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Yuan T, Gao X, Xiang N, Wei P, Zhang G. The genome assembly of Carex breviculmis provides evidence for its phylogenetic localization and environmental adaptation. ANNALS OF BOTANY 2024; 134:467-484. [PMID: 38822911 PMCID: PMC11341672 DOI: 10.1093/aob/mcae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/27/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND AND AIMS Carex breviculmis is a perennial herb with good resistance and is widely used for forage production and turf management. It is important in ecology, environmental protection and biodiversity conservation, but faces several challenges due to human activities. However, the absence of genome sequences has limited basic research and the improvement of wild plants. METHODS We annotated the genome of C. breviculmis and conducted a systematic analysis to explore its resistance to harsh environments. We also conducted a comparative analysis of Achnatherum splendens, which is similarly tolerant to harsh environments. KEY RESULTS The assembled the genome comprises 469.01 Mb, revealing 37 372 genes with a BUSCO completeness score of 99.0 %. The genome has 52.03 % repetitive sequences, primarily influenced by recent LTR insertions that have contributed to its expansion. Phylogenetic analysis suggested that C. breviculmis diverged from C. littledalei ~6.61 million years ago. Investigation of repetitive sequences and expanded gene families highlighted a rapid expansion of tandem duplicate genes, particularly in areas related to sugar metabolism, synthesis of various amino acids, and phenylpropanoid biosynthesis. Additionally, our analysis identified crucial genes involved in secondary metabolic pathways, such as glycolysis, phenylpropanoid biosynthesis and amino acid metabolism, which have undergone positive selection. We reconstructed the sucrose metabolic pathway and identified significant gene expansions, including 16 invertase, 9 sucrose phosphate synthase and 12 sucrose synthase genes associated with sucrose metabolism, which showed varying levels of expansion. CONCLUSIONS The expansion of these genes, coupled with subsequent positive selection, contributed to the ability of C. breviculmis to adapt to environmental stressors. This study lays the foundation for future research on the evolution of Carex plants, their environmental adaptations, and potential genetic breeding.
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Affiliation(s)
- Tao Yuan
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
- State Key Laboratory of Hybrid Rice, Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaoman Gao
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Niyan Xiang
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Pei Wei
- State Key Laboratory of Hybrid Rice, Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Guiyu Zhang
- State Key Laboratory of Hybrid Rice, Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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2
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Naish M, Henderson IR. The structure, function, and evolution of plant centromeres. Genome Res 2024; 34:161-178. [PMID: 38485193 PMCID: PMC10984392 DOI: 10.1101/gr.278409.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Centromeres are essential regions of eukaryotic chromosomes responsible for the formation of kinetochore complexes, which connect to spindle microtubules during cell division. Notably, although centromeres maintain a conserved function in chromosome segregation, the underlying DNA sequences are diverse both within and between species and are predominantly repetitive in nature. The repeat content of centromeres includes high-copy tandem repeats (satellites), and/or specific families of transposons. The functional region of the centromere is defined by loading of a specific histone 3 variant (CENH3), which nucleates the kinetochore and shows dynamic regulation. In many plants, the centromeres are composed of satellite repeat arrays that are densely DNA methylated and invaded by centrophilic retrotransposons. In some cases, the retrotransposons become the sites of CENH3 loading. We review the structure of plant centromeres, including monocentric, holocentric, and metapolycentric architectures, which vary in the number and distribution of kinetochore attachment sites along chromosomes. We discuss how variation in CENH3 loading can drive genome elimination during early cell divisions of plant embryogenesis. We review how epigenetic state may influence centromere identity and discuss evolutionary models that seek to explain the paradoxically rapid change of centromere sequences observed across species, including the potential roles of recombination. We outline putative modes of selection that could act within the centromeres, as well as the role of repeats in driving cycles of centromere evolution. Although our primary focus is on plant genomes, we draw comparisons with animal and fungal centromeres to derive a eukaryote-wide perspective of centromere structure and function.
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Affiliation(s)
- Matthew Naish
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Ian R Henderson
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
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3
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Hisanaga T, Wu S, Schafran P, Axelsson E, Akimcheva S, Dolan L, Li F, Berger F. The ancestral chromatin landscape of land plants. THE NEW PHYTOLOGIST 2023; 240:2085-2101. [PMID: 37823324 PMCID: PMC10952607 DOI: 10.1111/nph.19311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/29/2023] [Indexed: 10/13/2023]
Abstract
Recent studies have shown that correlations between chromatin modifications and transcription vary among eukaryotes. This is the case for marked differences between the chromatin of the moss Physcomitrium patens and the liverwort Marchantia polymorpha. Mosses and liverworts diverged from hornworts, altogether forming the lineage of bryophytes that shared a common ancestor with land plants. We aimed to describe chromatin in hornworts to establish synapomorphies across bryophytes and approach a definition of the ancestral chromatin organization of land plants. We used genomic methods to define the 3D organization of chromatin and map the chromatin landscape of the model hornwort Anthoceros agrestis. We report that nearly half of the hornwort transposons were associated with facultative heterochromatin and euchromatin and formed the center of topologically associated domains delimited by protein coding genes. Transposons were scattered across autosomes, which contrasted with the dense compartments of constitutive heterochromatin surrounding the centromeres in flowering plants. Most of the features observed in hornworts are also present in liverworts or in mosses but are distinct from flowering plants. Hence, the ancestral genome of bryophytes was likely a patchwork of units of euchromatin interspersed within facultative and constitutive heterochromatin. We propose this genome organization was ancestral to land plants.
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Affiliation(s)
- Tetsuya Hisanaga
- Gregor Mendel InstituteAustrian Academy of Sciences, Vienna BioCenterDr. Bohr‐Gasse 3Vienna1030Austria
| | - Shuangyang Wu
- Gregor Mendel InstituteAustrian Academy of Sciences, Vienna BioCenterDr. Bohr‐Gasse 3Vienna1030Austria
| | | | - Elin Axelsson
- Gregor Mendel InstituteAustrian Academy of Sciences, Vienna BioCenterDr. Bohr‐Gasse 3Vienna1030Austria
| | - Svetlana Akimcheva
- Gregor Mendel InstituteAustrian Academy of Sciences, Vienna BioCenterDr. Bohr‐Gasse 3Vienna1030Austria
| | - Liam Dolan
- Gregor Mendel InstituteAustrian Academy of Sciences, Vienna BioCenterDr. Bohr‐Gasse 3Vienna1030Austria
| | - Fay‐Wei Li
- Boyce Thompson InstituteIthacaNY14853USA
- Plant Biology SectionCornell UniversityIthacaNY14853USA
| | - Frédéric Berger
- Gregor Mendel InstituteAustrian Academy of Sciences, Vienna BioCenterDr. Bohr‐Gasse 3Vienna1030Austria
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4
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Ansai S, Toyoda A, Yoshida K, Kitano J. Repositioning of centromere-associated repeats during karyotype evolution in Oryzias fishes. Mol Ecol 2023. [PMID: 38014620 DOI: 10.1111/mec.17222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 11/04/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023]
Abstract
The karyotype, which is the number and shape of chromosomes, is a fundamental characteristic of all eukaryotes. Karyotypic changes play an important role in many aspects of evolutionary processes, including speciation. In organisms with monocentric chromosomes, it was previously thought that chromosome number changes were mainly caused by centric fusions and fissions, whereas chromosome shape changes, that is, changes in arm numbers, were mainly due to pericentric inversions. However, recent genomic and cytogenetic studies have revealed examples of alternative cases, such as tandem fusions and centromere repositioning, found in the karyotypic changes within and between species. Here, we employed comparative genomic approaches to investigate whether centromere repositioning occurred during karyotype evolution in medaka fishes. In the medaka family (Adrianichthyidae), the three phylogenetic groups differed substantially in their karyotypes. The Oryzias latipes species group has larger numbers of chromosome arms than the other groups, with most chromosomes being metacentric. The O. javanicus species group has similar numbers of chromosomes to the O. latipes species group, but smaller arm numbers, with most chromosomes being acrocentric. The O. celebensis species group has fewer chromosomes than the other two groups and several large metacentric chromosomes that were likely formed by chromosomal fusions. By comparing the genome assemblies of O. latipes, O. javanicus, and O. celebensis, we found that repositioning of centromere-associated repeats might be more common than simple pericentric inversion. Our results demonstrated that centromere repositioning may play a more important role in karyotype evolution than previously appreciated.
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Affiliation(s)
- Satoshi Ansai
- Laboratory of Genome Editing Breeding, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Japan
| | - Kohta Yoshida
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Japan
| | - Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Japan
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5
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Sidhwani P, Straight AF. Epigenetic inheritance and boundary maintenance at human centromeres. Curr Opin Struct Biol 2023; 82:102694. [PMID: 37657353 PMCID: PMC10530090 DOI: 10.1016/j.sbi.2023.102694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 07/31/2023] [Accepted: 08/07/2023] [Indexed: 09/03/2023]
Abstract
Centromeres are chromosomal regions that provide the foundation for microtubule attachment during chromosome segregation. Centromeres are epigenetically defined by nucleosomes containing the histone H3 variant centromere protein A (CENP-A) and, in many organisms, are surrounded by transcriptionally repressed pericentromeric chromatin marked by trimethylation of histone H3 lysine 9 (H3K9me3). Pericentromeric regions facilitate sister chromatid cohesion during mitosis, thereby supporting centromere function. Heterochromatin has a known propensity to spread into adjacent euchromatic domains unless it is properly bounded. Heterochromatin spreading into the centromere can disrupt kinetochore function, perturbing chromosome segregation and genome stability. In the fission yeast Schizosaccharomyces pombe, tRNA genes provide barriers to heterochromatin spread at the centromere, the absence of which results in abnormal meiotic chromosome segregation. How heterochromatin-centromere boundaries are established in humans is not understood. We propose models for stable epigenetic inheritance of centromeric domains in humans and discuss advances that will enable the discovery of novel regulators of this process.
