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Wang T, Zou Y, Meng H, Zheng P, Teng J, Huang N, Chen J. Securin acetylation prevents precocious separase activation and premature sister chromatid separation. Curr Biol 2024; 34:1295-1308.e5. [PMID: 38452759 DOI: 10.1016/j.cub.2024.02.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 01/08/2024] [Accepted: 02/15/2024] [Indexed: 03/09/2024]
Abstract
Lysine acetylation of non-histone proteins plays crucial roles in many cellular processes. In this study, we examine the role of lysine acetylation during sister chromatid separation in mitosis. We investigate the acetylation of securin at K21 by cell-cycle-dependent acetylome analysis and uncover its role in separase-triggered chromosome segregation during mitosis. Prior to the onset of anaphase, the acetylated securin via TIP60 prevents its degradation by the APC/CCDC20-mediated ubiquitin-proteasome system. This, in turn, restrains precocious activation of separase and premature separation of sister chromatids. Additionally, the acetylation-dependent stability of securin is also enhanced by its dephosphorylation. As anaphase approaches, HDAC1-mediated deacetylation of securin promotes its degradation, allowing released separase to cleave centromeric cohesin. Blocking securin deacetylation leads to longer anaphase duration and errors in chromosome segregation. Thus, this study illustrates the emerging role of securin acetylation dynamics in mitotic progression and genetic stability.
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Affiliation(s)
- Tianning Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China; Breast Disease Diagnosis and Treatment Center/Department of Thyroid Surgery, Central Hospital Affiliated to Shandong First Medical University, Jinan 250013, China; Research Center of Translational Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan 250013, China
| | - Yuhong Zou
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China
| | - Hui Meng
- Institute of Neuroscience, Translational Medicine Institute, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China
| | - Pengli Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China.
| | - Ning Huang
- Institute of Neuroscience, Translational Medicine Institute, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China.
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China; Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
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Pati D. Role of chromosomal cohesion and separation in aneuploidy and tumorigenesis. Cell Mol Life Sci 2024; 81:100. [PMID: 38388697 PMCID: PMC10884101 DOI: 10.1007/s00018-024-05122-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/28/2023] [Accepted: 01/09/2024] [Indexed: 02/24/2024]
Abstract
Cell division is a crucial process, and one of its essential steps involves copying the genetic material, which is organized into structures called chromosomes. Before a cell can divide into two, it needs to ensure that each newly copied chromosome is paired tightly with its identical twin. This pairing is maintained by a protein complex known as cohesin, which is conserved in various organisms, from single-celled ones to humans. Cohesin essentially encircles the DNA, creating a ring-like structure to handcuff, to keep the newly synthesized sister chromosomes together in pairs. Therefore, chromosomal cohesion and separation are fundamental processes governing the attachment and segregation of sister chromatids during cell division. Metaphase-to-anaphase transition requires dissolution of cohesins by the enzyme Separase. The tight regulation of these processes is vital for safeguarding genomic stability. Dysregulation in chromosomal cohesion and separation resulting in aneuploidy, a condition characterized by an abnormal chromosome count in a cell, is strongly associated with cancer. Aneuploidy is a recurring hallmark in many cancer types, and abnormalities in chromosomal cohesion and separation have been identified as significant contributors to various cancers, such as acute myeloid leukemia, myelodysplastic syndrome, colorectal, bladder, and other solid cancers. Mutations within the cohesin complex have been associated with these cancers, as they interfere with chromosomal segregation, genome organization, and gene expression, promoting aneuploidy and contributing to the initiation of malignancy. In summary, chromosomal cohesion and separation processes play a pivotal role in preserving genomic stability, and aberrations in these mechanisms can lead to aneuploidy and cancer. Gaining a deeper understanding of the molecular intricacies of chromosomal cohesion and separation offers promising prospects for the development of innovative therapeutic approaches in the battle against cancer.
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Affiliation(s)
- Debananda Pati
- Texas Children's Cancer Center, Department of Pediatrics Hematology/Oncology, Molecular and Cellular Biology, Baylor College of Medicine, 1102 Bates Avenue, Houston, TX, 77030, USA.
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Mokhtari K, Peymani M, Rashidi M, Hushmandi K, Ghaedi K, Taheriazam A, Hashemi M. Colon cancer transcriptome. Prog Biophys Mol Biol 2023; 180-181:49-82. [PMID: 37059270 DOI: 10.1016/j.pbiomolbio.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 04/16/2023]
Abstract
Over the last four decades, methodological innovations have continuously changed transcriptome profiling. It is now feasible to sequence and quantify the transcriptional outputs of individual cells or thousands of samples using RNA sequencing (RNA-seq). These transcriptomes serve as a connection between cellular behaviors and their underlying molecular mechanisms, such as mutations. This relationship, in the context of cancer, provides a chance to unravel tumor complexity and heterogeneity and uncover novel biomarkers or treatment options. Since colon cancer is one of the most frequent malignancies, its prognosis and diagnosis seem to be critical. The transcriptome technology is developing for an earlier and more accurate diagnosis of cancer which can provide better protectivity and prognostic utility to medical teams and patients. A transcriptome is a whole set of expressed coding and non-coding RNAs in an individual or cell population. The cancer transcriptome includes RNA-based changes. The combined genome and transcriptome of a patient may provide a comprehensive picture of their cancer, and this information is beginning to affect treatment decision-making in real-time. A full assessment of the transcriptome of colon (colorectal) cancer has been assessed in this review paper based on risk factors such as age, obesity, gender, alcohol use, race, and also different stages of cancer, as well as non-coding RNAs like circRNAs, miRNAs, lncRNAs, and siRNAs. Similarly, they have been examined independently in the transcriptome study of colon cancer.
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Affiliation(s)
- Khatere Mokhtari
- Department of Modern Biology, ACECR Institute of Higher Education (Isfahan Branch), Isfahan, Iran
| | - Maryam Peymani
- Department of Biology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
| | - Mohsen Rashidi
- Department Pharmacology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, 4815733971, Iran; The Health of Plant and Livestock Products Research Center, Mazandaran University of Medical Sciences, Sari, 4815733971, Iran
| | - Kiavash Hushmandi
- Department of Food Hygiene and Quality Control, Division of Epidemiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Kamran Ghaedi
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
| | - Afshin Taheriazam
- Farhikhtegan Medical Convergence Sciences Research Center, Farhikhtegan Hospital Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; Department of Orthopedics, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
| | - Mehrdad Hashemi
- Farhikhtegan Medical Convergence Sciences Research Center, Farhikhtegan Hospital Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
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Konecna M, Abbasi Sani S, Anger M. Separase and Roads to Disengage Sister Chromatids during Anaphase. Int J Mol Sci 2023; 24:ijms24054604. [PMID: 36902034 PMCID: PMC10003635 DOI: 10.3390/ijms24054604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023] Open
Abstract
Receiving complete and undamaged genetic information is vital for the survival of daughter cells after chromosome segregation. The most critical steps in this process are accurate DNA replication during S phase and a faithful chromosome segregation during anaphase. Any errors in DNA replication or chromosome segregation have dire consequences, since cells arising after division might have either changed or incomplete genetic information. Accurate chromosome segregation during anaphase requires a protein complex called cohesin, which holds together sister chromatids. This complex unifies sister chromatids from their synthesis during S phase, until separation in anaphase. Upon entry into mitosis, the spindle apparatus is assembled, which eventually engages kinetochores of all chromosomes. Additionally, when kinetochores of sister chromatids assume amphitelic attachment to the spindle microtubules, cells are finally ready for the separation of sister chromatids. This is achieved by the enzymatic cleavage of cohesin subunits Scc1 or Rec8 by an enzyme called Separase. After cohesin cleavage, sister chromatids remain attached to the spindle apparatus and their poleward movement on the spindle is initiated. The removal of cohesion between sister chromatids is an irreversible step and therefore it must be synchronized with assembly of the spindle apparatus, since precocious separation of sister chromatids might lead into aneuploidy and tumorigenesis. In this review, we focus on recent discoveries concerning the regulation of Separase activity during the cell cycle.
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Affiliation(s)
- Marketa Konecna
- Department of Genetics and Reproduction, Veterinary Research Institute, 621 00 Brno, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Science, 277 21 Libechov, Czech Republic
- Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic
| | - Soodabeh Abbasi Sani
- Department of Genetics and Reproduction, Veterinary Research Institute, 621 00 Brno, Czech Republic
- Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic
| | - Martin Anger
- Department of Genetics and Reproduction, Veterinary Research Institute, 621 00 Brno, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Science, 277 21 Libechov, Czech Republic
- Correspondence:
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Khan J, Al Asoom L, Al Sunni A, Rafique N, Latif R, Alabdali M, Alhariri A, Aloqaily M, Abdulazeez S, Jahan S, Banawas S, Borgio JF. Whole-Exome Sequencing Reveals Migraine-Associated Novel Functional Variants in Arab Ancestry Females: A Pilot Study. Brain Sci 2022; 12:1429. [DOI: 10.3390/brainsci12111429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022] Open
Abstract
Migraine, as the seventh most disabling neurological disease with 26.9% prevalence in Saudi females, lacks studies on identifying associated genes and pathways with migraines in the Arab population. This case control study aims to identify the migraine-associated novel genes and risk variants. More than 1900 Arab ancestry young female college students were screened: 103 fulfilled the ICHD-3 criteria for migraine and 20 cases confirmed in the neurology clinic were included for the study with age-matched healthy controls. DNA from blood samples were subjected to paired-end whole-exome sequencing. After quality control, 3365343 missense, frameshift, missense splice region variants and insertion–deletion (indels) polymorphisms were tested for association with migraine. Significant variants were validated using Sanger sequencing. A total of 17 (p-value 9.091 × 10−05) functional variants in 12 genes (RETNLB, SCAI, ADH4, ESPL1, CPT2, FLG, PPP4R1, SERPINB5, ZNF66, ETAA1, EXO1 and CPA6) were associated with higher migraine risk, including a stop-gained frameshift (-13-14*SX) variant in the gene RETNLB (rs5851607; p-value 3.446 × 10−06). Gene analysis revealed that half of the significant novel migraine risk genes were expressed in the temporal lobe (p-value 0.0058) of the cerebral cortex. This is the first study exploring the migraine risk of 17 functional variants in 12 genes among Saudi female migraineurs of Arab ancestry using whole-exome sequencing. Half of the significant genes were expressed in the temporal lobe, which expands migraine pathophysiology and early identification using biomarkers for research possibilities on personalised genetics.
