins that have been used as standards for both stepwise photobleaching and ratiometric comparison analysis. A detailed procedure for determining absolute protein number by ratiometric comparison is outlined in the second half of this chapter. Counting proteins by quantitative microscopy is a relatively simple yet very powerful analytical tool that will increase our understanding of protein complex composition.
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49
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Zaytsev AV, Ataullakhanov FI, Grishchuk EL. Highly Transient Molecular Interactions Underlie the Stability of Kinetochore-Microtubule Attachment During Cell Division. Cell Mol Bioeng 2013; 6. [PMID: 24376473 DOI: 10.1007/s12195-013-0309-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Chromosome segregation during mitosis is mediated by spindle microtubules that attach to chromosomal kinetochores with strong yet labile links. The exact molecular composition of the kinetochore-microtubule interface is not known but microtubules are thought to bind to kinetochores via the specialized microtubule-binding sites, which contain multiple microtubule-binding proteins. During prometaphase the lifetime of microtubule attachments is short but in metaphase it increases 3-fold, presumably owing to dephosphorylation of the microtubule-binding proteins that increases their affinity. Here, we use mathematical modeling to examine in quantitative and systematic manner the general relationships between the molecular properties of microtubule-binding proteins and the resulting stability of microtubule attachment to the protein-containing kinetochore site. We show that when the protein connections are stochastic, the physiological rate of microtubule turnover is achieved only if these molecular interactions are very transient, each lasting fraction of a second. This "microscopic" time is almost four orders of magnitude shorter than the characteristic time of kinetochore-microtubule attachment. Cooperativity of the microtubule-binding events further increases the disparity of these time scales. Furthermore, for all values of kinetic parameters the microtubule stability is very sensitive to the minor changes in the molecular constants. Such sensitivity of the lifetime of microtubule attachment to the kinetics and cooperativity of molecular interactions at the microtubule-binding site may hinder the accurate regulation of kinetochore-microtubule stability during mitotic progression, and it necessitates detailed experimental examination of the microtubule-binding properties of kinetochore-localized proteins.
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Affiliation(s)
- Anatoly V Zaytsev
- Physiology Department, Perelman School of Medicine, University of Pennsylvania, 3700 Hamilton Walk, A401 Richards Building, Philadelphia, PA 19104, USA
| | - Fazly I Ataullakhanov
- Center for Theoretical Problems of Physicochemical Pharmacology, RAS, Moscow, Russia, 119991 ; Physics Department, Moscow State University, Moscow, Russia, 119899 ; Laboratory of Biophysics, Federal Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia, 117198
| | - Ekaterina L Grishchuk
- Physiology Department, Perelman School of Medicine, University of Pennsylvania, 3700 Hamilton Walk, A401 Richards Building, Philadelphia, PA 19104, USA
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50
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Haase J, Mishra PK, Stephens A, Haggerty R, Quammen C, Taylor RM, Yeh E, Basrai MA, Bloom K. A 3D map of the yeast kinetochore reveals the presence of core and accessory centromere-specific histone. Curr Biol 2013; 23:1939-44. [PMID: 24076245 DOI: 10.1016/j.cub.2013.07.083] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/28/2013] [Accepted: 07/30/2013] [Indexed: 11/29/2022]
Abstract
The budding yeast kinetochore is ~68 nm in length with a diameter slightly larger than a 25 nm microtubule. The kinetochores from the 16 chromosomes are organized in a stereotypic cluster encircling central spindle microtubules. Quantitative analysis of the inner kinetochore cluster (Cse4, COMA) reveals structural features not apparent in singly attached kinetochores. The cluster of Cse4-containing kinetochores is physically larger perpendicular to the spindle axis relative to the cluster of Ndc80 molecules. If there was a single Cse4 (molecule or nucleosome) at the kinetochore attached to each microtubule plus end, the cluster of Cse4 would appear geometrically identical to Ndc80. Thus, the structure of the inner kinetochore at the surface of the chromosomes remains unsolved. We have used point fluorescence microscopy and statistical probability maps to deduce the two-dimensional mean position of representative components of the yeast kinetochore relative to the mitotic spindle in metaphase. Comparison of the experimental images to three-dimensional architectures from convolution of mathematical models reveals a pool of Cse4 radially displaced from Cse4 at the kinetochore and kinetochore microtubule plus ends. The pool of displaced Cse4 can be experimentally depleted in mRNA processing pat1Δ or xrn1Δ mutants. The peripheral Cse4 molecules do not template outer kinetochore components. This study suggests an inner kinetochore plate at the centromere-microtubule interface in budding yeast and yields information on the number of Ndc80 molecules at the microtubule attachment site.
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Affiliation(s)
- Julian Haase
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA
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