1
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Zhang S, Zheng Y, Li X, Zhang S, Hu H, Kuang W. Cellular senescence-related gene signature as a valuable predictor of prognosis in hepatocellular carcinoma. Aging (Albany NY) 2023; 15:3064-3093. [PMID: 37059592 DOI: 10.18632/aging.204658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/28/2023] [Indexed: 04/16/2023]
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) is a lethal tumor. Its prognosis prediction remains a challenge. Meanwhile, cellular senescence, one of the hallmarks of cancer, and its related prognostic genes signature can provide critical information for clinical decision-making. METHOD Using bulk RNA sequencing and microarray data of HCC samples, we established a senescence score model via multi-machine learning algorithms to predict the prognosis of HCC. Single-cell and pseudo-time trajectory analyses were used to explore the hub genes of the senescence score model in HCC sample differentiation. RESULT A machine learning model based on cellular senescence gene expression profiles was identified in predicting HCC prognosis. The feasibility and accuracy of the senescence score model were confirmed in external validation and comparison with other models. Moreover, we analyzed the immune response, immune checkpoints, and sensitivity to immunotherapy drugs of HCC patients in different prognostic risk groups. Pseudo-time analyses identified four hub genes in HCC progression, including CDCA8, CENPA, SPC25, and TTK, and indicated related cellular senescence. CONCLUSIONS This study identified a prognostic model of HCC by cellular senescence-related gene expression and insight into novel potential targeted therapies.
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Affiliation(s)
- Shuqiao Zhang
- First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Yilu Zheng
- Department of Hematology, The Seventh Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xinyu Li
- Medical College of Acupuncture-Moxibustion and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Shijun Zhang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Hao Hu
- First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Weihong Kuang
- Guangdong Key Laboratory for Research and Development of Natural Drugs, School of Pharmacy, The First Dongguan Affiliated Hospital of Guangdong Medical University, Guangdong Medical University, Dongguan, Guangdong, China
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2
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Kao Y, Tsai WC, Chen SH, Hsu SY, Huang LC, Chang CJ, Huang SM, Hueng DY. Shugosin 2 is a biomarker for pathological grading and survival prediction in patients with gliomas. Sci Rep 2021; 11:18541. [PMID: 34535705 PMCID: PMC8448842 DOI: 10.1038/s41598-021-97119-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/19/2021] [Indexed: 12/21/2022] Open
Abstract
Glioblastomas are the most common type of adult primary brain neoplasms. Clinically, it is helpful to identify biomarkers to predict the survival of patients with gliomas due to its poor outcome. Shugoshin 2 (SGO2) is critical in cell division and cell cycle progression in eukaryotes. However, the association of SGO2 with pathological grading and survival in patients with gliomas remains unclear. We analyzed the association between SGO2 expression and clinical outcomes from Gene Expression Omnibus (GEO) dataset profiles, The Cancer Genome Atlas (TCGA), and Chinese Glioma Genome Atlas (CGGA). SGO2 mRNA and protein expression in normal brain tissue and glioma cell lines were investigated via quantitative RT-PCR, Western blot, and IHC staining. The roles of SGO2 in proliferation, migration, and apoptosis of GBM cells were studied with wound-healing assay, BrdU assay, cell cycle analysis, and JC-1 assay. The protein–protein interaction (PPI) was analyzed via Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). SGO2 mRNA expression predicted higher grade gliomas than non-tumor brain tissues. Kaplan–Meier survival analysis showed that patients with high-grade gliomas with a higher SGO2 expression had worse survival outcomes. SGO2 mRNA and protein expression were upper regulated in gliomas than in normal brain tissue. Inhibition of SGO2 suppressed cell proliferation and migration. Also, PPI result showed SGO2 to be a potential hub protein, which was related to the expression of AURKB and FOXM1. SGO2 expression positively correlates with WHO pathological grading and patient survival, suggesting that SGO2 is a biomarker that is predictive of disease progression in patients with gliomas.
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Affiliation(s)
- Ying Kao
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.,Division of Neurosurgery, Department of Surgery, Taipei City Hospital Zhongxing Branch, Taipei, Taiwan, ROC.,University of Taipei, Taipei, Taiwan, ROC
| | - Wen-Chiuan Tsai
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC
| | - Ssu-Han Chen
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC
| | - Shao-Yuan Hsu
- Division of Neurosurgery, Department of Surgery, Taipei City Hospital, Renai Branch, Taipei, Taiwan, ROC
| | - Li-Chun Huang
- Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, ROC
| | - Chih-Ju Chang
- Division of Neurosurgery, Department of Surgery, Cathay General Hospital, Taipei, Taiwan, ROC.,Department of Medicine, School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan, ROC.,Department of Mechanical Engineering, National Central University, Taoyuan County, Taiwan, ROC
| | - Shih-Ming Huang
- Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, ROC
| | - Dueng-Yuan Hueng
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC. .,Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, ROC. .,Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC.
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3
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Zhang B, Zhou Q, Xie Q, Lin X, Miao W, Wei Z, Zheng T, Pang Z, Liu H, Chen X. SPC25 overexpression promotes tumor proliferation and is prognostic of poor survival in hepatocellular carcinoma. Aging (Albany NY) 2020; 13:2803-2821. [PMID: 33408271 PMCID: PMC7880370 DOI: 10.18632/aging.202329] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 11/08/2020] [Indexed: 12/29/2022]
Abstract
Background: The nuclear division cycle 80 (NDC80) complex assures proper chromosome segregation during the cell cycle progression. SPC25 is a crucial component of NDC80, and its role in hepatocellular carcinoma (HCC) has been explored recently. This study characterized the differential expression of SPC25 in HCC patients of different races and HBV infection status. Methods: Expression patterns of SPC25 were evaluated in TCGA and Chinese HCC patients. Kaplan-Meier analysis was applied to examine the predictive value of SPC25. In vitro and in vivo functional assays were conducted to explore the role of SPC25 in HCC. Bioinformatics methods were applied to investigate the regulatory mechanisms of SPC25. Findings: The mRNA levels of SPC25 were up-regulated in HCC. SPC25 has a significantly higher transcriptional level in Asian patients than Caucasian patients. SPC25 promoted HCC cell proliferation in vitro and tumor growth in vivo by accelerating the cell cycle. We identified transcription factors, miRNAs, and immune cells that may interact with SPC25. Interpretation: The findings suggest that increased expression of SPC25 is associated with poor prognosis of HCC and enhances the proliferative capacity of HCC cells. SPC25 could serve as a valuable prognostic marker and a novel treatment target for HCC.
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Affiliation(s)
- Baozhu Zhang
- Department of Oncology, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Qing Zhou
- Department of Core Facility, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Qiankun Xie
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Xiaohui Lin
- Department of Oncology, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Wenqiang Miao
- Department of Oncology, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Zhaoguang Wei
- Department of Oncology, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Tingting Zheng
- Department of Oncology, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Zuoliang Pang
- Department of Oncology, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Haosheng Liu
- Department of Core Facility, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
| | - Xi Chen
- Department of Core Facility, People's Hospital of Shenzhen Baoan District, The Affiliated Baoan Hospital of Shenzhen, Southern Medical University, Shenzhen 518101, Guangdong, China
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4
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Park J, Park HY, Kim S, Kim HS, Park JY, Go H, Lee CW. Pellino 1 inactivates mitotic spindle checkpoint by targeting BubR1 for ubiquitinational degradation. Oncotarget 2018; 8:32055-32067. [PMID: 28410192 PMCID: PMC5458268 DOI: 10.18632/oncotarget.16762] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/22/2017] [Indexed: 02/01/2023] Open
Abstract
Aberrant constitutive activation of receptor-mediated downstream signalling plays an active role in the deregulation of cell cycle control. The mitotic spindle checkpoint is important in preventing abnormal mitotic cell cycle with chromosome missegregation from achieving neoplastic aneuploidy. However, mechanisms coupling receptor-mediated signalling to mitotic spindle checkpoint regulation remain unclear. Pellino 1 is a receptor signal-responsive E3 ubiquitin ligase, and the application of certain receptor-mediated signalling regulates the expression and activity of Pellino 1. In the present study, Pellino 1 expression induced extensive chromosome aneuploidy and allowed abnormal mitotic cells to adapt and become aneuploid in vitro and in vivo. Pellino 1 directly interacted with BubR1, a key component of mitotic spindle checkpoint, in a mitotic cell-cycle dependent manner, and down-regulated the stability of BubR1 by ubiquitination-mediated degradation and induced mitotic dysfunction. In summary, Pellino 1 expression acts as an inhibitory signal of the homeostatic regulation of mitotic cell cycle and checkpoint, and thus contributes to the initiation and progression of neoplastic chromosome aneuploidy.