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Donne R, Saroul-Ainama M, Cordier P, Hammoutene A, Kabore C, Stadler M, Nemazanyy I, Galy-Fauroux I, Herrag M, Riedl T, Chansel-Da Cruz M, Caruso S, Bonnafous S, Öllinger R, Rad R, Unger K, Tran A, Couty JP, Gual P, Paradis V, Celton-Morizur S, Heikenwalder M, Revy P, Desdouets C. Replication stress triggered by nucleotide pool imbalance drives DNA damage and cGAS-STING pathway activation in NAFLD. Dev Cell 2022; 57:1728-1741.e6. [PMID: 35768000 DOI: 10.1016/j.devcel.2022.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 04/22/2022] [Accepted: 06/07/2022] [Indexed: 12/25/2022]
Abstract
Non-alcoholic steatotic liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. NAFLD has a major effect on the intrinsic proliferative properties of hepatocytes. Here, we investigated the mechanisms underlying the activation of DNA damage response during NAFLD. Proliferating mouse NAFLD hepatocytes harbor replication stress (RS) with an alteration of the replication fork's speed and activation of ATR pathway, which is sufficient to cause DNA breaks. Nucleotide pool imbalance occurring during NAFLD is the key driver of RS. Remarkably, DNA lesions drive cGAS/STING pathway activation, a major component of cells' intrinsic immune response. The translational significance of this study was reiterated by showing that lipid overload in proliferating HepaRG was sufficient to induce RS and nucleotide pool imbalance. Moreover, livers from NAFLD patients displayed nucleotide pathway deregulation and cGAS/STING gene alteration. Altogether, our findings shed light on the mechanisms by which damaged NAFLD hepatocytes might promote disease progression.
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Affiliation(s)
- Romain Donne
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Maëva Saroul-Ainama
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Pierre Cordier
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Adel Hammoutene
- Université Paris-Cité, Centre de recherche sur l'inflammation, INSERM U1149, CNRS, ERL8252, 75018 Paris, France
| | - Christelle Kabore
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Mira Stadler
- Division of Chronic Inflammation and Cancer (F180), German Cancer Research Center, Heidelberg, Germany
| | - Ivan Nemazanyy
- Platform for Metabolic Analyses, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS 3633, Paris, France
| | - Isabelle Galy-Fauroux
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Mounia Herrag
- Laboratory of Genome Dynamics in the Immune System, Labellisé Ligue, INSERM UMR 1163, Université Paris-Cité, Institut Imagine, Paris, France
| | - Tobias Riedl
- Division of Chronic Inflammation and Cancer (F180), German Cancer Research Center, Heidelberg, Germany
| | - Marie Chansel-Da Cruz
- Laboratory of Genome Dynamics in the Immune System, Labellisé Ligue, INSERM UMR 1163, Université Paris-Cité, Institut Imagine, Paris, France
| | - Stefano Caruso
- Functional Genomics of Solid Tumors Team, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, Université Paris 13, Labex Immuno-Oncology, Équipe Labellisée Ligue Contre le Cancer, Paris, France
| | | | - Rupert Öllinger
- Institute of Molecular Oncology and Functional Genomics, Rechts der Isar University Hospital, Munich, Germany
| | - Roland Rad
- Institute of Molecular Oncology and Functional Genomics, Rechts der Isar University Hospital, Munich, Germany
| | - Kristian Unger
- Research Unit of Radiation Cytogenetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Albert Tran
- Université Côte d'Azur, INSERM, U1065, C3M, CHU, Nice, France
| | - Jean-Pierre Couty
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Philippe Gual
- Université Côte d'Azur, INSERM, U1065, C3M, CHU, Nice, France
| | - Valérie Paradis
- Université Paris-Cité, Centre de recherche sur l'inflammation, INSERM U1149, CNRS, ERL8252, 75018 Paris, France; Service d'Anatomie Pathologique, Hôpital Beaujon, Assistance Publique-Hôpitaux de Paris, Clichy, France
| | - Séverine Celton-Morizur
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France
| | - Mathias Heikenwalder
- Division of Chronic Inflammation and Cancer (F180), German Cancer Research Center, Heidelberg, Germany
| | - Patrick Revy
- Laboratory of Genome Dynamics in the Immune System, Labellisé Ligue, INSERM UMR 1163, Université Paris-Cité, Institut Imagine, Paris, France
| | - Chantal Desdouets
- Team Proliferation, Stress and Liver Physiopathology, Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris-Cité, 75006 Paris, France.
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Yano K, Choijookhuu N, Ikenoue M, Fidya, Fukaya T, Sato K, Lee D, Taniguchi N, Chosa E, Nanashima A, Hishikawa Y. Spatiotemporal expression of HMGB2 regulates cell proliferation and hepatocyte size during liver regeneration. Sci Rep 2022; 12:11962. [PMID: 35831365 PMCID: PMC9279446 DOI: 10.1038/s41598-022-16258-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 07/07/2022] [Indexed: 11/09/2022] Open
Abstract
Liver regeneration is an extraordinarily complex process involving a variety of factors; however, the role of chromatin protein in hepatocyte proliferation is largely unknown. In this study, we investigated the functional role of high-mobility group box 2 (HMGB2), a chromatin protein in liver regeneration using wild-type and HMGB2-knockout (KO) mice. Liver tissues were sampled after 70% partial hepatectomy (PHx), and analyzed by immunohistochemistry, western blotting and flow cytometry using various markers of cell proliferation. In WT mice, hepatocyte proliferation was strongly correlated with the spatiotemporal expression of HMGB2; however, cell proliferation was significantly delayed in hepatocytes of HMGB2-KO mice. Quantitative PCR demonstrated that cyclin D1 and cyclin B1 mRNAs were significantly decreased in HMGB2-KO mice livers. Interestingly, hepatocyte size was significantly larger in HMGB2-KO mice at 36-72 h after PHx, and these results suggest that hepatocyte hypertrophy appeared in parallel with delayed cell proliferation. In vitro experiments demonstrated that cell proliferation was significantly decreased in HMGB2-KO cells. A significant delay in cell proliferation was also found in HMGB2-siRNA transfected cells. In summary, spatiotemporal expression of HMGB2 is important for regulation of hepatocyte proliferation and cell size during liver regeneration.
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Affiliation(s)
- Koichi Yano
- Department of Anatomy, Histochemistry and Cell Biology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan.,Department of Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Narantsog Choijookhuu
- Department of Anatomy, Histochemistry and Cell Biology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Makoto Ikenoue
- Department of Anatomy, Histochemistry and Cell Biology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan.,Department of Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Fidya
- Department of Anatomy, Histochemistry and Cell Biology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Tomohiro Fukaya
- Division of Immunology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Katsuaki Sato
- Division of Immunology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Deokcheol Lee
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889‑1692, Japan
| | - Noboru Taniguchi
- Department of Orthopaedic Surgery, Graduate School of Medical and Dental Sciences, Kagoshima University, 8‑35‑1 Sakuragaoka, Kagoshima, 890‑8520, Japan
| | - Etsuo Chosa
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889‑1692, Japan
| | - Atsushi Nanashima
- Department of Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Yoshitaka Hishikawa
- Department of Anatomy, Histochemistry and Cell Biology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan.
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Kalkan BM, Ozcan SC, Quintyne NJ, Reed SL, Acilan C. Keep Calm and Carry on with Extra Centrosomes. Cancers (Basel) 2022; 14:442. [PMID: 35053604 DOI: 10.3390/cancers14020442] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/01/2022] [Accepted: 01/03/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Precise chromosome segregation during mitosis is a vital event orchestrated by formation of bipolar spindle poles. Supernumerary centrosomes, caused by centrosome amplification, deteriorates mitotic processes, resulting in segregation defects leading to chromosomal instability (CIN). Centrosome amplification is frequently observed in various types of cancer and considered as a significant contributor to destabilization of chromosomes. This review provides a comprehensive overview of causes and consequences of centrosome amplification thoroughly describing molecular mechanisms. Abstract Aberrations in the centrosome number and structure can readily be detected at all stages of tumor progression and are considered hallmarks of cancer. Centrosome anomalies are closely linked to chromosome instability and, therefore, are proposed to be one of the driving events of tumor formation and progression. This concept, first posited by Boveri over 100 years ago, has been an area of interest to cancer researchers. We have now begun to understand the processes by which these numerical and structural anomalies may lead to cancer, and vice-versa: how key events that occur during carcinogenesis could lead to amplification of centrosomes. Despite the proliferative advantages that having extra centrosomes may confer, their presence can also lead to loss of essential genetic material as a result of segregational errors and cancer cells must deal with these deadly consequences. Here, we review recent advances in the current literature describing the mechanisms by which cancer cells amplify their centrosomes and the methods they employ to tolerate the presence of these anomalies, focusing particularly on centrosomal clustering.
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Abstract
Our understanding of the structure and function of mitotic chromosomes has come a long way since these iconic objects were first recognized more than 140 years ago, though many details remain to be elucidated. In this chapter, we start with the early history of chromosome studies and then describe the path that led to our current understanding of the formation and structure of mitotic chromosomes. We also discuss some of the remaining questions. It is now well established that each mitotic chromatid consists of a central organizing region containing a so-called "chromosome scaffold" from which loops of DNA project radially. Only a few key non-histone proteins and protein complexes are required to form the chromosome: topoisomerase IIα, cohesin, condensin I and condensin II, and the chromokinesin KIF4A. These proteins are concentrated along the axis of the chromatid. Condensins I and II are primarily responsible for shaping the chromosome and the scaffold, and they produce the loops of DNA by an ATP-dependent process known as loop extrusion. Modelling of Hi-C data suggests that condensin II adopts a spiral staircase arrangement with an extruded loop extending out from each step in a roughly helical pattern. Condensin I then forms loops nested within these larger condensin II loops, thereby giving rise to the final compaction of the mitotic chromosome in a process that requires Topo IIα.
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Affiliation(s)
- James R Paulson
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA.
| | - Damien F Hudson
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia
| | - Fernanda Cisneros-Soberanis
- Wellcome Trust Centre for Cell Biology, ICB, University of Edinburgh, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, ICB, University of Edinburgh, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK.
