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Chaba Z, Jain I, Tran PT. Fission yeast spindle dynamics and chromosome segregation fidelity show distinct thermosensitivity. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001048. [PMID: 38287927 PMCID: PMC10823497 DOI: 10.17912/micropub.biology.001048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/02/2024] [Accepted: 01/09/2024] [Indexed: 01/31/2024]
Abstract
Cellular processes rely on proteins with temperature-dependent stability and activity. While thermosensitivity in biological networks is well-explored, the effect of temperature on complex mechanochemical assemblies, like the spindle, is rarely studied. We examined fission yeast spindle dynamics and chromosome segregation from 15⁰C to 40⁰C. Our findings reveal that these parameters follow U-shaped temperature-dependent curves but reach their minima at different temperatures. Specifically, spindle dynamics peak around 35⁰C, whereas chromosome segregation defects are minimized at 25⁰C. This suggests a scenario in which mitotic errors are tolerated to expedite rapid cell cycle progression.
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Affiliation(s)
| | - Ishutesh Jain
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences - TIFR, Bangalore 560065, India
- Institut Curie, PSL Université, Sorbonne Université, CNRS UMR 144, Paris 75005, France
| | - Phong T. Tran
- Institut Curie, PSL Université, Sorbonne Université, CNRS UMR 144, Paris 75005, France
- University of Pennsylvania, Department of Cell and Developmental Biology, Philadelphia, PA 19104, USA
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2
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Takado M, Yamamoto TG, Chikashige Y, Matsumoto T. Fission yeast Wee1 is required for stable kinetochore-microtubule attachment. Open Biol 2024; 14:230379. [PMID: 38166399 PMCID: PMC10762435 DOI: 10.1098/rsob.230379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 11/21/2023] [Indexed: 01/04/2024] Open
Abstract
Wee1 is a cell cycle regulator that phosphorylates Cdk1/Cdc2 and inhibits G2/M transition. Loss of Wee1 in fission yeast results in an early onset of mitosis. Interestingly, we found that cells lacking Wee1 require the functional spindle checkpoint for their viability. Genetic analysis indicated that the requirement is not attributable to the early onset of mitosis. Live-cell imaging revealed that some kinetochores are not attached or bioriented in the wee1 mutant. Furthermore, Mad2, a component of the spindle checkpoint known to recognize unattached kinetochores, accumulates in the vicinity of the spindle, representing activation of the spindle checkpoint in the mutant. It appears that the wee1 mutant cannot maintain stable kinetochore-microtubule attachment, and relies on the delay imposed by the spindle checkpoint for establishing biorientation of kinetochores. This study revealed a role of Wee1 in ensuring accurate segregation of chromosomes during mitosis, and thus provided a basis for a new principle of cancer treatment with Wee1 inhibitors.
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Affiliation(s)
- Masahiro Takado
- Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Takaharu G. Yamamoto
- Kobe Frontier Research Center, Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Yuji Chikashige
- Kobe Frontier Research Center, Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Tomohiro Matsumoto
- Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
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3
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Li T, Gachet Y, Tournier S. MAARS Software for Automatic and Quantitative Analysis of Mitotic Progression. Methods Mol Biol 2024; 2740:275-293. [PMID: 38393482 DOI: 10.1007/978-1-0716-3557-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
In this chapter, we describe a software called MAARS (Mitotic Analysis And Recording System) that enables automatic and quantitative analysis of mitotic progression on an open-source platform. This computer-assisted analysis of cell division allows the unbiased acquisition of multiple parameters such as cell shape or size, metaphase or anaphase delays, as well as various mitotic abnormalities. This chapter describes the power of such an expert system to highlight the complexity of the mechanisms required to prevent mitotic chromosome segregation errors, leading to aneuploidy.
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Affiliation(s)
- Tong Li
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse Cedex, France
- Wellcome Sanger Institute, Cambridge, UK
| | - Yannick Gachet
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse Cedex, France.
| | - Sylvie Tournier
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse Cedex, France.
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4
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Onwubiko UN, Kalathil D, Koory E, Pokharel S, Roberts H, Mitoubsi A, Das M. Cdc42 prevents precocious Rho1 activation during cytokinesis in a Pak1-dependent manner. J Cell Sci 2023; 136:jcs261160. [PMID: 37039135 PMCID: PMC10163358 DOI: 10.1242/jcs.261160] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 03/15/2023] [Indexed: 04/12/2023] Open
Abstract
During cytokinesis, a series of coordinated events partition a dividing cell. Accurate regulation of cytokinesis is essential for proliferation and genome integrity. In fission yeast, these coordinated events ensure that the actomyosin ring and septum start ingressing only after chromosome segregation. How cytokinetic events are coordinated remains unclear. The GTPase Cdc42 promotes recruitment of certain cell wall-building enzymes whereas the GTPase Rho1 activates these enzymes. We show that Cdc42 prevents early Rho1 activation during fission yeast cytokinesis. Using an active Rho probe, we find that although the Rho1 activators Rgf1 and Rgf3 localize to the division site in early anaphase, Rho1 is not activated until late anaphase, just before the onset of ring constriction. We find that loss of Cdc42 activation enables precocious Rho1 activation in early anaphase. Furthermore, we provide functional and genetic evidence that Cdc42-dependent Rho1 inhibition is mediated by the Cdc42 target Pak1 kinase. Our work proposes a mechanism of Rho1 regulation by active Cdc42 to coordinate timely septum formation and cytokinesis fidelity.