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Affiliation(s)
- Jihyun Park
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Republic of Korea
| | - Hye-Young Park
- MOGAM Institute for Biomedical Research, Yongin 16924, Republic of Korea
| | - Suhyeon Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Hyun-Soo Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Ji Y Park
- Department of Pathology, Daegu Catholic University Medical Center, School of Medicine, Catholic University of Daegu, Daegu 42472, Republic of Korea
| | - Heounjeong Go
- Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, Korea
| | - Chang-Woo Lee
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Republic of Korea.,Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
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5
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Shin J, Jeong G, Park JY, Kim H, Lee I. MUN (MERISTEM UNSTRUCTURED), encoding a SPC24 homolog of NDC80 kinetochore complex, affects development through cell division in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:977-991. [PMID: 29356153 DOI: 10.1111/tpj.13823] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/24/2017] [Accepted: 12/14/2017] [Indexed: 05/22/2023]
Abstract
Kinetochore, a protein super-complex on the centromere of chromosomes, mediates chromosome segregation during cell division by providing attachment sites for spindle microtubules. The NDC80 complex, composed of four proteins, NDC80, NUF2, SPC24 and SPC25, is localized at the outer kinetochore and connects spindle fibers to the kinetochore. Although it is conserved across species, functional studies of this complex are rare in Arabidopsis. Here, we characterize a recessive mutant, meristem unstructured-1 (mun-1), exhibiting an abnormal phenotype with unstructured shoot apical meristem caused by ectopic expression of the WUSCHEL gene in unexpected tissues. mun-1 is a weak allele because of the insertion of T-DNA in the promoter region of the SPC24 homolog. The mutant exhibits stunted growth, embryo arrest, DNA aneuploidy, and defects in chromosome segregation with a low cell division rate. Null mutants of MUN from TALEN and CRISPR/Cas9-mediated mutagenesis showed zygotic embryonic lethality similar to nuf2-1; however, the null mutations were fully transmissible via pollen and ovules. Interactions among the components of the NDC80 complex were confirmed in a yeast two-hybrid assay and in planta co-immunoprecipitation. MUN is co-localized at the centromere with HTR12/CENH3, which is a centromere-specific histone variant, but MUN is not required to recruit HTR12/CENH3 to the kinetochore. Our results support that MUN is a functional homolog of SPC24 in Arabidopsis, which is required for proper cell division. In addition, we report the ectopic generations of stem cell niches by the malfunction of kinetochore components.
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Affiliation(s)
- Jinwoo Shin
- Laboratory of Plant Developmental Genetics, School of Biological Sciences, Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Goowon Jeong
- Laboratory of Plant Developmental Genetics, School of Biological Sciences, Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Jong-Yoon Park
- Laboratory of Plant Developmental Genetics, School of Biological Sciences, Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Hoyeun Kim
- Laboratory of Plant Developmental Genetics, School of Biological Sciences, Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Ilha Lee
- Laboratory of Plant Developmental Genetics, School of Biological Sciences, Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
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6
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Amin MA, McKenney RJ, Varma D. Antagonism between the dynein and Ndc80 complexes at kinetochores controls the stability of kinetochore-microtubule attachments during mitosis. J Biol Chem 2018; 293:5755-5765. [PMID: 29475948 DOI: 10.1074/jbc.ra117.001699] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/06/2018] [Indexed: 01/22/2023] Open
Abstract
Chromosome alignment and segregation during mitosis require kinetochore-microtubule (kMT) attachments that are mediated by the molecular motor dynein and the kMT-binding complex Ndc80. The Rod-ZW10-Zwilch (RZZ) complex is central to this coordination as it has an important role in dynein recruitment and has recently been reported to have a key function in the regulation of stable kMT attachments in Caenorhabditis elegans besides its role in activating the spindle assembly checkpoint (SAC). However, the mechanism by which these protein complexes control kMT attachments to drive chromosome motility during early mitosis is still unclear. Here, using in vitro total internal reflection fluorescence microscopy, we observed that higher concentrations of Ndc80 inhibited dynein binding to MTs, providing evidence that Ndc80 and dynein antagonize each other's function. High-resolution microscopy and siRNA-mediated functional disruption revealed that severe defects in chromosome alignment induced by depletion of dynein or the dynein adapter Spindly are rescued by codepletion of the RZZ component Rod in human cells. Interestingly, rescue of the chromosome alignment defects was independent of Rod function in SAC activation and was accompanied by a remarkable restoration of stable kMT attachments. Furthermore, the chromosome alignment rescue depended on the plus-end-directed motility of centromere protein E (CENP-E) because cells codepleted of CENP-E, Rod, and dynein could not establish stable kMT attachments or align their chromosomes properly. Our findings support the idea that dynein may control the function of the Ndc80 complex in stabilizing kMT attachments directly by interfering with Ndc80-MT binding or indirectly by controlling the Rod-mediated inhibition of Ndc80.
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Affiliation(s)
- Mohammed A Amin
- From the Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611 and
| | - Richard J McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616
| | - Dileep Varma
- From the Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611 and
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7
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Zhu Q, Zheng F, Liu AP, Qian J, Fu C, Lin Y. Shape Transformation of the Nuclear Envelope during Closed Mitosis. Biophys J 2017; 111:2309-2316. [PMID: 27851952 DOI: 10.1016/j.bpj.2016.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 09/28/2016] [Accepted: 10/07/2016] [Indexed: 11/18/2022] Open
Abstract
The nuclear envelope (NE) in lower eukaryotes such as Schizosaccharomyces pombe undergoes large morphology changes during closed mitosis. However, which physical parameters are important in governing the shape evolution of the NE, and how defects in the dividing chromosomes/microtubules are reflected in those parameters, are fundamental questions that remain unresolved. In this study, we show that improper separation of chromosomes in genetically deficient cells leads to membrane tethering or asymmetric division in contrast to the formation of two equal-sized daughter nuclei in wild-type cells. We hypothesize that the poleward force is transmitted to the nuclear membrane through its physical contact with the separated sister chromatids at the two spindle poles. A theoretical model is developed to predict the morphology evolution of the NE where key factors such as the work done by the poleward force and bending and surface energies stored in the membrane have been taken into account. Interestingly, the predicted phase diagram, summarizing the dependence of nuclear shape on the size of the load transmission regions, and the pole-to-pole distance versus surface area relationship all quantitatively agree well with our experimental observations, suggesting that this model captures the essential physics involved in closed mitosis.
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Affiliation(s)
- Qian Zhu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Fan Zheng
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Jin Qian
- Department of Engineering Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chuanhai Fu
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China.
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8
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Blázquez M, Medina P, Crespo B, Gómez A, Zanuy S. Identification of conserved genes triggering puberty in European sea bass males (Dicentrarchus labrax) by microarray expression profiling. BMC Genomics 2017; 18:441. [PMID: 28583077 PMCID: PMC5460432 DOI: 10.1186/s12864-017-3823-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 05/25/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spermatogenesis is a complex process characterized by the activation and/or repression of a number of genes in a spatio-temporal manner. Pubertal development in males starts with the onset of the first spermatogenesis and implies the division of primary spermatogonia and their subsequent entry into meiosis. This study is aimed at the characterization of genes involved in the onset of puberty in European sea bass, and constitutes the first transcriptomic approach focused on meiosis in this species. RESULTS European sea bass testes collected at the onset of puberty (first successful reproduction) were grouped in stage I (resting stage), and stage II (proliferative stage). Transition from stage I to stage II was marked by an increase of 11ketotestosterone (11KT), the main fish androgen, whereas the transcriptomic study resulted in 315 genes differentially expressed between the two stages. The onset of puberty induced 1) an up-regulation of genes involved in cell proliferation, cell cycle and meiosis progression, 2) changes in genes related with reproduction and growth, and 3) a down-regulation of genes included in the retinoic acid (RA) signalling pathway. The analysis of GO-terms and biological pathways showed that cell cycle, cell division, cellular metabolic processes, and reproduction were affected, consistent with the early events that occur during the onset of puberty. Furthermore, changes in the expression of three RA nuclear receptors point at the importance of the RA-signalling pathway during this period, in agreement with its role in meiosis. CONCLUSION The results contribute to boost our knowledge of the early molecular and endocrine events that trigger pubertal development and the onset of spermatogenesis in fish. These include an increase in 11KT plasma levels and changes in the expression of several genes involved in cell proliferation, cell cycle progression, meiosis or RA-signalling pathway. Moreover, the results can be applied to study meiosis in this economically important fish species for Mediterranean countries, and may help to develop tools for its sustainable aquaculture.
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Affiliation(s)
- Mercedes Blázquez
- Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain. .,Instituto de Ciencias del Mar, Consejo Superior de Investigaciones Científicas (ICM-CSIC), Passeig Maritim 37-49, 08003, Barcelona, Spain.
| | - Paula Medina
- Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain.,Instituto de Ciencias del Mar, Consejo Superior de Investigaciones Científicas (ICM-CSIC), Passeig Maritim 37-49, 08003, Barcelona, Spain.,Present address: Universidad de Antofagasta, Avda Angamos 601, Antofagasta, Chile
| | - Berta Crespo
- Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain.,Present address: UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Ana Gómez
- Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain
| | - Silvia Zanuy
- Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain.
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9
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Senaratne AP, Drinnenberg IA. All that is old does not wither: Conservation of outer kinetochore proteins across all eukaryotes? J Cell Biol 2017; 216:291-293. [PMID: 28108523 PMCID: PMC5294794 DOI: 10.1083/jcb.201701025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Senaratne and Drinnenberg discuss the potential universality of eukaryotic kinetochore proteins based on new work by D’Archivio and Wickstead. The kinetochore drives faithful chromosome segregation in all eukaryotes, yet the underlying machinery is diverse across species. D’Archivio and Wickstead (2017. J. Cell Biol.https://doi.org/10.1083/jcb.201608043) apply sensitive homology predictions to identify proteins in kinetoplastids with similarity to canonical outer kinetochore proteins, suggesting some degree of universality in the eukaryotic kinetochore.
