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Ballmer D, Akiyoshi B. Dynamic localization of the chromosomal passenger complex in trypanosomes is controlled by the orphan kinesins KIN-A and KIN-B. eLife 2024; 13:RP93522. [PMID: 38564240 PMCID: PMC10987093 DOI: 10.7554/elife.93522] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024] Open
Abstract
The chromosomal passenger complex (CPC) is an important regulator of cell division, which shows dynamic subcellular localization throughout mitosis, including kinetochores and the spindle midzone. In traditional model eukaryotes such as yeasts and humans, the CPC consists of the catalytic subunit Aurora B kinase, its activator INCENP, and the localization module proteins Borealin and Survivin. Intriguingly, Aurora B and INCENP as well as their localization pattern are conserved in kinetoplastids, an evolutionarily divergent group of eukaryotes that possess unique kinetochore proteins and lack homologs of Borealin or Survivin. It is not understood how the kinetoplastid CPC assembles nor how it is targeted to its subcellular destinations during the cell cycle. Here, we identify two orphan kinesins, KIN-A and KIN-B, as bona fide CPC proteins in Trypanosoma brucei, the kinetoplastid parasite that causes African sleeping sickness. KIN-A and KIN-B form a scaffold for the assembly of the remaining CPC subunits. We show that the C-terminal unstructured tail of KIN-A interacts with the KKT8 complex at kinetochores, while its N-terminal motor domain promotes CPC translocation to spindle microtubules. Thus, the KIN-A:KIN-B complex constitutes a unique 'two-in-one' CPC localization module, which directs the CPC to kinetochores from S phase until metaphase and to the central spindle in anaphase. Our findings highlight the evolutionary diversity of CPC proteins and raise the possibility that kinesins may have served as the original transport vehicles for Aurora kinases in early eukaryotes.
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Affiliation(s)
- Daniel Ballmer
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological SciencesEdinburghUnited Kingdom
| | - Bungo Akiyoshi
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological SciencesEdinburghUnited Kingdom
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2
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Ballmer D, Lou HJ, Ishii M, Turk BE, Akiyoshi B. An unconventional regulatory circuitry involving Aurora B controls anaphase onset and error-free chromosome segregation in trypanosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576407. [PMID: 38293145 PMCID: PMC10827227 DOI: 10.1101/2024.01.20.576407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Accurate chromosome segregation during mitosis requires that all chromosomes establish stable bi-oriented attachments with the spindle apparatus. Kinetochores form the interface between chromosomes and spindle microtubules and as such are under tight control by complex regulatory circuitry. As part of the chromosomal passenger complex (CPC), the Aurora B kinase plays a central role within this circuitry by destabilizing improper kinetochore-microtubule attachments and relaying the attachment status to the spindle assembly checkpoint, a feedback control system that delays the onset of anaphase by inhibiting the anaphase-promoting complex/cyclosome. Intriguingly, Aurora B is conserved even in kinetoplastids, an evolutionarily divergent group of eukaryotes, whose kinetochores are composed of a unique set of structural and regulatory proteins. Kinetoplastids do not have a canonical spindle checkpoint and it remains unclear how their kinetochores are regulated to ensure the fidelity and timing of chromosome segregation. Here, we show in Trypanosoma brucei, the kinetoplastid parasite that causes African sleeping sickness, that inhibition of Aurora B using an analogue-sensitive approach arrests cells in metaphase, with a reduction in properly bi-oriented kinetochores. Aurora B phosphorylates several kinetochore proteins in vitro, including the N-terminal region of the divergent Bub1-like protein KKT14. Depletion of KKT14 partially overrides the cell cycle arrest caused by Aurora B inhibition, while overexpression of a non-phosphorylatable KKT14 protein results in a prominent delay in the metaphase-to-anaphase transition. Finally, we demonstrate using a nanobody-based system that re-targeting the catalytic module of the CPC to the outer kinetochore is sufficient to promote mitotic exit but causes massive chromosome mis-segregation in anaphase. Our results indicate that the CPC and KKT14 are involved in an unconventional pathway controlling mitotic exit and error-free chromosome segregation in trypanosomes.
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Affiliation(s)
- Daniel Ballmer
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Hua Jane Lou
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Midori Ishii
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent Edinburgh, EH9 3BF, United Kingdom
| | - Benjamin E. Turk
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Bungo Akiyoshi
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent Edinburgh, EH9 3BF, United Kingdom
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3
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Landeros A, Wallace DA, Rahi A, Magdongon CB, Suraneni P, Amin MA, Chakraborty M, Adam SA, Foltz DR, Varma D. Nuclear lamin A-associated proteins are required for centromere assembly. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.25.559341. [PMID: 37808683 PMCID: PMC10557622 DOI: 10.1101/2023.09.25.559341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Many Lamin A-associated proteins (LAAP's) that are key constituents of the nuclear envelope (NE), assemble at the "core" domains of chromosomes during NE reformation and mitotic exit. However, the identity and function of the chromosomal core domains remain ill-defined. Here, we show that a distinct section of the core domain overlaps with the centromeres/kinetochores of chromosomes during mitotic telophase. The core domain can thus be demarcated into a kinetochore proximal core (KPC) on one side of the segregated chromosomes and the kinetochore distal core (KDC) on the opposite side, close to the central spindle. We next tested if centromere assembly is connected to NE re-formation. We find that centromere assembly is markedly perturbed after inhibiting the function of LMNA and the core-localized LAAPs, BANF1 and Emerin. We also find that the LAAPs exhibit multiple biochemical interactions with the centromere and inner kinetochore proteins. Consistent with this, normal mitotic progression and chromosome segregation was severely impeded after inhibiting LAAP function. Intriguingly, the inhibition of centromere function also interferes with the assembly of LAAP components at the core domain, suggesting a mutual dependence of LAAP and centromeres for their assembly at the core domains. Finally, we find that the localization of key proteins involved in the centromeric loading of CENP-A, including the Mis18 complex and HJURP were markedly affected in LAAP-inhibited cells. Our evidence points to a model where LAAP assembly at the core domain serves a key function in loading new copies of centromeric proteins during or immediately after mitotic exit.