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Wang R, Zang W, Hu B, Deng D, Ling X, Zhou H, Su M, Jiang J. Serum ESPL1 Can Be Used as a Biomarker for Patients With Hepatitis B Virus-Related Liver Cancer: A Chinese Case-Control Study. Technol Cancer Res Treat 2020; 19:1533033820980785. [PMID: 33308056 PMCID: PMC7739072 DOI: 10.1177/1533033820980785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
AIMS To investigate the feasibility of serum extra spindle pole bodies-like 1 (ESPL1) used as a biomarker for patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). METHODS 131 chronic HBV-infection patients were recruited and divided into HBV S gene integration, non-HBV S gene integration, chronic hepatitis B (CHB), HBV-related liver cirrhosis (LC) and HBV-related HCC group, 24 non-HBV-related HCC patients were selected as HCC control group, 30 people without HBV-infection as healthy control group. Serum ESPL1 were detected and compared. RESULTS ESPL1 level of integration group was significantly higher than that of non-integration group (346.7 vs 199.6 ng/ml, P = 0.000) and healthy control group (346.7 vs 41.3 ng/ml, P = 0.000). ESPL1 level of non-integration group was significantly higher than that of healthy control group (199.6 vs 41.3 ng/ml, P = 0.000); ESPL1 levels in chronic HBV-infection related groups were increased in turn according to CHB group (95.8 ng/ml), HBV-related LC group (268.2 ng/ml), HBV-related HCC group (279.9 ng/ml) and integration group (346.7 ng/ml). Except that there was no significant difference in ESPL1 levels between HBV-related LC and HCC group (P = 0.662), pairwise comparisons between other groups showed significant differences (P < 0.05). ESPL1 level of HBV-related HCC group was significantly higher than that of non-HBV-related HCC group (279.9 vs 46.6 ng/ml, P = 0.000), there was no noticeable difference between non-HBV-related HCC and healthy control group (46.6 vs 41.3 ng/ml, P = 0.848). ESPL1 level of HBV-related HCC group after resection was significantly lower than that of before resection (178.4 vs 260.8 ng/ml, P = 0.000). CONCLUSIONS Chronic HBV-infection patients with high ESPL1 level may indicate HBV S gene integration and is a high-risk population for HBV-related HCC. Serum ESPL1 can be used as a biomarker for screening HBV-related HCC high-risk population and monitoring recurrence.
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Affiliation(s)
- Rongming Wang
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Weiwei Zang
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Bobin Hu
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Deli Deng
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Xiaozhang Ling
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Huikun Zhou
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Minghua Su
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Jianning Jiang
- Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
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11
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Kumar P, Cheng H, Paudyal S, Nakamura LV, Zhang N, Li JT, Sasidharan R, Jeong M, Pati D. Haploinsufficiency of cohesin protease, Separase, promotes regeneration of hematopoietic stem cells in mice. Stem Cells 2020; 38:1624-1636. [PMID: 32997844 DOI: 10.1002/stem.3280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/23/2020] [Accepted: 08/31/2020] [Indexed: 11/09/2022]
Abstract
Cohesin recently emerged as a new regulator of hematopoiesis and leukemia. In addition to cohesin, whether proteins that regulate cohesin's function have any direct role in hematopoiesis and hematologic diseases have not been fully examined. Separase, encoded by the ESPL1 gene, is an important regulator of cohesin's function. Canonically, protease activity of Separase resolves sister chromatid cohesion by cleaving cohesin subunit-Rad21 at the onset of anaphase. Using a Separase haploinsufficient mouse model, we have uncovered a novel role of Separase in hematopoiesis. We report that partial disruption of Separase distinctly alters the functional characteristics of hematopoietic stem/progenitor cells (HSPCs). Although analyses of peripheral blood and bone marrow of Espl1+/Hyp mice broadly displayed unperturbed hematopoietic parameters during normal hematopoiesis, further probing of the composition of early hematopoietic cells in Espl1+/Hyp bone marrow revealed a mild reduction in the frequencies of the Lin- Sca1+ Kit- (LSK) or LSK CD48+ CD150- multipotent hematopoietic progenitors population without a significant change in either long-term or short-term hematopoietic stem cells (HSCs) subsets at steady state. Surprisingly, however, we found that Separase haploinsufficiency promotes regeneration activity of HSCs in serial in vivo repopulation assays. In vitro colony formation assays also revealed an enhanced serial replating capacity of hematopoietic progenitors isolated from Espl1+/Hyp mice. Microarray analysis of differentially expressed genes showed that Separase haploinsufficiency in HSCs (SP-KSL) leads to enrichment of gene signatures that are upregulated in HSCs compared to committed progenitors and mature cells. Taken together, our findings demonstrate a key role of Separase in promoting hematopoietic regeneration of HSCs.
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Affiliation(s)
- Praveen Kumar
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Haizi Cheng
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Samridhdi Paudyal
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Lanelle V Nakamura
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Nenggang Zhang
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Jessica T Li
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | | | - Mira Jeong
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Debananda Pati
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
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12
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Galofré C, Asensio E, Ubach M, Torres IM, Quintanilla I, Castells A, Camps J. Centrosome reduction in newly-generated tetraploid cancer cells obtained by separase depletion. Sci Rep 2020; 10:9152. [PMID: 32499568 DOI: 10.1038/s41598-020-65975-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/17/2020] [Indexed: 12/29/2022] Open
Abstract
Tetraploidy, a common feature in cancer, results in the presence of extra centrosomes, which has been associated with chromosome instability (CIN) and aneuploidy. Deregulation in the number of centrosomes triggers tumorigenesis. However, how supernumerary centrosomes evolve during the emergence of tetraploid cells remains yet to be elucidated. Here, generating tetraploid isogenic clones in colorectal cancer and in non-transformed cells, we show that near-tetraploid clones exhibit a significant increase in the number of centrosomes. Moreover, we find that centrosome area in near-tetraploids is twice as large as in near-diploids. To evaluate whether centrosome clustering was occurring, we next analysed the number of centrioles revealing centriole amplification. Notwithstanding, more than half of the near-tetraploids maintained in culture do not present centrosome aberrations. To test whether cells progressively lost centrioles after becoming near-tetraploid, we transiently transfected diploid cells with siRNA against ESPL1/Separase, a protease responsible for triggering anaphase, to generate newly near-tetraploid cells. Finally, using this model, we assessed the number of centrioles at different time-points after tetraploidization finding that near-tetraploids rapidly lose centrosomes over time. Taken together, these data demonstrate that although most cells reduce supernumerary centrosomes after tetraploidization, a small fraction retains extra centrioles, potentially resulting in CIN.
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13
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Hellmuth S, Stemmann O. Separase-triggered apoptosis enforces minimal length of mitosis. Nature 2020; 580:542-7. [PMID: 32322059 DOI: 10.1038/s41586-020-2187-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 02/10/2020] [Indexed: 01/13/2023]
Abstract
Prolonged mitosis often results in apoptosis1. Shortened mitosis causes tumorigenic aneuploidy, but it is unclear whether it also activates the apoptotic machinery2. Separase, a cysteine protease and trigger of all eukaryotic anaphases, has a caspase-like catalytic domain but has not previously been associated with cell death3,4. Here we show that human cells that enter mitosis with already active separase rapidly undergo death in mitosis owing to direct cleavage of anti-apoptotic MCL1 and BCL-XL by separase. Cleavage not only prevents MCL1 and BCL-XL from sequestering pro-apoptotic BAK, but also converts them into active promoters of death in mitosis. Our data strongly suggest that the deadliest cleavage fragment, the C-terminal half of MCL1, forms BAK/BAX-like pores in the mitochondrial outer membrane. MCL1 and BCL-XL are turned into separase substrates only upon phosphorylation by NEK2A. Early mitotic degradation of this kinase is therefore crucial for preventing apoptosis upon scheduled activation of separase in metaphase. Speeding up mitosis by abrogation of the spindle assembly checkpoint results in a temporal overlap of the enzymatic activities of NEK2A and separase and consequently in cell death. We propose that NEK2A and separase jointly check on spindle assembly checkpoint integrity and eliminate cells that are prone to chromosome missegregation owing to accelerated progression through early mitosis.
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14
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Hellmuth S, Gómez-H L, Pendás AM, Stemmann O. Securin-independent regulation of separase by checkpoint-induced shugoshin-MAD2. Nature 2020; 580:536-541. [PMID: 32322060 DOI: 10.1038/s41586-020-2182-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 01/31/2020] [Indexed: 01/27/2023]
Abstract
Separation of eukaryotic sister chromatids during the cell cycle is timed by the spindle assembly checkpoint (SAC) and ultimately triggered when separase cleaves cohesion-mediating cohesin1-3. Silencing of the SAC during metaphase activates the ubiquitin ligase APC/C (anaphase-promoting complex, also known as the cyclosome) and results in the proteasomal destruction of the separase inhibitor securin1. In the absence of securin, mammalian chromosomes still segregate on schedule, but it is unclear how separase is regulated under these conditions4,5. Here we show that human shugoshin 2 (SGO2), an essential protector of meiotic cohesin with unknown functions in the soma6,7, is turned into a separase inhibitor upon association with SAC-activated MAD2. SGO2-MAD2 can functionally replace securin and sequesters most separase in securin-knockout cells. Acute loss of securin and SGO2, but not of either protein individually, resulted in separase deregulation associated with premature cohesin cleavage and cytotoxicity. Similar to securin8,9, SGO2 is a competitive inhibitor that uses a pseudo-substrate sequence to block the active site of separase. APC/C-dependent ubiquitylation and action of the AAA-ATPase TRIP13 in conjunction with the MAD2-specific adaptor p31comet liberate separase from SGO2-MAD2 in vitro. The latter mechanism facilitates a considerable degree of sister chromatid separation in securin-knockout cells that lack APC/C activity. Thus, our results identify an unexpected function of SGO2 in mitotically dividing cells and a mechanism of separase regulation that is independent of securin but still supervised by the SAC.
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Affiliation(s)
| | - Laura Gómez-H
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Salamanca, Spain
| | - Alberto M Pendás
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Salamanca, Spain
| | - Olaf Stemmann
- Chair of Genetics, University of Bayreuth, Bayreuth, Germany.
