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GRANT Motif Regulates CENP-A Incorporation and Restricts RNA Polymerase II Accessibility at Centromere. Genes (Basel) 2022; 13:genes13101697. [PMID: 36292582 PMCID: PMC9602348 DOI: 10.3390/genes13101697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 11/24/2022] Open
Abstract
Precise chromosome segregation is essential for maintaining genomic stability, and its proper execution centers on the centromere, a chromosomal locus that mounts the kinetochore complex to mediate attachment of chromosomes to the spindle microtubules. The location of the centromere is epigenetically determined by a centromere-specific histone H3 variant, CENP-A. Many human cancers exhibit overexpression of CENP-A, which correlates with occurrence of aneuploidy in these malignancies. Centromeric targeting of CENP-A depends on its histone fold, but recent studies showed that the N-terminal tail domain (NTD) also plays essential roles. Here, we investigated implications of NTD in conferring aneuploidy formation when CENP-A is overexpressed in fission yeast. A series of mutant genes progressively lacking one amino acid of the NTD have been constructed for overexpression in wild-type cells using the intermediate strength nmt41 promoter. Constructs hosting disrupted GRANT (Genomic stability-Regulating site within CENP-A N-Terminus) motif in NTD results in growth retardation, aneuploidy, increased localization to the centromere, upregulated RNA polymerase II accessibility and transcriptional derepression of the repressive centromeric chromatin, suggesting that GRANT residues fine-tune centromeric CENP-A incorporation and restrict RNA polymerase II accessibility. This work highlighted the importance of CENP-A NTD, particularly the GRANT motif, in aneuploidy formation of overexpressed CENP-A in fission yeast.
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Mahlke MA, Nechemia-Arbely Y. Guarding the Genome: CENP-A-Chromatin in Health and Cancer. Genes (Basel) 2020; 11:genes11070810. [PMID: 32708729 PMCID: PMC7397030 DOI: 10.3390/genes11070810] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/10/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023] Open
Abstract
Faithful chromosome segregation is essential for the maintenance of genomic integrity and requires functional centromeres. Centromeres are epigenetically defined by the histone H3 variant, centromere protein A (CENP-A). Here we highlight current knowledge regarding CENP-A-containing chromatin structure, specification of centromere identity, regulation of CENP-A deposition and possible contribution to cancer formation and/or progression. CENP-A overexpression is common among many cancers and predicts poor prognosis. Overexpression of CENP-A increases rates of CENP-A deposition ectopically at sites of high histone turnover, occluding CCCTC-binding factor (CTCF) binding. Ectopic CENP-A deposition leads to mitotic defects, centromere dysfunction and chromosomal instability (CIN), a hallmark of cancer. CENP-A overexpression is often accompanied by overexpression of its chaperone Holliday Junction Recognition Protein (HJURP), leading to epigenetic addiction in which increased levels of HJURP and CENP-A become necessary to support rapidly dividing p53 deficient cancer cells. Alterations in CENP-A posttranslational modifications are also linked to chromosome segregation errors and CIN. Collectively, CENP-A is pivotal to genomic stability through centromere maintenance, perturbation of which can lead to tumorigenesis.
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Affiliation(s)
- Megan A. Mahlke
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA;
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yael Nechemia-Arbely
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA;
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Correspondence: ; Tel.: +1-412-623-3228; Fax: +1-412-623-7828
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Boudichevskaia A, Houben A, Fiebig A, Prochazkova K, Pecinka A, Lermontova I. Depletion of KNL2 Results in Altered Expression of Genes Involved in Regulation of the Cell Cycle, Transcription, and Development in Arabidopsis. Int J Mol Sci 2019; 20:ijms20225726. [PMID: 31731608 PMCID: PMC6888302 DOI: 10.3390/ijms20225726] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 11/17/2022] Open
Abstract
Centromeres contain specialized nucleosomes at which histone H3 is partially replaced by the centromeric histone H3 variant cenH3 that is required for the assembly, maintenance, and proper function of kinetochores during mitotic and meiotic divisions. Previously, we identified a KINETOCHORE NULL 2 (KNL2) of Arabidopsis thaliana that is involved in the licensing of centromeres for the cenH3 recruitment. We also demonstrated that a knockout mutant for KNL2 shows mitotic and meiotic defects, slower development, reduced growth rate, and fertility. To analyze an effect of KNL2 mutation on global gene transcription of Arabidopsis, we performed RNA-sequencing experiments using seedling and flower bud tissues of knl2 and wild-type plants. The transcriptome data analysis revealed a high number of differentially expressed genes (DEGs) in knl2 plants. The set was enriched in genes involved in the regulation of the cell cycle, transcription, development, and DNA damage repair. In addition to comprehensive information regarding the effects of KNL2 mutation on the global gene expression, physiological changes in plants are also presented, which provides an integrated understanding of the critical role played by KNL2 in plant growth and development.