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Affiliation(s)
- Adriana Landeros
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Destiny A. Wallace
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Amit Rahi
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Christine B. Magdongon
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Praveen Suraneni
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Mohammed A. Amin
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Manas Chakraborty
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Stephen A. Adam
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Daniel R. Foltz
- Dept. of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
| | - Dileep Varma
- Dept. of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave Chicago, IL 60611
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4
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Zaqout S, Kaindl AM. Autosomal Recessive Primary Microcephaly: Not Just a Small Brain. Front Cell Dev Biol 2022; 9:784700. [PMID: 35111754 PMCID: PMC8802810 DOI: 10.3389/fcell.2021.784700] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/01/2021] [Indexed: 02/06/2023] Open
Abstract
Microcephaly or reduced head circumference results from a multitude of abnormal developmental processes affecting brain growth and/or leading to brain atrophy. Autosomal recessive primary microcephaly (MCPH) is the prototype of isolated primary (congenital) microcephaly, affecting predominantly the cerebral cortex. For MCPH, an accelerating number of mutated genes emerge annually, and they are involved in crucial steps of neurogenesis. In this review article, we provide a deeper look into the microcephalic MCPH brain. We explore cytoarchitecture focusing on the cerebral cortex and discuss diverse processes occurring at the level of neural progenitors, early generated and mature neurons, and glial cells. We aim to thereby give an overview of current knowledge in MCPH phenotype and normal brain growth.
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Affiliation(s)
- Sami Zaqout
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
| | - Angela M. Kaindl
- Institute of Cell and Neurobiology, Charité—Universitätsmedizin Berlin, Berlin, Germany
- Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Charité—Universitätsmedizin Berlin, Berlin, Germany
- Department of Pediatric Neurology, Charité—Universitätsmedizin Berlin, Berlin, Germany
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5
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Hori T, Fukagawa T. Artificial generation of centromeres and kinetochores to understand their structure and function. Exp Cell Res 2020; 389:111898. [PMID: 32035949 DOI: 10.1016/j.yexcr.2020.111898] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/18/2020] [Accepted: 02/05/2020] [Indexed: 01/19/2023]
Abstract
The centromere is an essential genomic region that provides the surface to form the kinetochore, which binds to the spindle microtubes to mediate chromosome segregation during mitosis and meiosis. Centromeres of most organisms possess highly repetitive sequences, making it difficult to study these loci. However, an unusual centromere called a "neocentromere," which does not contain repetitive sequences, was discovered in a patient and can be generated experimentally. Recent advances in genome biology techniques allow us to analyze centromeric chromatin using neocentromeres. In addition to neocentromeres, artificial kinetochores have been generated on non-centromeric loci, using protein tethering systems. These are powerful tools to understand the mechanism of the centromere specification and kinetochore assembly. In this review, we introduce recent studies utilizing the neocentromeres and artificial kinetochores and discuss current problems in centromere biology.
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Affiliation(s)
- Tetsuya Hori
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, 565-0871, Japan.
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, 565-0871, Japan.
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6
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Shan F, Diwu Y, Yang X, Tu X. Expression and Interactions of Kinetoplastid Kinetochore Proteins (KKTs) from Trypanosoma brucei. Protein Pept Lett 2019; 26:860-868. [PMID: 31621553 DOI: 10.2174/0929866526666190723152359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023]
Abstract
Background:
Kinetochores are the macromolecular protein complex that drives
chromosome segregation by interacting with centromeric DNA and spindle microtubules in
eukaryotes. Kinetochores in well studied eukaryotes bind DNA through widely conserved
components like Centromere Protein (CENP)-A and bind microtubules through the Ndc80
complex. However, unconventional type of kinetochore proteins (KKT1-20) were identified in
evolutionarily divergent kinetoplastid species such as Trypanosoma brucei (T. brucei), indicating
that chromosome segregation is driven by a distinct set of proteins. KKT proteins are comprised of
sequential α-helixes that tend to form coiled-coil structures, which will further lead to
polymerization and misfolding of proteins, resulting in the formation of inclusion bodies.
Results and Conclusion:
We expressed and purified the stable KKT proteins with Maltose Binding
Protein (MBP) fusion tag in E. coli or Protein A tag in Human Embryonic Kidney (HEK) 293T
cells. Furthermore, we identified interactions among KKT proteins using yeast two-hybrid system.
The study provides an important basis for further better understanding of the structure and function
of KKT proteins.