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Affiliation(s)
- Pragya Sidhwani
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States. https://twitter.com/@pra_sidh
| | - Aaron F Straight
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States.
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6
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Zhu J, Guo Q, Choi M, Liang Z, Yuen KWY. Centromeric and pericentric transcription and transcripts: their intricate relationships, regulation, and functions. Chromosoma 2023:10.1007/s00412-023-00801-x. [PMID: 37401943 PMCID: PMC10356649 DOI: 10.1007/s00412-023-00801-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 07/05/2023]
Abstract
Centromeres are no longer considered to be silent. Both centromeric and pericentric transcription have been discovered, and their RNA transcripts have been characterized and probed for functions in numerous monocentric model organisms recently. Here, we will discuss the challenges in centromere transcription studies due to the repetitive nature and sequence similarity in centromeric and pericentric regions. Various technological breakthroughs have helped to tackle these challenges and reveal unique features of the centromeres and pericentromeres. We will briefly introduce these techniques, including third-generation long-read DNA and RNA sequencing, protein-DNA and RNA-DNA interaction detection methods, and epigenomic and nucleosomal mapping techniques. Interestingly, some newly analyzed repeat-based holocentromeres also resemble the architecture and the transcription behavior of monocentromeres. We will summarize evidences that support the functions of the transcription process and stalling, and those that support the functions of the centromeric and pericentric RNAs. The processing of centromeric and pericentric RNAs into multiple variants and their diverse structures may also provide clues to their functions. How future studies may address the separation of functions of specific centromeric transcription steps, processing pathways, and the transcripts themselves will also be discussed.
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Affiliation(s)
- Jing Zhu
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong, China
| | - Qiao Guo
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong, China
- Institute of Molecular Physiology, Gaoke Innovation Center, Shenzhen Bay Laboratory, Guangming District, Guangqiao Road, Shenzhen, China
| | - Minjun Choi
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong, China
| | - Zhoubin Liang
- Institute of Molecular Physiology, Gaoke Innovation Center, Shenzhen Bay Laboratory, Guangming District, Guangqiao Road, Shenzhen, China
| | - Karen Wing Yee Yuen
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong, China.
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7
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Henderson IR. Creating synthetic maize centromeres. NATURE PLANTS 2023; 9:379-380. [PMID: 36928773 DOI: 10.1038/s41477-023-01366-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Ian R Henderson
- Department of Plant Sciences, University of Cambridge, Cambridge, UK.
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8
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Centromere Chromatin Dynamics at a Glance. EPIGENOMES 2022; 6:epigenomes6040039. [PMID: 36412794 PMCID: PMC9680212 DOI: 10.3390/epigenomes6040039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
The centromere is a specialized DNA locus that ensures the faithful segregation of chromosomes during cell division. It does so by directing the assembly of an essential proteinaceous structure called the kinetochore. The centromere identity is primarily epigenetically defined by a nucleosome containing an H3 variant called CENP-A as well as by the interplay of several factors such as differential chromatin organization driven by CENP-A and H2A.Z, centromere-associated proteins, and post-translational modifications. At the centromere, CENP-A is not just a driving force for kinetochore assembly but also modifies the structural and dynamic properties of the centromeric chromatin, resulting in a distinctive chromatin organization. An additional level of regulation of the centromeric chromatin conformation is provided by post-translational modifications of the histones in the CENP-A nucleosomes. Further, H2A.Z is present in the regions flanking the centromere for heterochromatinization. In this review, we focus on the above-mentioned factors to describe how they contribute to the organization of the centromeric chromatin: CENP-A at the core centromere, post-translational modifications that decorate CENP-A, and the variant H2A.Z.
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9
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Dibus N, Korinek V, Cermak L. FBXO38 Ubiquitin Ligase Controls Centromere Integrity via ZXDA/B Stability. Front Cell Dev Biol 2022; 10:929288. [PMID: 35813202 PMCID: PMC9260856 DOI: 10.3389/fcell.2022.929288] [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: 04/26/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022] Open
Abstract
Alterations in the gene encoding the E3 ubiquitin ligase substrate receptor FBXO38 have been associated with several diseases, including early-onset motor neuronopathy. However, the cellular processes affected by the enzymatic action of FBXO38 are not yet known. Here, we identify the zinc finger proteins ZXDA/B as its interaction partners. FBXO38 controls the stability of ZXDA/B proteins via ubiquitination and proteasome-dependent degradation. We show that ZXDA/B proteins associate with the centromeric protein CENP-B and that the interaction between ZXDA/B and FBXO38 or CENP-B is mutually exclusive. Functionally, ZXDA/B factors control the protein level of chromatin-associated CENP-B. Furthermore, their inappropriate stabilization leads to upregulation of CENP-A and CENP-B positive centromeric chromatin. Thus we demonstrate a previously unknown role of cullin-dependent protein degradation in the control of centromeric chromatin integrity.
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Affiliation(s)
- Nikol Dibus
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
| | - Vladimir Korinek
- Laboratory of Cell and Developmental Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Lukas Cermak
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
- *Correspondence: Lukas Cermak,
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10
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Dong Q, Yang J, Gao J, Li F. Recent insights into mechanisms preventing ectopic centromere formation. Open Biol 2021; 11:210189. [PMID: 34493071 PMCID: PMC8424319 DOI: 10.1098/rsob.210189] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The centromere is a specialized chromosomal structure essential for chromosome segregation. Centromere dysfunction leads to chromosome segregation errors and genome instability. In most eukaryotes, centromere identity is specified epigenetically by CENP-A, a centromere-specific histone H3 variant. CENP-A replaces histone H3 in centromeres, and nucleates the assembly of the kinetochore complex. Mislocalization of CENP-A to non-centromeric regions causes ectopic assembly of CENP-A chromatin, which has a devastating impact on chromosome segregation and has been linked to a variety of human cancers. How non-centromeric regions are protected from CENP-A misincorporation in normal cells is largely unexplored. Here, we review the most recent advances on the mechanisms underlying the prevention of ectopic centromere formation, and discuss the implications in human disease.
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Affiliation(s)
- Qianhua Dong
- Department of Biology, New York University, New York, NY 10003-6688, USA
| | - Jinpu Yang
- Department of Biology, New York University, New York, NY 10003-6688, USA
| | - Jinxin Gao
- Department of Biology, New York University, New York, NY 10003-6688, USA
| | - Fei Li
- Department of Biology, New York University, New York, NY 10003-6688, USA
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11
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Schotanus K, Yadav V, Heitman J. Epigenetic dynamics of centromeres and neocentromeres in Cryptococcus deuterogattii. PLoS Genet 2021; 17:e1009743. [PMID: 34464380 PMCID: PMC8407549 DOI: 10.1371/journal.pgen.1009743] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Deletion of native centromeres in the human fungal pathogen Cryptococcus deuterogattii leads to neocentromere formation. Native centromeres span truncated transposable elements, while neocentromeres do not and instead span actively expressed genes. To explore the epigenetic organization of neocentromeres, we analyzed the distribution of the heterochromatic histone modification H3K9me2, 5mC DNA methylation and the euchromatin mark H3K4me2. Native centromeres are enriched for both H3K9me2 and 5mC DNA methylation marks and are devoid of H3K4me2, while neocentromeres do not exhibit any of these features. Neocentromeres in cen10Δ mutants are unstable and chromosome-chromosome fusions occur. After chromosome fusion, the neocentromere is inactivated and the native centromere of the chromosome fusion partner remains as the sole, active centromere. In the present study, the active centromere of a fused chromosome was deleted to investigate if epigenetic memory promoted the re-activation of the inactive neocentromere. Our results show that the inactive neocentromere is not re-activated and instead a novel neocentromere forms directly adjacent to the deleted centromere of the fused chromosome. To study the impact of transcription on centromere stability, the actively expressed URA5 gene was introduced into the CENP-A bound regions of a native centromere. The introduction of the URA5 gene led to a loss of CENP-A from the native centromere, and a neocentromere formed adjacent to the native centromere location. Remarkably, the inactive, native centromere remained enriched for heterochromatin, yet the integrated gene was expressed and devoid of H3K9me2. A cumulative analysis of multiple CENP-A distribution profiles revealed centromere drift in C. deuterogattii, a previously unreported phenomenon in fungi. The CENP-A-binding shifted within the ORF-free regions and showed a possible association with a truncated transposable element. Taken together, our findings reveal that neocentromeres in C. deuterogattii are highly unstable and are not marked with an epigenetic memory, distinguishing them from native centromeres. Linear eukaryotic chromosomes require a specific chromosomal region, the centromere, where the macromolecular kinetochore protein complex assembles. In most organisms, centromeres are located in gene-free, repeat-rich chromosomal regions and may or may not be associated with heterochromatic epigenetic marks. We report that the native centromeres of the human fungal pathogen Cryptococcus deuterogattii are enriched with heterochromatin marks. Deleting a centromere in C. deuterogattii results in formation of neocentromeres that span genes. In some cases, neocentromeres are unstable leading to chromosome-chromosome fusions and neocentromere inactivation. These neocentromeres, unlike native centromeres, lack any of the tested heterochromatic marks or any epigenetic memory. We also found that neocentromere formation can be triggered not only by deletion of the native centromere but also by disrupting its function via insertion of a gene. These results show that neocentromere dynamics in this fungal pathogen are unique among organisms studied so far. Our results also revealed key differences between epigenetics of native centromeres between C. deuterogattii and its sister species, C. neoformans. These finding provide an opportunity to test and study the evolution of centromeres, as well as neocentromeres, in this species complex and how it might contribute to their genome evolution.