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Affiliation(s)
- Aruni P Senaratne
- Institut Curie, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique UMR 3664, F-75005 Paris, France.,Sorbonne Universités, University Pierre-and-Marie-Curie, F-75005 Paris, France
| | - Ines A Drinnenberg
- Institut Curie, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique UMR 3664, F-75005 Paris, France
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10
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Liu Y, Hu H, Zhang C, Wang H, Zhang W, Wang Z, Li M, Zhang W, Zhou D, Jiang T. Co-expression of mitosis-regulating genes contributes to malignant progression and prognosis in oligodendrogliomas. Oncotarget 2016; 6:38257-69. [PMID: 26468983 PMCID: PMC4741997 DOI: 10.18632/oncotarget.5499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/30/2015] [Indexed: 12/30/2022] Open
Abstract
The clinical prognosis of patients with glioma is determined by tumor grades, but tumors of different subtypes with equal malignancy grade usually have different prognosis that is largely determined by genetic abnormalities. Oligodendrogliomas (ODs) are the second most common type of gliomas. In this study, integrative analyses found that distribution of TCGA transcriptomic subtypes was associated with grade progression in ODs. To identify critical gene(s) associated with tumor grades and TCGA subtypes, we analyzed 34 normal brain tissue (NBT), 146 WHO grade II and 130 grade III ODs by microarray and RNA sequencing, and identified a co-expression network of six genes (AURKA, NDC80, CENPK, KIAA0101, TIMELESS and MELK) that was associated with tumor grades and TCGA subtypes as well as Ki-67 expression. Validation of the six genes was performed by qPCR in additional 28 ODs. Importantly, these genes also were validated in four high-grade recurrent gliomas and the initial lower-grade gliomas resected from the same patients. Finally, the RNA data on two genes with the highest discrimination potential (AURKA and NDC80) and Ki-67 were validated on an independent cohort (5 NBTs and 86 ODs) by immunohistochemistry. Knockdown of AURKA and NDC80 by siRNAs suppressed Ki-67 expression and proliferation of gliomas cells. Survival analysis showed that high expression of the six genes corporately indicated a poor survival outcome. Correlation and protein interaction analysis provided further evidence for this co-expression network. These data suggest that the co-expression of the six mitosis-regulating genes was associated with malignant progression and prognosis in ODs.
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Affiliation(s)
- Yanwei Liu
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China
| | - Huimin Hu
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China
| | - Chuanbao Zhang
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China
| | - Haoyuan Wang
- Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Wenlong Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zheng Wang
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China
| | - Mingyang Li
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China
| | - Wei Zhang
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China.,National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Dabiao Zhou
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China
| | - Tao Jiang
- Department of Molecular Neuropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Brain Tumor Center, Beijing Institute for Brain Disorders, Beijing, China.,Chinese Glioma Cooperative Group (CGCG), China.,National Clinical Research Center for Neurological Diseases, Beijing, China
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11
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Luo Y, Ji X, Liu J, Li Z, Wang W, Chen W, Wang J, Liu Q, Zhang X. Moderate intensity static magnetic fields affect mitotic spindles and increase the antitumor efficacy of 5-FU and Taxol. Bioelectrochemistry 2016; 109:31-40. [DOI: 10.1016/j.bioelechem.2016.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 12/31/2015] [Accepted: 01/01/2016] [Indexed: 11/30/2022]
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12
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Li C, Zhang Y, Yang Q, Ye F, Sun SY, Chen ES, Liou YC. NuSAP modulates the dynamics of kinetochore microtubules by attenuating MCAK depolymerisation activity. Sci Rep 2016; 6:18773. [PMID: 26733216 PMCID: PMC4702128 DOI: 10.1038/srep18773] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 11/26/2015] [Indexed: 11/15/2022] Open
Abstract
Nucleolar and spindle-associated protein (NuSAP) is a microtubule-associated protein that functions as a microtubule stabiliser. Depletion of NuSAP leads to severe mitotic defects, however the mechanism by which NuSAP regulates mitosis remains elusive. In this study, we identify the microtubule depolymeriser, mitotic centromere-associated kinesin (MCAK), as a novel binding partner of NuSAP. We show that NuSAP regulates the dynamics and depolymerisation activity of MCAK. Phosphorylation of MCAK by Aurora B kinase, a component of the chromosomal passenger complex, significantly enhances the interaction of NuSAP with MCAK and modulates the effects of NuSAP on the depolymerisation activity of MCAK. Our results reveal an underlying mechanism by which NuSAP controls kinetochore microtubule dynamics spatially and temporally by modulating the depolymerisation function of MCAK in an Aurora B kinase-dependent manner. Hence, this study provides new insights into the function of NuSAP in spindle formation during mitosis.
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Affiliation(s)
- Chenyu Li
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, 117543, Republic of Singapore
| | - Yajun Zhang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, 117543, Republic of Singapore
| | - Qiaoyun Yang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, 117543, Republic of Singapore
| | - Fan Ye
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, 117543, Republic of Singapore
| | - Stella Ying Sun
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, 117543, Republic of Singapore
| | - Ee Sin Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Republic of Singapore
| | - Yih-Cherng Liou
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, 117543, Republic of Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117573, Republic of Singapore
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13
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Chen CT, Kelly M, Leon JD, Nwagbara B, Ebbert P, Ferguson DJP, Lowery LA, Morrissette N, Gubbels MJ. Compartmentalized Toxoplasma EB1 bundles spindle microtubules to secure accurate chromosome segregation. Mol Biol Cell 2015; 26:4562-76. [PMID: 26466679 PMCID: PMC4678015 DOI: 10.1091/mbc.e15-06-0437] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/02/2015] [Indexed: 11/11/2022] Open
Abstract
The opportunistic apicomplexan parasite Toxoplasma gondii divides by intertwined closed mitosis and internal budding. Centrosome positioning and MT acetylation control spindle dynamics, and the MT-associated protein TgEB1 residing in the nucleus contributes to mitotic fidelity by bundling the spindle MTs. Toxoplasma gondii replicates asexually by a unique internal budding process characterized by interwoven closed mitosis and cytokinesis. Although it is known that the centrosome coordinates these processes, the spatiotemporal organization of mitosis remains poorly defined. Here we demonstrate that centrosome positioning around the nucleus may signal spindle assembly: spindle microtubules (MTs) are first assembled when the centrosome moves to the basal side and become extensively acetylated after the duplicated centrosomes reposition to the apical side. We also tracked the spindle MTs using the MT plus end–binding protein TgEB1. Endowed by a C-terminal NLS, TgEB1 resides in the nucleoplasm in interphase and associates with the spindle MTs during mitosis. TgEB1 also associates with the subpellicular MTs at the growing end of daughter buds toward the completion of karyokinesis. Depletion of TgEB1 results in escalated disintegration of kinetochore clustering. Furthermore, we show that TgEB1’s MT association in Toxoplasma and in a heterologous system (Xenopus) is based on the same principles. Finally, overexpression of a high-MT-affinity TgEB1 mutant promotes the formation of overstabilized MT bundles, resulting in avulsion of otherwise tightly clustered kinetochores. Overall we conclude that centrosome position controls spindle activity and that TgEB1 is critical for mitotic integrity.
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Affiliation(s)
- Chun-Ti Chen
- Department of Biology, Boston College, Chestnut Hill, MA 02467
| | - Megan Kelly
- Department of Biology, Boston College, Chestnut Hill, MA 02467
| | - Jessica de Leon
- Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697
| | | | - Patrick Ebbert
- Department of Biology, Boston College, Chestnut Hill, MA 02467
| | - David J P Ferguson
- Nuffield Department of Clinical Laboratory Science, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | | | - Naomi Morrissette
- Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697
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14
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Sutradhar S, Basu S, Paul R. Intercentrosomal angular separation during mitosis plays a crucial role for maintaining spindle stability. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:042714. [PMID: 26565279 DOI: 10.1103/physreve.92.042714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Indexed: 06/05/2023]
Abstract
Cell division through proper spindle formation is one of the key puzzles in cell biology. In most mammalian cells, chromosomes spontaneously arrange to achieve a stable bipolar spindle during metaphase which eventually ensures proper segregation of the DNA into the daughter cells. In this paper, we present a robust three-dimensional mechanistic model to investigate the formation and maintenance of a bipolar mitotic spindle in mammalian cells under different physiological constraints. Using realistic parameters, we test spindle viability by measuring the spindle length and studying the chromosomal configuration. The model strikingly predicts a feature of the spindle instability arising from the insufficient intercentrosomal angular separation and impaired sliding of the interpolar microtubules. In addition, our model successfully reproduces chromosomal patterns observed in mammalian cells, when activity of different motor proteins is perturbed.
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Affiliation(s)
- S Sutradhar
- Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - S Basu
- Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - R Paul
- Indian Association for the Cultivation of Science, Kolkata 700032, India
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15
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Surana U, Liang H, Lim HH. Staging a recovery from mitotic arrest: Unusual ways of Cdk1. BIOARCHITECTURE 2014; 2:33-37. [PMID: 22754627 PMCID: PMC3383719 DOI: 10.4161/bioa.20421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Checkpoint controls, the surveillance pathways that impose "an order of execution" on the major cell cycle events, are critical to the maintenance of genome stability. When cells fail to execute a cellular event or do so erroneously due to misregulation or exposure to genotoxic stresses, these evolutionarily conserved regulatory circuits prevent passage to the subsequent event, thus bringing the cell cycle to a halt. Once the checkpoint stimulus is removed, cells recover from the arrest and eventually resume cell cycle progression. While the activation, execution and maintenance, the three major aspects of the checkpoint controls, have been investigated in detail, the recovery process remains underexplored. It is not clear if cells recover passively upon dissipation of the checkpoint signals or require an active participation by specific effectors. A recent study in the yeast Saccharomyces cerevisiae uncovered two previously unsuspected functions of Cdk1 in efficient recovery from the spindle assembly checkpoint (SAC) imposed arrest. An inability to fulfil these requirements in the absence of Cdk1 makes it virtually impossible for cells to recover from the mitotic arrest. Given the conserved nature of the SAC, these findings may have implications for vertebrate cells.
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Affiliation(s)
- Uttam Surana
- Institute of Molecular and Cell Biology; Proteos, Singapore
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16
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Yun Y, Holt JE, Lane SIR, McLaughlin EA, Merriman JA, Jones KT. Reduced ability to recover from spindle disruption and loss of kinetochore spindle assembly checkpoint proteins in oocytes from aged mice. Cell Cycle 2014; 13:1938-47. [PMID: 24758999 DOI: 10.4161/cc.28897] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Currently, maternal aging in women, based on mouse models, is thought to raise oocyte aneuploidy rates, because chromosome cohesion deteriorates during prophase arrest, and Sgo2, a protector of centromeric cohesion, is lost. Here we show that the most common mouse strain, C57Bl6/J, is resistant to maternal aging, showing little increase in aneuploidy or Sgo2 loss. Instead it demonstrates significant kinetochore-associated loss in the spindle assembly checkpoint protein Mad2 and phosphorylated Aurora C, which is involved in microtubule-kinetochore error correction. Their loss affects the fidelity of bivalent segregation but only when spindle organization is impaired during oocyte maturation. These findings have an impact clinically regarding the handling of human oocytes ex vivo during assisted reproductive techniques and suggest there is a genetic basis to aneuploidy susceptibility.