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Affiliation(s)
- Anastassia Boudichevskaia
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466 Seeland, Germany; (A.H.); (A.F.)
- Correspondence: (A.B.); (I.L.); Tel.: +49/39482 5477 (A.B.); +49/39482 5570 (I.L.)
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466 Seeland, Germany; (A.H.); (A.F.)
| | - Anne Fiebig
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466 Seeland, Germany; (A.H.); (A.F.)
| | - Klara Prochazkova
- Institute of Experimental Botany, Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Šlechtitelů 31, CZ-77900 Olomouc, Czech Republic; (K.P.); (A.P.)
| | - Ales Pecinka
- Institute of Experimental Botany, Czech Acad Sci, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Šlechtitelů 31, CZ-77900 Olomouc, Czech Republic; (K.P.); (A.P.)
| | - Inna Lermontova
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466 Seeland, Germany; (A.H.); (A.F.)
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
- Correspondence: (A.B.); (I.L.); Tel.: +49/39482 5477 (A.B.); +49/39482 5570 (I.L.)
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4
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Lee M, Kim IS, Park KC, Kim JS, Baek SH, Kim KI. Mitosis-specific phosphorylation of Mis18α by Aurora B kinase enhances kinetochore recruitment of polo-like kinase 1. Oncotarget 2017; 9:1563-1576. [PMID: 29416714 PMCID: PMC5788582 DOI: 10.18632/oncotarget.22707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 10/28/2017] [Indexed: 01/11/2023] Open
Abstract
Mis18α, a component of Mis18 complex comprising of Mis18α, Mis18β, and M18BP1, is known to localize at the centromere from late telophase to early G1 phase and plays a priming role in CENP-A deposition. Although its role in CENP-A deposition is well established, the other function of Mis18α remains unknown. Here, we elucidate a new function of Mis18α that is critical for the proper progression of cell cycle independent of its role in CENP-A deposition. We find that Aurora B kinase phosphorylates Mis18α during mitosis not affecting neither centromere localization of Mis18 complex nor centromere loading of CENP-A. However, the replacement of endogenous Mis18α by phosphorylation-defective mutant causes mitotic defects including micronuclei formation, chromosome misalignment, and chromosomal bridges. Together, our data demonstrate that Aurora B kinase-mediated mitotic phosphorylation of Mis18α is a crucial event for faithful cell cycle progression through the enhanced recruitment of polo-like kinase 1 to the kinetochore.
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Affiliation(s)
- Minkyoung Lee
- Creative Research Initiatives Center for Chromatin Dynamics, Department of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Ik Soo Kim
- Creative Research Initiatives Center for Chromatin Dynamics, Department of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Koog Chan Park
- Department of Biological Sciences, Cellular Heterogeneity Research Center, Sookmyung Women's University, Seoul 04310, South Korea
| | - Jong-Seo Kim
- Center for RNA Research, Institute for Basic Science, Department of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Sung Hee Baek
- Creative Research Initiatives Center for Chromatin Dynamics, Department of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Keun Il Kim
- Department of Biological Sciences, Cellular Heterogeneity Research Center, Sookmyung Women's University, Seoul 04310, South Korea
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5
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A Dual Inhibitory Mechanism Sufficient to Maintain Cell-Cycle-Restricted CENP-A Assembly. Mol Cell 2016; 65:231-246. [PMID: 28017591 DOI: 10.1016/j.molcel.2016.11.021] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 09/19/2016] [Accepted: 11/14/2016] [Indexed: 11/22/2022]
Abstract
Chromatin featuring the H3 variant CENP-A at the centromere is critical for its mitotic function and epigenetic maintenance. Assembly of centromeric chromatin is restricted to G1 phase through inhibitory action of Cdk1/2 kinases in other phases of the cell cycle. Here, we identify the two key targets sufficient to maintain cell-cycle control of CENP-A assembly. We uncovered a single phosphorylation site in the licensing factor M18BP1 and a cyclin A binding site in the CENP-A chaperone, HJURP, that mediated specific inhibitory phosphorylation. Simultaneous expression of mutant proteins lacking these residues results in complete uncoupling from the cell cycle. Consequently, CENP-A assembly is fully recapitulated under high Cdk activities, indistinguishable from G1 assembly. We find that Cdk-mediated inhibition is exerted by sequestering active factors away from the centromere. Finally, we show that displacement of M18BP1 from the centromere is critical for the assembly mechanism of CENP-A.