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Affiliation(s)
- Klaas Schotanus
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - Vikas Yadav
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joseph Heitman
- Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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12
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Morrison O, Thakur J. Molecular Complexes at Euchromatin, Heterochromatin and Centromeric Chromatin. Int J Mol Sci 2021; 22:6922. [PMID: 34203193 PMCID: PMC8268097 DOI: 10.3390/ijms22136922] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/19/2023] Open
Abstract
Chromatin consists of a complex of DNA and histone proteins as its core components and plays an important role in both packaging DNA and regulating DNA metabolic pathways such as DNA replication, transcription, recombination, and chromosome segregation. Proper functioning of chromatin further involves a network of interactions among molecular complexes that modify chromatin structure and organization to affect the accessibility of DNA to transcription factors leading to the activation or repression of the transcription of target DNA loci. Based on its structure and compaction state, chromatin is categorized into euchromatin, heterochromatin, and centromeric chromatin. In this review, we discuss distinct chromatin factors and molecular complexes that constitute euchromatin-open chromatin structure associated with active transcription; heterochromatin-less accessible chromatin associated with silencing; centromeric chromatin-the site of spindle binding in chromosome segregation.
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Affiliation(s)
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd #2006, Atlanta, GA 30322, USA;
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13
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CENP-A nucleosome-a chromatin-embedded pedestal for the centromere: lessons learned from structural biology. Essays Biochem 2021; 64:205-221. [PMID: 32720682 PMCID: PMC7475651 DOI: 10.1042/ebc20190074] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/16/2020] [Accepted: 06/19/2020] [Indexed: 11/17/2022]
Abstract
The centromere is a chromosome locus that directs equal segregation of chromosomes during cell division. A nucleosome containing the histone H3 variant CENP-A epigenetically defines the centromere. Here, we summarize findings from recent structural biology studies, including several CryoEM structures, that contributed to elucidate specific features of the CENP-A nucleosome and molecular determinants of its interactions with CENP-C and CENP-N, the only two centromere proteins that directly bind to it. Based on those findings, we propose a role of the CENP-A nucleosome in the organization of centromeric chromatin beyond binding centromeric proteins.
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14
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Mihìc P, Hédouin S, Francastel C. Centromeres Transcription and Transcripts for Better and for Worse. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 60:169-201. [PMID: 34386876 DOI: 10.1007/978-3-030-74889-0_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Centromeres are chromosomal regions that are essential for the faithful transmission of genetic material through each cell division. They represent the chromosomal platform on which assembles a protein complex, the kinetochore, which mediates attachment to the mitotic spindle. In most organisms, centromeres assemble on large arrays of tandem satellite repeats, although their DNA sequences and organization are highly divergent among species. It has become evident that centromeres are not defined by underlying DNA sequences, but are instead epigenetically defined by the deposition of the centromere-specific histone H3 variant, CENP-A. In addition, and although long regarded as silent chromosomal loci, centromeres are in fact transcriptionally competent in most species, yet at low levels in normal somatic cells, but where the resulting transcripts participate in centromere architecture, identity, and function. In this chapter, we discuss the various roles proposed for centromere transcription and their transcripts, and the potential molecular mechanisms involved. We also discuss pathological cases in which unscheduled transcription of centromeric repeats or aberrant accumulation of their transcripts are pathological signatures of chromosomal instability diseases. In sum, tight regulation of centromeric satellite repeats transcription is critical for healthy development and tissue homeostasis, and thus prevents the emergence of disease states.
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Affiliation(s)
- Pia Mihìc
- Université De Paris, Epigenetics and Cell Fate, CNRS UMR7216, Paris, France
| | - Sabrine Hédouin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Claire Francastel
- Université De Paris, Epigenetics and Cell Fate, CNRS UMR7216, Paris, France.
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15
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Abstract
The kinetochore is a complex structure whose function is absolutely essential. Unlike the centromere, the kinetochore at first appeared remarkably well conserved from yeast to humans, especially the microtubule-binding outer kinetochore. However, recent efforts towards biochemical reconstitution of diverse kinetochores challenge the notion of a similarly conserved architecture for the constitutively centromere-associated network of the inner kinetochore. This review briefly summarizes the evidence from comparative genomics for interspecific variability in inner kinetochore composition and focuses on novel biochemical evidence indicating that even homologous inner kinetochore protein complexes are put to different uses in different organisms.
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Affiliation(s)
- G E Hamilton
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - T N Davis
- Department of Biochemistry, University of Washington, Seattle, WA, USA
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16
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Das A, Black BE, Lampson MA. Maternal inheritance of centromeres through the germline. Curr Top Dev Biol 2020; 140:35-54. [PMID: 32591081 DOI: 10.1016/bs.ctdb.2020.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The centromere directs chromosome segregation but is not itself genetically encoded. In most species, centromeres are epigenetically defined by the presence of a histone H3 variant CENP-A, independent of the underlying DNA sequence. Therefore, to maintain centromeres and ensure accurate chromosome segregation, CENP-A nucleosomes must be inherited across generations through the germline. In this chapter we discuss three aspects of maternal centromere inheritance. First, we propose mechanisms for maintaining CENP-A nucleosomes through the prolonged prophase arrest in mammalian oocytes. Second, we review mechanisms by which selfish centromeres bias their transmission through female meiosis. Third, we discuss regulation of centromere size through early embryonic development.
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Affiliation(s)
- Arunika Das
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
| | - Michael A Lampson
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States.
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17
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Guin K, Chen Y, Mishra R, Muzaki SRBM, Thimmappa BC, O'Brien CE, Butler G, Sanyal A, Sanyal K. Spatial inter-centromeric interactions facilitated the emergence of evolutionary new centromeres. eLife 2020; 9:e58556. [PMID: 32469306 PMCID: PMC7292649 DOI: 10.7554/elife.58556] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022] Open
Abstract
Centromeres of Candida albicans form on unique and different DNA sequences but a closely related species, Candida tropicalis, possesses homogenized inverted repeat (HIR)-associated centromeres. To investigate the mechanism of centromere type transition, we improved the fragmented genome assembly and constructed a chromosome-level genome assembly of C. tropicalis by employing PacBio sequencing, chromosome conformation capture sequencing (3C-seq), chromoblot, and genetic analysis of engineered aneuploid strains. Further, we analyzed the 3D genome organization using 3C-seq data, which revealed spatial proximity among the centromeres as well as telomeres of seven chromosomes in C. tropicalis. Intriguingly, we observed evidence of inter-centromeric translocations in the common ancestor of C. albicans and C. tropicalis. Identification of putative centromeres in closely related Candida sojae, Candida viswanathii and Candida parapsilosis indicates loss of ancestral HIR-associated centromeres and establishment of evolutionary new centromeres (ENCs) in C. albicans. We propose that spatial proximity of the homologous centromere DNA sequences facilitated karyotype rearrangements and centromere type transitions in human pathogenic yeasts of the CUG-Ser1 clade.
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Affiliation(s)
- Krishnendu Guin
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
| | - Yao Chen
- School of Biological Sciences, Nanyang Technological UniversitySingaporeSingapore
| | - Radha Mishra
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
| | | | - Bhagya C Thimmappa
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
| | - Caoimhe E O'Brien
- School Of Biomolecular & Biomed Science, Conway Institute of Biomolecular and Biomedical Research, University College DublinDublinIreland
| | - Geraldine Butler
- School Of Biomolecular & Biomed Science, Conway Institute of Biomolecular and Biomedical Research, University College DublinDublinIreland
| | - Amartya Sanyal
- School of Biological Sciences, Nanyang Technological UniversitySingaporeSingapore
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBangaloreIndia
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18
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Schotanus K, Heitman J. Centromere deletion in Cryptococcus deuterogattii leads to neocentromere formation and chromosome fusions. eLife 2020; 9:56026. [PMID: 32310085 PMCID: PMC7188483 DOI: 10.7554/elife.56026] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/16/2020] [Indexed: 02/06/2023] Open
Abstract
The human fungal pathogen Cryptococcus deuterogattii is RNAi-deficient and lacks active transposons in its genome. C. deuterogattii has regional centromeres that contain only transposon relics. To investigate the impact of centromere loss on the C. deuterogattii genome, either centromere 9 or 10 was deleted. Deletion of either centromere resulted in neocentromere formation and interestingly, the genes covered by these neocentromeres maintained wild-type expression levels. In contrast to cen9∆ mutants, cen10∆ mutant strains exhibited growth defects and were aneuploid for chromosome 10. At an elevated growth temperature (37°C), the cen10∆ chromosome was found to have undergone fusion with another native chromosome in some isolates and this fusion restored wild-type growth. Following chromosomal fusion, the neocentromere was inactivated, and the native centromere of the fused chromosome served as the active centromere. The neocentromere formation and chromosomal fusion events observed in this study in C. deuterogattii may be similar to events that triggered genomic changes within the Cryptococcus/Kwoniella species complex and may contribute to speciation throughout the eukaryotic domain.
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Affiliation(s)
- Klaas Schotanus
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
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19
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Feng JX, Riddle NC. Epigenetics and genome stability. Mamm Genome 2020; 31:181-195. [PMID: 32296924 DOI: 10.1007/s00335-020-09836-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 04/07/2020] [Indexed: 12/19/2022]
Abstract
Maintaining genome stability is essential to an organism's health and survival. Breakdown of the mechanisms protecting the genome and the resulting genome instability are an important aspect of the aging process and have been linked to diseases such as cancer. Thus, a large network of interconnected pathways is responsible for ensuring genome integrity in the face of the continuous challenges that induce DNA damage. While these pathways are diverse, epigenetic mechanisms play a central role in many of them. DNA modifications, histone variants and modifications, chromatin structure, and non-coding RNAs all carry out a variety of functions to ensure that genome stability is maintained. Epigenetic mechanisms ensure the functions of centromeres and telomeres that are essential for genome stability. Epigenetic mechanisms also protect the genome from the invasion by transposable elements and contribute to various DNA repair pathways. In this review, we highlight the integral role of epigenetic mechanisms in the maintenance of genome stability and draw attention to issues in need of further study.