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Affiliation(s)
- Yan Yun
- School of Biomedical Sciences & Pharmacy; University of Newcastle; Callaghan, NSW, Australia
| | - Janet E Holt
- School of Biomedical Sciences & Pharmacy; University of Newcastle; Callaghan, NSW, Australia
| | - Simon I R Lane
- School of Biomedical Sciences & Pharmacy; University of Newcastle; Callaghan, NSW, Australia; Centre for Biological Sciences; Faculty of Natural and Environmental Sciences; University of Southampton; Southampton, UK
| | - Eileen A McLaughlin
- School of Environmental and Life Sciences; University of Newcastle; Callaghan, NSW, Australia
| | - Julie A Merriman
- School of Biomedical Sciences & Pharmacy; University of Newcastle; Callaghan, NSW, Australia; Centre for Biological Sciences; Faculty of Natural and Environmental Sciences; University of Southampton; Southampton, UK
| | - Keith T Jones
- School of Biomedical Sciences & Pharmacy; University of Newcastle; Callaghan, NSW, Australia; Centre for Biological Sciences; Faculty of Natural and Environmental Sciences; University of Southampton; Southampton, UK
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17
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Hec1 inhibition alters spindle morphology and chromosome alignment in porcine oocytes. Mol Biol Rep 2014; 41:5089-95. [DOI: 10.1007/s11033-014-3374-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
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18
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Verma SC, Cai Q, Kreider E, Lu J, Robertson ES. Comprehensive analysis of LANA interacting proteins essential for viral genome tethering and persistence. PLoS One 2013; 8:e74662. [PMID: 24040311 PMCID: PMC3770571 DOI: 10.1371/journal.pone.0074662] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 08/05/2013] [Indexed: 12/12/2022] Open
Abstract
Kaposi’s sarcoma associated herpesvirus is tightly linked to multiple human malignancies including Kaposi’s sarcoma (KS), Primary Effusion Lymphoma (PEL) and Multicentric Castleman’s Disease (MCD). KSHV like other herpesviruses establishes life-long latency in the infected host by persisting as chromatin and tethering to host chromatin through the virally encoded protein Latency Associated Nuclear Antigen (LANA). LANA, a multifunctional protein, is capable of binding to a large number of cellular proteins responsible for transcriptional regulation of various cellular and viral pathways involved in blocking cell death and promoting cell proliferation. This leads to enhanced cell division and replication of the viral genome, which segregates faithfully in the dividing tumor cells. The mechanism of genome segregation is well known and the binding of LANA to nucleosomal proteins, throughout the cell cycle, suggests that these interactions play an important role in efficient segregation. Various biochemical methods have identified a large number of LANA binding proteins, including histone H2A/H2B, histone H1, MeCP2, DEK, CENP-F, NuMA, Bub1, HP-1, and Brd4. These nucleosomal proteins may have various functions in tethering of the viral genome during specific phases of the viral life cycle. Therefore, we performed a comprehensive analysis of their interaction with LANA using a number of different assays. We show that LANA binds to core nucleosomal histones and also associates with other host chromatin proteins including histone H1 and high mobility group proteins (HMGs). We used various biochemical assays including co-immunoprecipitation and in-vivo localization by split GFP and fluorescence resonance energy transfer (FRET) to demonstrate their association.
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Affiliation(s)
- Subhash C. Verma
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno, Nevada, United States of America
- * E-mail: (ESR); (SCV)
| | - Qiliang Cai
- MOE& MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine of Fudan University, Shanghai, China
| | - Edward Kreider
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jie Lu
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Erle S. Robertson
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (ESR); (SCV)
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19
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Coupling unbiased mutagenesis to high-throughput DNA sequencing uncovers functional domains in the Ndc80 kinetochore protein of Saccharomyces cerevisiae. Genetics 2013; 195:159-70. [PMID: 23833183 DOI: 10.1534/genetics.113.152728] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
During mitosis, kinetochores physically link chromosomes to the dynamic ends of spindle microtubules. This linkage depends on the Ndc80 complex, a conserved and essential microtubule-binding component of the kinetochore. As a member of the complex, the Ndc80 protein forms microtubule attachments through a calponin homology domain. Ndc80 is also required for recruiting other components to the kinetochore and responding to mitotic regulatory signals. While the calponin homology domain has been the focus of biochemical and structural characterization, the function of the remainder of Ndc80 is poorly understood. Here, we utilized a new approach that couples high-throughput sequencing to a saturating linker-scanning mutagenesis screen in Saccharomyces cerevisiae. We identified domains in previously uncharacterized regions of Ndc80 that are essential for its function in vivo. We show that a helical hairpin adjacent to the calponin homology domain influences microtubule binding by the complex. Furthermore, a mutation in this hairpin abolishes the ability of the Dam1 complex to strengthen microtubule attachments made by the Ndc80 complex. Finally, we defined a C-terminal segment of Ndc80 required for tetramerization of the Ndc80 complex in vivo. This unbiased mutagenesis approach can be generally applied to genes in S. cerevisiae to identify functional properties and domains.
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20
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Microtubule attachment and spindle assembly checkpoint signalling at the kinetochore. Nat Rev Mol Cell Biol 2013; 14:25-37. [PMID: 23258294 DOI: 10.1038/nrm3494] [Citation(s) in RCA: 473] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In eukaryotes, chromosome segregation during cell division is facilitated by the kinetochore, a multiprotein structure that is assembled on centromeric DNA. The kinetochore attaches chromosomes to spindle microtubules, modulates the stability of these attachments and relays the microtubule-binding status to the spindle assembly checkpoint (SAC), a cell cycle surveillance pathway that delays chromosome segregation in response to unattached kinetochores. Recent studies are shaping current thinking on how each of these kinetochore-centred processes is achieved, and how their integration ensures faithful chromosome segregation, focusing on the essential roles of kinase-phosphatase signalling and the microtubule-binding KMN protein network.
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21
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Fiorentino FP, Marchesi I, Giordano A. On the role of retinoblastoma family proteins in the establishment and maintenance of the epigenetic landscape. J Cell Physiol 2013; 228:276-84. [PMID: 22718354 DOI: 10.1002/jcp.24141] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RB family members are negative regulators of the cell cycle, involved in numerous biological processes such as cellular senescence, development and differentiation. Disruption of RB family pathways are linked to loss of cell cycle control, cellular immortalization and cancer. RB family, and in particular the most studied member RB/p105, has been considered a tumor suppressor gene by more than three decades, and numerous efforts have been done to understand his molecular activity. However, the epigenetic mechanisms behind Rb-mediated tumor suppression have been uncovered only in recent years. In this review, the role of RB family members in cancer epigenetics will be discussed. We start with an introduction to epigenomes, chromatin modifications and cancer epigenetics. In order to provide a clear picture of the involvement of RB family in the epigenetic field, we describe the RB family role in the epigenetic landscape dynamics based on the heterochromatin variety involved, facultative or constitutive. We want to stress that, despite dissimilar modulations, RB family is involved in both mammalian varieties of heterochromatin establishment and maintenance and that disruption of RB family pathways drives to alterations of both heterochromatin structures, thus to the global epigenetic landscape.
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Affiliation(s)
- Francesco Paolo Fiorentino
- Department of Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA.
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22
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The Ndc80 kinetochore complex directly modulates microtubule dynamics. Proc Natl Acad Sci U S A 2012; 109:16113-8. [PMID: 22908300 DOI: 10.1073/pnas.1209615109] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The conserved Ndc80 complex is an essential microtubule-binding component of the kinetochore. Recent findings suggest that the Ndc80 complex influences microtubule dynamics at kinetochores in vivo. However, it was unclear if the Ndc80 complex mediates these effects directly, or by affecting other factors localized at the kinetochore. Using a reconstituted system in vitro, we show that the human Ndc80 complex directly stabilizes the tips of disassembling microtubules and promotes rescue (the transition from microtubule shortening to growth). In vivo, an N-terminal domain in the Ndc80 complex is phosphorylated by the Aurora B kinase. Mutations that mimic phosphorylation of the Ndc80 complex prevent stable kinetochore-microtubule attachment, and mutations that block phosphorylation damp kinetochore oscillations. We find that the Ndc80 complex with Aurora B phosphomimetic mutations is defective at promoting microtubule rescue, even when robustly coupled to disassembling microtubule tips. This impaired ability to affect dynamics is not simply because of weakened microtubule binding, as an N-terminally truncated complex with similar binding affinity is able to promote rescue. Taken together, these results suggest that in addition to regulating attachment stability, Aurora B controls microtubule dynamics through phosphorylation of the Ndc80 complex.
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23
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Wang Y, Zhang X, Zhang H, Lu Y, Huang H, Dong X, Chen J, Dong J, Yang X, Hang H, Jiang T. Coiled-coil networking shapes cell molecular machinery. Mol Biol Cell 2012; 23:3911-22. [PMID: 22875988 PMCID: PMC3459866 DOI: 10.1091/mbc.e12-05-0396] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Coiled coil is a principal oligomerization motif. A comprehensive map of coiled-coil interactions (CCIs) in yeast is reported. Computational analysis reveals that CCIs are extensively involved in cell machinery organization. Disrupting the CCIs in the kinetochore leads to defects in kinetochore assembly and cell division. The highly abundant α-helical coiled-coil motif not only mediates crucial protein–protein interactions in the cell but is also an attractive scaffold in synthetic biology and material science and a potential target for disease intervention. Therefore a systematic understanding of the coiled-coil interactions (CCIs) at the organismal level would help unravel the full spectrum of the biological function of this interaction motif and facilitate its application in therapeutics. We report the first identified genome-wide CCI network in Saccharomyces cerevisiae, which consists of 3495 pair-wise interactions among 598 predicted coiled-coil regions. Computational analysis revealed that the CCI network is specifically and functionally organized and extensively involved in the organization of cell machinery. We further show that CCIs play a critical role in the assembly of the kinetochore, and disruption of the CCI network leads to defects in kinetochore assembly and cell division. The CCI network identified in this study is a valuable resource for systematic characterization of coiled coils in the shaping and regulation of a host of cellular machineries and provides a basis for the utilization of coiled coils as domain-based probes for network perturbation and pharmacological applications.