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Skin-Specific Deletion of Mis18α Impedes Proliferation and Stratification of Epidermal Keratinocytes. J Invest Dermatol 2016; 137:414-421. [PMID: 27670610 DOI: 10.1016/j.jid.2016.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 07/27/2016] [Accepted: 09/02/2016] [Indexed: 11/21/2022]
Abstract
The Mis18 proteins (Mis18α, Mis18β, and M18BP1) are pivotal to the deposition of CENP-A at the centromere during cell cycle progression and are indispensable for embryonic development. Here, we show that Mis18α is critical for the proliferation of keratinocytes and stratification of the epidermis. Mice lacking Mis18α in the epidermis died shortly after birth, showing skin abnormalities like thin and translucent skin and defective skin barrier functions. The epidermis of newborn Mis18α-deficient mice lacked distinct stratification and mature hair follicles, with a reduction in the number of proliferating cells and increased cell death in the basal layer. Earlier expression of the Cre recombinase from keratin-14 promoter in the ventral region resulted in earlier keratinocyte death in the ventral part compared with the dorsal part in the absence of Mis18α, leading to more severe malformation of the ventral epidermal layers. As observed in Mis18α-deficient mouse keratinocytes, knockdown of Mis18α in HaCaT cells caused marked loss of centromeric CENP-A dots and chromosomal misalignment. Overall, we propose that Mis18α is important for epidermal cell proliferation and stratification, because it is required for the deposition of CENP-A at the centromeric nucleosomes.
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Richet N, Liu D, Legrand P, Velours C, Corpet A, Gaubert A, Bakail M, Moal-Raisin G, Guerois R, Compper C, Besle A, Guichard B, Almouzni G, Ochsenbein F. Structural insight into how the human helicase subunit MCM2 may act as a histone chaperone together with ASF1 at the replication fork. Nucleic Acids Res 2015; 43:1905-17. [PMID: 25618846 PMCID: PMC4330383 DOI: 10.1093/nar/gkv021] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
MCM2 is a subunit of the replicative helicase machinery shown to interact with histones H3 and H4 during the replication process through its N-terminal domain. During replication, this interaction has been proposed to assist disassembly and assembly of nucleosomes on DNA. However, how this interaction participates in crosstalk with histone chaperones at the replication fork remains to be elucidated. Here, we solved the crystal structure of the ternary complex between the histone-binding domain of Mcm2 and the histones H3-H4 at 2.9 Å resolution. Histones H3 and H4 assemble as a tetramer in the crystal structure, but MCM2 interacts only with a single molecule of H3-H4. The latter interaction exploits binding surfaces that contact either DNA or H2B when H3-H4 dimers are incorporated in the nucleosome core particle. Upon binding of the ternary complex with the histone chaperone ASF1, the histone tetramer dissociates and both MCM2 and ASF1 interact simultaneously with the histones forming a 1:1:1:1 heteromeric complex. Thermodynamic analysis of the quaternary complex together with structural modeling support that ASF1 and MCM2 could form a chaperoning module for histones H3 and H4 protecting them from promiscuous interactions. This suggests an additional function for MCM2 outside its helicase function as a proper histone chaperone connected to the replication pathway.
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Affiliation(s)
- Nicolas Richet
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Danni Liu
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | | | - Christophe Velours
- Laboratoire d'Enzymologie et de Biologie Structurale, CNRS UPR 3082, 1 avenue de la Terrasse, Gif-sur-Yvette, F-91190, France
| | - Armelle Corpet
- Institut Curie, Centre de Recherche, CNRS UMR 3664, Equipe Labellisée Ligue contre le Cancer, and Université Pierre et Marie Curie, Université Sorbonne PSL*, Paris, F-75248, France
| | - Albane Gaubert
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - May Bakail
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Gwenaelle Moal-Raisin
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Raphael Guerois
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Christel Compper
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Arthur Besle
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Berengère Guichard
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
| | - Genevieve Almouzni
- Institut Curie, Centre de Recherche, CNRS UMR 3664, Equipe Labellisée Ligue contre le Cancer, and Université Pierre et Marie Curie, Université Sorbonne PSL*, Paris, F-75248, France
| | - Françoise Ochsenbein
- CEA, iBiTec-S, SB2SM, Laboratoire de Biologie Structurale et Radiobiologie, France Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Batiment 144, Gif-sur-Yvette, F-91191, France
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8
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Annunziato AT. Assembling chromatin: the long and winding road. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1819:196-210. [PMID: 24459722 DOI: 10.1016/j.bbagrm.2011.07.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
It has been over 35 years since the acceptance of the "chromatin subunit" hypothesis, and the recognition that nucleosomes are the fundamental repeating units of chromatin fibers. Major subjects of inquiry in the intervening years have included the steps involved in chromatin assembly, and the chaperones that escort histones to DNA. The following commentary offers an historical perspective on inquiries into the processes by which nucleosomes are assembled on replicating and nonreplicating chromatin. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.