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Affiliation(s)
- Justina X Feng
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicole C Riddle
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA.
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20
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Centromere chromatin structure - Lessons from neocentromeres. Exp Cell Res 2020; 389:111899. [PMID: 32044308 DOI: 10.1016/j.yexcr.2020.111899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/01/2020] [Accepted: 02/07/2020] [Indexed: 11/22/2022]
Abstract
Centromeres are highly specialized genomic loci that function during mitosis to maintain genome stability. Formed primarily on repetitive α-satellite DNA sequence characterisation of native centromeric chromatin structure has remained challenging. Fortuitously, neocentromeres are formed on a unique DNA sequence and represent an excellent model to interrogate centromeric chromatin structure. This review uncovers the specific findings from independent neocentromere studies that have advanced our understanding of canonical centromere chromatin structure.
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21
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Bracewell R, Chatla K, Nalley MJ, Bachtrog D. Dynamic turnover of centromeres drives karyotype evolution in Drosophila. eLife 2019; 8:e49002. [PMID: 31524597 PMCID: PMC6795482 DOI: 10.7554/elife.49002] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/12/2019] [Indexed: 12/21/2022] Open
Abstract
Centromeres are the basic unit for chromosome inheritance, but their evolutionary dynamics is poorly understood. We generate high-quality reference genomes for multiple Drosophila obscura group species to reconstruct karyotype evolution. All chromosomes in this lineage were ancestrally telocentric and the creation of metacentric chromosomes in some species was driven by de novo seeding of new centromeres at ancestrally gene-rich regions, independently of chromosomal rearrangements. The emergence of centromeres resulted in a drastic size increase due to repeat accumulation, and dozens of genes previously located in euchromatin are now embedded in pericentromeric heterochromatin. Metacentric chromosomes secondarily became telocentric in the pseudoobscura subgroup through centromere repositioning and a pericentric inversion. The former (peri)centric sequences left behind shrunk dramatically in size after their inactivation, yet contain remnants of their evolutionary past, including increased repeat-content and heterochromatic environment. Centromere movements are accompanied by rapid turnover of the major satellite DNA detected in (peri)centromeric regions.
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Affiliation(s)
- Ryan Bracewell
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Kamalakar Chatla
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Matthew J Nalley
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Doris Bachtrog
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
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22
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Scelfo A, Fachinetti D. Keeping the Centromere under Control: A Promising Role for DNA Methylation. Cells 2019; 8:cells8080912. [PMID: 31426433 PMCID: PMC6721688 DOI: 10.3390/cells8080912] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 08/06/2019] [Accepted: 08/15/2019] [Indexed: 01/22/2023] Open
Abstract
In order to maintain cell and organism homeostasis, the genetic material has to be faithfully and equally inherited through cell divisions while preserving its integrity. Centromeres play an essential task in this process; they are special sites on chromosomes where kinetochores form on repetitive DNA sequences to enable accurate chromosome segregation. Recent evidence suggests that centromeric DNA sequences, and epigenetic regulation of centromeres, have important roles in centromere physiology. In particular, DNA methylation is abundant at the centromere, and aberrant DNA methylation, observed in certain tumors, has been correlated to aneuploidy and genomic instability. In this review, we evaluate past and current insights on the relationship between centromere function and the DNA methylation pattern of its underlying sequences.
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Affiliation(s)
- Andrea Scelfo
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75005 Paris, France.
| | - Daniele Fachinetti
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75005 Paris, France.
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23
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Sreekumar L, Jaitly P, Chen Y, Thimmappa BC, Sanyal A, Sanyal K. Cis- and Trans-chromosomal Interactions Define Pericentric Boundaries in the Absence of Conventional Heterochromatin. Genetics 2019; 212:1121-1132. [PMID: 31142612 PMCID: PMC6707466 DOI: 10.1534/genetics.119.302179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 05/22/2019] [Indexed: 01/28/2023] Open
Abstract
The diploid budding yeast Candida albicans harbors unique CENPA-rich 3- to 5-kb regions that form the centromere (CEN) core on each of its eight chromosomes. The epigenetic nature of these CENs does not permit the stabilization of a functional kinetochore on an exogenously introduced CEN plasmid. The flexible nature of such centromeric chromatin is exemplified by the reversible silencing of a transgene upon its integration into the CENPA-bound region. The lack of a conventional heterochromatin machinery and the absence of defined boundaries of CENPA chromatin makes the process of CEN specification in this organism elusive. Additionally, upon native CEN deletion, C. albicans can efficiently activate neocentromeres proximal to the native CEN locus, hinting at the importance of CEN-proximal regions. In this study, we examine this CEN-proximity effect and identify factors for CEN specification in C. albicans We exploit a counterselection assay to isolate cells that can silence a transgene when integrated into the CEN-flanking regions. We show that the frequency of reversible silencing of the transgene decreases from the central core of CEN7 to its peripheral regions. Using publicly available C. albicans high-throughput chromosome conformation capture data, we identify a 25-kb region centering on the CENPA-bound core that acts as CEN-flanking compact chromatin (CFCC). Cis- and trans-chromosomal interactions associated with the CFCC spatially segregates it from bulk chromatin. We further show that neocentromere activation on chromosome 7 occurs within this specified region. Hence, this study identifies a specialized CEN-proximal domain that specifies and restricts the centromeric activity to a unique region.
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Affiliation(s)
- Lakshmi Sreekumar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Priya Jaitly
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Yao Chen
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore 637551
| | - Bhagya C Thimmappa
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Amartya Sanyal
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore 637551
| | - Kaustuv Sanyal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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24
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Tong P, Pidoux AL, Toda NRT, Ard R, Berger H, Shukla M, Torres-Garcia J, Müller CA, Nieduszynski CA, Allshire RC. Interspecies conservation of organisation and function between nonhomologous regional centromeres. Nat Commun 2019; 10:2343. [PMID: 31138803 PMCID: PMC6538654 DOI: 10.1038/s41467-019-09824-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 03/27/2019] [Indexed: 01/31/2023] Open
Abstract
Despite the conserved essential function of centromeres, centromeric DNA itself is not conserved. The histone-H3 variant, CENP-A, is the epigenetic mark that specifies centromere identity. Paradoxically, CENP-A normally assembles on particular sequences at specific genomic locations. To gain insight into the specification of complex centromeres, here we take an evolutionary approach, fully assembling genomes and centromeres of related fission yeasts. Centromere domain organization, but not sequence, is conserved between Schizosaccharomyces pombe, S. octosporus and S. cryophilus with a central CENP-ACnp1 domain flanked by heterochromatic outer-repeat regions. Conserved syntenic clusters of tRNA genes and 5S rRNA genes occur across the centromeres of S. octosporus and S. cryophilus, suggesting conserved function. Interestingly, nonhomologous centromere central-core sequences from S. octosporus and S. cryophilus are recognized in S. pombe, resulting in cross-species establishment of CENP-ACnp1 chromatin and functional kinetochores. Therefore, despite the lack of sequence conservation, Schizosaccharomyces centromere DNA possesses intrinsic conserved properties that promote assembly of CENP-A chromatin.
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Affiliation(s)
- Pin Tong
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK
| | - Alison L. Pidoux
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK
| | - Nicholas R. T. Toda
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK ,0000 0001 2203 0006grid.464101.6Present Address: UPMC CNRS, Roscoff Marine Station, Place Georges Teissier, 29680 Roscoff, France
| | - Ryan Ard
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK ,0000 0001 0674 042Xgrid.5254.6Present Address: Copenhagen Plant Science Centre, University of Copenhagen, Bülowsvej 34, 1870 Frederiksberg C, Denmark
| | - Harald Berger
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK ,0000 0001 2298 5320grid.5173.0Present Address: Symbiocyte, Universität für Bodenkultur Wien, University of Natural Resources and Life Sciences, 1180 Vienna, Austria
| | - Manu Shukla
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK
| | - Jesus Torres-Garcia
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK
| | - Carolin A. Müller
- 0000 0004 1936 8948grid.4991.5Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE UK
| | - Conrad A. Nieduszynski
- 0000 0004 1936 8948grid.4991.5Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE UK
| | - Robin C. Allshire
- 0000 0004 1936 7988grid.4305.2Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Mayfield Road, Edinburgh, EH9 3BF UK
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25
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Fernandes JB, Wlodzimierz P, Henderson IR. Meiotic recombination within plant centromeres. CURRENT OPINION IN PLANT BIOLOGY 2019; 48:26-35. [PMID: 30954771 DOI: 10.1016/j.pbi.2019.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/21/2019] [Accepted: 02/28/2019] [Indexed: 05/18/2023]
Abstract
Meiosis is a conserved eukaryotic cell division that increases genetic diversity in sexual populations. During meiosis homologous chromosomes pair and undergo recombination that can result in reciprocal genetic exchange, termed crossover. The frequency of crossover is highly variable along chromosomes, with hot spots and cold spots. For example, the centromeres that contain the kinetochore, which attach chromosomes to the microtubular spindle, are crossover cold spots. Plant centromeres typically consist of large tandemly repeated arrays of satellite sequences and retrotransposons, a subset of which assemble CENH3-variant nucleosomes, which bind to kinetochore proteins. Although crossovers are suppressed in centromeres, there is abundant evidence for gene conversion and homologous recombination between repeats, which plays a role in satellite array change. We review the evidence for recombination within plant centromeres and the implications for satellite sequence evolution. We speculate on the genetic and epigenetic features of centromeres that may influence meiotic recombination in these regions. We also highlight unresolved questions relating to centromere function and sequence change and how the advent of new technologies promises to provide insights.