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Affiliation(s)
- Yongqiang Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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24
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Rivera T, Ghenoiu C, Rodríguez-Corsino M, Mochida S, Funabiki H, Losada A. Xenopus Shugoshin 2 regulates the spindle assembly pathway mediated by the chromosomal passenger complex. EMBO J 2012; 31:1467-79. [PMID: 22274615 PMCID: PMC3321187 DOI: 10.1038/emboj.2012.4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 12/22/2011] [Indexed: 12/13/2022] Open
Abstract
Shugoshins (Sgo) are conserved proteins that act as protectors of centromeric cohesion and as sensors of tension for the machinery that eliminates improper kinetochore-microtubule attachments. Most vertebrates contain two Sgo proteins, but their specific functions are not always clear. Xenopus laevis Sgo1, XSgo1, protects centromeric cohesin from the prophase dissociation pathway. Here, we report the identification of XSgo2 and show that it does not regulate cohesion. Instead, we find that it participates in bipolar spindle assembly. Both Sgo proteins interact physically with the Chromosomal Passenger Complex (CPC) containing Aurora B, a key regulator of mitosis, but the functional consequences of such interaction are distinct. XSgo1 is required for proper localization of the CPC while XSgo2 positively contributes to its activation and the subsequent phosphorylation of at least one key substrate for bipolar spindle assembly, the microtubule depolymerizing kinesin MCAK (Mitotic Centromere-Associated Kinesin). Thus, the two Xenopus Sgo proteins have non-overlapping functions in chromosome segregation. Our results further suggest that this functional specificity could rely on the association of XSgo1 and XSgo2 with different regulatory subunits of the PP2A complex.
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Affiliation(s)
- Teresa Rivera
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Cristina Ghenoiu
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY, USA
- Department of Molecular Biology, Weill Cornell Graduate School of Biomedical Sciences, Cornell Medical School, New York, NY, USA
| | - Miriam Rodríguez-Corsino
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Satoru Mochida
- Cell Cycle Control Group, Kumamoto University, Kumamoto City, Japan
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Ana Losada
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
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25
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Cdk1 promotes kinetochore bi-orientation and regulates Cdc20 expression during recovery from spindle checkpoint arrest. EMBO J 2011; 31:403-16. [PMID: 22056777 DOI: 10.1038/emboj.2011.385] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 10/02/2011] [Indexed: 11/08/2022] Open
Abstract
The spindle assembly checkpoint (SAC), an evolutionarily conserved surveillance pathway, prevents chromosome segregation in response to conditions that disrupt the kinetochore-microtubule attachment. Removal of the checkpoint-activating stimulus initiates recovery during which spindle integrity is restored, kinetochores become bi-oriented, and cells initiate anaphase. Whether recovery ensues passively after the removal of checkpoint stimulus, or requires mediation by specific effectors remains uncertain. Here, we report two unrecognized functions of yeast Cdk1 required for efficient recovery from SAC-induced arrest. We show that Cdk1 promotes kinetochore bi-orientation during recovery by restraining premature spindle elongation thereby extinguishing SAC signalling. Moreover, Cdk1 is essential for sustaining the expression of Cdc20, an activator of the anaphase promoting complex/cyclosome (APC/C) required for anaphase progression. We suggest a model in which Cdk1 activity promotes recovery from SAC-induced mitotic arrest by regulating bi-orientation and APC/C activity. Our findings provide fresh insights into the regulation of mitosis and have implications for the therapeutic efficacy of anti-mitotic drugs.
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26
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Abstract
The Ndc80 complex lies at the heart of the kinetochore, a large protein machine that accurately segregates chromosomes during cell division. The Ndc80 complex has structural roles in assembling the kinetochore, but also functions to congress chromosomes and to signal the spindle checkpoint. It directly binds to microtubules and is currently the best candidate for the long-sought protein that couples microtubule depolymerization to chromosome movement. A combination of structural and genetic data has recently converged to generate the first models for this fascinating motor activity. Additionally, recent data point to an increasingly dynamic role for Ndc80 in the kinetochore-one which involves not only simple binding to microtubules but also shifts in complex shape and its location within the overall kinetochore structure. In this review, we discuss recent advances in our understanding of the Ndc80 complex and address future areas of research.
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27
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Sun SC, Zhang DX, Lee SE, Xu YN, Kim NH. Ndc80 regulates meiotic spindle organization, chromosome alignment, and cell cycle progression in mouse oocytes. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2011; 17:431-439. [PMID: 21600073 DOI: 10.1017/s1431927611000274] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Ndc80 (called Hec1 in human), the core component of the Ndc80 complex, is involved in regulation of both kinetochore-microtubule interactions and the spindle assembly checkpoint in mitosis; however, its role in meiosis remains unclear. Here, we report Ndc80 expression, localization, and possible functions in mouse oocyte meiosis. Ndc80 mRNA levels gradually increased during meiosis. Immunofluorescent staining showed that Ndc80 was restricted to the germinal vesicle and associated with spindle microtubules from the Pro-MI to MII stages. Ndc80 was localized on microtubules and asters in the cytoplasm after taxol treatment, while Ndc80 staining was diffuse after disruption of microtubules by nocodazole treatment, confirming its microtubule localization. Disruption of Ndc80 function by either siRNA injection or antibody injection resulted in severe chromosome misalignment, spindle disruption, and precocious polar body extrusion. Our data show a unique localization pattern of Ndc80 in mouse oocytes and suggest that Ndc80 may be required for chromosome alignment and spindle organization, and may regulate spindle checkpoint activity during mouse oocyte meiosis.
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Affiliation(s)
- Shao-Chen Sun
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Korea
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28
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Kajstura J, Hosoda T, Bearzi C, Rota M, Maestroni S, Urbanek K, Leri A, Anversa P. The human heart: a self-renewing organ. Clin Transl Sci 2010; 1:80-6. [PMID: 20443822 DOI: 10.1111/j.1752-8062.2008.00030.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The dogma that the heart is a static organ which contains an irreplaceable population of cardiomyocytes prevailed in the cardiovascular field for the last several decades. However, the recent identification of progenitor cells that give rise to differentiated myocytes has prompted a re-interpretation of cardiac biology. The heart cannot be viewed any longer as a postmitotic organ characterized by a predetermined number of myocytes that is defined at birth and is preserved throughout life. The myocardium constitutes a dynamic entity in which new young parenchymal cells are formed to substitute old damaged dying myocytes. The regenerative ability of the heart was initially documented with a classic morphometric approach and more recently with the demonstration that DNA synthesis, mitosis, and cytokinesis take place in the newly formed myocytes of the normal and pathologic heart. Importantly, replicating myocytes correspond to the differentiated progeny of cardiac stem cells. These findings point to the possibility of novel therapeutic strategies for the diseased heart.
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Affiliation(s)
- Jan Kajstura
- Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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Asbury CL, Tien JF, Davis TN. Kinetochores' gripping feat: conformational wave or biased diffusion? Trends Cell Biol 2010; 21:38-46. [PMID: 20951587 DOI: 10.1016/j.tcb.2010.09.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/01/2010] [Accepted: 09/07/2010] [Indexed: 12/30/2022]
Abstract
Climbing up a cliff while the rope unravels underneath your fingers does not sound like a well-planned adventure. Yet chromosomes face a similar challenge during each cell division. Their alignment and accurate segregation depends on staying attached to the assembling and disassembling tips of microtubule fibers. This coupling is mediated by kinetochores, intricate machines that attach chromosomes to an ever-changing microtubule substrate. Two models for kinetochore-microtubule coupling were proposed a quarter century ago: conformational wave and biased diffusion. These models differ in their predictions for how coupling is performed and regulated. The availability of purified kinetochore proteins has enabled biochemical and biophysical analyses of the kinetochore-microtubule interface. Here, we discuss what these studies reveal about the contributions of each model.
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Affiliation(s)
- Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA.
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Abstract
Non-essential extra-chromosomal DNA elements such as plasmids are responsible for their own propagation in dividing host cells, and one means to ensure this is to carry a miniature active segregation system reminiscent of the mitotic spindle. Plasmids that are maintained at low numbers in prokaryotic cells have developed a range of such active partitioning systems, which are characterized by an impressive simplicity and efficiency and which are united by the use of dynamic, nucleotide-driven filaments to separate and position DNA molecules. A comparison of different plasmid segregation systems reveals (i) how unrelated filament-forming and DNA-binding proteins have been adopted and modified to create a range of simple DNA segregating complexes and (ii) how subtle changes in the few components of these DNA segregation machines has led to a remarkable diversity in the molecular mechanisms of closely related segregation systems. Here, our current understanding of plasmid segregation systems is reviewed and compared with other DNA segregation systems, and this is extended by a discussion of basic principles of plasmid segregation systems, evolutionary implications and the relationship between an autonomous DNA element and its host cell.
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Affiliation(s)
- Jeanne Salje
- MRC Laboratory of Molecular Biology, Cambridge, UK.
