101
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Wang F, Higgins JMG. Histone modifications and mitosis: countermarks, landmarks, and bookmarks. Trends Cell Biol 2012; 23:175-84. [PMID: 23246430 DOI: 10.1016/j.tcb.2012.11.005] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 11/12/2012] [Accepted: 11/13/2012] [Indexed: 11/30/2022]
Abstract
The roles of post-translational histone modifications in regulating transcription and DNA damage have been widely studied and discussed. Although mitotic histone marks, particularly phosphorylation, were discovered four decades ago, their roles in mitosis have been outlined only in the past few years. Here we aim to provide an integrated view of how histone modifications act as 'countermarks', 'landmarks', and 'bookmarks' to displace, recruit, and 'remember' the location of regulatory proteins during and shortly after mitosis. These capabilities allow histone marks to help downregulate interphase functions such as transcription during mitosis, to facilitate chromatin events required to accomplish chromosome segregation, and to contribute to the maintenance of epigenetic states through mitosis.
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Affiliation(s)
- Fangwei Wang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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102
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De Rop V, Padeganeh A, Maddox PS. CENP-A: the key player behind centromere identity, propagation, and kinetochore assembly. Chromosoma 2012; 121:527-38. [PMID: 23095988 PMCID: PMC3501172 DOI: 10.1007/s00412-012-0386-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/01/2012] [Accepted: 10/01/2012] [Indexed: 12/26/2022]
Abstract
Chromosome segregation is the one of the great problems in biology with complexities spanning from biophysics and polymer dynamics to epigenetics. Here, we summarize the current knowledge and highlight gaps in understanding of the mechanisms controlling epigenetic regulation of chromosome segregation.
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Affiliation(s)
- Valérie De Rop
- Institute for Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec H3C 3J7 Canada
| | - Abbas Padeganeh
- Institute for Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec H3C 3J7 Canada
| | - Paul S. Maddox
- Institute for Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec H3C 3J7 Canada
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103
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Shivaraju M, Unruh JR, Slaughter BD, Mattingly M, Berman J, Gerton JL. Cell-cycle-coupled structural oscillation of centromeric nucleosomes in yeast. Cell 2012; 150:304-16. [PMID: 22817893 DOI: 10.1016/j.cell.2012.05.034] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 03/16/2012] [Accepted: 05/18/2012] [Indexed: 11/17/2022]
Abstract
The centromere is a specialized chromosomal structure that regulates chromosome segregation. Centromeres are marked by a histone H3 variant. In budding yeast, the histone H3 variant Cse4 is present in a single centromeric nucleosome. Experimental evidence supports several different models for the structure of centromeric nucleosomes. To investigate Cse4 copy number in live yeast, we developed a method coupling fluorescence correlation spectroscopy and calibrated imaging. We find that centromeric nucleosomes have one copy of Cse4 during most of the cell cycle, whereas two copies are detected at anaphase. The proposal of an anaphase-coupled structural change is supported by Cse4-Cse4 interactions, incorporation of Cse4, and the absence of Scm3 in anaphase. Nucleosome reconstitution and ChIP suggests both Cse4 structures contain H2A/H2B. The increase in Cse4 intensity and deposition at anaphase are also observed in Candida albicans. Our experimental evidence supports a cell-cycle-coupled oscillation of centromeric nucleosome structure in yeast.
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104
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Abstract
The composition and structure of centromeric nucleosomes, which contain the histone H3 variant CENP-A, is intensely debated. Two independent studies in this issue, in yeast and human cells, now suggest that CENP-A nucleosomes adopt different structures depending on the stage of the cell cycle.
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105
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Eskat A, Deng W, Hofmeister A, Rudolphi S, Emmerth S, Hellwig D, Ulbricht T, Döring V, Bancroft JM, McAinsh AD, Cardoso MC, Meraldi P, Hoischen C, Leonhardt H, Diekmann S. Step-wise assembly, maturation and dynamic behavior of the human CENP-P/O/R/Q/U kinetochore sub-complex. PLoS One 2012; 7:e44717. [PMID: 23028590 PMCID: PMC3445539 DOI: 10.1371/journal.pone.0044717] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 08/06/2012] [Indexed: 11/18/2022] Open
Abstract
Kinetochores are multi-protein megadalton assemblies that are required for attachment of microtubules to centromeres and, in turn, the segregation of chromosomes in mitosis. Kinetochore assembly is a cell cycle regulated multi-step process. The initial step occurs during interphase and involves loading of the 15-subunit constitutive centromere associated complex (CCAN), which contains a 5-subunit (CENP-P/O/R/Q/U) sub-complex. Here we show using a fluorescent three-hybrid (F3H) assay and fluorescence resonance energy transfer (FRET) in living mammalian cells that CENP-P/O/R/Q/U subunits exist in a tightly packed arrangement that involves multifold protein-protein interactions. This sub-complex is, however, not pre-assembled in the cytoplasm, but rather assembled on kinetochores through the step-wise recruitment of CENP-O/P heterodimers and the CENP-P, -O, -R, -Q and -U single protein units. SNAP-tag experiments and immuno-staining indicate that these loading events occur during S-phase in a manner similar to the nucleosome binding components of the CCAN, CENP-T/W/N. Furthermore, CENP-P/O/R/Q/U binding to the CCAN is largely mediated through interactions with the CENP-N binding protein CENP-L as well as CENP-K. Once assembled, CENP-P/O/R/Q/U exchanges slowly with the free nucleoplasmic pool indicating a low off-rate for individual CENP-P/O/R/Q/U subunits. Surprisingly, we then find that during late S-phase, following the kinetochore-binding step, both CENP-Q and -U but not -R undergo oligomerization. We propose that CENP-P/O/R/Q/U self-assembles on kinetochores with varying stoichiometry and undergoes a pre-mitotic maturation step that could be important for kinetochores switching into the correct conformation necessary for microtubule-attachment.
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Affiliation(s)
| | - Wen Deng
- Department of Biology II, Center for Integrated Protein Science, Ludwig Maximilians University Munich, Planegg-Martinsried, Munich, Germany
| | | | | | | | | | | | | | - James M. Bancroft
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Andrew D. McAinsh
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | | | | | - Heinrich Leonhardt
- Department of Biology II, Center for Integrated Protein Science, Ludwig Maximilians University Munich, Planegg-Martinsried, Munich, Germany
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107
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Chromatin: Nucleosomal dynamics at centromeres. Nat Rev Mol Cell Biol 2012; 13:539. [PMID: 22914287 DOI: 10.1038/nrm3423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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