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Affiliation(s)
- Fangzhen Shan
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Yating Diwu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiao Yang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaoming Tu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
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7
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8
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Zhu P, Jin J, Liao Y, Li J, Yu XZ, Liao W, He S. A novel prognostic biomarker SPC24 up-regulated in hepatocellular carcinoma. Oncotarget 2016; 6:41383-97. [PMID: 26515591 PMCID: PMC4747413 DOI: 10.18632/oncotarget.5510] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 09/05/2015] [Indexed: 12/16/2022] Open
Abstract
SPC24 is an important component of the nuclear division cycle 80 (Ndc80) kinetochore complex, which plays an essential role in the coupling of kinetochore to spindle microtubules (MTs) and the accurate segregation of chromosomes during mitosis. However, the functional role of SPC24 in hepatocellular carcinoma (HCC) remains unknown. Here, we detected the expression of SPC24 in HCC and analyzed its association with clinicopathologic features and prognosis of HCC patients. The expression of SPC24 mRNA was investigated in 212 cases of paired HCC and adjacent liver tissues by quantitative real-time PCR (qRT-PCR) and in the tissues of 20 HCC patients by semi-quantitative RT-PCR. Additionally, the expression of SPC24 protein was detected in 69 cases of HCC by immunohistochemistry (IHC) or in 2 cases of HCC tissues by Western-blotting. Furthermore, small interfering RNA (siRNA)-mediated silencing of SPC24 was employed in SMMC7721 and HepG2 human HCC cells to investigate cell proliferation, invasion and apoptosis. Survival curves were plotted using the Kaplan-Meier method, and differences in survival probability were obtained using the log-rank test. Independent predictors associated with disease-free survival (DFS) and overall survival (OS) were analyzed using the Cox proportional-hazards regression model. In this study, we showed that SPC24 was noticeably increased in HCC tissues compared to normal adjacent noncancerous tissues, at both mRNA and protein levels. High expression of SPC24 was significantly correlated with alpha-fetoprotein (AFP) (p = 0.044), median size (p = 0.030), tumor number (p = 0.019), and Barcelona-Clinic Liver Cancer (BCLC) stage (p = 0.015). Kaplan-Meier analysis showed that the DFS and OS of high SPC24 expression group was significantly shorter than that of low SPC24 expression group (p < 0.001; p = 0.001; respectively). The prognostic impact of SPC24 was further confirmed by stratified survival analysis. Importantly, multivariate analysis identified SPC24 upregualtion (p = 0.001), PVTT (p = 0.007), size of tumor > 5 cm (p < 0.001) as independent risk factors of DFS after resection, and SPC24 upregualtion (p < 0.001), PVTT (p = 0.029), size of tumor > 5 cm (p = 0.002), recurrence (p < 0.001) as independent prognostic factors for the OS of HCC patients. Additionally, siRNA-mediated silencing of SPC24 dramatically suppressed cell growth, adhesion, invasion and increased apoptosis in HCC cells. In conclusion, these results showed for the first time that SPC24 expression was significantly up-regulated in HCC, which may act as a novel prognostic biomarker for patients suffering from this deadly disease. Additionally, silence of SPC24 inhibiting HCC cell growth indicated that SPC24 may be a promising molecular target for HCC therapy.
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Affiliation(s)
- Pengpeng Zhu
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, People's Republic of China
| | - Junfei Jin
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, People's Republic of China.,Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, Guilin Medical University, Guilin, Guangxi, People's Republic of China
| | - Yan Liao
- Disease Prevention and Control Center of Guilin, Guilin, Guangxi, People's Republic of China
| | - Jun Li
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, People's Republic of China
| | - Xue-Zhong Yu
- Department of Microbiology & Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Weijia Liao
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, People's Republic of China.,Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, Guilin Medical University, Guilin, Guangxi, People's Republic of China
| | - Songqing He
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, People's Republic of China.,Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, Guilin Medical University, Guilin, Guangxi, People's Republic of China
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9
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Kang Y, Wang J, Neff A, Kratzer S, Kimura H, Davis RE. Differential Chromosomal Localization of Centromeric Histone CENP-A Contributes to Nematode Programmed DNA Elimination. Cell Rep 2016; 16:2308-16. [PMID: 27545882 DOI: 10.1016/j.celrep.2016.07.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 06/13/2016] [Accepted: 07/27/2016] [Indexed: 02/08/2023] Open
Abstract
The stability of the genome is paramount to organisms. However, diverse eukaryotes carry out programmed DNA elimination in which portions or entire chromsomes are lost in early development or during sex determination. During early development of the parasitic nematode, Ascaris suum, 13% of the genome is eliminated. How different genomic segments are reproducibly retained or discarded is unknown. Here, we show that centromeric histone CENP-A localization plays a key role in this process. We show that Ascaris chromosomes are holocentric during germline mitoses, with CENP-A distributed along their length. Prior to DNA elimination in the four-cell embryo, CENP-A is significantly diminished in chromosome regions that will be lost. This leads to the absence of kinetochores and microtubule attachment sites necessary for chromosome segregation, resulting in loss of these regions upon mitosis. Our data suggest that changes in CENP-A localization specify which portions of chromosomes will be lost during programmed DNA elimination.
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Affiliation(s)
- Yuanyuan Kang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jianbin Wang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Ashley Neff
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Stella Kratzer
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Hiroshi Kimura
- Department of Biological Sciences, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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10
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Beh TT, MacKinnon RN, Kalitsis P. Active centromere and chromosome identification in fixed cell lines. Mol Cytogenet 2016; 9:28. [PMID: 27011768 PMCID: PMC4804480 DOI: 10.1186/s13039-016-0236-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 03/17/2016] [Indexed: 02/01/2023] Open
Abstract
Background The centromere plays a crucial role in ensuring the fidelity of chromosome segregation during cell divisions. However, in cancer and constitutional disorders, the presence of more than one active centromere on a chromosome may be a contributing factor to chromosome instability and could also have predictive value in disease progression, making the detection of properly functioning centromeres important. Thus far, antibodies that are widely used for functional centromere detection mainly work on freshly harvested cells whereas most cytogenetic samples are stored long-term in methanol-acetic acid fixative. Hence, we aimed to identify antibodies that would recognise active centromere antigens on methanol-acetic acid fixed cells. Results A panel of active centromere protein antibodies was tested and we found that a rabbit monoclonal antibody against human CENP-C recognises the active centromeres of cells fixed in methanol-acetic acid. We then tested and compared combinations of established methods namely centromere fluorescence in situ hybridisation (cenFISH), centromere protein immunofluorescence (CENP-IF) and multicolour FISH (mFISH), and showed the usefulness of CENP-IF together with cenFISH followed by mFISH (CENP-IF-cenFISH-mFISH) with the aforementioned anti-CENP-C antibody. We further demonstrated the utility of our method in two cancer cell lines with high proportion of centromere defects namely neocentromere and functional dicentric. Conclusions We propose the incorporation of the CENP-IF-cenFISH-mFISH method using a commercially available rabbit monoclonal anti-CENP-C into established methods such as dicentric chromosome assay (DCA), prenatal karyotype screening in addition to constitutional and cancer karyotyping. This method will provide a more accurate assessment of centromere abnormality status in chromosome instability disorders.