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Bub1 and CENP-F can contribute to Kaposi's sarcoma-associated herpesvirus genome persistence by targeting LANA to kinetochores. J Virol 2010; 84:9718-32. [PMID: 20660191 DOI: 10.1128/jvi.00713-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The latency-associated nuclear antigen (LANA) encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) is critical for segregation of viral episomes to progeny nuclei and allows for maintenance of the viral genome in newly divided daughter cells. LANA binds to KSHV terminal repeat (TR) DNA and simultaneously associates with chromatin-bound cellular proteins. This process tethers the viral episomes to host chromosomes. However, the mechanism of tethering is complex and involves multiple protein-protein interactions. Our previous proteomics studies which showed the association of LANA with centromeric protein F (CENP-F) prompted us to further study whether LANA targets centromeric proteins for persistence of KSHV episomes during cell division. Here we show that LANA colocalized with CENP-F as speckles, some of which are paired at centromeric regions of a subset of chromosomes in KSHV-infected JSC-1 cells. We also confirm that both the amino and carboxy termini of LANA can bind to CENP-F. Moreover, LANA associated with another kinetochore protein, Bub1 (budding uninhibited by benzimidazole 1), which is known to form a complex with CENP-F. Importantly, we demonstrated the dynamic association of LANA and Bub1/CENP-F and the colocalization between Bub1, LANA, and the KSHV episome tethered to the host chromosome using fluorescence in situ hybridization (FISH). Knockdown of Bub1 expression by lentivirus-delivered short hairpin RNA (shRNA) dramatically reduced the number of KSHV genome copies, whereas no dramatic effect was seen with CENP-F knockdown. Therefore, the interaction between LANA and the kinetochore proteins CENP-F and Bub1 is important for KSHV genome tethering and its segregation to new daughter cells, with Bub1 potentially playing a more critical role in the long-term persistence of the viral genome in the infected cell.
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Tien JF, Umbreit NT, Gestaut DR, Franck AD, Cooper J, Wordeman L, Gonen T, Asbury CL, Davis TN. Cooperation of the Dam1 and Ndc80 kinetochore complexes enhances microtubule coupling and is regulated by aurora B. J Cell Biol 2010; 189:713-23. [PMID: 20479468 PMCID: PMC2872917 DOI: 10.1083/jcb.200910142] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 04/02/2010] [Indexed: 01/27/2023] Open
Abstract
The coupling of kinetochores to dynamic spindle microtubules is crucial for chromosome positioning and segregation, error correction, and cell cycle progression. How these fundamental attachments are made and persist under tensile forces from the spindle remain important questions. As microtubule-binding elements, the budding yeast Ndc80 and Dam1 kinetochore complexes are essential and not redundant, but their distinct contributions are unknown. In this study, we show that the Dam1 complex is a processivity factor for the Ndc80 complex, enhancing the ability of the Ndc80 complex to form load-bearing attachments to and track with dynamic microtubule tips in vitro. Moreover, the interaction between the Ndc80 and Dam1 complexes is abolished when the Dam1 complex is phosphorylated by the yeast aurora B kinase Ipl1. This provides evidence for a mechanism by which aurora B resets aberrant kinetochore-microtubule attachments. We propose that the action of the Dam1 complex as a processivity factor in kinetochore-microtubule attachment is regulated by conserved signals for error correction.
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Affiliation(s)
- Jerry F. Tien
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Neil T. Umbreit
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Daniel R. Gestaut
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Andrew D. Franck
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Jeremy Cooper
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Linda Wordeman
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Tamir Gonen
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Charles L. Asbury
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Trisha N. Davis
- Department of Biochemistry, Department of Physiology and Biophysics, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
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DNA binding of centromere protein C (CENPC) is stabilized by single-stranded RNA. PLoS Genet 2010; 6:e1000835. [PMID: 20140237 PMCID: PMC2816676 DOI: 10.1371/journal.pgen.1000835] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 01/04/2010] [Indexed: 11/19/2022] Open
Abstract
Centromeres are the attachment points between the genome and the cytoskeleton: centromeres bind to kinetochores, which in turn bind to spindles and move chromosomes. Paradoxically, the DNA sequence of centromeres has little or no role in perpetuating kinetochores. As such they are striking examples of genetic information being transmitted in a manner that is independent of DNA sequence (epigenetically). It has been found that RNA transcribed from centromeres remains bound within the kinetochore region, and this local population of RNA is thought to be part of the epigenetic marking system. Here we carried out a genetic and biochemical study of maize CENPC, a key inner kinetochore protein. We show that DNA binding is conferred by a localized region 122 amino acids long, and that the DNA-binding reaction is exquisitely sensitive to single-stranded RNA. Long, single-stranded nucleic acids strongly promote the binding of CENPC to DNA, and the types of RNAs that stabilize DNA binding match in size and character the RNAs present on kinetochores in vivo. Removal or replacement of the binding module with HIV integrase binding domain causes a partial delocalization of CENPC in vivo. The data suggest that centromeric RNA helps to recruit CENPC to the inner kinetochore by altering its DNA binding characteristics. Here we address the issue of how genetic information is passed from one generation to the next without the involvement of specific DNA sequences. This type of inheritance is referred to as epigenetics. Centromeric sequences are highly variable and in many cases are not sufficient for centromere function. Rather, secondary features of the DNA, such as methylation or associated RNA molecules may serve to recruit key centromere binding proteins. Prior data from several species have established that single-stranded RNAs are surprisingly abundant on centromeric chromatin. Here we identified the DNA-binding domain of a key centromere binding protein in maize (CENPC) and showed that it requires single-stranded RNA to effectively bind DNA in vitro. When the DNA/RNA binding domain was deleted, the accuracy of CENPC targeting to centromeres was reduced but not abolished. The results bolster the view that centromere-bound RNA is one component of the epigenetic determination process that assures centromeres are stably inherited. In addition, our data suggest a general mechanism for how RNA can influence the binding of chromatin proteins to DNA.
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Matsson L. Spindle checkpoint regulated by nonequilibrium collective spindle-chromosome interaction; relationship to single DNA molecule force-extension formula. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:502101. [PMID: 21836210 DOI: 10.1088/0953-8984/21/50/502101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The spindle checkpoint, which blocks segregation until all sister chromatid pairs have been stably connected to the two spindle poles, is perhaps the biggest mystery of the cell cycle. The main reason seems to be that the spatial correlations imposed by microtubules between stably attached kinetochores and the nonlinear dependence of the system on the increasing number of such kinetochores have been disregarded in earlier spindle checkpoint studies. From these missing parts a non-equilibrium collective spindle-chromosome interaction is obtained here for budding yeast (Saccharomyces cerevisiae) cells. The interaction, which is based on a non-equilibrium statistical mechanics, can sense and count the number of stably attached kinetochores and sense the threshold for segregation. It blocks segregation until all sister chromatids pairs have been bi-oriented and regulates tension such that segregation becomes synchronized, thus explaining how the cell might decide to segregate replicated chromosomes. The model also predicts kinetochore oscillations at a frequency which agrees well with observation. Finally, a relationship between this spindle-chromosome dynamics and the force-extension formula obtained in a single DNA molecule experiment is obtained.
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Affiliation(s)
- Leif Matsson
- Department of Physics, University of Gothenburg, SE-412 96 Göteborg, Sweden
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Wu G, Wei R, Cheng E, Ngo B, Lee WH. Hec1 contributes to mitotic centrosomal microtubule growth for proper spindle assembly through interaction with Hice1. Mol Biol Cell 2009; 20:4686-95. [PMID: 19776357 DOI: 10.1091/mbc.e08-11-1123] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Previous studies have stipulated Hec1 as a conserved kinetochore component critical for mitotic control in part by directly binding to kinetochore fibers of the mitotic spindle and by recruiting spindle assembly checkpoint proteins Mad1 and Mad2. Hec1 has also been reported to localize to centrosomes, but its function there has yet to be elucidated. Here, we show that Hec1 specifically colocalizes with Hice1, a previously characterized centrosomal microtubule-binding protein, at the spindle pole region during mitosis. In addition, the C-terminal region of Hec1 directly binds to the coiled-coil domain 1 of Hice1. Depletion of Hice1 by small interfering RNA (siRNA) reduced levels of Hec1 in the cell, preferentially at centrosomes and spindle pole vicinity. Reduction of de novo microtubule nucleation from mitotic centrosomes can be observed in cells treated with Hec1 or Hice1 siRNA. Consistently, neutralization of Hec1 or Hice1 by specific antibodies impaired microtubule aster formation from purified mitotic centrosomes in vitro. Last, disruption of the Hec1/Hice1 interaction by overexpressing Hice1DeltaCoil1, a mutant defective in Hec1 interaction, elicited abnormal spindle morphology often detected in Hec1 and Hice1 deficient cells. Together, the results suggest that Hec1, through cooperation with Hice1, contributes to centrosome-directed microtubule growth to facilitate establishing a proper mitotic spindle.
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Affiliation(s)
- Guikai Wu
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
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Cheung CHA, Coumar MS, Hsieh HP, Chang JY. Aurora kinase inhibitors in preclinical and clinical testing. Expert Opin Investig Drugs 2009; 18:379-98. [PMID: 19335272 DOI: 10.1517/13543780902806392] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Mitosis is a key step in the cell cycle governing the distribution of genetic material to the daughter cells. Any aberration in this process could lead to genomic instability. Aurora A, B and C, are members of the serine/threonine kinase family. Aurora kinases are essential for spindle assembly, centrosome maturation, chromosomal segregation and cytokinesis during mitosis. Abnormalities in the mitotic process through overexpression/amplification of aurora kinase have been linked to genomic instability leading to tumorigenesis. Hence, use of aurora kinase small molecule inhibitors as potential molecular-targeted therapeutic intervention for cancer is being pursued by various researchers. OBJECTIVE To review the literature of aurora kinase inhibitors in clinical and preclinical testing. METHOD Pubmed, Scifinder and (www.clinicaltrials.gov) databases were used to search the literature for aurora kinase. CONCLUSION/RESULTS: Approximately 13 aurora kinase inhibitors are under Phase I/II evaluation at present for various cancers of different origins; and several others are in preclinical testing. Details of their preclinical/clinical results and important considerations for future aurora kinase inhibitor development are discussed. Considering the fact that aurora kinase plays an important role in the mitosis process and is involved in tumorigenesis, development of aurora kinase inhibitors for the treatment of cancer, either as a single agent or in combination with existing cancer treatment is warranted.