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9
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Abstract
All living organisms require accurate mechanisms to faithfully inherit their genetic material during cell division. The centromere is a unique locus on each chromosome that supports a multiprotein structure called the kinetochore. During mitosis, the kinetochore is responsible for connecting chromosomes to spindle microtubules, allowing faithful segregation of the duplicated genome. In most organisms, centromere position and function is not defined by the local DNA sequence context but rather by an epigenetic chromatin-based mechanism. Centromere protein A (CENP-A) is central to this process, as chromatin assembled from this histone H3 variant is essential for assembly of the centromere complex, as well as for its epigenetic maintenance. As a major determinant of centromere function, CENP-A assembly requires tight control, both in its specificity for the centromere and in timing of assembly. In the last few years, there have been several new insights into the molecular mechanism that allow this process to occur. We will review these here and discuss the general implications of the mechanism of cell cycle coupling of centromere inheritance.
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Nechemia-Arbely Y, Fachinetti D, Cleveland DW. Replicating centromeric chromatin: spatial and temporal control of CENP-A assembly. Exp Cell Res 2012; 318:1353-60. [PMID: 22561213 DOI: 10.1016/j.yexcr.2012.04.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 04/17/2012] [Accepted: 04/19/2012] [Indexed: 11/17/2022]
Abstract
The centromere is the fundamental unit for insuring chromosome inheritance. This complex region has a distinct type of chromatin in which histone H3 is replaced by a structurally different homologue identified in humans as CENP-A. In metazoans, specific DNA sequences are neither required nor sufficient for centromere identity. Rather, an epigenetic mark comprised of CENP-A containing chromatin is thought to be the major determinant of centromere identity. In this view, CENP-A deposition and chromatin assembly are fundamental processes for the maintenance of centromeric identity across mitotic and meiotic divisions. Several lines of evidence support CENP-A deposition in metazoans occurring at only one time in the cell cycle. Such cell cycle-dependent loading of CENP-A is found in divergent species from human to fission yeast, albeit with differences in the cell cycle point at which CENP-A is assembled. Cell cycle dependent CENP-A deposition requires multiple assembly factors for its deposition and maintenance. This review discusses the regulation of new CENP-A deposition and its relevance to centromere identity and inheritance.
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Affiliation(s)
- Yael Nechemia-Arbely
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
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11
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Kim IS, Lee M, Park KC, Jeon Y, Park JH, Hwang EJ, Jeon TI, Ko S, Lee H, Baek SH, Kim KI. Roles of Mis18α in epigenetic regulation of centromeric chromatin and CENP-A loading. Mol Cell 2012; 46:260-73. [PMID: 22516971 DOI: 10.1016/j.molcel.2012.03.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 01/31/2012] [Accepted: 03/16/2012] [Indexed: 01/28/2023]
Abstract
The Mis18 complex has been identified as a critical factor for the centromeric localization of a histone H3 variant, centromeric protein A (CENP-A), which is responsible for the specification of centromere identity in the chromosome. However, the functional role of Mis18 complex is largely unknown. Here, we generated Mis18α conditional knockout mice and found that Mis18α deficiency resulted in lethality at early embryonic stage with severe defects in chromosome segregation caused by mislocalization of CENP-A. Further, we demonstrate Mis18α's crucial role for epigenetic regulation of centromeric chromatin by reinforcing centromeric localization of DNMT3A/3B. Mis18α interacts with DNMT3A/3B, and this interaction is critical for maintaining DNA methylation and hence regulating epigenetic states of centromeric chromatin. Mis18α deficiency led to reduced DNA methylation, altered histone modifications, and uncontrolled noncoding transcripts in centromere region by decreased DNMT3A/3B enrichment. Together, our findings uncover the functional mechanism of Mis18α and its pivotal role in mammalian cell cycle.
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Affiliation(s)
- Ik Soo Kim
- Department of Biological Sciences, Creative Research Initiative Center for Chromatin Dynamics, Seoul National University, Seoul, South Korea
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Falk SJ, Black BE. Centromeric chromatin and the pathway that drives its propagation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:313-21. [PMID: 22154124 DOI: 10.1016/j.bbagrm.2011.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 01/03/2023]
Abstract
The centromere is the locus that directs chromosomal inheritance at cell division. While centromeres in diverse eukaryotes are commonly found at sites of repetitive DNA, their location is epigenetically specified. The histone H3 variant CENP-A is the prime candidate for epigenetically marking the centromere, and recent work has uncovered several additional proteins that play key roles in centromere assembly and maintenance. We describe advances in the identification and characterization of proteins that form the centromere, and focus on recent findings that have advanced our understanding of the assembly of functional centromeric chromatin. This article is part of a Special Issue entitled: Histone chaperones and chromatin assembly.