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Affiliation(s)
- Thian T Beh
- Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Melbourne, VIC 3052 Australia ; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Melbourne, VIC 3052 Australia
| | - Ruth N MacKinnon
- Victorian Cancer Cytogenetics Service, St Vincent's Hospital, Fitzroy, Melbourne, VIC 3065 Australia ; Department of Medicine, St Vincent's Hospital, University of Melbourne, Fitzroy, Melbourne, VIC 3065 Australia
| | - Paul Kalitsis
- Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Melbourne, VIC 3052 Australia ; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Melbourne, VIC 3052 Australia
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11
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Freitag M. The kinetochore interaction network (KIN) of ascomycetes. Mycologia 2016; 108:485-505. [PMID: 26908646 DOI: 10.3852/15-182] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 10/23/2015] [Indexed: 01/13/2023]
Abstract
Chromosome segregation relies on coordinated activity of a large assembly of proteins, the kinetochore interaction network (KIN). How conserved the underlying mechanisms driving the epigenetic phenomenon of centromere and kinetochore assembly and maintenance are remains unclear, even though various eukaryotic models have been studied. More than 50 different proteins, many in multiple copies, comprise the KIN or are associated with fungal centromeres and kinetochores. Proteins isolated from immune sera recognized centromeric regions on chromosomes and thus were named centromere proteins (CENPs). CENP-A, sometimes called centromere-specific H3 (CenH3), is incorporated into nucleosomes within or near centromeres. The constitutive centromere-associated network (CCAN) assembles on this specialized chromatin, likely based on specific interactions with and requiring presence of CENP-C. The outer kinetochore comprises the Knl1-Mis12-Ndc80 (KMN) protein complexes that connect CCAN to spindles, accomplished by binding and stabilizing microtubules (MTs) and in the process generating load-bearing assemblies for chromatid segregation. In most fungi the Dam1/DASH complex connects the KMN complexes to MTs. Fungi present a rich resource to investigate mechanistic commonalities but also differences in kinetochore architecture. While ascomycetes have sets of CCAN and KMN proteins that are conserved with those of budding yeast or metazoans, searching other major branches of the fungal kingdom revealed that CCAN proteins are poorly conserved at the primary sequence level. Several conserved binding motifs or domains within KMN complexes have been described recently, and these features of ascomycete KIN proteins are shared with most metazoan proteins. In addition, several ascomycete-specific domains have been identified here.
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Affiliation(s)
- Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331-7305
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12
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DeLuca KF, Herman JA, DeLuca JG. Measuring Kinetochore-Microtubule Attachment Stability in Cultured Cells. Methods Mol Biol 2016; 1413:147-168. [PMID: 27193848 DOI: 10.1007/978-1-4939-3542-0_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Duplicated sister chromatids connect to the mitotic spindle through kinetochores, large proteinaceous structures built at sites of centromeric heterochromatin. Kinetochores are responsible for harnessing the forces generated by microtubule polymerization and depolymerization to power chromosome movements. The fidelity of chromosome segregation relies on proper kinetochore function, as precise regulation of the attachment between kinetochores and microtubules is essential to prevent mitotic errors, which are linked to the initiation and progression of cancer and the formation of birth defects (Godek et al., Nat Rev Mol Cell Biol 16(1):57-64, 2014; Ricke and van Deursen, Semin Cell Dev Biol 22(6):559-565, 2011; Holland and Cleveland, EMBO Rep 13(6):501-514, 2012). Here we describe assays to quantitatively measure kinetochore-microtubule attachment stability in cultured cells.
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Affiliation(s)
- Keith F DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, MRB 237, Fort Collins, CO, 80523, USA
| | - Jacob A Herman
- Department of Biochemistry and Molecular Biology, Colorado State University, MRB 237, Fort Collins, CO, 80523, USA
| | - Jennifer G DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, MRB 237, Fort Collins, CO, 80523, USA.
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13
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Agarwal S, Varma D. How the SAC gets the axe: Integrating kinetochore microtubule attachments with spindle assembly checkpoint signaling. BIOARCHITECTURE 2015; 5:1-12. [PMID: 26430805 DOI: 10.1080/19490992.2015.1090669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Mitosis entails the bona fide segregation of duplicated chromosomes. This process is accomplished by the attachment of kinetochores on chromosomes to microtubules (MTs) of the mitotic spindle. Once the appropriate attachment is achieved, the spindle assembly checkpoint (SAC) that delays the premature onset of anaphase needs to be silenced for the cell to proceed to anaphase and cytokinesis. Therefore, while it is imperative to preserve the SAC when kinetochores are unattached, it is of paramount importance that SAC components are removed post kinetochore microtubule (kMT) attachment. Precise knowledge of how kMT attachments trigger the removal of SAC components from kinetochores or how the checkpoint proteins feedback in to the attachment machinery remains elusive. This review aims to describe the recent advances that provide an insight into the interplay of molecular events that coordinate and regulate the SAC activity in response to kMT attachment during cell division.