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CENP-K and CENP-H may form coiled-coils in the kinetochores. ACTA ACUST UNITED AC 2009; 52:352-9. [PMID: 19381461 DOI: 10.1007/s11427-009-0050-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 12/01/2008] [Indexed: 10/20/2022]
Abstract
Kinetochores are large proteinaceous structure on the surface of chromosomes' primary constriction during mitosis. They link chromosomes to spindle microtubules and also regulate the spindle assembly checkpoint, which is crucial for correct chromosome segregation in all eukaryotes. The better known core networks of kinetochores include the KMN network (K, KNL1; M, Mis12 complex; N, Ndc80 complex)and CCAN (constitutive centromere-associated network). However, the detailed molecular mechanism of the kinetochore protein network remains unclear. This study demonstrates that CENP-H and CENP-K form quite stable subcomplex by TAP (tandem affinity purification) with HEK 293 cells which express TAP-CENP-K, with the ratio of purified CENP-H and CENP-K being close to 1: 1 even with high salt. Bioinformatic analysis suggests that CENP-H and CENP-K are enriched with coiled-coil regions. This implies that CENP-H and CENP-K form heterodimeric coiled-coils. Furthermore, the functional regions which form the complex are respectively located on their N- and C-terminals, but the association between the C-terminals is more complex. It is possible that this is the first identified heterodimeric coiled-coils within the inner kinetochore, which is directly involved in the attachment between kinetochores and the spindle microtubules.
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Deng M, Gao J, Suraneni P, Li R. Kinetochore-independent chromosome poleward movement during anaphase of meiosis II in mouse eggs. PLoS One 2009; 4:e5249. [PMID: 19365562 PMCID: PMC2664963 DOI: 10.1371/journal.pone.0005249] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 03/22/2009] [Indexed: 11/18/2022] Open
Abstract
Kinetochores are considered to be the key structures that physically connect spindle microtubules to the chromosomes and play an important role in chromosome segregation during mitosis. Due to different mechanisms of spindle assembly between centrosome-containing mitotic cells and acentrosomal meiotic oocytes, it is unclear how a meiotic spindle generates the poleward forces to drive two rounds of meiotic chromosome segregation to achieve genome haploidization. We took advantage of the fact that DNA beads are able to induce bipolar spindle formation without kinetochores and studied the behavior of DNA beads in the induced spindle in mouse eggs during meiosis II. Interestingly, DNA beads underwent poleward movements that were similar in timing and speed to the meiotic chromosomes, although all the beads moved together to the same spindle pole. Disruption of dynein function abolished the poleward movements of DNA beads but not of the meiotic chromosomes, suggesting the existence of different dynein-dependent and dynein-independent force generation mechanisms for the chromosome poleward movement, and the latter may be dependent on the presence of kinetochores. Consistent with the observed DNA bead poleward movement, sperm haploid chromatin (which also induced bipolar spindle formation after injection to a metaphase egg without forming detectable kinetochore structures) also underwent similar poleward movement at anaphase as DNA beads. The results suggest that in the chromatin-induced meiotic spindles, kinetochore attachments to spindle microtubules are not absolutely required for chromatin poleward movements at anaphase.
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Affiliation(s)
- Manqi Deng
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- * E-mail: (MD); (RL)
| | - Juntao Gao
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Praveen Suraneni
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Rong Li
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- * E-mail: (MD); (RL)
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Caldwell CM, Kaplan KB. The role of APC in mitosis and in chromosome instability. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 656:51-64. [PMID: 19928352 DOI: 10.1007/978-1-4419-1145-2_5] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The established role of APC in regulating microtubules and actin in polarized epithelia naturally raises the possibility that APC similarly influences the mitotic cytoskeleton. The recent accumulation of experimental evidence in mitotic cells supports this supposition. APC associates with mitotic spindle microtubules, most notably at the plus-ends of microtubules that interact with kinetochores. Genetic experiments implicate APC in the regulation of spindle microtubule dynamics, probably through its interaction with the microtubule plus-end binding protein, EB1. Moreover, functional data show that APC modulates kinetochore-microtubule attachments and is required for the spindle checkpoint to detect transiently misaligned chromosomes. Together this evidence points to a role for APC in maintaining mitotic fidelity. Such a role is particularly significant when considered in the context of the chromosome instability observed in colorectal tumors bearing mutations in APC. The prevalence of APC truncation mutants in colorectal tumors and the ability of these alleles to act dominantly to inhibit the mitotic spindle place chromosome instability at the earliest stage of colorectal cancer progression (i.e., prior to deregulation of beta-catenin). This may contribute to the autosomal dominant predisposition of patients with familial adenomatous polyposis to develop colon cancer. In this chapter, we will review the literature linking APC to regulation of mitotic fidelity and discuss the implications for dividing epithelial cells in the intestine.
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Maddox PS. Confocal imaging of cell division. CURRENT PROTOCOLS IN CYTOMETRY 2008; Chapter 12:12.11.1-12.11.13. [PMID: 18770643 DOI: 10.1002/0471142956.cy1211s43] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Imaging of subcellular events has been key to recent advances in the basic knowledge base as well as drug discovery for disease states such as cancer. In a snowball effect, advances in imaging have spurred new investigations, which have increased the demand for new technologies. The study of cell division serves as an example of this cycle. Here, application of spinning disk confocal technology to the study of cell division is discussed. While these studies have increased understanding of fundamental mechanisms in several mitotic events, new imaging technologies in the future will unlock more secrets of cell biology.
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Affiliation(s)
- Paul S Maddox
- Department of Pathology and Cell Biology, Université de Montréal, Montreal, Canada
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Gassmann R, Essex A, Hu JS, Maddox PS, Motegi F, Sugimoto A, O'Rourke SM, Bowerman B, McLeod I, Yates JR, Oegema K, Cheeseman IM, Desai A. A new mechanism controlling kinetochore-microtubule interactions revealed by comparison of two dynein-targeting components: SPDL-1 and the Rod/Zwilch/Zw10 complex. Genes Dev 2008; 22:2385-99. [PMID: 18765790 DOI: 10.1101/gad.1687508] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chromosome segregation requires stable bipolar attachments of spindle microtubules to kinetochores. The dynein/dynactin motor complex localizes transiently to kinetochores and is implicated in chromosome segregation, but its role remains poorly understood. Here, we use the Caenorhabditis elegans embryo to investigate the function of kinetochore dynein by analyzing the Rod/Zwilch/Zw10 (RZZ) complex and the associated coiled-coil protein SPDL-1. Both components are essential for Mad2 targeting to kinetochores and spindle checkpoint activation. RZZ complex inhibition, which abolishes both SPDL-1 and dynein/dynactin targeting to kinetochores, slows but does not prevent the formation of load-bearing kinetochore-microtubule attachments and reduces the fidelity of chromosome segregation. Surprisingly, inhibition of SPDL-1, which abolishes dynein/dynactin targeting to kinetochores without perturbing RZZ complex localization, prevents the formation of load-bearing attachments during most of prometaphase and results in extensive chromosome missegregation. Coinhibition of SPDL-1 along with the RZZ complex reduces the phenotypic severity to that observed following RZZ complex inhibition alone. We propose that the RZZ complex can inhibit the formation of load-bearing attachments and that this activity of the RZZ complex is normally controlled by dynein/dynactin localized via SPDL-1. This mechanism could coordinate the hand-off from initial weak dynein-mediated lateral attachments, which help orient kinetochores and enhance their ability to capture microtubules, to strong end-coupled attachments that drive chromosome segregation.
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Affiliation(s)
- Reto Gassmann
- Ludwig Institute for Cancer Research/Dept of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, USA
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Integration site preference of xenotropic murine leukemia virus-related virus, a new human retrovirus associated with prostate cancer. J Virol 2008; 82:9964-77. [PMID: 18684813 DOI: 10.1128/jvi.01299-08] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Xenotropic murine leukemia virus-related virus (XMRV) is a new human gammaretrovirus identified in prostate cancer tissue from patients homozygous for a reduced-activity variant of the antiviral enzyme RNase L. Neither a casual relationship between XMRV infection and prostate cancer nor a mechanism of tumorigenesis has been established. To determine the integration site preferences of XMRV and the potential risk of proviral insertional mutagenesis, we carried out a genome-wide analysis of viral integration sites in the prostate cell line DU145 after an acute XMRV infection and compared the integration site pattern of XMRV with those found for murine leukemia virus and two human retroviruses, human immunodeficiency virus type 1 and human T-cell leukemia virus type 1. Among all retroviruses analyzed, XMRV has the strongest preference for transcription start sites, CpG islands, DNase-hypersensitive sites, and gene-dense regions; all are features frequently associated with structurally open transcription regulatory regions of a chromosome. Analyses of XMRV integration sites in tissues from prostate cancer patients found a similar preference for the aforementioned chromosomal features. Additionally, XMRV integration sites in cancer tissues were associated with cancer breakpoints, common fragile sites, microRNA, and cancer-related genes, suggesting a selection process that favors certain chromosomal integration sites. In both acutely infected cells and cancer tissues, no common integration site was detected within or near proto-oncogenes or tumor suppressor genes. These results are consistent with a model in which XMRV may contribute to tumorigenicity via a paracrine mechanism.