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15
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Holder J, Poser E, Barr FA. Getting out of mitosis: spatial and temporal control of mitotic exit and cytokinesis by PP1 and PP2A. FEBS Lett 2019; 593:2908-2924. [PMID: 31494926 DOI: 10.1002/1873-3468.13595] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/31/2019] [Accepted: 08/19/2019] [Indexed: 12/11/2022]
Abstract
Here, we will review the evidence showing that mitotic exit is initiated by regulated proteolysis and then driven by the PPP family of phosphoserine/threonine phosphatases. Rapid APC/CCDC20 and ubiquitin-dependent proteolysis of cyclin B and securin initiates sister chromatid separation, the first step of mitotic exit. Because proteolysis of Aurora and Polo family kinases dependent on APC/CCDH1 is relatively slow, this creates a new regulatory state, anaphase, different to G2 and M-phase. We will discuss how the CDK1-counteracting phosphatases PP1 and PP2A-B55, together with Aurora and Polo kinases, contribute to the temporal regulation and order of events in the different stages of mitotic exit from anaphase to cytokinesis. For PP2A-B55, these timing properties are created by the ENSA-dependent inhibitory pathway and differential recognition of phosphoserine and phosphothreonine. Finally, we will discuss how Aurora B and PP2A-B56 are needed for the spatial regulation of anaphase spindle formation and how APC/C-dependent destruction of PLK1 acts as a timer for abscission, the final event of cytokinesis.
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Affiliation(s)
- James Holder
- Department of Biochemistry, University of Oxford, UK
| | - Elena Poser
- Department of Biochemistry, University of Oxford, UK
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16
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Lepage CC, Morden CR, Palmer MCL, Nachtigal MW, McManus KJ. Detecting Chromosome Instability in Cancer: Approaches to Resolve Cell-to-Cell Heterogeneity. Cancers (Basel) 2019; 11:E226. [PMID: 30781398 DOI: 10.3390/cancers11020226] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 02/07/2023] Open
Abstract
Chromosome instability (CIN) is defined as an increased rate of chromosome gains and losses that manifests as cell-to-cell karyotypic heterogeneity and drives cancer initiation and evolution. Current research efforts are aimed at identifying the etiological origins of CIN, establishing its roles in cancer pathogenesis, understanding its implications for patient prognosis, and developing novel therapeutics that are capable of exploiting CIN. Thus, the ability to accurately identify and evaluate CIN is critical within both research and clinical settings. Here, we provide an overview of quantitative single cell approaches that evaluate and resolve cell-to-cell heterogeneity and CIN, and discuss considerations when selecting the most appropriate approach to suit both research and clinical contexts.
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17
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Vassilev A, Lee CY, Vassilev B, Zhu W, Ormanoglu P, Martin SE, DePamphilis ML. Identification of genes that are essential to restrict genome duplication to once per cell division. Oncotarget 2018; 7:34956-76. [PMID: 27144335 PMCID: PMC5085202 DOI: 10.18632/oncotarget.9008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/07/2016] [Indexed: 12/02/2022] Open
Abstract
Nuclear genome duplication is normally restricted to once per cell division, but aberrant events that allow excess DNA replication (EDR) promote genomic instability and aneuploidy, both of which are characteristics of cancer development. Here we provide the first comprehensive identification of genes that are essential to restrict genome duplication to once per cell division. An siRNA library of 21,584 human genes was screened for those that prevent EDR in cancer cells with undetectable chromosomal instability. Candidates were validated by testing multiple siRNAs and chemical inhibitors on both TP53+ and TP53- cells to reveal the relevance of this ubiquitous tumor suppressor to preventing EDR, and in the presence of an apoptosis inhibitor to reveal the full extent of EDR. The results revealed 42 genes that prevented either DNA re-replication or unscheduled endoreplication. All of them participate in one or more of eight cell cycle events. Seventeen of them have not been identified previously in this capacity. Remarkably, 14 of the 42 genes have been shown to prevent aneuploidy in mice. Moreover, suppressing a gene that prevents EDR increased the ability of the chemotherapeutic drug Paclitaxel to induce EDR, suggesting new opportunities for synthetic lethalities in the treatment of human cancers.
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Affiliation(s)
- Alex Vassilev
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2753, USA
| | - Chrissie Y Lee
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2753, USA.,Current address: NantBioscience, Culver City, CA 90232, USA
| | - Boris Vassilev
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2753, USA
| | - Wenge Zhu
- Department of Biochemistry and Molecular Biology, George Washington University, Washington DC 20037, USA
| | - Pinar Ormanoglu
- National Center of Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Scott E Martin
- National Center of Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA.,Current Address: Genentech, Inc., South San Francisco, CA 94080, USA
| | - Melvin L DePamphilis
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2753, USA
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18
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Cucco F, Palumbo E, Camerini S, D’Alessio B, Quarantotti V, Casella ML, Rizzo IM, Cukrov D, Delia D, Russo A, Crescenzi M, Musio A. Separase prevents genomic instability by controlling replication fork speed. Nucleic Acids Res 2018; 46:267-278. [PMID: 29165708 PMCID: PMC5758895 DOI: 10.1093/nar/gkx1172] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/26/2017] [Accepted: 11/10/2017] [Indexed: 01/21/2023] Open
Abstract
Proper chromosome segregation is crucial for preserving genomic integrity, and errors in this process cause chromosome mis-segregation, which may contribute to cancer development. Sister chromatid separation is triggered by Separase, an evolutionary conserved protease that cleaves the cohesin complex, allowing the dissolution of sister chromatid cohesion. Here we provide evidence that Separase participates in genomic stability maintenance by controlling replication fork speed. We found that Separase interacted with the replication licensing factors MCM2-7, and genome-wide data showed that Separase co-localized with MCM complex and cohesin. Unexpectedly, the depletion of Separase increased the fork velocity about 1.5-fold and caused a strong acetylation of cohesin's SMC3 subunit and altered checkpoint response. Notably, Separase silencing triggered genomic instability in both HeLa and human primary fibroblast cells. Our results show a novel mechanism for fork progression mediated by Separase and thus the basis for genomic instability associated with tumorigenesis.
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Affiliation(s)
- Francesco Cucco
- Institute for Biomedical and Genetic Research, National Research Council, Pisa, Italy
| | - Elisa Palumbo
- Department of Biology, University of Padua, Padua, Italy
| | - Serena Camerini
- Department of Cell Biology and Neurosciences, National Institute of Health, Rome, Italy
| | - Barbara D’Alessio
- Institute for Biomedical and Genetic Research, National Research Council, Pisa, Italy
| | - Valentina Quarantotti
- Institute for Biomedical and Genetic Research, National Research Council, Pisa, Italy
| | - Maria Luisa Casella
- Department of Cell Biology and Neurosciences, National Institute of Health, Rome, Italy
| | - Ilaria Maria Rizzo
- Institute for Biomedical and Genetic Research, National Research Council, Pisa, Italy
| | - Dubravka Cukrov
- Institute for Biomedical and Genetic Research, National Research Council, Pisa, Italy
| | - Domenico Delia
- Fondazione IRCCS Istituto Nazionale Tumori, Department of Experimental Oncology, Milan, Italy
| | - Antonella Russo
- Department of Biology, University of Padua, Padua, Italy
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Marco Crescenzi
- Department of Cell Biology and Neurosciences, National Institute of Health, Rome, Italy
| | - Antonio Musio
- Institute for Biomedical and Genetic Research, National Research Council, Pisa, Italy
- Tumour Institute of Tuscany, Florence, Italy
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19
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Abstract
As carriers of the genetic material, chromosomes are of prime interest in the life sciences. Although all aspects of chromosome biology should ideally be studied in living cells, the isolation of chromosomes can greatly facilitate their analysis. This can be achieved by lysing mitotic or meiotic cells under conditions where their content, including their chromosomes, is spread out on the surface of microscopy glass slides. Here we describe three such chromosome spreading techniques, which have been instrumental in analyzing chromosomes from either mouse oocytes or mammalian cultured cells in mitosis. For both chromosomes from oocytes and mitotic cells, we describe immunofluorescence protocols that enable the visualization of proteins with specific antibodies. For mitotic chromosomes, we also provide a classic protocol for Giemsa staining. This protocol cannot be used to localize proteins but is useful to determine structural features of chromosomes, such as sister chromatid cohesion and chromosome condensation. The question of how chromosome nondisjunction during the meiotic division causes aneuploidy is of great interest in oocyte chromosome research. Because we have found that ploidy in mouse oocytes can be determined more reliably in fixed cells than in spread chromosomes, we also describe a protocol for the in situ fixation and immunofluorescence analysis of chromosomes in mouse oocytes.
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Affiliation(s)
- Mariana C C Silva
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Gordana Wutz
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Kikuë Tachibana
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
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20
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Abstract
In this era of high-resolution mapping of chromosome territories, topological interactions, and chromatin states, it is increasingly appreciated that the positioning of chromosomes and their interactions within the nucleus is critical for cellular function. Due to their large size and distinctive structure, polytene chromosomes have contributed a wealth of knowledge regarding chromosome regulation. In this review, we discuss the diversity of polytene chromosomes in nature and in disease, examine the recurring structural features of polytene chromosomes in terms of what they reveal about chromosome biology, and discuss recent advances regarding how polytene chromosomes are assembled and disassembled. After over 130 years of study, these giant chromosomes are still powerful tools to understand chromosome biology.
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Affiliation(s)
- Benjamin M Stormo
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Donald T Fox
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, 27710, USA.
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21
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Zhang N, Pati D. Biology and insights into the role of cohesin protease separase in human malignancies. Biol Rev Camb Philos Soc 2017; 92:2070-2083. [PMID: 28177203 DOI: 10.1111/brv.12321] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/05/2017] [Accepted: 01/12/2017] [Indexed: 12/11/2022]
Abstract
Separase, an enzyme that resolves sister chromatid cohesion during the metaphase-to-anaphase transition, plays a pivotal role in chromosomal segregation and cell division. Separase protein, encoded by the extra spindle pole bodies like 1 (ESPL1) gene, is overexpressed in numerous human cancers including breast, bone, brain, and prostate. Separase is oncogenic, and its overexpression is sufficient to induce mammary tumours in mice. Either acute or chronic overexpression of separase in mouse mammary glands leads to aneuploidy and tumorigenesis, and inhibition of separase enzymatic activity decreases the growth of human breast tumour xenografts in mice. This review focuses on the biology of and insights into the molecular mechanisms of separase as an oncogene, and its significance and implications for human cancers.