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Affiliation(s)
- Shivangi Agarwal
- a Department of Cell and Molecular Biology ; Feinberg School of Medicine; Northwestern University ; Chicago , IL USA
| | - Dileep Varma
- a Department of Cell and Molecular Biology ; Feinberg School of Medicine; Northwestern University ; Chicago , IL USA
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14
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Fachinetti D, Han JS, McMahon MA, Ly P, Abdullah A, Wong AJ, Cleveland DW. DNA Sequence-Specific Binding of CENP-B Enhances the Fidelity of Human Centromere Function. Dev Cell 2015; 33:314-27. [PMID: 25942623 DOI: 10.1016/j.devcel.2015.03.020] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 02/09/2015] [Accepted: 03/25/2015] [Indexed: 12/31/2022]
Abstract
Human centromeres are specified by a stably inherited epigenetic mark that maintains centromere position and function through a two-step mechanism relying on self-templating centromeric chromatin assembled with the histone H3 variant CENP-A, followed by CENP-A-dependent nucleation of kinetochore assembly. Nevertheless, natural human centromeres are positioned within specific megabase chromosomal regions containing α-satellite DNA repeats, which contain binding sites for the DNA sequence-specific binding protein CENP-B. We now demonstrate that CENP-B directly binds both CENP-A's amino-terminal tail and CENP-C, a key nucleator of kinetochore assembly. DNA sequence-dependent binding of CENP-B within α-satellite repeats is required to stabilize optimal centromeric levels of CENP-C. Chromosomes bearing centromeres without bound CENP-B, including the human Y chromosome, are shown to mis-segregate in cells at rates several-fold higher than chromosomes with CENP-B-containing centromeres. These data demonstrate a DNA sequence-specific enhancement by CENP-B of the fidelity of epigenetically defined human centromere function.
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Affiliation(s)
- Daniele Fachinetti
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA.
| | - Joo Seok Han
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Moira A McMahon
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Peter Ly
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Amira Abdullah
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Alex J Wong
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA.
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15
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Abstract
In order to understand the three-dimensional structure of the functional kinetochore in vertebrates, we require a complete list and stoichiometry for the protein components of the kinetochore, which can be provided by genetic and proteomic experiments. We also need to know how the chromatin-containing CENP-A, which makes up the structural foundation for the kinetochore, is folded, and how much of that DNA is involved in assembling the kinetochore. In this MS, we demonstrate that functioning metaphase kinetochores in chicken DT40 cells contain roughly 50 kb of DNA, an amount that corresponds extremely closely to the length of chromosomal DNA associated with CENP-A in ChIP-seq experiments. Thus, during kinetochore assembly, CENP-A chromatin is compacted into the inner kinetochore plate without including significant amounts of flanking pericentromeric heterochromatin.
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Affiliation(s)
- Susana Abreu Ribeiro
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, King's Buildings, Mayfield Road, Edinburgh, EH9 3JR, Scotland, UK
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16
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Mirzaa GM, Vitre B, Carpenter G, Abramowicz I, Gleeson JG, Paciorkowski AR, Cleveland DW, Dobyns WB, O’Driscoll M. Mutations in CENPE define a novel kinetochore-centromeric mechanism for microcephalic primordial dwarfism. Hum Genet 2014; 133:1023-39. [PMID: 24748105 PMCID: PMC4415612 DOI: 10.1007/s00439-014-1443-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 03/31/2014] [Indexed: 11/30/2022]
Abstract
Defects in centrosome, centrosomal-associated and spindle-associated proteins are the most frequent cause of primary microcephaly (PM) and microcephalic primordial dwarfism (MPD) syndromes in humans. Mitotic progression and segregation defects, microtubule spindle abnormalities and impaired DNA damage-induced G2-M cell cycle checkpoint proficiency have been documented in cell lines from these patients. This suggests that impaired mitotic entry, progression and exit strongly contribute to PM and MPD. Considering the vast protein networks involved in coordinating this cell cycle stage, the list of potential target genes that could underlie novel developmental disorders is large. One such complex network, with a direct microtubule-mediated physical connection to the centrosome, is the kinetochore. This centromeric-associated structure nucleates microtubule attachments onto mitotic chromosomes. Here, we described novel compound heterozygous variants in CENPE in two siblings who exhibit a profound MPD associated with developmental delay, simplified gyri and other isolated abnormalities. CENPE encodes centromere-associated protein E (CENP-E), a core kinetochore component functioning to mediate chromosome congression initially of misaligned chromosomes and in subsequent spindle microtubule capture during mitosis. Firstly, we present a comprehensive clinical description of these patients. Then, using patient cells we document abnormalities in spindle microtubule organization, mitotic progression and segregation, before modeling the cellular pathogenicity of these variants in an independent cell system. Our cellular analysis shows that a pathogenic defect in CENP-E, a kinetochore-core protein, largely phenocopies PCNT-mutated microcephalic osteodysplastic primordial dwarfism-type II patient cells. PCNT encodes a centrosome-associated protein. These results highlight a common underlying pathomechanism. Our findings provide the first evidence for a kinetochore-based route to MPD in humans.