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Vader G, Lens SMA. The Aurora kinase family in cell division and cancer. Biochim Biophys Acta Rev Cancer 2008; 1786:60-72. [PMID: 18662747 DOI: 10.1016/j.bbcan.2008.07.003] [Citation(s) in RCA: 220] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 07/14/2008] [Accepted: 07/18/2008] [Indexed: 12/15/2022]
Abstract
The Aurora protein kinase family (consisting of Aurora-A, -B and -C) is an important group of enzymes that controls several aspects of cell division in mammalian cells. Dysfunction of these kinases has been associated with a failure to maintain a stable chromosome content, a state that can contribute to tumourigenesis. Additionally, Aurora-A is frequently found amplified in a variety of tumour types and displays oncogenic activity. On the other hand, therapeutic inhibition of these kinases has shown great promise as potential anti-cancer treatment, most likely because of their essential roles during cell division. This review will focus on our present understanding of the different roles played by these kinases, their regulation throughout cell division, their deregulation in human cancers and on the progress that is made in targeting these important regulators in the treatment of cancer.
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Affiliation(s)
- Gerben Vader
- Laboratory of Experimental Oncology, Department of Medical Oncology, University Medical Center Utrecht, Stratenum 2.125, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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Ciferri C, Pasqualato S, Screpanti E, Varetti G, Santaguida S, Reis GD, Maiolica A, Polka J, De Luca JG, De Wulf P, Salek M, Rappsilber J, Moores CA, Salmon ED, Musacchio A. Implications for kinetochore-microtubule attachment from the structure of an engineered Ndc80 complex. Cell 2008; 133:427-39. [PMID: 18455984 PMCID: PMC4754795 DOI: 10.1016/j.cell.2008.03.020] [Citation(s) in RCA: 408] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 02/06/2008] [Accepted: 03/20/2008] [Indexed: 01/07/2023]
Abstract
Kinetochores are proteinaceous assemblies that mediate the interaction of chromosomes with the mitotic spindle. The 180 kDa Ndc80 complex is a direct point of contact between kinetochores and microtubules. Its four subunits contain coiled coils and form an elongated rod structure with functional globular domains at either end. We crystallized an engineered "bonsai" Ndc80 complex containing a shortened rod domain but retaining the globular domains required for kinetochore localization and microtubule binding. The structure reveals a microtubule-binding interface containing a pair of tightly interacting calponin-homology (CH) domains with a previously unknown arrangement. The interaction with microtubules is cooperative and predominantly electrostatic. It involves positive charges in the CH domains and in the N-terminal tail of the Ndc80 subunit and negative charges in tubulin C-terminal tails and is regulated by the Aurora B kinase. We discuss our results with reference to current models of kinetochore-microtubule attachment and centromere organization.
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Affiliation(s)
- Claudio Ciferri
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Sebastiano Pasqualato
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Emanuela Screpanti
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Gianluca Varetti
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Stefano Santaguida
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Gabriel Dos Reis
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Alessio Maiolica
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | - Jessica Polka
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA
| | - Jennifer G. De Luca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Peter De Wulf
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy
| | | | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK
| | - Carolyn A. Moores
- School of Crystallography, Birkbeck College, University of London, London WC1E 7HX, UK
| | - Edward D. Salmon
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA
| | - Andrea Musacchio
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, I 20139 Milan, Italy,Research Unit of the Italian Institute of Technology (IIT) Foundation at the IFOM-IEO Campus, Via Adamello 16, I-20139 Milan, Italy,Correspondence:
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45
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Romao M, Tanaka K, Sibarita JB, Ly-Hartig NTB, Tanaka TU, Antony C. Three-dimensional electron microscopy analysis of ndc10-1 mutant reveals an aberrant organization of the mitotic spindle and spindle pole body defects in Saccharomyces cerevisiae. J Struct Biol 2008; 163:18-28. [PMID: 18515145 DOI: 10.1016/j.jsb.2008.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 03/21/2008] [Accepted: 03/31/2008] [Indexed: 10/22/2022]
Abstract
Kinetochore components play a major role in regulating the transmission of genetic information during cell division. Ndc10p, a kinetochore component of the essential CBF3 complex in budding yeast is required for chromosome attachment to the mitotic spindle. ndc10-1 mutant was shown to display chromosome mis-segregation as well as an aberrant mitotic spindle (Goh and Kilmartin, 1993). In addition, Ndc10p localizes along the spindle microtubules (Muller-Reichert et al., 2003). To further understand the role of Ndc10p in the mitotic apparatus, we performed a three-dimensional electron microscopy (EM) reconstruction of mitotic spindles from serial sections of cryo-immobilized ndc10-1 mutant cells. This analysis reveals a dramatic reduction in the number of microtubules present in the half-spindle, which is connected to the newly formed spindle pole body (SPB) in ndc10-1 cells. Moreover, in contrast to wild-type (WT) cells, ndc10-1 cells showed a significantly lower signal intensity of the SPB components Spc42p and Spc110p fused with GFP, in mother cell bodies compared with buds. A subsequent EM analysis also showed clear defects in the newly formed SPB, which remains in the mother cell during anaphase. These results suggest that Ndc10p is required for maturation of the newly formed SPB. Intriguingly, mutations in other kinetochore components, ndc80-1 and spc24-1, showed kinetochore detachment from the spindle, similar to ndc10-1, but did not display defects in SPBs. This suggests that unattached kinetochores are not sufficient to cause SPB defects in ndc10-1 cells. We propose that Ndc10p, alongside its role in kinetochore-microtubule interaction, is also essential for SPB maturation and mitotic spindle integrity.
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Affiliation(s)
- Maryse Romao
- Institut Curie UMR144 CNRS, 26 rue d'Ulm, 75248 Paris cedex 05, France
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46
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Abstract
In the budding yeast Saccharomyces cerevisiae, microtubule-organizing centers called spindle pole bodies (SPBs) are embedded in the nuclear envelope, which remains intact throughout the cell cycle (closed mitosis). Kinetochores are tethered to SPBs by microtubules during most of the cell cycle, including G1 and M phases; however, it has been a topic of debate whether microtubule interaction is constantly maintained or transiently disrupted during chromosome duplication. Here, we show that centromeres are detached from microtubules for 1-2 min and displaced away from a spindle pole in early S phase. These detachment and displacement events are caused by centromere DNA replication, which results in disassembly of kinetochores. Soon afterward, kinetochores are reassembled, leading to their recapture by microtubules. We also show how kinetochores are subsequently transported poleward by microtubules. Our study gives new insights into kinetochore-microtubule interaction and kinetochore duplication during S phase in a closed mitosis.
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47
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Abstract
SUMO proteins are small ubiquitin-like modifiers found in all eukaryotes that become covalently conjugated to other cellular proteins. The SUMO conjugation pathway is biochemically similar to ubiquitin conjugation, although the enzymes within the pathway act exclusively on SUMO proteins. This post-translational modification controls many processes. Here, I will focus on evidence that SUMOylation plays a critical role(s) in mitosis: Early studies showed a genetic requirement for SUMO pathway components in the process of cell division, while later findings implicated SUMOylation in the control of mitotic chromosome structure, cell cycle progression, kinetochore function and cytokinesis. Recent insights into the targets of SUMOylation are likely to be extremely helpful in understanding each of these aspects. Finally, growing evidence suggests that SUMOylation is a downstream target of regulation through Ran, a small GTPase with important functions in both interphase nuclear trafficking and mitotic spindle assembly.
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Affiliation(s)
- Mary Dasso
- Laboratory of Gene Regulation and Development, NICHD/NIH, Building 18, Room 106, MSC-5431, Bethesda, MD 20892, USA.
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48
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Cyclin B1 is localized to unattached kinetochores and contributes to efficient microtubule attachment and proper chromosome alignment during mitosis. Cell Res 2008; 18:268-80. [DOI: 10.1038/cr.2008.11] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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49
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Tanaka TU, Desai A. Kinetochore-microtubule interactions: the means to the end. Curr Opin Cell Biol 2008; 20:53-63. [PMID: 18182282 PMCID: PMC2358929 DOI: 10.1016/j.ceb.2007.11.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 11/26/2007] [Indexed: 01/08/2023]
Abstract
Kinetochores are proteinaceous complexes containing dozens of components; they are assembled at centromeric DNA regions and provide the major microtubule attachment site on chromosomes during cell division. Recent studies have defined the kinetochore components comprising the direct interface with spindle microtubules, primarily through structural and functional analysis of the Ndc80 and Dam1 complexes. These studies have facilitated our understanding of how kinetochores remain attached to the end of dynamic microtubules and how proper orientation of a kinetochore-microtubule attachment is promoted on the mitotic spindle. In this article, we review these recent studies and summarize their key findings.
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Affiliation(s)
- Tomoyuki U Tanaka
- Wellcome Trust Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, MSI/WTB/JBC Complex, Dundee, UK.
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50
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Walczak CE, Heald R. Mechanisms of mitotic spindle assembly and function. INTERNATIONAL REVIEW OF CYTOLOGY 2008; 265:111-58. [PMID: 18275887 DOI: 10.1016/s0074-7696(07)65003-7] [Citation(s) in RCA: 290] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mitotic spindle is the macromolecular machine that segregates chromosomes to two daughter cells during mitosis. The major structural elements of the spindle are microtubule polymers, whose intrinsic polarity and dynamic properties are critical for bipolar spindle organization and function. In most cell types, spindle microtubule nucleation occurs primarily at two centrosomes, which define the spindle poles, but microtubules can also be generated by the chromosomes and within the spindle itself. Many associated factors help organize the spindle, including molecular motors and regulators of microtubule dynamics. The past decade has provided a wealth of information on the molecular players that are critical for spindle assembly as well as a high-resolution view of the intricate movements and dynamics of the spindle microtubules and the chromosomes. In this chapter we provide a historical account of the key observations leading to current models of spindle assembly, as well as an up-to-date status report on this exciting field.
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Affiliation(s)
- Claire E Walczak
- Medical Sciences Program, Indiana University, Bloomington, Indiana 47405, USA
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