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Silva MCC, Bodor DL, Stellfox ME, Martins NMC, Hochegger H, Foltz DR, Jansen LET. Cdk activity couples epigenetic centromere inheritance to cell cycle progression. Dev Cell 2011; 22:52-63. [PMID: 22169070 DOI: 10.1016/j.devcel.2011.10.014] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 08/25/2011] [Accepted: 10/18/2011] [Indexed: 11/24/2022]
Abstract
Centromeres form the site of chromosome attachment to microtubules during mitosis. Identity of these loci is maintained epigenetically by nucleosomes containing the histone H3 variant CENP-A. Propagation of CENP-A chromatin is uncoupled from DNA replication initiating only during mitotic exit. We now demonstrate that inhibition of Cdk1 and Cdk2 activities is sufficient to trigger CENP-A assembly throughout the cell cycle in a manner dependent on the canonical CENP-A assembly machinery. We further show that the key CENP-A assembly factor Mis18BP1(HsKNL2) is phosphorylated in a cell cycle-dependent manner that controls its centromere localization during mitotic exit. These results strongly support a model in which the CENP-A assembly machinery is poised for activation throughout the cell cycle but kept in an inactive noncentromeric state by Cdk activity during S, G2, and M phases. Alleviation of this inhibition in G1 phase ensures tight coupling between DNA replication, cell division, and subsequent centromere maturation.
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14
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Moree B, Meyer CB, Fuller CJ, Straight AF. CENP-C recruits M18BP1 to centromeres to promote CENP-A chromatin assembly. ACTA ACUST UNITED AC 2011; 194:855-71. [PMID: 21911481 PMCID: PMC3207292 DOI: 10.1083/jcb.201106079] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
CENP-C provides a link between existing CENP-A chromatin and the proteins required for new CENP-A nucleosome assembly. Eukaryotic chromosomes segregate by attaching to microtubules of the mitotic spindle through a chromosomal microtubule binding site called the kinetochore. Kinetochores assemble on a specialized chromosomal locus termed the centromere, which is characterized by the replacement of histone H3 in centromeric nucleosomes with the essential histone H3 variant CENP-A (centromere protein A). Understanding how CENP-A chromatin is assembled and maintained is central to understanding chromosome segregation mechanisms. CENP-A nucleosome assembly requires the Mis18 complex and the CENP-A chaperone HJURP. These factors localize to centromeres in telophase/G1, when new CENP-A chromatin is assembled. The mechanisms that control their targeting are unknown. In this paper, we identify a mechanism for recruiting the Mis18 complex protein M18BP1 to centromeres. We show that depletion of CENP-C prevents M18BP1 targeting to metaphase centromeres and inhibits CENP-A chromatin assembly. We find that M18BP1 directly binds CENP-C through conserved domains in the CENP-C protein. Thus, CENP-C provides a link between existing CENP-A chromatin and the proteins required for new CENP-A nucleosome assembly.
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Affiliation(s)
- Ben Moree
- Department of Biochemistry, Stanford University Medical School, Stanford, CA 94305, USA
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15
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Deposition, turnover, and release of CENH3 at Arabidopsis centromeres. Chromosoma 2011; 120:633-40. [PMID: 21842230 DOI: 10.1007/s00412-011-0338-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 07/14/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
The kinetochore is a complex multiprotein structure located at centromeres and required for the proper segregation of chromosomes during mitosis and meiosis. An important role in kinetochore assembly and function plays the centromeric histone H3 variant (CENH3). Cell cycle stage of CENH3 deposition to centromeres varies between different organisms. We confirmed by in vivo studies that deposition of Arabidopsis CENH3 takes place at centromeres during G2 and demonstrated that additionally a low turnover of CENH3 occurs along the cell cycle, apparently for replacement of damaged protein. Furthermore, enhanced yellow fluorescent protein (EYFP)-CENH3 of photobleached chromocenters is not replaced by EYFP-CENH3 molecules from unbleached centromeres of the same nucleus, indicating a stable incorporation of CENH3 into centromeric nucleosomes. In differentiated endopolyploid nuclei however, the amount of CENH3 at centromeres declines with age.