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Affiliation(s)
- Ghayda M. Mirzaa
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Benjamin Vitre
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Gillian Carpenter
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Falmer, Brighton, BN1 9RQ, United Kingdom
| | - Iga Abramowicz
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Falmer, Brighton, BN1 9RQ, United Kingdom
| | - Joseph G. Gleeson
- Department of Neurosciences and Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Alex R. Paciorkowski
- Departments of Neurology, Pediatrics & Biomedical Genetics, Center for Neural Development & Disease, University of Rochester Medical Center, Rochester, NY, USA
| | - Don W. Cleveland
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - William B. Dobyns
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Mark O’Driscoll
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Falmer, Brighton, BN1 9RQ, United Kingdom
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17
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The Robertsonian phenomenon in the house mouse: mutation, meiosis and speciation. Chromosoma 2014; 123:529-44. [PMID: 25053180 DOI: 10.1007/s00412-014-0477-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/08/2014] [Accepted: 07/09/2014] [Indexed: 01/01/2023]
Abstract
Many different chromosomal races with reduced chromosome number due to the presence of Robertsonian fusion metacentrics have been described in western Europe and northern Africa, within the distribution area of the western house mouse Mus musculus domesticus. This subspecies of house mouse has become the ideal model for studies to elucidate the processes of chromosome mutation and fixation that lead to the formation of chromosomal races and for studies on the impact of chromosome heterozygosities on reproductive isolation and speciation. In this review, we briefly describe the history of the discovery of the first and subsequent metacentric races in house mice; then, we focus on the molecular composition of the centromeric regions involved in chromosome fusion to examine the molecular characteristics that may explain the great variability of the karyotype that house mice show. The influence that metacentrics exert on the nuclear architecture of the male meiocytes and the consequences on meiotic progression are described to illustrate the impact that chromosomal heterozygosities exert on fertility of house mice-of relevance to reproductive isolation and speciation. The evolutionary significance of the Robertsonian phenomenon in the house mouse is discussed in the final section of this review.
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18
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Abstract
The centromere is the chromosomal locus essential for chromosome inheritance and genome stability. Human centromeres are located at repetitive alpha satellite DNA arrays that compose approximately 5% of the genome. Contiguous alpha satellite DNA sequence is absent from the assembled reference genome, limiting current understanding of centromere organization and function. Here, we review the progress in centromere genomics spanning the discovery of the sequence to its molecular characterization and the work done during the Human Genome Project era to elucidate alpha satellite structure and sequence variation. We discuss exciting recent advances in alpha satellite sequence assembly that have provided important insight into the abundance and complex organization of this sequence on human chromosomes. In light of these new findings, we offer perspectives for future studies of human centromere assembly and function.
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Affiliation(s)
- Megan E. Aldrup-MacDonald
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; E-Mail:
- Division of Human Genetics, Duke University, Durham, NC 27710, USA
| | - Beth A. Sullivan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; E-Mail:
- Division of Human Genetics, Duke University, Durham, NC 27710, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-919-684-9038
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19
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Akiyoshi B, Gull K. Discovery of unconventional kinetochores in kinetoplastids. Cell 2014; 156:1247-1258. [PMID: 24582333 PMCID: PMC3978658 DOI: 10.1016/j.cell.2014.01.049] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/06/2014] [Accepted: 01/10/2014] [Indexed: 11/17/2022]
Abstract
The kinetochore is the macromolecular protein complex that directs chromosome segregation in eukaryotes. It has been widely assumed that the core kinetochore consists of proteins that are common to all eukaryotes. However, no conventional kinetochore components have been identified in any kinetoplastid genome, thus challenging this assumption of universality. Here, we report the identification of 19 kinetochore proteins (KKT1–19) in Trypanosoma brucei. The majority is conserved among kinetoplastids, but none of them has detectable homology to conventional kinetochore proteins. These proteins instead have a variety of features not found in conventional kinetochore proteins. We propose that kinetoplastids build kinetochores using a distinct set of proteins. These findings provide important insights into the longstanding problem of the position of the root of the eukaryotic tree of life. Conventional kinetochore proteins cannot be identified in any kinetoplastid genome 19 kinetochore proteins were identified in Trypanosoma brucei Kinetoplastids possess unconventional kinetochores This discovery supports the hypothesis that kinetoplastids branched very early
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Affiliation(s)
- Bungo Akiyoshi
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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20
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The CENP-O complex requirement varies among different cell types. Chromosome Res 2014; 22:293-303. [PMID: 24481920 PMCID: PMC4129241 DOI: 10.1007/s10577-014-9404-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 01/14/2014] [Accepted: 01/15/2014] [Indexed: 11/21/2022]
Abstract
CENP-U (CENP-50) is a component of the CENP-O complex, which includes CENP-O, CENP-P, CENP-Q, CENP-R, and CENP-U and is constitutively localized at kinetochores throughout the cell cycle in vertebrates. Although CENP-U deficiency results in some mitotic defects in chicken DT40 cells, CENP-U-deficient chicken DT40 cells are viable. To examine the functional roles of CENP-U in an organism-dependent context, we generated CENP-U-deficient mice. The CENP-U-deficient mice died during early embryogenesis (approximately E7.5). Thus, conditional CENP-U-deficient mouse ES cells were generated to analyze CENP-U-deficient phenotypes at the cell level. When CENP-U was disrupted in the mouse ES cells, all CENP-O complex proteins disappeared from kinetochores. In contrast, other kinetochore proteins were recruited in CENP-U-deficient mouse ES cells as CENP-U-deficient DT40 cells. However, the CENP-U-deficient ES cells died after exhibiting abnormal mitotic behavior. Although CENP-U was essential for cell viability during mouse early embryogenesis, CENP-U-deficient mouse embryonic fibroblast cells were viable, similar to the DT40 cells. Thus, although both DT40 and ES cells with CENP-U deficiency have similar mitotic defects, cellular responses to mitotic defects vary among different cell types.