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Affiliation(s)
- Joiselle B Fernandes
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Piotr Wlodzimierz
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Ian R Henderson
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom.
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26
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Centromere Repeats: Hidden Gems of the Genome. Genes (Basel) 2019; 10:genes10030223. [PMID: 30884847 PMCID: PMC6471113 DOI: 10.3390/genes10030223] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/07/2019] [Accepted: 03/11/2019] [Indexed: 01/08/2023] Open
Abstract
Satellite DNAs are now regarded as powerful and active contributors to genomic and chromosomal evolution. Paired with mobile transposable elements, these repetitive sequences provide a dynamic mechanism through which novel karyotypic modifications and chromosomal rearrangements may occur. In this review, we discuss the regulatory activity of satellite DNA and their neighboring transposable elements in a chromosomal context with a particular emphasis on the integral role of both in centromere function. In addition, we discuss the varied mechanisms by which centromeric repeats have endured evolutionary processes, producing a novel, species-specific centromeric landscape despite sharing a ubiquitously conserved function. Finally, we highlight the role these repetitive elements play in the establishment and functionality of de novo centromeres and chromosomal breakpoints that underpin karyotypic variation. By emphasizing these unique activities of satellite DNAs and transposable elements, we hope to disparage the conventional exemplification of repetitive DNA in the historically-associated context of ‘junk’.
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27
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Cell Cycle-Regulated Transcription of CENP-A by the MBF Complex Ensures Optimal Level of CENP-A for Centromere Formation. Genetics 2019; 211:861-875. [PMID: 30635289 DOI: 10.1534/genetics.118.301745] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/04/2019] [Indexed: 11/18/2022] Open
Abstract
The centromere plays an essential role in chromosome segregation. In most eukaryotes, centromeres are epigenetically defined by the conserved histone H3 variant CENP-A. Proper centromere assembly is dependent upon the tight regulation of CENP-A level. Cell cycle regulation of CENP-A transcription appears to be a universal feature across eukaryotes, but the molecular mechanism underlying the temporal control of CENP-A transcription and how such regulation contributes to centromere function remains elusive. CENP-A in fission yeast has been shown to be transcribed before S phase. Using various synchronization methods, we confirmed that CENP-A transcription occurs at G1, leading to an almost twofold increase of the protein during S phase. Through a genetic screen, we identified the MBF (MluI box-binding factors) complex as a key regulator of temporal control of CENP-A transcription. The periodic transcription of CENP-A is lost in MBF mutants, resulting in CENP-A mislocalization and chromosome segregation defects. We identified the MCB (MluI cell cycle box) motif in the CENP-A promoter, and further showed that the MBF complex binds to the motif to restrict CENP-A transcription to G1. Mutations of the MCB motif cause constitutive CENP-A expression and deleterious effects on cell survival. Using promoters driving transcription to different cell cycle stages, we found that timing of CENP-A transcription is dispensable for its centromeric localization. Our data instead indicate that cell cycle-regulated CENP-A transcription is a key step to ensure that a proper amount of CENP-A is generated across generations. This study provides mechanistic insights into the regulation of cell cycle-dependent CENP-A transcription, as well as its importance on centromere function.
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28
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McNulty SM, Sullivan BA. Going the distance: Neocentromeres make long-range contacts with heterochromatin. J Cell Biol 2019; 218:5-7. [PMID: 30538139 PMCID: PMC6314541 DOI: 10.1083/jcb.201811172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neocentromeres are ectopic centromeres that form at noncanonical, usually nonrepetitive, genomic locations. Nishimura et al. (2019. J. Cell Biol. https://doi.org/10.1083/jcb.201805003) explore the three-dimensional architecture of vertebrate neocentromeres, leading to a model for centromere function and maintenance via nuclear clustering with heterochromatin.
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Affiliation(s)
- Shannon M McNulty
- Department of Molecular Genetics and Microbiology, Division of Human Genetics, Duke University Medical Center, Durham, NC
| | - Beth A Sullivan
- Department of Molecular Genetics and Microbiology, Division of Human Genetics, Duke University Medical Center, Durham, NC
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29
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Shukla M, Tong P, White SA, Singh PP, Reid AM, Catania S, Pidoux AL, Allshire RC. Centromere DNA Destabilizes H3 Nucleosomes to Promote CENP-A Deposition during the Cell Cycle. Curr Biol 2018; 28:3924-3936.e4. [PMID: 30503616 PMCID: PMC6303189 DOI: 10.1016/j.cub.2018.10.049] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 09/12/2018] [Accepted: 10/22/2018] [Indexed: 12/31/2022]
Abstract
Active centromeres are defined by the presence of nucleosomes containing CENP-A, a histone H3 variant, which alone is sufficient to direct kinetochore assembly. Once assembled at a location, CENP-A chromatin and kinetochores are maintained at that location through a positive feedback loop where kinetochore proteins recruited by CENP-A promote deposition of new CENP-A following replication. Although CENP-A chromatin itself is a heritable entity, it is normally associated with specific sequences. Intrinsic properties of centromeric DNA may favor the assembly of CENP-A rather than H3 nucleosomes. Here we investigate histone dynamics on centromere DNA. We show that during S phase, histone H3 is deposited as a placeholder at fission yeast centromeres and is subsequently evicted in G2, when we detect deposition of the majority of new CENP-ACnp1. We also find that centromere DNA has an innate property of driving high rates of turnover of H3-containing nucleosomes, resulting in low nucleosome occupancy. When placed at an ectopic chromosomal location in the absence of any CENP-ACnp1 assembly, centromere DNA appears to retain its ability to impose S phase deposition and G2 eviction of H3, suggesting that features within centromere DNA program H3 dynamics. Because RNA polymerase II (RNAPII) occupancy on this centromere DNA coincides with H3 eviction in G2, we propose a model in which RNAPII-coupled chromatin remodeling promotes replacement of H3 with CENP-ACnp1 nucleosomes.
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Affiliation(s)
- Manu Shukla
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK.
| | - Pin Tong
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Sharon A White
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Puneet P Singh
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Angus M Reid
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Sandra Catania
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Alison L Pidoux
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Robin C Allshire
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, UK.
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30
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Cook DM, Bennett M, Friedman B, Lawrimore J, Yeh E, Bloom K. Fork pausing allows centromere DNA loop formation and kinetochore assembly. Proc Natl Acad Sci U S A 2018; 115:11784-11789. [PMID: 30373818 PMCID: PMC6243264 DOI: 10.1073/pnas.1806791115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
De novo kinetochore assembly, but not template-directed assembly, is dependent on COMA, the kinetochore complex engaged in cohesin recruitment. The slowing of replication fork progression by treatment with phleomycin (PHL), hydroxyurea, or deletion of the replication fork protection protein Csm3 can activate de novo kinetochore assembly in COMA mutants. Centromere DNA looping at the site of de novo kinetochore assembly can be detected shortly after exposure to PHL. Using simulations to explore the thermodynamics of DNA loops, we propose that loop formation is disfavored during bidirectional replication fork migration. One function of replication fork stalling upon encounters with DNA damage or other blockades may be to allow time for thermal fluctuations of the DNA chain to explore numerous configurations. Biasing thermodynamics provides a mechanism to facilitate macromolecular assembly, DNA repair, and other nucleic acid transactions at the replication fork. These loop configurations are essential for sister centromere separation and kinetochore assembly in the absence of the COMA complex.
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Affiliation(s)
- Diana M Cook
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Maggie Bennett
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Brandon Friedman
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Josh Lawrimore
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Elaine Yeh
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
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31
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Piégu B, Arensburger P, Guillou F, Bigot Y. But where did the centromeres go in the chicken genome models? Chromosome Res 2018; 26:297-306. [PMID: 30225548 DOI: 10.1007/s10577-018-9585-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/31/2018] [Accepted: 09/03/2018] [Indexed: 11/30/2022]
Abstract
The chicken genome was the third vertebrate to be sequenced. To date, its sequence and feature annotations are used as the reference for avian models in genome sequencing projects developed on birds and other Sauropsida species, and in genetic studies of domesticated birds of economic and evolutionary biology interest. Therefore, an accurate description of this genome model is important to a wide number of scientists. Here, we review the location and features of a very basic element, the centromeres of chromosomes in the galGal5 genome model. Centromeres are elements that are not determined by their DNA sequence but by their epigenetic status, in particular by the accumulation of the histone-like protein CENP-A. Comparison of data from several public sources (primarily marker probes flanking centromeres using fluorescent in situ hybridization done on giant lampbrush chromosomes and CENP-A ChIP-seq datasets) with galGal5 annotations revealed that centromeres are likely inappropriately mapped in 9 of the 16 galGal5 chromosome models in which they are described. Analysis of karyology data confirmed that the location of the main CENP-A peaks in chromosomes is the best means of locating the centromeres in 25 galGal5 chromosome models, the majority of which (16) are fully sequenced and assembled. This data re-analysis reaffirms that several sources of information should be examined to produce accurate genome annotations, particularly for basic structures such as centromeres that are epigenetically determined.
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Affiliation(s)
- Benoît Piégu
- PRC, UMR INRA0085, CNRS 7247, Centre INRA Val de Loire, 37380, Nouzilly, France
| | - Peter Arensburger
- Biological Sciences Department, California State Polytechnic University, Pomona, CA, 91768, USA
| | - Florian Guillou
- PRC, UMR INRA0085, CNRS 7247, Centre INRA Val de Loire, 37380, Nouzilly, France
| | - Yves Bigot
- PRC, UMR INRA0085, CNRS 7247, Centre INRA Val de Loire, 37380, Nouzilly, France.