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Affiliation(s)
- Nenggang Zhang
- Departments of Pediatrics and Molecular and Cellular Biology, Texas Children's Cancer Center, Baylor College of Medicine, 1102 Bates St., FC1220, Houston, TX 77030, U.S.A
| | - Debananda Pati
- Departments of Pediatrics and Molecular and Cellular Biology, Texas Children's Cancer Center, Baylor College of Medicine, 1102 Bates St., FC1220, Houston, TX 77030, U.S.A
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22
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Abstract
Separase has a critical role in dissolving the cohesion among sister chromatids during chromosome segregation 1–7. Separase is over-expressed in human tumors, making it a potential target for drug discovery 8. The protease activity of separase is strictly regulated by the inhibitor securin, which forms a tight complex with separase and may also stabilize this enzyme 9–16. Separases are large, 140–250 kD enzymes, with an N-terminal α-helical region and a caspase-like catalytic domain (CD) at the C-terminus. While crystal structures of the C-terminal two domains of separase 17 and low-resolution electron microscopy reconstructions of the separase-securin complex 18,19 have been reported, the atomic structures of full-length separase and especially the complex with securin are not known. Here we report crystal structures at up to 2.6 Å resolution of the yeast Saccharomyces cerevisiae separase-securin complex. The α-helical region of separase (also known as Esp1) contains four domains (I–IV), and a substrate-binding domain (SD) immediately precedes the CD and has tight associations with it. The separase-securin complex assumes a highly elongated structure. Residues 258–373 of securin (Pds1), named the separase interaction segment (SIS), is primarily in an extended conformation and traverses the entire length of separase, having interactions with all of its domains. Most importantly, residues 258–269 of securin are located in the separase active site, illuminating its mechanism of inhibition. Biochemical studies confirm the structural observations and indicate that contacts outside the separase active site are crucial for stabilizing the complex, thereby defining an important function for the helical region of separase.
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Affiliation(s)
- Shukun Luo
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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23
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Vassilev A, DePamphilis ML. Links between DNA Replication, Stem Cells and Cancer. Genes (Basel). 2017;8. [PMID: 28125050 PMCID: PMC5333035 DOI: 10.3390/genes8020045] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/02/2017] [Accepted: 01/12/2017] [Indexed: 12/31/2022] Open
Abstract
Cancers can be categorized into two groups: those whose frequency increases with age, and those resulting from errors during mammalian development. The first group is linked to DNA replication through the accumulation of genetic mutations that occur during proliferation of developmentally acquired stem cells that give rise to and maintain tissues and organs. These mutations, which result from DNA replication errors as well as environmental insults, fall into two categories; cancer driver mutations that initiate carcinogenesis and genome destabilizing mutations that promote aneuploidy through excess genome duplication and chromatid missegregation. Increased genome instability results in accelerated clonal evolution leading to the appearance of more aggressive clones with increased drug resistance. The second group of cancers, termed germ cell neoplasia, results from the mislocation of pluripotent stem cells during early development. During normal development, pluripotent stem cells that originate in early embryos give rise to all of the cell lineages in the embryo and adult, but when they mislocate to ectopic sites, they produce tumors. Remarkably, pluripotent stem cells, like many cancer cells, depend on the Geminin protein to prevent excess DNA replication from triggering DNA damage-dependent apoptosis. This link between the control of DNA replication during early development and germ cell neoplasia reveals Geminin as a potential chemotherapeutic target in the eradication of cancer progenitor cells.
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Abstract
Proper and timely segregation of genetic endowment is necessary for survival and perpetuation of every species. Mis-segregation of chromosomes and resulting aneuploidy leads to genetic instability, which can jeopardize the survival of an individual or population as a whole. Abnormality with segregation of genetic contents has been associated with several medical consequences including cancer, sterility, mental retardation, spontaneous abortion, miscarriages, and other birth related defects. Separase, by irreversible cleavage of cohesin complex subunit, paves the way for metaphase/anaphase transition during the cell cycle. Both over or reduced expression and altered level of separase have been associated with several medical consequences including cancer, as a result separase now emerges as an important oncogene and potential molecular target for medical intervenes. Recently, separase is also found to be essential in separation and duplication of centrioles. Here, I review the role of separase in mitosis, meiosis, non-canonical roles of separase, separase regulation, as a regulator of centriole disengagement, nonproteolytic roles, diverse substrates, structural insights, and association of separase with cancer. At the ends, I proposed a model which showed that separase is active throughout the cell cycle and there is a mere increase in separase activity during metaphase contrary to the common believes that separase is inactive throughout cell cycle except for metaphase. J. Cell. Biochem. 118: 1283-1299, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ravinder Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, Maharashtra, India
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25
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Abstract
Cohesin is a large ring-shaped protein complex, conserved from yeast to human, which participates in most DNA transactions that take place in the nucleus. It mediates sister chromatid cohesion, which is essential for chromosome segregation and homologous recombination (HR)-mediated DNA repair. Together with architectural proteins and transcriptional regulators, such as CTCF and Mediator, respectively, it contributes to genome organization at different scales and thereby affects transcription, DNA replication, and locus rearrangement. Although cohesin is essential for cell viability, partial loss of function can affect these processes differently in distinct cell types. Mutations in genes encoding cohesin subunits and regulators of the complex have been identified in several cancers. Understanding the functional significance of these alterations may have relevant implications for patient classification, risk prediction, and choice of treatment. Moreover, identification of vulnerabilities in cancer cells harboring cohesin mutations may provide new therapeutic opportunities and guide the design of personalized treatments.
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Affiliation(s)
- Magali De Koninck
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | - Ana Losada
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
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26
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Abstract
Significance: All organs suffer wounds to some extent during an animal's lifetime and to compensate for cell loss, tissues often rely on cell division. However, many organs are made up of differentiated cells with only a limited capacity to divide. It is not well understood how cells are replaced in the absence of cell division. Recent Advances: Recent studies in the model organism Drosophila melanogaster have proven that wound-induced polyploidy (WIP) is an essential mechanism to replace tissue mass and restore tissue integrity in the absence of cell division. In this repair mechanism, preexisting differentiated cells increase their DNA content and cell size by becoming polyploid. Critical Issues: Cells within mammalian organs such as the liver, heart, and cornea have also been observed to increase their DNA ploidy in response to injury, suggesting that WIP may be an evolutionarily conserved mechanism to compensate for cell loss. Future Directions: The Hippo signal transduction pathway is required for differentiated cells to initiate WIP in Drosophila. Continued studies in Drosophila will help to identify other signaling pathways required for WIP as well as the conserved mechanisms that polyploid cells may play during wound repair in all organisms.
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Affiliation(s)
- Vicki P. Losick
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland
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27
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Abstract
Duplicating chromosomes once each cell cycle produces sister chromatid pairs, which separate accurately at anaphase. In contrast, reduplicating chromosomes without separation frequently produces polytene chromosomes, a barrier to accurate mitosis. Chromosome reduplication occurs in many contexts, including: polytene tissue development, polytene tumors, and following treatment with mitosis-blocking chemotherapeutics. However, mechanisms responding to or resolving polyteny during mitosis are poorly understood. Here, using Drosophila, we uncover two distinct reduplicated chromosome responses. First, when reduplicated polytene chromosomes persist into metaphase, an anaphase delay prevents tissue malformation and apoptosis. Second, reduplicated polytene chromosomes can also separate prior to metaphase through a spindle-independent mechanism termed Separation-Into-Recent-Sisters (SIRS). Both reduplication responses require the spindle assembly checkpoint protein Mad2. While Mad2 delays anaphase separation of metaphase polytene chromosomes, Mad2’s control of overall mitotic timing ensures efficient SIRS. Our results pinpoint mechanisms enabling continued proliferation after genome reduplication, a finding with implications for cancer progression and prevention. DOI:http://dx.doi.org/10.7554/eLife.15204.001 Before a cell divides, it duplicates all its genetic information, which is stored on chromosomes. Then, each chromosome evenly divides into two new cells so that each cell ends up with identical copies of the genetic information. Because the cellular machinery that evenly divides chromosomes is built to recognize chromosomes that were duplicated exactly once, it is important to maintain this pattern of alternating one round of duplication with one round of division. Cells that instead duplicate their chromosomes more than once can make mistakes during division that are associated with diseases such as cancer. Chromosomes with extra duplications are present in normal tissues such as the placenta of mammals. They can also occur in human diseases and may even result from chemotherapy treatment. However, we know almost nothing about how cells respond to these problematic chromosomes when dividing. By studying cells from the Drosophila melanogaster species of fruit fly, Stormo and Fox discovered two distinct ways in which cells respond to extra chromosome duplications. One response occurs in cells that were experimentally engineered to undergo an extra chromosome duplication. These cells delay division so that the chromosome separation machinery can somehow adapt to the challenge of separating more than two chromosome copies at once. The second response occurs in cells that naturally undergo extra chromosome duplications before division. In these cells, Stormo and Fox discovered a new type of chromosome separation, whereby the extra chromosome copies move apart from each other before cell division. In doing so the chromosomes can better interact with the chromosome separation machinery during division. Stormo and Fox also found that a protein named Mad2 is important in both responses, and gives the cell enough time to respond to extra chromosome copies. Without Mad2, the separation of chromosomes with extra duplications is too hasty, and can lead to severe cell division errors and cause organs to form incorrectly. Having uncovered two new responses that cells use to adapt to extra chromosomes, it will now be important to find other proteins like Mad2 that are important in these events. Understanding these processes and the proteins involved in more detail could help to prevent diseases that are associated with extra chromosomes. DOI:http://dx.doi.org/10.7554/eLife.15204.002
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Affiliation(s)
- Benjamin M Stormo
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Donald T Fox
- Department of Cell Biology, Duke University Medical Center, Durham, United States.,Department of Pharamacology and Cancer biology, Duke University Medical Center, Durham, United States
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28
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Bachmann G, Richards MW, Winter A, Beuron F, Morris E, Bayliss R. A closed conformation of the Caenorhabditis elegans separase-securin complex. Open Biol 2016; 6:160032. [PMID: 27249343 PMCID: PMC4852461 DOI: 10.1098/rsob.160032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/18/2016] [Indexed: 11/12/2022] Open
Abstract
The protease separase plays a key role in sister chromatid disjunction and centriole disengagement. To maintain genomic stability, separase activity is strictly regulated by binding of an inhibitory protein, securin. Despite its central role in cell division, the separase and securin complex is poorly understood at the structural level. This is partly owing to the difficulty of generating a sufficient quantity of homogeneous, stable protein. Here, we report the production of Caenorhabditis elegans separase-securin complex, and its characterization using biochemical methods and by negative staining electron microscopy. Single particle analysis generated a density map at a resolution of 21-24 Å that reveals a close, globular structure of complex connectivity harbouring two lobes. One lobe matches closely a homology model of the N-terminal HEAT repeat domain of separase, whereas the second lobe readily accommodates homology models of the separase C-terminal death and caspase-like domains. The globular structure of the C. elegans separase-securin complex contrasts with the more elongated structure previously described for the Homo sapiens complex, which could represent a different functional state of the complex, suggesting a mechanism for the regulation of separase activity through conformational change.