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21
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Graham AN, Kalitsis P. Chromosome Y centromere array deletion leads to impaired centromere function. PLoS One 2014; 9:e86875. [PMID: 24466276 PMCID: PMC3899357 DOI: 10.1371/journal.pone.0086875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 12/17/2013] [Indexed: 11/18/2022] Open
Abstract
The centromere is an essential chromosomal structure that is required for the faithful distribution of replicated chromosomes to daughter cells. Defects in the centromere can compromise the stability of chromosomes resulting in segregation errors. We have characterised the centromeric structure of the spontaneous mutant mouse strain, BALB/cWt, which exhibits a high rate of Y chromosome instability. The Y centromere DNA array shows a de novo interstitial deletion and a reduction in the level of the foundation centromere protein, CENP-A, when compared to the non-deleted centromere array in the progenitor strain. These results suggest there is a lower threshold limit of centromere size that ensures full kinetochore function during cell division.
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Affiliation(s)
- Alison N. Graham
- Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Paul Kalitsis
- Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
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22
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Cheerambathur DK, Desai A. Linked in: formation and regulation of microtubule attachments during chromosome segregation. Curr Opin Cell Biol 2014; 26:113-22. [PMID: 24529253 DOI: 10.1016/j.ceb.2013.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/11/2013] [Accepted: 12/11/2013] [Indexed: 11/29/2022]
Abstract
Accurate segregation of the replicated genome during cell division depends on dynamic attachments formed between chromosomes and the microtubule polymers of the spindle. Here we review recent advances in mechanistic analysis of microtubule attachment formation and regulation.
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Affiliation(s)
- Dhanya K Cheerambathur
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA.
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23
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Caldas GV, DeLuca JG. KNL1: bringing order to the kinetochore. Chromosoma 2013; 123:169-81. [PMID: 24310619 DOI: 10.1007/s00412-013-0446-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 11/30/2022]
Abstract
KNL1 is an evolutionarily conserved kinetochore-associated protein essential for accurate chromosome segregation in eukaryotic cells. This large scaffold protein, predicted to be almost entirely unstructured, is involved in diverse mitotic processes including kinetochore assembly, chromosome congression, and mitotic checkpoint signaling. How this kinetochore "hub" coordinates protein-protein interactions spatially and temporally during mitosis to orchestrate these processes is an area of active investigation. Here we summarize the current understanding of KNL1 and discuss possible mechanisms by which this protein actively contributes to multiple aspects of mitotic progression.
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Affiliation(s)
- Gina V Caldas
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
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24
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Tanaka TU, Clayton L, Natsume T. Three wise centromere functions: see no error, hear no break, speak no delay. EMBO Rep 2013; 14:1073-83. [PMID: 24232185 PMCID: PMC3849490 DOI: 10.1038/embor.2013.181] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 10/18/2013] [Indexed: 12/17/2022] Open
Abstract
The main function of the centromere is to promote kinetochore assembly for spindle microtubule attachment. Two additional functions of the centromere, however, are becoming increasingly clear: facilitation of robust sister-chromatid cohesion at pericentromeres and advancement of replication of centromeric regions. The combination of these three centromere functions ensures correct chromosome segregation during mitosis. Here, we review the mechanisms of the kinetochore-microtubule interaction, focusing on sister-kinetochore bi-orientation (or chromosome bi-orientation). We also discuss the biological importance of robust pericentromeric cohesion and early centromere replication, as well as the mechanisms orchestrating these two functions at the microtubule attachment site.
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Affiliation(s)
- Tomoyuki U Tanaka
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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25
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Krasikova A, Fukagawa T, Zlotina A. High-resolution mapping and transcriptional activity analysis of chicken centromere sequences on giant lampbrush chromosomes. Chromosome Res 2013; 20:995-1008. [PMID: 23143648 DOI: 10.1007/s10577-012-9321-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Exploration into morphofunctional organisation of centromere DNA sequences is important for understanding the mechanisms of kinetochore specification and assembly. In-depth epigenetic analysis of DNA fragments associated with centromeric nucleosome proteins has demonstrated unique features of centromere organisation in chicken karyotype: there are both mature centromeres, which comprise chromosome-specific homogeneous arrays of tandem repeats, and recently evolved primitive centromeres, which consist of non-tandemly organised DNA sequences. In this work, we describe the arrangement and transcriptional activity of chicken centromere repeats for Cen1, Cen2, Cen3, Cen4, Cen7, Cen8, and Cen11 and non-repetitive centromere sequences of chromosomes 5, 27, and Z using highly elongated lampbrush chromosomes, which are characteristic of the diplotene stage of oogenesis. The degree of chromatin packaging and fine spatial organisations of tandemly repetitive and non-tandemly repetitive centromeric sequences significantly differ at the lampbrush stage. Using DNA/RNA FISH, we have demonstrated that during the lampbrush stage, DNA sequences are transcribed within the centromere regions of chromosomes that lack centromere-specific tandem repeats. In contrast, chromosome-specific centromeric repeats Cen1, Cen2, Cen3, Cen4, Cen7, Cen8, and Cen11 do not demonstrate any transcriptional activity during the lampbrush stage. In addition, we found that CNM repeat cluster localises adjacent to non-repetitive centromeric sequences in chicken microchromosome 27 indicating that centromere region in this chromosome is repeat-rich. Cross-species FISH allowed localisation of the sequences homologous to centromeric DNA of chicken chromosomes 5 and 27 in centromere regions of quail orthologous chromosomes.
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Affiliation(s)
- Alla Krasikova
- Saint-Petersburg State University, Oranienbaumskoie sch. 2, Stary Peterhof, Saint-Petersburg, 198504, Russia.