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Assembly of Drosophila centromeric chromatin proteins during mitosis. PLoS Genet 2011; 7:e1002068. [PMID: 21589899 PMCID: PMC3093364 DOI: 10.1371/journal.pgen.1002068] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/22/2011] [Indexed: 01/19/2023] Open
Abstract
Semi-conservative segregation of nucleosomes to sister chromatids during DNA replication creates gaps that must be filled by new nucleosome assembly. We analyzed the cell-cycle timing of centromeric chromatin assembly in Drosophila, which contains the H3 variant CID (CENP-A in humans), as well as CENP-C and CAL1, which are required for CID localization. Pulse-chase experiments show that CID and CENP-C levels decrease by 50% at each cell division, as predicted for semi-conservative segregation and inheritance, whereas CAL1 displays higher turnover. Quench-chase-pulse experiments demonstrate that there is a significant lag between replication and replenishment of centromeric chromatin. Surprisingly, new CID is recruited to centromeres in metaphase, by a mechanism that does not require an intact mitotic spindle, but does require proteasome activity. Interestingly, new CAL1 is recruited to centromeres before CID in prophase. Furthermore, CAL1, but not CENP-C, is found in complex with pre-nucleosomal CID. Finally, CENP-C displays yet a different pattern of incorporation, during both interphase and mitosis. The unusual timing of CID recruitment and unique dynamics of CAL1 identify a distinct centromere assembly pathway in Drosophila and suggest that CAL1 is a key regulator of centromere propagation. The centromere is essential for kinetochore formation, chromosome attachment to spindle microtubules, and equal segregation of the genome to daughter cells. Centromeres are epigenetically inherited through a unique type of chromatin which contains centromere-specific proteins. At each round of DNA replication, centromeric proteins become diluted and must be replenished to ensure faithful maintenance of the centromere locus through cell division. Whether divergent eukaryotes share a common strategy for centromere identity and propagation remains an unanswered question. Here, we examine how Drosophila centromere proteins re-distribute after replication, and we determine the cell-cycle dynamics of their replenishment. We show that three chromatin components required for centromere maintenance display distinct dynamics during the cell cycle; surprisingly, two components are assembled at centromeres during mitosis. These results suggest a new model for regulation of centromere assembly in Drosophila, which emphasizes a key role for the Dipteran-specific protein CAL1.
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Black BE, Jansen LET, Foltz DR, Cleveland DW. Centromere identity, function, and epigenetic propagation across cell divisions. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2011; 75:403-18. [PMID: 21467140 PMCID: PMC3140419 DOI: 10.1101/sqb.2010.75.038] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The key to understanding centromere identity is likely to lie in the chromatin containing the histone H3 variant CENP-A. CENP-A is the prime candidate to carry the epigenetic information that specifies the chromosomal location of the centromere in nearly all eukaryotic species, raising questions fundamental to understanding chromosome inheritance: How is the epigenetic centromere mark propagated? What physical properties of CENP-A-containing complexes are important for epigenetically marking centromeres? What are the molecules that recognize centromeric chromatin and serve as the foundation for the mitotic kinetochore? We discuss recent advances from our research groups that have yielded substantial insight into these questions and present our current understanding of the centromere. Future work promises an understanding of the molecular processes that confer fidelity to genome transmission at cell division.
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Affiliation(s)
- B E Black
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059, USA.
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Bernad R, Sánchez P, Rivera T, Rodríguez-Corsino M, Boyarchuk E, Vassias I, Ray-Gallet D, Arnaoutov A, Dasso M, Almouzni G, Losada A. Xenopus HJURP and condensin II are required for CENP-A assembly. ACTA ACUST UNITED AC 2011; 192:569-82. [PMID: 21321101 PMCID: PMC3044122 DOI: 10.1083/jcb.201005136] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Chromatin structure imposed by condensin II at centromeres enables xHJURP-mediated incorporation of CENP-A. Centromeric protein A (CENP-A) is the epigenetic mark of centromeres. CENP-A replenishment is necessary in each cell cycle to compensate for the dilution associated to DNA replication, but how this is achieved mechanistically is largely unknown. We have developed an assay using Xenopus egg extracts that can recapitulate the spatial and temporal specificity of CENP-A deposition observed in human cells, providing us with a robust in vitro system amenable to molecular dissection. Here we show that this deposition depends on Xenopus Holliday junction–recognizing protein (xHJURP), a member of the HJURP/Scm3 family recently identified in yeast and human cells, further supporting the essential role of these chaperones in CENP-A loading. Despite little sequence homology, human HJURP can substitute for xHJURP. We also report that condensin II, but not condensin I, is required for CENP-A assembly and contributes to retention of centromeric CENP-A nucleosomes both in mitosis and interphase. We propose that the chromatin structure imposed by condensin II at centromeres enables CENP-A incorporation initiated by xHJURP.