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Affiliation(s)
- Gudrun Bachmann
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Mark W Richards
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK Department of Molecular and Cell Biology, University of Leicester, Leicester LE2 9HN, UK Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Anja Winter
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE2 9HN, UK
| | - Fabienne Beuron
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Edward Morris
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Richard Bayliss
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK Department of Molecular and Cell Biology, University of Leicester, Leicester LE2 9HN, UK Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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29
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Losick VP, Jun AS, Spradling AC. Wound-Induced Polyploidization: Regulation by Hippo and JNK Signaling and Conservation in Mammals. PLoS One 2016; 11:e0151251. [PMID: 26958853 PMCID: PMC4784922 DOI: 10.1371/journal.pone.0151251] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 02/25/2016] [Indexed: 12/13/2022] Open
Abstract
Tissue integrity and homeostasis often rely on the proliferation of stem cells or differentiated cells to replace lost, aged, or damaged cells. Recently, we described an alternative source of cell replacement- the expansion of resident, non-dividing diploid cells by wound-induced polyploidization (WIP). Here we show that the magnitude of WIP is proportional to the extent of cell loss using a new semi-automated assay with single cell resolution. Hippo and JNK signaling regulate WIP; unexpectedly however, JNK signaling through AP-1 limits rather than stimulates the level of Yki activation and polyploidization in the Drosophila epidermis. We found that polyploidization also quantitatively compensates for cell loss in a mammalian tissue, mouse corneal endothelium, where increased cell death occurs with age in a mouse model of Fuchs Endothelial Corneal Dystrophy (FECD). Our results suggest that WIP is an evolutionarily conserved homeostatic mechanism that maintains the size and synthetic capacity of adult tissues.
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Affiliation(s)
- Vicki P. Losick
- Department of Embryology, Carnegie Institution for Science, Howard Hughes Medical Institute, 3250 San Martin Dr., Baltimore, MD 21218, United States of America
| | - Albert S. Jun
- Wilmer Eye Institute, Johns Hopkins School of Medicine, 400 N. Broadway, Baltimore, MD 21231, United States of America
| | - Allan C. Spradling
- Department of Embryology, Carnegie Institution for Science, Howard Hughes Medical Institute, 3250 San Martin Dr., Baltimore, MD 21218, United States of America
- * E-mail:
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30
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Thompson LL, McManus KJ. A novel multiplexed, image-based approach to detect phenotypes that underlie chromosome instability in human cells. PLoS One 2015; 10:e0123200. [PMID: 25893404 PMCID: PMC4404342 DOI: 10.1371/journal.pone.0123200] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/19/2015] [Indexed: 11/30/2022] Open
Abstract
Chromosome instability (CIN) is characterized by a progressive change in chromosome numbers. It is a characteristic common to virtually all tumor types, and is commonly observed in highly aggressive and drug resistant tumors. Despite this information, the majority of human CIN genes have yet to be elucidated. In this study, we developed and validated a multiplexed, image-based screen capable of detecting three different phenotypes associated with CIN. Large-scale chromosome content changes were detected by quantifying changes in nuclear volumes following RNAi-based gene silencing. Using a DsRED-LacI reporter system to fluorescently label chromosome 11 within a human fibrosarcoma cell line, we were able to detect deviations from the expected number of two foci per nucleus (one focus/labelled chromosome) that occurred following CIN gene silencing. Finally, micronucleus enumeration was performed, as an increase in micronucleus formation is a classic hallmark of CIN. To validate the ability of each assay to detect phenotypes that underlie CIN, we silenced the established CIN gene, SMC1A. Following SMC1A silencing we detected an increase in nuclear volumes, a decrease in the number of nuclei harboring two DsRED-LacI foci, and an increase in micronucleus formation relative to controls (untreated and siGAPDH). Similar results were obtained in an unrelated human fibroblast cell line. The results of this study indicate that each assay is capable of detecting CIN-associated phenotypes, and can be utilized in future experiments to uncover novel human CIN genes, which will provide novel insight into the pathogenesis of cancer.
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Affiliation(s)
- Laura L. Thompson
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
- Manitoba Institute of Cell Biology, Winnipeg, Manitoba, Canada
| | - Kirk J. McManus
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
- Manitoba Institute of Cell Biology, Winnipeg, Manitoba, Canada
- * E-mail:
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31
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Hellmuth S, Pöhlmann C, Brown A, Böttger F, Sprinzl M, Stemmann O. Positive and negative regulation of vertebrate separase by Cdk1-cyclin B1 may explain why securin is dispensable. J Biol Chem 2015; 290:8002-10. [PMID: 25659430 DOI: 10.1074/jbc.m114.615310] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sister chromatid cohesion is established during replication by entrapment of both dsDNAs within the cohesin ring complex. It is dissolved in anaphase when separase, a giant cysteine endopeptidase, cleaves the Scc1/Rad21 subunit of cohesin, thereby triggering chromosome segregation. Separase is held inactive by association with securin until this anaphase inhibitor is destroyed at the metaphase-to-anaphase transition by ubiquitin-dependent degradation. The relevant ubiquitin ligase, the anaphase-promoting complex/cyclosome, also targets cyclin B1, thereby causing inactivation of Cdk1 and mitotic exit. Although separase is essential, securin knock-out mice are surprisingly viable and fertile. Capitalizing on our previous finding that Cdk1-cyclin B1 can also bind and inhibit separase, we investigated whether this kinase might be suitable to maintain faithful timing and execution of anaphase in the absence of securin. We found that, similar to securin, Cdk1-cyclin B1 regulates separase in both a positive and negative manner. Although securin associates with nascent separase to co-translationally assist proper folding, Cdk1-cyclin B1 acts on native state separase. Upon entry into mitosis, Cdk1-cyclin B1-dependent phosphorylation of Ser-1126 renders separase prone to inactivation by aggregation/precipitation. Stable association of Cdk1-cyclin B1 with phosphorylated separase counteracts this tendency and stabilizes separase in an inhibited yet activatable state. These opposing effects are suited to prevent premature cleavage of cohesin in early mitosis while ensuring timely activation of separase by anaphase-promoting complex/cyclosome-dependent degradation of cyclin B1. Coupling sister chromatid separation with subsequent exit from mitosis by this simplified mode might have been the common scheme of mitotic control prior to the evolution of securin.
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Affiliation(s)
| | | | | | | | - Mathias Sprinzl
- Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
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Zhang N, Pati D. C-terminus of Sororin interacts with SA2 and regulates sister chromatid cohesion. Cell Cycle 2015; 14:820-6. [PMID: 25608232 PMCID: PMC4614265 DOI: 10.1080/15384101.2014.1000206] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 01/11/2023] Open
Abstract
Sororin is a conserved protein required for accurate separation of sister chromatids in each cell cycle. Sororin is recruited to chromatin during DNA replication, protects sister chromatid cohesion in S and G2 phase, and regulates the resolution of sister chromatid cohesion in mitosis. Sororin binds to cohesin complex, but how Sororin and cohesin subunits interact remains unclear. Here we report that the C-terminus of Sororin, especially the last 12 amino acid (aa) residues, is important for Sororin to bind cohesin core subunit SA2. Deletion of the last 12aa residues not only inhibits the interactions between Sororin and SA2 but also causes precocious chromosome separation. Our data suggest that the C-terminus of Sororin functions as an anchor binding to SA2, which facilitates other conserved motifs on Sororin to interact with other proteins to regulate sister chromatid cohesion and separation.
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Affiliation(s)
- Nenggang Zhang
- Texas Children's Cancer Center; Department of Pediatric Hematology/Oncology; Baylor College of Medicine; Houston, TX USA
| | - Debananda Pati
- Texas Children's Cancer Center; Department of Pediatric Hematology/Oncology; Baylor College of Medicine; Houston, TX USA
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33
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Abstract
Chromosome segregation is a tightly regulated process through which duplicated genetic materials are equally partitioned into daughter cells. During the past decades, tremendous efforts have been made to understand the molecular mechanism of chromosome segregation using animals and yeasts as model systems. Recently, new insights into chromosome segregation have gradually emerged using trypanosome, an early branching parasitic protozoan, as a model organism. To uncover the unique aspects of chromosome segregation in trypanosome, which potentially could serve as new drug targets for anti-trypanosome chemotherapy, it is necessary to perform a comparative analysis of the chromosome segregation machinery between trypanosome and its human host. Here, we briefly review the current knowledge about chromosome segregation in human and Trypanosoma brucei, with a focus on the regulation of cohesin and securin degradation triggered by the activation of the anaphase promoting complex/cyclosome (APC/C). We also include yeasts in our comparative analysis since some of the original discoveries were made using budding and fission yeasts as the model organisms and, therefore, these could provide hints about the evolution of the machinery. We highlight both common and unique features in these model systems and also provide perspectives for future research in trypanosome.