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26
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Ross KE, Arighi CN, Ren J, Natale DA, Huang H, Wu CH. Use of the protein ontology for multi-faceted analysis of biological processes: a case study of the spindle checkpoint. Front Genet 2013; 4:62. [PMID: 23637705 PMCID: PMC3636526 DOI: 10.3389/fgene.2013.00062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/05/2013] [Indexed: 11/13/2022] Open
Abstract
As a member of the Open Biomedical Ontologies (OBO) foundry, the Protein Ontology (PRO) provides an ontological representation of protein forms and complexes and their relationships. Annotations in PRO can be assigned to individual protein forms and complexes, each distinguishable down to the level of post-translational modification, thereby allowing for a more precise depiction of protein function than is possible with annotations to the gene as a whole. Moreover, PRO is fully interoperable with other OBO ontologies and integrates knowledge from other protein-centric resources such as UniProt and Reactome. Here we demonstrate the value of the PRO framework in the investigation of the spindle checkpoint, a highly conserved biological process that relies extensively on protein modification and protein complex formation. The spindle checkpoint maintains genomic integrity by monitoring the attachment of chromosomes to spindle microtubules and delaying cell cycle progression until the spindle is fully assembled. Using PRO in conjunction with other bioinformatics tools, we explored the cross-species conservation of spindle checkpoint proteins, including phosphorylated forms and complexes; studied the impact of phosphorylation on spindle checkpoint function; and examined the interactions of spindle checkpoint proteins with the kinetochore, the site of checkpoint activation. Our approach can be generalized to any biological process of interest.
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Affiliation(s)
- Karen E Ross
- Center for Bioinformatics and Computational Biology, University of Delaware Newark, DE, USA
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27
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Tschernyschkow S, Herda S, Gruenert G, Döring V, Görlich D, Hofmeister A, Hoischen C, Dittrich P, Diekmann S, Ibrahim B. Rule-based modeling and simulations of the inner kinetochore structure. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 113:33-45. [PMID: 23562479 DOI: 10.1016/j.pbiomolbio.2013.03.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Combinatorial complexity is a central problem when modeling biochemical reaction networks, since the association of a few components can give rise to a large variation of protein complexes. Available classical modeling approaches are often insufficient for the analysis of very large and complex networks in detail. Recently, we developed a new rule-based modeling approach that facilitates the analysis of spatial and combinatorially complex problems. Here, we explore for the first time how this approach can be applied to a specific biological system, the human kinetochore, which is a multi-protein complex involving over 100 proteins. RESULTS Applying our freely available SRSim software to a large data set on kinetochore proteins in human cells, we construct a spatial rule-based simulation model of the human inner kinetochore. The model generates an estimation of the probability distribution of the inner kinetochore 3D architecture and we show how to analyze this distribution using information theory. In our model, the formation of a bridge between CenpA and an H3 containing nucleosome only occurs efficiently for higher protein concentration realized during S-phase but may be not in G1. Above a certain nucleosome distance the protein bridge barely formed pointing towards the importance of chromatin structure for kinetochore complex formation. We define a metric for the distance between structures that allow us to identify structural clusters. Using this modeling technique, we explore different hypothetical chromatin layouts. CONCLUSIONS Applying a rule-based network analysis to the spatial kinetochore complex geometry allowed us to integrate experimental data on kinetochore proteins, suggesting a 3D model of the human inner kinetochore architecture that is governed by a combinatorial algebraic reaction network. This reaction network can serve as bridge between multiple scales of modeling. Our approach can be applied to other systems beyond kinetochores.
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Affiliation(s)
- Sergej Tschernyschkow
- Bio Systems Analysis Group, Institute of Computer Science, Jena Centre for Bioinformatics and Friedrich Schiller University, Jena, Germany.
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28
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Varma D, Salmon ED. The KMN protein network--chief conductors of the kinetochore orchestra. J Cell Sci 2013; 125:5927-36. [PMID: 23418356 DOI: 10.1242/jcs.093724] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Successful completion of mitosis requires that sister kinetochores become attached end-on to the plus ends of spindle microtubules (MTs) in prometaphase, thereby forming kinetochore microtubules (kMTs) that tether one sister to one spindle pole and the other sister to the opposite pole. Sites for kMT attachment provide at least four key functions: robust and dynamic kMT anchorage; force generation that can be coupled to kMT plus-end dynamics; correction of errors in kMT attachment; and control of the spindle assembly checkpoint (SAC). The SAC typically delays anaphase until chromosomes achieve metaphase alignment with each sister kinetochore acquiring a full complement of kMTs. Although it has been known for over 30 years that MT motor proteins reside at kinetochores, a highly conserved network of protein complexes, called the KMN network, has emerged in recent years as the primary interface between the kinetochore and kMTs. This Commentary will summarize recent advances in our understanding of the role of the KMN network for the key kinetochore functions, with a focus on human cells.
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Affiliation(s)
- Dileep Varma
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA.
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29
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Vagnarelli P. Chromatin reorganization through mitosis. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2013; 90:179-224. [PMID: 23582205 DOI: 10.1016/b978-0-12-410523-2.00006-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chromosome condensation is one of the major chromatin-remodeling events that occur during cell division. The changes in chromatin compaction and higher-order structure organization are essential requisites for ensuring a faithful transmission of the replicated genome to daughter cells. Although the observation of mitotic chromosome condensation has fascinated Scientists for a century, we are still far away from understanding how the process works from a molecular point of view. In this chapter, I will analyze our current understanding of chromatin condensation during mitosis with particular attention to the major molecular players that trigger and maintain this particular chromatin conformation. However, within the chromosome, not all regions of the chromatin are organized in the same manner. I will address separately the structure and functions of particular chromatin domains such as the centromere. Finally, the transition of the chromatin through mitosis represents just an interlude for gene expression between two cell cycles. How the transcriptional information that governs cell linage identity is transmitted from mother to daughter represents a big and interesting question. I will present how cells take care of the aspect ensuring that mitotic chromosome condensation and the block of transcription does not wipe out the cell identity.
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Affiliation(s)
- Paola Vagnarelli
- Heinz Wolff Building, Brunel University, Uxbridge, United Kingdom.
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