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Affiliation(s)
- Rafael Bernad
- Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
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Olins AL, Langhans M, Monestier M, Schlotterer A, Robinson DG, Viotti C, Zentgraf H, Zwerger M, Olins DE. An epichromatin epitope: persistence in the cell cycle and conservation in evolution. Nucleus 2011; 2:47-60. [PMID: 21647299 PMCID: PMC3104809 DOI: 10.4161/nucl.2.1.13271] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 09/15/2010] [Accepted: 09/16/2010] [Indexed: 11/19/2022] Open
Abstract
Interphase nuclear architecture is disrupted and rapidly reformed with each cell division cycle. Successive cell generations exhibit a "memory" of this nuclear architecture, as well as for gene expression. Furthermore, many features of nuclear and mitotic chromosome structure are recognizably species and tissue specific. We wish to know what properties of the underlying chromatin structure may determine these conserved features of nuclear architecture. Employing a particular mouse autoimmune anti-nucleosome monoclonal antibody (PL2-6), combined with deconvolution immunofluorescence microscopy, we present evidence for a unique epitope (involving a ternary complex of histones H2A and H2B and DNA) which is localized only at the exterior chromatin surface of interphase nuclei and mitotic chromosomes in mammalian, invertebrate and plant systems. As only the surface chromatin region is identified with antibody PL2-6, we have assigned it the name "epichromatin". We describe an "epichromatin hypothesis", suggesting that epichromatin may have a unique evolutionary conserved conformation which facilitates interaction with the reforming post-mitotic nuclear envelope and a rapid return of interphase nuclear architecture.
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Affiliation(s)
- Ada L Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, Portland, ME USA. ted proteins (ARPs), a
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Abstract
In eukaryotes, DNA is organized into chromatin, a dynamic structure that enables DNA to be accessed for processes such as transcription, replication and repair. To form, maintain or alter this organization according to cellular needs, histones, the main protein component of chromatin, are deposited, replaced, exchanged and post-translationally modified. Histone variants, which exhibit specialized deposition modes in relation to the cell cycle and possibly particular chromatin regions, add an additional level of complexity in the regulation of histone flow. During their metabolism, from their synthesis to their delivery for nucleosome formation, the histones are escorted by proteins called histone chaperones. In the present chapter we summarize our current knowledge concerning histone chaperones and their interaction with particular histones based on key structural properties. From a compilation of selected histone chaperones identified to date, we discuss how they may be placed in a network to regulate histone dynamics. Finally, we provide working models to explain how H3 variants, deposited on to DNA using different histone chaperone machineries, can be transmitted or lost through cell divisions.
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A small GTPase molecular switch regulates epigenetic centromere maintenance by stabilizing newly incorporated CENP-A. Nat Cell Biol 2010; 12:1186-93. [DOI: 10.1038/ncb2129] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 10/20/2010] [Indexed: 12/12/2022]
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Olins AL, Ernst A, Zwerger M, Herrmann H, Olins DE. An in vitro model for Pelger-Huët anomaly: stable knockdown of lamin B receptor in HL-60 cells. Nucleus 2010; 1:506-12. [PMID: 21327094 PMCID: PMC3027054 DOI: 10.4161/nucl.1.6.13271] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 08/03/2010] [Accepted: 08/06/2010] [Indexed: 11/19/2022] Open
Abstract
The principal human blood granulocyte (neutrophil) possesses a lobulated and deformable nucleus, important to facilitate rapid egress from blood vessels as these cells migrate to sites of bacterial or fungal infection. This unusual nuclear shape is a product of elevated levels of an integral membrane protein of the nuclear envelope lamin B receptor (LBR) and of decreased amounts of lamin A/C. In humans, a genetic deficiency of LBR produces Pelger-Huët anomaly, resulting in blood neutrophils that exhibit hypolobulated nuclei with redistributed heterochromatin. Structural changes in nuclear architecture occur during granulopoiesis within bone marrow. The exact mechanisms of this nuclear shape change and of heterochromatin redistribution remain largely unknown. As a tool to facilitate analysis of these mechanisms, a stable LBR knockdown subline of HL-60 cells was established. During in vitro granulopoiesis induced with retinoic acid, the LBR knockdown cells retain an ovoid shaped nucleus with reduced levels of lamin A/C; while, the parent cells develop highly lobulated nuclei. In contrast, macrophage forms induced in LBR knockdown cells by in vitro treatment with phorbol ester were indistinguishable from the parent cells, judged by both nuclear shape and attached cell morphology. The capability of differentiation of LBR knockdown HL-60 cells should facilitate a detailed analysis of the molecular relationship between LBR levels, granulocyte nuclear shape and heterochromatin distribution.
