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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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Schalch T, Steiner FA. Structure of centromere chromatin: from nucleosome to chromosomal architecture. Chromosoma 2017; 126:443-455. [PMID: 27858158 PMCID: PMC5509776 DOI: 10.1007/s00412-016-0620-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 12/14/2022]
Abstract
The centromere is essential for the segregation of chromosomes, as it serves as attachment site for microtubules to mediate chromosome segregation during mitosis and meiosis. In most organisms, the centromere is restricted to one chromosomal region that appears as primary constriction on the condensed chromosome and is partitioned into two chromatin domains: The centromere core is characterized by the centromere-specific histone H3 variant CENP-A (also called cenH3) and is required for specifying the centromere and for building the kinetochore complex during mitosis. This core region is generally flanked by pericentric heterochromatin, characterized by nucleosomes containing H3 methylated on lysine 9 (H3K9me) that are bound by heterochromatin proteins. During mitosis, these two domains together form a three-dimensional structure that exposes CENP-A-containing chromatin to the surface for interaction with the kinetochore and microtubules. At the same time, this structure supports the tension generated during the segregation of sister chromatids to opposite poles. In this review, we discuss recent insight into the characteristics of the centromere, from the specialized chromatin structures at the centromere core and the pericentromere to the three-dimensional organization of these regions that make up the functional centromere.
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Affiliation(s)
- Thomas Schalch
- Department of Molecular Biology, Sciences III, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland.
| | - Florian A Steiner
- Department of Molecular Biology, Sciences III, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland.
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Musacchio A, Desai A. A Molecular View of Kinetochore Assembly and Function. BIOLOGY 2017; 6:E5. [PMID: 28125021 PMCID: PMC5371998 DOI: 10.3390/biology6010005] [Citation(s) in RCA: 310] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/16/2017] [Accepted: 01/17/2017] [Indexed: 12/15/2022]
Abstract
Kinetochores are large protein assemblies that connect chromosomes to microtubules of the mitotic and meiotic spindles in order to distribute the replicated genome from a mother cell to its daughters. Kinetochores also control feedback mechanisms responsible for the correction of incorrect microtubule attachments, and for the coordination of chromosome attachment with cell cycle progression. Finally, kinetochores contribute to their own preservation, across generations, at the specific chromosomal loci devoted to host them, the centromeres. They achieve this in most species by exploiting an epigenetic, DNA-sequence-independent mechanism; notable exceptions are budding yeasts where a specific sequence is associated with centromere function. In the last 15 years, extensive progress in the elucidation of the composition of the kinetochore and the identification of various physical and functional modules within its substructure has led to a much deeper molecular understanding of kinetochore organization and the origins of its functional output. Here, we provide a broad summary of this progress, focusing primarily on kinetochores of humans and budding yeast, while highlighting work from other models, and present important unresolved questions for future studies.
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Affiliation(s)
- Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, Dortmund 44227, Germany.
- Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen 45117, Germany.
| | - Arshad Desai
- Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA.
- Department of Cellular & Molecular Medicine, 9500 Gilman Dr., La Jolla, CA 92093, USA.
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Carvalho NDM, Pinheiro VSS, Carmo EJ, Goll LG, Schneider CH, Gross MC. The Organization of Repetitive DNA in the Genomes of Amazonian Lizard Species in the Family Teiidae. Cytogenet Genome Res 2016; 147:161-8. [PMID: 26867142 DOI: 10.1159/000443714] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2015] [Indexed: 11/19/2022] Open
Abstract
Repetitive DNA is the largest fraction of the eukaryote genome and comprises tandem and dispersed sequences. It presents variations in relation to its composition, number of copies, distribution, dynamics, and genome organization, and participates in the evolutionary diversification of different vertebrate species. Repetitive sequences are usually located in the heterochromatin of centromeric and telomeric regions of chromosomes, contributing to chromosomal structures. Therefore, the aim of this study was to physically map repetitive DNA sequences (5S rDNA, telomeric sequences, tropomyosin gene 1, and retroelements Rex1 and SINE) of mitotic chromosomes of Amazonian species of teiids (Ameiva ameiva, Cnemidophorus sp. 1, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin) to understand their genome organization and karyotype evolution. The mapping of repetitive sequences revealed a distinct pattern in Cnemidophorus sp. 1, whereas the other species showed all sequences interspersed in the heterochromatic region. Physical mapping of the tropomyosin 1 gene was performed for the first time in lizards and showed that in addition to being functional, this gene has a structural function similar to the mapped repetitive elements as it is located preferentially in centromeric regions and termini of chromosomes.