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32
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Heterochromatin and RNAi regulate centromeres by protecting CENP-A from ubiquitin-mediated degradation. PLoS Genet 2018; 14:e1007572. [PMID: 30089114 PMCID: PMC6101405 DOI: 10.1371/journal.pgen.1007572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 08/20/2018] [Accepted: 07/18/2018] [Indexed: 01/03/2023] Open
Abstract
Centromere is a specialized chromatin domain that plays a vital role in chromosome segregation. In most eukaryotes, centromere is surrounded by the epigenetically distinct heterochromatin domain. Heterochromatin has been shown to contribute to centromere function, but the precise role of heterochromatin in centromere specification remains elusive. Centromeres in most eukaryotes, including fission yeast (Schizosaccharomyces pombe), are defined epigenetically by the histone H3 (H3) variant CENP-A. In contrast, the budding yeast Saccharomyces cerevisiae has genetically-defined point centromeres. The transition between regional centromeres and point centromeres is considered as one of the most dramatic evolutionary events in centromere evolution. Here we demonstrated that Cse4, the budding yeast CENP-A homolog, can localize to centromeres in fission yeast and partially substitute fission yeast CENP-ACnp1. But overexpression of Cse4 results in its localization to heterochromatic regions. Cse4 is subject to efficient ubiquitin-dependent degradation in S. pombe, and its N-terminal domain dictates its centromere distribution via ubiquitination. Notably, without heterochromatin and RNA interference (RNAi), Cse4 fails to associate with centromeres. We showed that RNAi-dependent heterochromatin mediates centromeric localization of Cse4 by protecting Cse4 from ubiquitin-dependent degradation. Heterochromatin also contributes to the association of native CENP-ACnp1 with centromeres via the same mechanism. These findings suggest that protection of CENP-A from degradation by heterochromatin is a general mechanism used for centromere assembly, and also provide novel insights into centromere evolution.
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33
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Mis16 Switches Function from a Histone H4 Chaperone to a CENP-A Cnp1-Specific Assembly Factor through Eic1 Interaction. Structure 2018; 26:960-971.e4. [PMID: 29804820 DOI: 10.1016/j.str.2018.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/11/2018] [Accepted: 04/17/2018] [Indexed: 11/20/2022]
Abstract
The Mis18 complex, composed of Mis16, Eic1, and Mis18 in fission yeast, selectively deposits the centromere-specific histone H3 variant, CENP-ACnp1, at centromeres. How the intact Mis18 holo-complex oligomerizes and how Mis16, a well-known ubiquitous histone H4 chaperone, plays a centromere-specific role in the Mis18 holo-complex, remain unclear. Here, we report the stoichiometry of the intact Mis18 holo-complex as (Mis16)2:(Eic1)2:(Mis18)4 using analytical ultracentrifugation. We further determine the crystal structure of Schizosaccharomyces pombe Mis16 in complex with the C-terminal portion of Eic1 (Eic1-CT). Notably, Mis16 accommodates Eic1-CT through the binding pocket normally occupied by histone H4, indicating that Eic1 and H4 compete for the same binding site, providing a mechanism for Mis16 to switch its binding partner from histone H4 to Eic1. Thus, our analyses not only determine the stoichiometry of the intact Mis18 holo-complex but also uncover the molecular mechanism by which Mis16 plays a centromere-specific role through Eic1 association.
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34
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Tesner P, Drabova J, Stolfa M, Kudr M, Kyncl M, Moslerova V, Novotna D, Kremlikova Pourova R, Kocarek E, Rasplickova T, Sedlacek Z, Vlckova M. A boy with developmental delay and mosaic supernumerary inv dup(5)(p15.33p15.1) leading to distal 5p tetrasomy - case report and review of the literature. Mol Cytogenet 2018; 11:29. [PMID: 29760779 PMCID: PMC5941596 DOI: 10.1186/s13039-018-0377-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/20/2018] [Indexed: 01/01/2023] Open
Abstract
Background With only 11 patients reported, 5p tetrasomy belongs to rare postnatal findings. Most cases are due to small supernumerary marker chromosomes (sSMCs) or isochromosomes. The patients share common but unspecific symptoms such as developmental delay, seizures, ventriculomegaly, hypotonia, and fifth finger clinodactyly. Simple interstitial duplications leading to trisomies of parts of 5p are much more frequent and better described. Duplications encompassing 5p13.2 cause a defined syndrome with macrocephaly, distinct facial phenotype, heart defects, talipes equinovarus, feeding difficulties, respiratory distress and anomalies of the central nervous system, developmental delay and hypotonia. Case presentation We present a boy with dysmorphic features, developmental delay, intellectual disability and congenital anomalies, and a mosaic sSMC inv dup(5)(p15.33p15.1). He is the fourth and the oldest reported patient with distal 5p tetrasomy. His level of mosaicism was significantly different in lymphocytes (13.2%) and buccal cells (64.7%). The amplification in our patient is smaller than that in the three previously published patients but the only phenotype difference is the absence of seizures in our patient. Conclusions Our observations indicate that for the assessment of prognosis, especially with respect to intellectual functioning, the level of mosaicism could be more important than the extent of amplification and the number of extra copies. Evaluation of the phenotypical effect of rare chromosomal aberrations is challenging and each additional case is valuable for refinement of the genotype-phenotype correlation. Moreover, our patient demonstrates that if the phenotype is severe and if the level of sSMC mosaicism is low in lymphocytes, other tissues should be tested. Electronic supplementary material The online version of this article (10.1186/s13039-018-0377-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pavel Tesner
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Jana Drabova
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Miroslav Stolfa
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Martin Kudr
- 2Department of Paediatric Neurology, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Martin Kyncl
- 3Department of Radiology, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Veronika Moslerova
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Drahuse Novotna
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Radka Kremlikova Pourova
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Eduard Kocarek
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Tereza Rasplickova
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Zdenek Sedlacek
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
| | - Marketa Vlckova
- 1Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, V Uvalu 84, 15006 Prague 5, Czech Republic
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35
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What is behind “centromere repositioning”? Chromosoma 2018; 127:229-234. [DOI: 10.1007/s00412-018-0672-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 12/11/2022]
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36
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Shrestha RL, Ahn GS, Staples MI, Sathyan KM, Karpova TS, Foltz DR, Basrai MA. Mislocalization of centromeric histone H3 variant CENP-A contributes to chromosomal instability (CIN) in human cells. Oncotarget 2018; 8:46781-46800. [PMID: 28596481 PMCID: PMC5564523 DOI: 10.18632/oncotarget.18108] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/10/2017] [Indexed: 11/25/2022] Open
Abstract
Chromosomal instability (CIN) is a hallmark of many cancers and a major contributor to tumorigenesis. Centromere and kinetochore associated proteins such as the evolutionarily conserved centromeric histone H3 variant CENP-A, associate with centromeric DNA for centromere function and chromosomal stability. Stringent regulation of cellular CENP-A levels prevents its mislocalization in yeast and flies to maintain genome stability. CENP-A overexpression and mislocalization are observed in several cancers and reported to be associated with increased invasiveness and poor prognosis. We examined whether there is a direct relationship between mislocalization of overexpressed CENP-A and CIN using HeLa and chromosomally stable diploid RPE1 cell lines as model systems. Our results show that mislocalization of overexpressed CENP-A to chromosome arms leads to chromosome congression defects, lagging chromosomes, micronuclei formation and a delay in mitotic exit. CENP-A overexpressing cells showed altered localization of centromere and kinetochore associated proteins such as CENP-C, CENP-T and Nuf2 leading to weakened native kinetochores as shown by reduced interkinetochore distance and CIN. Importantly, our results show that mislocalization of CENP-A to chromosome arms is one of the major contributors for CIN as depletion of histone chaperone DAXX prevents CENP-A mislocalization and rescues the reduced interkinetochore distance and CIN phenotype in CENP-A overexpressing cells. In summary, our results establish that CENP-A overexpression and mislocalization result in a CIN phenotype in human cells. This study provides insights into how overexpression of CENP-A may contribute to CIN in cancers and underscore the importance of understanding the pathways that prevent CENP-A mislocalization for genome stability.
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Affiliation(s)
| | - Grace S Ahn
- Genetics Branch, CCR, NCI, NIH, Bethesda, MD, USA
| | | | - Kizhakke M Sathyan
- Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Tatiana S Karpova
- Laboratory of Receptor Biology and Gene Expression, CCR, NCI, NIH, Bethesda, MD, USA
| | - Daniel R Foltz
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, IL, USA
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37
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Klein SJ, O'Neill RJ. Transposable elements: genome innovation, chromosome diversity, and centromere conflict. Chromosome Res 2018; 26:5-23. [PMID: 29332159 PMCID: PMC5857280 DOI: 10.1007/s10577-017-9569-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 12/21/2022]
Abstract
Although it was nearly 70 years ago when transposable elements (TEs) were first discovered “jumping” from one genomic location to another, TEs are now recognized as contributors to genomic innovations as well as genome instability across a wide variety of species. In this review, we illustrate the ways in which active TEs, specifically retroelements, can create novel chromosome rearrangements and impact gene expression, leading to disease in some cases and species-specific diversity in others. We explore the ways in which eukaryotic genomes have evolved defense mechanisms to temper TE activity and the ways in which TEs continue to influence genome structure despite being rendered transpositionally inactive. Finally, we focus on the role of TEs in the establishment, maintenance, and stabilization of critical, yet rapidly evolving, chromosome features: eukaryotic centromeres. Across centromeres, specific types of TEs participate in genomic conflict, a balancing act wherein they are actively inserting into centromeric domains yet are harnessed for the recruitment of centromeric histones and potentially new centromere formation.