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Affiliation(s)
- Ada L Olins
- Department of Biology, Bowdoin College, Brunswick, ME, USA
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Mehta GD, Agarwal MP, Ghosh SK. Centromere identity: a challenge to be faced. Mol Genet Genomics 2010; 284:75-94. [PMID: 20585957 DOI: 10.1007/s00438-010-0553-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 06/16/2010] [Indexed: 11/26/2022]
Abstract
The centromere is a genetic locus, required for faithful chromosome segregation, where spindle fibers attach to the chromosome through kinetochore. Loss of centromere or formation of multiple centromeres on a single chromosome leads to chromosome missegregation or chromosome breakage, respectively, which are detrimental for fitness and survival of a cell. Therefore, understanding the mechanism of centromere locus determination on the chromosome and perpetuation of such a locus in subsequent generation (known as centromere identity) is very fundamental to combat conditions like aneuploidy, spontaneous abortion, developmental defects, cell lethality and cancer. Recent studies have come up with different models to explain centromere identity. However, the exact mechanism still remains elusive. It has been observed that most eukaryotic centromeres are determined epigenetically rather than by a DNA sequence. The epigenetic marks that are instrumental in determining centromere identity are the histone H3 variant, CENP-A and the specialized posttranslational modification of the core histones. Here we will review the recent studies on the factors responsible for generating unique centromeric chromatin and how it perpetuates during cell division giving the present-day models. We will further focus on the probable mechanism of de novo centromere formation with an example of neocentromere. As a matter of similitude, this review will include marking extrachromosomal chromatin to be served as a partitioning locus by deposition of CENP-A homolog in budding yeast.
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Affiliation(s)
- Gunjan D Mehta
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
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Down the rabbit hole of centromere assembly and dynamics. Curr Opin Cell Biol 2010; 22:392-402. [PMID: 20303726 DOI: 10.1016/j.ceb.2010.02.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 02/15/2010] [Accepted: 02/24/2010] [Indexed: 12/19/2022]
Abstract
The centromere is perhaps the most iconic feature on a eukaryotic chromosome. An amateur enthusiast equipped with a light microscope can easily identify the center of each metacentric chromosome, marking the spot responsible for accurate genome segregation. This review will highlight findings that provide novel insights into how centromeres are assembled and disassembled, the role centromeric proteins play in repair, epigenetic features uniquely found at the centromere, and the three dimensional organization of centromeres caught in the act of mitosis. These advances have unveiled a veritable wonderland of non-canonical features that drive centromere function.
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Alonso A, Hasson D, Cheung F, Warburton PE. A paucity of heterochromatin at functional human neocentromeres. Epigenetics Chromatin 2010; 3:6. [PMID: 20210998 PMCID: PMC2845132 DOI: 10.1186/1756-8935-3-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 03/08/2010] [Indexed: 12/29/2022] Open
Abstract
Background Centromeres are responsible for the proper segregation of replicated chromatids during cell division. Neocentromeres are fully functional ectopic human centromeres that form on low-copy DNA sequences and permit analysis of centromere structure in relation to the underlying DNA sequence. Such structural analysis is not possible at endogenous centromeres because of the large amounts of repetitive alpha satellite DNA present. Results High-resolution chromatin immunoprecipitation (ChIP) on CHIP (microarray) analysis of three independent neocentromeres from chromosome 13q revealed that each neocentromere contained ~100 kb of centromere protein (CENP)-A in a two-domain organization. Additional CENP-A domains were observed in the vicinity of neocentromeres, coinciding with CpG islands at the 5' end of genes. Analysis of histone H3 dimethylated at lysine 4 (H3K4me2) revealed small domains at each neocentromere. However, these domains of H3K4me2 were also found in the equivalent non-neocentric chromosomes. A surprisingly minimal (~15 kb) heterochromatin domain was observed at one of the neocentromeres, which formed in an unusual transposon-free region distal to the CENP-A domains. Another neocentromere showed a distinct absence of nearby significant domains of heterochromatin. A subtle defect in centromere cohesion detected at these neocentromeres may be due to the paucity of heterochromatin domains. Conclusions This high-resolution mapping suggests that H3K4me2 does not seem sufficiently abundant to play a structural role at neocentromeres, as proposed for endogenous centromeres. Large domains of heterochromatin also do not appear necessary for centromere function. Thus, this study provides important insight into the structural requirements of human centromere function.
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Affiliation(s)
- Alicia Alonso
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA
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