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Affiliation(s)
- Natalia D M Carvalho
- Laboratx00F3;rio de Citogenx00F4;mica Animal, Instituto de Cix00EA;ncias Biolx00F3;gicas, Universidade Federal do Amazonas, Manaus, Brazil
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Discovering centromere proteins: from cold white hands to the A, B, C of CENPs. Nat Rev Mol Cell Biol 2015; 16:443-9. [PMID: 25991376 DOI: 10.1038/nrm4001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The kinetochore is a complex molecular machine that directs chromosome segregation during mitosis. It is one of the most elaborate subcellular protein structures in eukaryotes, comprising more than 100 different proteins. Inner kinetochore proteins associate with specialized centromeric chromatin containing the histone H3 variant centromere protein A (CENP-A) in place of H3. Outer kinetochore proteins bind to microtubules and signal to delay anaphase onset when microtubules are absent. Since the first kinetochore proteins were discovered and cloned 30 years ago using autoimmune sera from patients with scleroderma-spectrum disease, much has been learnt about the composition, functions and regulation of this remarkable structure.
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Schubert V, Lermontova I, Schubert I. Loading of the centromeric histone H3 variant during meiosis-how does it differ from mitosis? Chromosoma 2014; 123:491-7. [PMID: 24806806 DOI: 10.1007/s00412-014-0466-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/16/2014] [Accepted: 04/28/2014] [Indexed: 12/11/2022]
Abstract
In eukaryotic phyla studied so far, the essential centromeric histone H3 variant (CENH3) is loaded to centromeric nucleosomes after S-phase (except for yeast) but before mitotic segregation (except for metazoan). While the C-terminal part of CENH3 seems to be sufficient for mitotic centromere function in plants, meiotic centromeres neither load nor tolerate impaired CENH3 molecules. However, details about CENH3 deposition in meiocytes are unknown (except for Drosophila). Therefore, we quantified fluorescence signals after the immunostaining of CENH3 along meiotic and mitotic nuclear division cycles of rye, a monocotyledonous plant. One peak of fluorescence intensity appeared in the early meiotic prophase of pollen mother cells and a second one during interkinesis, both followed by a decrease of CENH3. Then, the next loading occurred in the male gametophyte before its first mitotic division. These data indicate that CENH3 loading differs between mitotic and meiotic nuclei. Contrary to the situation in mitotic cycles, CENH3 deposition is biphasic during meiosis and apparently linked with a quality check, a removal of impaired CENH3 molecules, and a general loss of CENH3 after each loading phase. These steps ensure an endowment of centromeres with a sufficient amount of correct CENH3 molecules as a prerequisite for centromere maintenance during mitotic cycles of the microgametophyte and the progeny. From a comparison with data available for Drosophila, we hypothesise that the post-divisional mitotic CENH3 loading in metazoans is evolutionarily derived from the post-divisional meiotic loading phase, while the pre-divisional first meiotic loading has been conserved among eukaryotes.
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Affiliation(s)
- Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466, Gatersleben, Germany,
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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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Padeganeh A, Ryan J, Boisvert J, Ladouceur AM, Dorn J, Maddox P. Octameric CENP-A Nucleosomes Are Present at Human Centromeres throughout the Cell Cycle. Curr Biol 2013; 23:764-9. [DOI: 10.1016/j.cub.2013.03.037] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/26/2013] [Accepted: 03/13/2013] [Indexed: 11/17/2022]
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Lidsky PV, Sprenger F, Lehner CF. Distinct modes of centromere protein dynamics during cell cycle progression in Drosophila S2R+ cells. J Cell Sci 2013; 126:4782-93. [DOI: 10.1242/jcs.134122] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Centromeres are specified epigenetically in animal cells. Therefore, faithful chromosome inheritance depends critically on the accurate maintenance of epigenetic centromere marks during progression through the cell cycle. Clarification of the mechanisms that control centromere protein behavior during the cell cycle should profit from the relative simplicity of the protein cast at Drosophila centromeres. Thus we have analyzed the dynamics of the three key players Cid/Cenp-A, Cenp-C and Cal1 in S2R+ cells using quantitative microscopy and fluorescence recovery after photobleaching in combination with novel fluorescent cell cycle markers. As revealed by the observed protein abundances and mobilities, centromeres proceed through at least five distinct states during the cell cycle, distinguished in part by unexpected Cid behavior. In addition to the predominant Cid loading onto centromeres during G1, a considerable but transient increase was detected during early mitosis. Low level of Cid loading was detected in late S and G2, starting at the reported time of centromere DNA replication. Our results disclose the complexities of Drosophila centromere protein dynamics and its intricate coordination with cell cycle progression.
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