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Affiliation(s)
- Xianxian Han
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, TX 77030, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, TX 77030, USA
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Chen T, Sun Y, Ji P, Kopetz S, Zhang W. Topoisomerase IIα in chromosome instability and personalized cancer therapy. Oncogene 2014; 34:4019-31. [PMID: 25328138 PMCID: PMC4404185 DOI: 10.1038/onc.2014.332] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/08/2014] [Accepted: 09/08/2014] [Indexed: 12/29/2022]
Abstract
Genome instability is a hallmark of cancer cells. Chromosome instability (CIN), which is often mutually exclusive from hypermutation genotypes, represents a distinct subtype of genome instability. Hypermutations in cancer cells are due to defects in DNA repair genes, but the cause of CIN is still elusive. However, because of the extensive chromosomal abnormalities associated with CIN, its cause is likely a defect in a network of genes that regulate mitotic checkpoints and chromosomal organization and segregation. Emerging evidence has shown that the chromosomal decatenation checkpoint, which is critical for chromatin untangling and packing during genetic material duplication, is defective in cancer cells with CIN. The decatenation checkpoint is known to be regulated by a family of enzymes called topoisomerases. Among them, the gene encoding topoisomerase IIα (TOP2A) is commonly altered at both gene copy number and gene expression level in cancer cells. Thus, abnormal alterations of TOP2A, its interacting proteins, and its modifications may play a critical role in CIN in human cancers. Clinically, a large arsenal of topoisomerase inhibitors have been used to suppress DNA replication in cancer. However, they often lead to the secondary development of leukemia because of their effect on the chromosomal decatenation checkpoint. Therefore, topoisomerase drugs must be used judiciously and administered on an individual basis. In this review, we highlight the biological function of TOP2A in chromosome segregation and the mechanisms that regulate this enzyme's expression and activity. We also review the roles of TOP2A and related proteins in human cancers, and raise a perspective for how to target TOP2A in personalized cancer therapy.
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Affiliation(s)
- T Chen
- 1] Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA [2] Department of Endoscopy Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Y Sun
- Department of Pathology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - P Ji
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - S Kopetz
- Department of Gastrointestinal Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - W Zhang
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Abstract
Cyclins B1 and B2 are frequently elevated in human cancers and are associated with tumour aggressiveness and poor clinical outcome; however, whether and how B-type cyclins drive tumorigenesis is unknown. Here we show that cyclin B1 and B2 transgenic mice are highly prone to tumours, including tumour types where B-type cyclins serve as prognosticators. Cyclins B1 and B2 both induce aneuploidy when overexpressed but through distinct mechanisms, with cyclin B1 inhibiting separase activation, leading to anaphase bridges, and cyclin B2 triggering aurora-A-mediated Plk1 hyperactivation, resulting in accelerated centrosome separation and lagging chromosomes. Complementary experiments revealed that cyclin B2 and p53 act antagonistically to control aurora-A-mediated centrosome splitting and accurate chromosome segregation in normal cells. These data demonstrate a causative link between B-type cyclin overexpression and tumour pathophysiology, and uncover previously unknown functions of cyclin B2 and p53 in centrosome separation that may be perturbed in many human cancers.
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Affiliation(s)
- Hyun-Ja Nam
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - Jan M. van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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36
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Abstract
The universal triggering event of eukaryotic chromosome segregation is cleavage of centromeric cohesin by separase. Prior to anaphase, most separase is kept inactive by association with securin. Protein phosphatase 2A (PP2A) constitutes another binding partner of human separase, but the functional relevance of this interaction has remained enigmatic. We demonstrate that PP2A stabilizes separase-associated securin by dephosphorylation, while phosphorylation of free securin enhances its polyubiquitylation by the ubiquitin ligase APC/C and proteasomal degradation. Changing PP2A substrate phosphorylation sites to alanines slows degradation of free securin, delays separase activation, lengthens early anaphase, and results in anaphase bridges and DNA damage. In contrast, separase-associated securin is destabilized by introduction of phosphorylation-mimetic aspartates or extinction of separase-associated PP2A activity. G2- or prometaphase-arrested cells suffer from unscheduled activation of separase when endogenous securin is replaced by aspartate-mutant securin. Thus, PP2A-dependent stabilization of separase-associated securin prevents precocious activation of separase during checkpoint-mediated arrests with basal APC/C activity and increases the abruptness and fidelity of sister chromatid separation in anaphase.
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Affiliation(s)
| | | | - Cuiping Pan
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Olaf Stemmann
- Chair of Genetics, University of Bayreuth, Bayreuth, Germany
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Edgar BA, Zielke N, Gutierrez C. Endocycles: a recurrent evolutionary innovation for post-mitotic cell growth. Nat Rev Mol Cell Biol 2014; 15:197-210. [PMID: 24556841 DOI: 10.1038/nrm3756] [Citation(s) in RCA: 244] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In endoreplication cell cycles, known as endocycles, cells successively replicate their genomes without segregating chromosomes during mitosis and thereby become polyploid. Such cycles, for which there are many variants, are widespread in protozoa, plants and animals. Endocycling cells can achieve ploidies of >200,000 C (chromatin-value); this increase in genomic DNA content allows a higher genomic output, which can facilitate the construction of very large cells or enhance macromolecular secretion. These cells execute normal S phases, using a G1-S regulatory apparatus similar to the one used by mitotic cells, but their capability to segregate chromosomes has been suppressed, typically by downregulation of mitotic cyclin-dependent kinase activity. Endocycles probably evolved many times, and the various endocycle mechanisms found in nature highlight the versatility of the cell cycle control machinery.
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38
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Adhikari D, Liu K. The regulation of maturation promoting factor during prophase I arrest and meiotic entry in mammalian oocytes. Mol Cell Endocrinol 2014; 382:480-487. [PMID: 23916417 DOI: 10.1016/j.mce.2013.07.027] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/25/2013] [Accepted: 07/26/2013] [Indexed: 11/30/2022]
Abstract
Mammalian oocytes arrest at prophase of meiosis I at around birth and they remain arrested at this stage until puberty when the preovulatory surge of luteinizing hormone (LH) causes ovulation. Prophase I arrest in the immature oocyte results from the maintenance of low activity of maturation promoting factor (MPF), which consists of a catalytic subunit (CDK1) and regulatory subunit (cyclin B1). Phosphorylation-mediated inactivation of CDK1 and constant degradation of cyclin B1 keep MPF activity low during prophase I arrest. LH-mediated signaling manipulates a vast array of molecules to activate CDK1. Active CDK1 not only phosphorylates different meiotic phosphoproteins during the resumption of meiosis but also inhibits their rapid dephosphorylation by inhibiting the activities of CDK1 antagonizing protein phosphatases (PPs). In this way, CDK1 both phosphorylates its substrates and protects them from being dephosphorylated. Accumulating evidence suggests that the net MPF activity that drives the resumption of meiosis in oocytes depends on the activation status of CDK1 antagonizing PPs. This review aims to provide a summary of the current understanding of the signaling pathways involved in regulating MPF activity during prophase I arrest and reentry into meiosis of mammalian oocytes.
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Affiliation(s)
- Deepak Adhikari
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
| | - Kui Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
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39
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Abstract
Studies on budding yeast have exposed the highly conserved mechanisms by which duplicated chromosomes are evenly distributed to daughter cells at the metaphase-anaphase transition. The establishment of proteinaceous bridges between sister chromatids, a function provided by a ring-shaped complex known as cohesin, is central to accurate segregation. It is the destruction of this cohesin that triggers the segregation of chromosomes following their proper attachment to microtubules. Since it is irreversible, this process must be tightly controlled and driven to completion. Furthermore, during meiosis, modifications must be put in place to allow the segregation of maternal and paternal chromosomes in the first division for gamete formation. Here, I review the pioneering work from budding yeast that has led to a molecular understanding of the establishment and destruction of cohesion.
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Affiliation(s)
- Adele L Marston
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
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40
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Tedeschi A, Wutz G, Huet S, Jaritz M, Wuensche A, Schirghuber E, Davidson IF, Tang W, Cisneros DA, Bhaskara V, Nishiyama T, Vaziri A, Wutz A, Ellenberg J, Peters JM. Wapl is an essential regulator of chromatin structure and chromosome segregation. Nature 2013; 501:564-8. [PMID: 23975099 PMCID: PMC6080692 DOI: 10.1038/nature12471] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 07/16/2013] [Indexed: 12/23/2022]
Abstract
Mammalian genomes contain several billion base pairs of DNA that are packaged in chromatin fibres. At selected gene loci, cohesin complexes have been proposed to arrange these fibres into higher-order structures, but how important this function is for determining overall chromosome architecture and how the process is regulated are not well understood. Using conditional mutagenesis in the mouse, here we show that depletion of the cohesin-associated protein Wapl stably locks cohesin on DNA, leads to clustering of cohesin in axial structures, and causes chromatin condensation in interphase chromosomes. These findings reveal that the stability of cohesin-DNA interactions is an important determinant of chromatin structure, and indicate that cohesin has an architectural role in interphase chromosome territories. Furthermore, we show that regulation of cohesin-DNA interactions by Wapl is important for embryonic development, expression of genes such as c-myc (also known as Myc), and cell cycle progression. In mitosis, Wapl-mediated release of cohesin from DNA is essential for proper chromosome segregation and protects cohesin from cleavage by the protease separase, thus enabling mitotic exit in the presence of functional cohesin complexes.
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Affiliation(s)
- Antonio Tedeschi
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, 1030 Vienna, Austria
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41
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Abstract
Sister chromatid separation depends on the activity of separase, which in turn requires the proteolysis of its inhibitor, securin. It has been speculated that securin also supports the activation of separase. In this study, we found that PTTG1 was the major securin isoform expressed in most normal and cancer cell lines. Remarkably, a highly homologous isoform called PTTG2 was unable to interact with separase. Using chimeras between PTTG1 and PTTG2 and other approaches, we pinpointed a single amino acid that accounted for the loss of securin function in PTTG2. Mutation of the homologous position in PTTG1 (H(134)) switched PTTG1 from an inhibitor into an activator of separase. In agreement with this, PTTG1 lacking H(134) was able to trigger premature sister chromatid separation. Conversely, introduction of H(134) into PTTG2 is sufficient to allow it to bind separase. These data demonstrate that while the motif containing H(134) has a strong affinity for separase and is involved in inhibiting it, another domain(s) is involved in activating separase and has a weaker affinity for it. Although PTTG2 lacks securin function, its differences from PTTG1 provide evidence of independent inhibitory and activating functions of PTTG1 on separase.