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Affiliation(s)
- Savannah J Klein
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Rachel J O'Neill
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA.
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38
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Contreras-Galindo R, Fischer S, Saha AK, Lundy JD, Cervantes PW, Mourad M, Wang C, Qian B, Dai M, Meng F, Chinnaiyan A, Omenn GS, Kaplan MH, Markovitz DM. Rapid molecular assays to study human centromere genomics. Genome Res 2017; 27:2040-2049. [PMID: 29141960 PMCID: PMC5741061 DOI: 10.1101/gr.219709.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 10/27/2017] [Indexed: 01/16/2023]
Abstract
The centromere is the structural unit responsible for the faithful segregation of chromosomes. Although regulation of centromeric function by epigenetic factors has been well-studied, the contributions of the underlying DNA sequences have been much less well defined, and existing methodologies for studying centromere genomics in biology are laborious. We have identified specific markers in the centromere of 23 of the 24 human chromosomes that allow for rapid PCR assays capable of capturing the genomic landscape of human centromeres at a given time. Use of this genetic strategy can also delineate which specific centromere arrays in each chromosome drive the recruitment of epigenetic modulators. We further show that, surprisingly, loss and rearrangement of DNA in centromere 21 is associated with trisomy 21. This new approach can thus be used to rapidly take a snapshot of the genetics and epigenetics of each specific human centromere in nondisjunction disorders and other biological settings.
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Affiliation(s)
| | - Sabrina Fischer
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA.,Laboratory of Molecular Virology, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay 11400
| | - Anjan K Saha
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA.,Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan 48109, USA.,Program in Cancer Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - John D Lundy
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Patrick W Cervantes
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Mohamad Mourad
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Claire Wang
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Brian Qian
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Manhong Dai
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Fan Meng
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Psychiatry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Arul Chinnaiyan
- Michigan Center for Translational Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Gilbert S Omenn
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Human Genetics.,Departments of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Mark H Kaplan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - David M Markovitz
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA.,Program in Cancer Biology, University of Michigan, Ann Arbor, Michigan 48109, USA.,Program in Immunology, University of Michigan, Ann Arbor, Michigan 48109, USA.,Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
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39
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Hernández-Saavedra D, Strakovsky RS, Ostrosky-Wegman P, Pan YX. Epigenetic Regulation of Centromere Chromatin Stability by Dietary and Environmental Factors. Adv Nutr 2017; 8:889-904. [PMID: 29141972 PMCID: PMC5683002 DOI: 10.3945/an.117.016402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The centromere is a genomic locus required for the segregation of the chromosomes during cell division. This chromosomal region together with pericentromeres has been found to be susceptible to damage, and thus the perturbation of the centromere could lead to the development of aneuploidic events. Metabolic abnormalities that underlie the generation of cancer include inflammation, oxidative stress, cell cycle deregulation, and numerous others. The micronucleus assay, an early clinical marker of cancer, has been shown to provide a reliable measure of genotoxic damage that may signal cancer initiation. In the current review, we will discuss the events that lead to micronucleus formation and centromeric and pericentromeric chromatin instability, as well transcripts emanating from these regions, which were previously thought to be inactive. Studies were selected in PubMed if they reported the effects of nutritional status (macro- and micronutrients) or environmental toxicant exposure on micronucleus frequency or any other chromosomal abnormality in humans, animals, or cell models. Mounting evidence from epidemiologic, environmental, and nutritional studies provides a novel perspective on the origination of aneuploidic events. Although substantial evidence exists describing the role that nutritional status and environmental toxicants have on the generation of micronuclei and other nuclear aberrations, limited information is available to describe the importance of macro- and micronutrients on centromeric and pericentromeric chromatin stability. Moving forward, studies that specifically address the direct link between nutritional status, excess, or deficiency and the epigenetic regulation of the centromere will provide much needed insight into the nutritional and environmental regulation of this chromosomal region and the initiation of aneuploidy.
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Affiliation(s)
| | | | | | - Yuan-Xiang Pan
- Division of Nutritional Sciences,,Department of Food Science and Human Nutrition,,Illinois Informatics Institute, University of Illinois at Urbana-Champaign, Champaign, IL; and
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40
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Xenopus laevis M18BP1 Directly Binds Existing CENP-A Nucleosomes to Promote Centromeric Chromatin Assembly. Dev Cell 2017; 42:190-199.e10. [PMID: 28743005 DOI: 10.1016/j.devcel.2017.06.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/12/2017] [Accepted: 06/23/2017] [Indexed: 11/21/2022]
Abstract
Vertebrate centromeres are epigenetically defined by nucleosomes containing the histone H3 variant, CENP-A. CENP-A nucleosome assembly requires the three-protein Mis18 complex (Mis18α, Mis18β, and M18BP1) that recruits the CENP-A chaperone HJURP to centromeres, but how the Mis18 complex recognizes centromeric chromatin is unknown. Using Xenopus egg extract, we show that direct, cell-cycle-regulated binding of M18BP1 to CENP-A nucleosomes recruits the Mis18 complex to interphase centromeres to promote new CENP-A nucleosome assembly. We demonstrate that Xenopus M18BP1 binds CENP-A nucleosomes using a motif that is widely conserved except in mammals. The M18BP1 motif resembles a CENP-A nucleosome binding motif in CENP-C, and we show that CENP-C competes with M18BP1 for CENP-A nucleosome binding at centromeres. We show that both CENP-C and M18BP1 recruit HJURP to centromeres for new CENP-A assembly. This study defines cellular mechanisms for recruiting CENP-A assembly factors to existing CENP-A nucleosomes for the epigenetic inheritance of centromeres.
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41
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Zhao H, Zeng Z, Koo DH, Gill BS, Birchler JA, Jiang J. Recurrent establishment of de novo centromeres in the pericentromeric region of maize chromosome 3. Chromosome Res 2017; 25:299-311. [PMID: 28831743 DOI: 10.1007/s10577-017-9564-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 01/01/2023]
Abstract
Centromeres can arise de novo from non-centromeric regions, which are often called "neocentromeres." Neocentromere formation provides the best evidence for the concept that centromere function is not determined by the underlying DNA sequences, but controlled by poorly understood epigenetic mechanisms. Numerous neocentromeres have been reported in several plant and animal species. However, it has been elusive how and why a specific chromosomal region is chosen to be a new centromere during the neocentromere activation events. We report recurrent establishment of neocentromeres in a pericentromeric region of chromosome 3 in maize (Zea mays). This latent region is located in the short arm and is only 2 Mb away from the centromere (Cen3) of chromosome 3. At least three independent neocentromere activation events, which were likely induced by different mechanisms, occurred within this latent region. We mapped the binding domains of CENH3, the centromere-specific H3 histone variant, of the three neocentromeres and analyzed the genomic and epigenomic features associated with Cen3, the de novo centromeres and an inactivated centromere derived from an ancestral chromosome. Our results indicate that lack of genes and transcription and a relatively high level of DNA methylation in this pericentromeric region may provide a favorable chromatin environment for neocentromere activation.
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Affiliation(s)
- Hainan Zhao
- Department of Horticulture, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Zixian Zeng
- Department of Horticulture, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Dal-Hoe Koo
- Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506, USA
| | - Bikram S Gill
- Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506, USA
| | - James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
| | - Jiming Jiang
- Department of Horticulture, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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42
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Das A, Smoak EM, Linares-Saldana R, Lampson MA, Black BE. Centromere inheritance through the germline. Chromosoma 2017; 126:595-604. [PMID: 28791511 DOI: 10.1007/s00412-017-0640-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 11/30/2022]
Abstract
The centromere directs chromosome segregation and genetic inheritance but is not itself heritable in a canonical, DNA-based manner. In most species, centromeres are epigenetically defined by the presence of a histone H3 variant centromere protein A (CENP-A), independent of underlying DNA sequence. Therefore, centromere inheritance depends on maintaining the CENP-A nucleosome mark across generations. Experiments in cycling somatic cells have led to a model in which centromere identity is maintained by a cell cycle-coupled CENP-A chromatin assembly pathway. However, the processes of animal gametogenesis pose unique challenges to centromere inheritance because of the extended cell cycle arrest and the massive genome reorganization in the female and male germline, respectively. Here, we review our current understanding of germline centromere inheritance and highlight outstanding questions.
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Affiliation(s)
- Arunika Das
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Evan M Smoak
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Graduate Program in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ricardo Linares-Saldana
- Graduate Program in Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael A Lampson
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Graduate Program in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Graduate Program in Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Ben E Black
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Graduate Program in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Graduate Program in Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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43
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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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44
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Abstract
Centromeres are essential for cell division and growth in all eukaryotes, and knowledge of their sequence and structure guides the development of artificial chromosomes for functional cellular biology studies. Centromeric proteins are conserved among eukaryotes; however, centromeric DNA sequences are highly variable. We combined forward and reverse genetic approaches with chromatin immunoprecipitation to identify centromeres of the model diatom Phaeodactylum tricornutum We observed 25 unique centromere sequences typically occurring once per chromosome, a finding that helps to resolve nuclear genome organization and indicates monocentric regional centromeres. Diatom centromere sequences contain low-GC content regions but lack repeats or other conserved sequence features. Native and foreign sequences with similar GC content to P. tricornutum centromeres can maintain episomes and recruit the diatom centromeric histone protein CENH3, suggesting nonnative sequences can also function as diatom centromeres. Thus, simple sequence requirements may enable DNA from foreign sources to persist in the nucleus as extrachromosomal episomes, revealing a potential mechanism for organellar and foreign DNA acquisition.