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42
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Abstract
The liver has a remarkable capacity to regenerate. Even with surgical removal (partial hepatectomy) of 70% of liver mass, the remnant tissue grows to recover the original mass and functions. Liver regeneration after partial hepatectomy has been studied extensively since the 19th century, establishing the long-standing model that hepatocytes, which account for most of the liver weight, proliferate to recover the original mass of the liver. The basis of this model is the fact that almost all hepatocytes undergo S phase, as shown by the incorporation of radioactive nucleotides during liver regeneration. However, DNA replication does not necessarily indicate the execution of cell division, and a possible change in hepatocyte size is not considered in the model. In addition, as 15-30% of hepatocytes in adult liver are binuclear, the difference in nuclear number may affect the mode of cell division during regeneration. Thus, the traditional model seems to be oversimplified. Recently, we developed new techniques to investigate the process of liver regeneration, and revealed interesting features of hepatocytes. In this review, we first provide a historical overview of how the widely accepted model of liver regeneration was established and then discuss some overlooked observations together with our recent findings. Finally, we describe the revised model and perspectives on liver regeneration research.
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Affiliation(s)
- Yuichiro Miyaoka
- Laboratory of Cell Growth and Differentiation, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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43
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Abstract
Meiotic divisions (meiosis I and II) are specialized cell divisions to generate haploid gametes. The first meiotic division with the separation of chromosomes is named reductional division. The second division, which takes place immediately after meiosis I without intervening S-phase, is equational, with the separation of sister chromatids, similar to mitosis. This meiotic segregation pattern requires the two-step removal of the cohesin complex holding sister chromatids together: cohesin is removed from chromosome arms that have been subjected to homologous recombination in meiosis I and from the centromere region in meiosis II. Cohesin in the centromere region is protected from removal in meiosis I, but this protection has to be removed--deprotected--for sister chromatid segregation in meiosis II. Whereas the mechanisms of cohesin protection are quite well understood, the mechanisms of deprotection have been largely unknown until recently. In this review I summarize our current knowledge on cohesin deprotection.
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Howard-Till RA, Lukaszewicz A, Novatchkova M, Loidl J. A single cohesin complex performs mitotic and meiotic functions in the protist tetrahymena. PLoS Genet 2013; 9:e1003418. [PMID: 23555314 PMCID: PMC3610610 DOI: 10.1371/journal.pgen.1003418] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 02/12/2013] [Indexed: 01/08/2023] Open
Abstract
The cohesion of sister chromatids in the interval between chromosome replication and anaphase is important for preventing the precocious separation, and hence nondisjunction, of chromatids. Cohesion is accomplished by a ring-shaped protein complex, cohesin; and its release at anaphase occurs when separase cleaves the complex's α-kleisin subunit. Cohesin has additional roles in facilitating DNA damage repair from the sister chromatid and in regulating gene expression. We tested the universality of the present model of cohesion by studying cohesin in the evolutionarily distant protist Tetrahymena thermophila. Localization of tagged cohesin components Smc1p and Rec8p (the α-kleisin) showed that cohesin is abundant in mitotic and meiotic nuclei. RNAi knockdown experiments demonstrated that cohesin is crucial for normal chromosome segregation and meiotic DSB repair. Unexpectedly, cohesin does not detach from chromosome arms in anaphase, yet chromosome segregation depends on the activity of separase (Esp1p). When Esp1p is depleted by RNAi, chromosomes become polytenic as they undergo multiple rounds of replication, but fail to separate. The cohesion of such bundles of numerous chromatids suggests that chromatids may be connected by factors in addition to topological linkage by cohesin rings. Although cohesin is not detected in transcriptionally active somatic nuclei, its loss causes a slight defect in their amitotic division. Notably, Tetrahymena uses a single version of α-kleisin for both mitosis and meiosis. Therefore, we propose that the differentiation of mitotic and meiotic cohesins found in most other model systems is not due to the need of a specialized meiotic cohesin, but due to additional roles of mitotic cohesin.
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Affiliation(s)
- Rachel A. Howard-Till
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Agnieszka Lukaszewicz
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Maria Novatchkova
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
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45
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Panigrahi AK, Pati D. Higher-order orchestration of hematopoiesis: is cohesin a new player? Exp Hematol 2012; 40:967-73. [PMID: 23022223 PMCID: PMC3595174 DOI: 10.1016/j.exphem.2012.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 09/10/2012] [Accepted: 09/21/2012] [Indexed: 12/20/2022]
Abstract
Hematopoiesis-the process that generates distinct lineage-committed blood cells from a single multipotent hematopoietic stem cell-is a complex process of cellular differentiation regulated by a set of dynamic transcriptional programs. Cytokines and growth factors, transcription factors, chromatin remodeling, and modifying enzymes have been suggested to enact critical roles during hematopoiesis, leading to the development of myeloid, lymphoid, erythroid and platelet precursors. How is such a complex process orchestrated? Is there a higher order of hematopoiesis regulation? These are some of the unresolved questions in the field of hematopoiesis. Here, we suggest that cohesin, which is known to mediate chromosomal cohesion between sister chromatids, may have a central role in the orchestration of hematopoiesis and serve as a master transcriptional regulator.
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Affiliation(s)
- Anil K Panigrahi
- Texas Children's Cancer Center, Department of Pediatric Hematology/Oncology, Baylor College of Medicine, Houston, TX 77030, USA.
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46
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Abstract
Deviation from a balanced genome by either gain or loss of entire chromosomes is generally tolerated poorly in all eukaryotic systems studied to date. Errors in mitotic or meiotic cell division lead to aneuploidy, which places a burden of additional or insufficient gene products from the missegregated chromosomes on the daughter cells. The burden of aneuploidy often manifests itself as impaired fitness of individual cells and whole organisms, in which abnormal development is also characteristic. However, most human cancers, noted for their rapid growth, also display various levels of aneuploidy. Here we discuss the detrimental, potentially beneficial, and sometimes puzzling effects of aneuploidy on cellular and organismal fitness and tissue function as well as its role in diseases such as cancer and neurodegeneration.
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Affiliation(s)
- Jake J Siegel
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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47
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Holland AJ, Cleveland DW. Losing balance: the origin and impact of aneuploidy in cancer. EMBO Rep 2012; 13:501-14. [PMID: 22565320 DOI: 10.1038/embor.2012.55] [Citation(s) in RCA: 206] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/03/2012] [Indexed: 02/06/2023] Open
Abstract
Most solid human tumours are aneuploid, that is, they contain an abnormal number of chromosomes. Paradoxically, however, aneuploidy has been reported to induce a stress response that suppresses cellular proliferation in vitro. Here, we review the progress in our understanding of the causes and effects of aneuploidy in cancer and discuss how, in specific contexts, aneuploidy can provide a growth advantage and facilitate cellular transformation. We also explore the emerging possibilities for targeting the cause or consequences of aneuploidy therapeutically.
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48
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Pfau SJ, Amon A. Chromosomal instability and aneuploidy in cancer: from yeast to man. EMBO Rep 2012; 13:515-27. [PMID: 22614003 DOI: 10.1038/embor.2012.65] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/24/2012] [Indexed: 01/10/2023] Open
Abstract
Aneuploidy is frequently associated with disease and developmental abnormalities. It is also a key characteristic of cancer. Several model systems have been developed to study the role of chromosomal instability and aneuploidy in tumorigenesis. The results are surprisingly complex, with the conditions sometimes promoting and sometimes inhibiting tumour formation. Here, we review the effects of aneuploidy and chromosomal instability in cells and model systems of cancer, propose a model that could explain these complex findings and discuss how the aneuploid condition could be exploited in cancer therapy.
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49
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Miyaoka Y, Ebato K, Kato H, Arakawa S, Shimizu S, Miyajima A. Hypertrophy and unconventional cell division of hepatocytes underlie liver regeneration. Curr Biol 2012; 22:1166-75. [PMID: 22658593 DOI: 10.1016/j.cub.2012.05.016] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/28/2012] [Accepted: 05/09/2012] [Indexed: 02/08/2023]
Abstract
BACKGROUND The size of organs and tissues is basically determined by the number and size of their cells. However, little attention has been paid to this fundamental concept. The liver has a remarkable ability to regenerate after surgical resection (partial hepatectomy [PHx]), and hepatocytes account for about 80% of liver weight, so we investigate how the number and size of hepatocytes contribute to liver regeneration in mice. It has been generally accepted that hepatocytes undergo one or two rounds of cell division after 70% PHx. However, ploidy of hepatocytes is known to increase during regeneration, suggesting an unconventional cell cycle. We therefore examine cell cycle of hepatocytes in detail. RESULTS By developing a method for genetic fate mapping and a high-throughput imaging system of individual hepatocytes, we show that cellular hypertrophy makes the first contribution to liver regeneration; i.e., regeneration after 30% PHx is achieved solely by hypertrophy without cell division, and hypertrophy precedes proliferation after 70% PHx. Proliferation and hypertrophy almost equally contribute to regeneration after 70% PHx. Furthermore, although most hepatocytes enter cell cycle after 70% PHx, not all hepatocytes undergo cell division. In addition, binuclear hepatocytes undergo reductive divisions to generate two mononuclear daughter hepatocytes in some cases. CONCLUSIONS Our findings demonstrate the importance of hypertrophy and the unconventional cell division cycle of hepatocytes in regeneration, prompting a significant revision of the generally accepted model of liver regeneration.
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Affiliation(s)
- Yuichiro Miyaoka
- Laboratory of Cell Growth and Differentiation, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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50
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Abstract
Tight regulation of cell cycle is of critical importance for eukaryotic biology and is achieved through a combined action of a large number of highly specialized proteins. Separases are evolutionarily conserved caspase-like proteases playing a crucial role in cell cycle regulation, as they execute sister chromatid separation at metaphase to anaphase transition. In contrast to extensively studied yeast and metazoan separases, very little is known about the role of separases in plant biology. Here we describe the molecular mechanisms of separase-mediated chromatid segregation in yeast and metazoan models, discuss new emerging but less-understood functions of separases and highlight major gaps in our knowledge about plant separases.
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Affiliation(s)
- Panagiotis N Moschou
- Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden.
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