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45
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Ly P, Cleveland DW. Interrogating cell division errors using random and chromosome-specific missegregation approaches. Cell Cycle 2017. [PMID: 28650219 DOI: 10.1080/15384101.2017.1325047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Accurate segregation of the duplicated genome in mitosis is essential for maintaining genetic stability. Errors in this process can cause numerical and/or structural chromosome abnormalities - hallmark genomic features commonly associated with both tumorigenesis and developmental disorders. A cell-based approach was recently developed permitting inducible missegregation of the human Y chromosome by selectively disrupting kinetochore assembly onto the Y centromere. Although this strategy initially requires several steps of genetic manipulation, it is easy to use, highly efficient and specific for the Y without affecting the autosomes or the X, and does not require cell cycle synchronization or mitotic perturbation. Here we describe currently available tools for studying chromosome segregation errors, aneuploidy, and micronuclei, as well as discuss how the Y-specific missegregation system has been used to elucidate how chromosomal micronucleation can trigger a class of extensive rearrangements termed chromothripsis. The combinatorial use of these different tools will allow unresolved aspects of cell division defects and chromosomal instability to be experimentally explored.
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Affiliation(s)
- Peter Ly
- a Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine , University of California at San Diego , La Jolla , CA , USA
| | - Don W Cleveland
- a Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine , University of California at San Diego , La Jolla , CA , USA
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46
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Villa N, Conconi D, Benussi DG, Tornese G, Crosti F, Sala E, Dalprà L, Pecile V. A complete duplication of X chromosome resulting in a tricentric isochromosome originated by centromere repositioning. Mol Cytogenet 2017. [PMID: 28630649 PMCID: PMC5470200 DOI: 10.1186/s13039-017-0323-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neocentromeres are rare and considered chromosomal aberrations, because a non-centromeric region evolves in an active centromere by mutation. The literature reported several structural anomalies of X chromosome and they influence the female reproductive capacity or are associated to Turner syndrome in the presence of monosomy X cell line. CASE PRESENTATION We report a case of chromosome X complex rearrangement found in a prenatal diagnosis. The fetal karyotype showed a mosaicism with a 45,X cell line and a 46 chromosomes second line with a big marker, instead of a sex chromosome. The marker morphology and fluorescence in situ hybridization (FISH) characterization allowed us to identify a tricentric X chromosome constituted by two complete X chromosome fused at the p arms telomere and an active neocentromere in the middle, at the union of the two Xp arms, where usually are the telomeric regions. FISH also showed the presence of a paracentric inversion of both Xp arms. Furthermore, fragility figures were found in 56% of metaphases from peripheral blood lymphocytes culture at birth: a shorter marker chromosome and an apparently acentric fragment frequently lost. CONCLUSIONS At our knowledge, this is the first isochromosome of an entire non-acrocentric chromosome. The neocentromere is constituted by canonical sequences but localized in an unusual position and the original centromeres are inactivated. We speculated that marker chromosome was the result of a double rearrangement: firstly, a paracentric inversion which involved the Xp arm, shifting a part of the centromere at the p end and subsequently a duplication of the entire X chromosome, which gave rise to an isochromosome. It is possible to suppose that the first event could be a result of a non-allelic homologous recombination mediated by inverted low-copy repeats. As expected, our case shows a Turner phenotype with mild facial features and no major skeletal deformity, normal psychomotor development and a spontaneous development of puberty and menarche, although with irregular menses since the last follow-up.
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Affiliation(s)
- N Villa
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy
| | - D Conconi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - D Gambel Benussi
- Medical Genetics, Institute for Maternal and Child Health I.R.C.C.S. "Burlo Garofolo", Trieste, Italy
| | - G Tornese
- Department of Pediatrics, Institute for Maternal and Child Health I.R.C.C.S. "Burlo Garofolo", Trieste, Italy
| | - F Crosti
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy
| | - E Sala
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy
| | - L Dalprà
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy.,School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - V Pecile
- Medical Genetics, Institute for Maternal and Child Health I.R.C.C.S. "Burlo Garofolo", Trieste, Italy
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47
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Gent JI, Wang N, Dawe RK. Stable centromere positioning in diverse sequence contexts of complex and satellite centromeres of maize and wild relatives. Genome Biol 2017. [PMID: 28637491 PMCID: PMC5480163 DOI: 10.1186/s13059-017-1249-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background Paradoxically, centromeres are known both for their characteristic repeat sequences (satellite DNA) and for being epigenetically defined. Maize (Zea mays mays) is an attractive model for studying centromere positioning because many of its large (~2 Mb) centromeres are not dominated by satellite DNA. These centromeres, which we call complex centromeres, allow for both assembly into reference genomes and for mapping short reads from ChIP-seq with antibodies to centromeric histone H3 (cenH3). Results We found frequent complex centromeres in maize and its wild relatives Z. mays parviglumis, Z. mays mexicana, and particularly Z. mays huehuetenangensis. Analysis of individual plants reveals minor variation in the positions of complex centromeres among siblings. However, such positional shifts are stochastic and not heritable, consistent with prior findings that centromere positioning is stable at the population level. Centromeres are also stable in multiple F1 hybrid contexts. Analysis of repeats in Z. mays and other species (Zea diploperennis, Zea luxurians, and Tripsacum dactyloides) reveals tenfold differences in abundance of the major satellite CentC, but similar high levels of sequence polymorphism in individual CentC copies. Deviation from the CentC consensus has little or no effect on binding of cenH3. Conclusions These data indicate that complex centromeres are neither a peculiarity of cultivation nor inbreeding in Z. mays. While extensive arrays of CentC may be the norm for other Zea and Tripsacum species, these data also reveal that a wide diversity of DNA sequences and multiple types of genetic elements in and near centromeres support centromere function and constrain centromere positions. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1249-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, USA
| | - Na Wang
- Department of Plant Biology, University of Georgia, Athens, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, USA. .,Department of Genetics, University of Georgia, Athens, USA.
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48
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Wada N, Kazuki Y, Kazuki K, Inoue T, Fukui K, Oshimura M. Maintenance and Function of a Plant Chromosome in Human Cells. ACS Synth Biol 2017; 6:301-310. [PMID: 27696824 DOI: 10.1021/acssynbio.6b00180] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Replication, segregation, gene expression, and inheritance are essential features of all eukaryotic chromosomes. To delineate the extent of conservation of chromosome functions between humans and plants during evolutionary history, we have generated the first human cell line containing an Arabidopsis chromosome. The Arabidopsis chromosome was mitotically stable in hybrid cells following cell division, and initially existed as a translocated chromosome. During culture, the translocated chromosomes then converted to two types of independent plant chromosomes without human DNA sequences, with reproducibility. One pair of localization signals of CENP-A, a marker of functional centromeres was detected in the Arabidopsis genomic region in independent plant chromosomes. These results suggest that the chromosome maintenance system was conserved between human and plants. Furthermore, the expression of plant endogenous genes was observed in the hybrid cells, implicating that the plant chromosomal region existed as euchromatin in a human cell background and the gene expression system is conserved between two organisms. The present study suggests that the essential chromosome functions are conserved between evolutionarily distinct organisms such as humans and plants. Systematic analyses of hybrid cells may lead to the production of a shuttle vector between animal and plant, and a platform for the genome writing.
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Affiliation(s)
| | | | | | | | - Kiichi Fukui
- Department
of Biotechnology, Graduate School of Engineering, Osaka University, 565-0871, Osaka, Japan
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49
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Abstract
Centromeric chromatin undergoes major changes in composition and architecture during each cell cycle. These changes in specialized chromatin facilitate kinetochore formation in mitosis to ensure proper chromosome segregation. Thus, proper orchestration of centromeric chromatin dynamics during interphase, including replication in S phase, is crucial. We provide the current view concerning the centromeric architecture associated with satellite repeat sequences in mammals and its dynamics during the cell cycle. We summarize the contributions of deposited histone variants and their chaperones, other centromeric components - including proteins and their post-translational modifications, and RNAs - and we link the expression and deposition timing of each component during the cell cycle. Because neocentromeres occur at ectopic sites, we highlight how cell cycle processes can go wrong, leading to neocentromere formation and potentially disease.
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Affiliation(s)
- Sebastian Müller
- Institut Curie, PSL Research University, CNRS, UMR3664, Equipe Labellisée Ligue contre le Cancer, F-75005 Paris, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS, UMR3664, Equipe Labellisée Ligue contre le Cancer, F-75005 Paris, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR3664, F-75005 Paris, France
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50
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Zasadzińska E, Foltz DR. Orchestrating the Specific Assembly of Centromeric Nucleosomes. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:165-192. [PMID: 28840237 DOI: 10.1007/978-3-319-58592-5_7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Centromeres are chromosomal loci that are defined epigenetically in most eukaryotes by incorporation of a centromere-specific nucleosome in which the canonical histone H3 variant is replaced by Centromere Protein A (CENP-A). Therefore, the assembly and propagation of centromeric nucleosomes are critical for maintaining centromere identify and ensuring genomic stability. Centromeres direct chromosome segregation (during mitosis and meiosis) by recruiting the constitutive centromere-associated network of proteins throughout the cell cycle that in turn recruits the kinetochore during mitosis. Assembly of centromere-specific nucleosomes in humans requires the dedicated CENP-A chaperone HJURP, and the Mis18 complex to couple the deposition of new CENP-A to the site of the pre-existing centromere, which is essential for maintaining centromere identity. Human CENP-A deposition occurs specifically in early G1, into pre-existing chromatin, and several additional chromatin-associated complexes regulate CENP-A nucleosome deposition and stability. Here we review the current knowledge on how new CENP-A nucleosomes are assembled selectively at the existing centromere in different species and how this process is controlled to ensure stable epigenetic inheritance of the centromere.
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Affiliation(s)
- Ewelina Zasadzińska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Daniel R Foltz
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA. .,Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA. .,Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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