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Affiliation(s)
- Udo N. Onwubiko
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Dhanya Kalathil
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
| | - Emma Koory
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Sahara Pokharel
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Hayden Roberts
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Ahmad Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Maitreyi Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
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5
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Kuzdere T, Flury V, Schalch T, Iesmantavicius V, Hess D, Bühler M. Differential phosphorylation of Clr4 SUV39H by Cdk1 accompanies a histone H3 methylation switch that is essential for gametogenesis. EMBO Rep 2022; 24:e55928. [PMID: 36408846 PMCID: PMC9827552 DOI: 10.15252/embr.202255928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/18/2022] [Accepted: 10/27/2022] [Indexed: 11/22/2022] Open
Abstract
Methylation of histone H3 at lysine 9 (H3K9) is a hallmark of heterochromatin that plays crucial roles in gene silencing, genome stability, and chromosome segregation. In Schizosaccharomyces pombe, Clr4 mediates both di- and tri-methylation of H3K9. Although H3K9 methylation has been intensely studied in mitotic cells, its role during sexual differentiation remains unclear. Here, we map H3K9 methylation genome-wide during meiosis and show that constitutive heterochromatin temporarily loses H3K9me2 and becomes H3K9me3 when cells commit to meiosis. Cells lacking the ability to tri-methylate H3K9 exhibit meiotic chromosome segregation defects. Finally, the H3K9 methylation switch is accompanied by differential phosphorylation of Clr4 by the cyclin-dependent kinase Cdk1. Our results suggest that a conserved master regulator of the cell cycle controls the specificity of an H3K9 methyltransferase to prevent ectopic H3K9 methylation and to ensure faithful gametogenesis.
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Affiliation(s)
- Tahsin Kuzdere
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland,University of BaselBaselSwitzerland
| | - Valentin Flury
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland,University of BaselBaselSwitzerland
| | - Thomas Schalch
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical BiologyUniversity of LeicesterLeicesterUK
| | | | - Daniel Hess
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland,University of BaselBaselSwitzerland
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6
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Arginylation Regulates Cytoskeleton Organization and Cell Division and Affects Mitochondria in Fission Yeast. Mol Cell Biol 2022; 42:e0026122. [PMID: 36226970 PMCID: PMC9670973 DOI: 10.1128/mcb.00261-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Protein arginylation mediated by arginyltransferase Ate1 is a posttranslational modification of emerging importance implicated in the regulation of mammalian embryogenesis, the cardiovascular system, tissue morphogenesis, cell migration, neurodegeneration, cancer, and aging. Ate1 deletion results in embryonic lethality in mice but does not affect yeast viability, making yeast an ideal system to study the molecular pathways regulated by arginylation. Here, we conducted a global analysis of cytoskeleton-related arginylation-dependent phenotypes in Schizosaccharomyces pombe, a fission yeast species that shares many fundamental features of higher eukaryotic cells. Our studies revealed roles of Ate1 in cell division, cell polarization, organelle transport, and interphase cytoskeleton organization and dynamics. We also found a role of Ate1 in mitochondria morphology and maintenance. Furthermore, targeted mass spectrometry analysis of the total Sc. pombe arginylome identified a number of arginylated proteins, including those that play direct roles in these processes; lack of their arginylation may be responsible for ate1-knockout phenotypes. Our work outlines global biological processes potentially regulated by arginylation and paves the way to unraveling the functions of protein arginylation that are conserved at multiple levels of evolution and potentially constitute the primary role of this modification in vivo.
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7
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Zareiesfandabadi P, Elting MW. Force by minus-end motors Dhc1 and Klp2 collapses the S. pombe spindle after laser ablation. Biophys J 2022; 121:263-276. [PMID: 34951983 PMCID: PMC8790213 DOI: 10.1016/j.bpj.2021.12.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/19/2021] [Accepted: 12/16/2021] [Indexed: 01/21/2023] Open
Abstract
A microtubule-based machine called the mitotic spindle segregates chromosomes when eukaryotic cells divide. In the fission yeast Schizosaccharomyces pombe, which undergoes closed mitosis, the spindle forms a single bundle of microtubules inside the nucleus. During elongation, the spindle extends via antiparallel microtubule sliding by molecular motors. These extensile forces from the spindle are thought to resist compressive forces from the nucleus. We probe the mechanism and maintenance of this force balance via laser ablation of spindles at various stages of mitosis. We find that spindle pole bodies collapse toward each other after ablation, but spindle geometry is often rescued, allowing spindles to resume elongation. Although this basic behavior has been previously observed, many questions remain about the phenomenon's dynamics, mechanics, and molecular requirements. In this work, we find that previously hypothesized viscoelastic relaxation of the nucleus cannot explain spindle shortening in response to laser ablation. Instead, spindle collapse requires microtubule dynamics and is powered by the minus-end-directed motor proteins dynein Dhc1 and kinesin-14 Klp2, but it does not require the minus-end-directed kinesin Pkl1.
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Affiliation(s)
| | - Mary Williard Elting
- Department of Physics, North Carolina State University, Raleigh, North Carolina,Cluster for Quantitative and Computational Developmental Biology, North Carolina State University, Raleigh, North Carolina,Corresponding author
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8
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Nambu M, Kishikawa A, Yamada T, Ichikawa K, Kira Y, Itabashi Y, Honda A, Yamada K, Murakami H, Yamamoto A. Direct evaluation of cohesin-mediated sister kinetochore associations at meiosis I in fission yeast. J Cell Sci 2022; 135:jcs259102. [PMID: 34851403 DOI: 10.1242/jcs.259102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/16/2021] [Indexed: 11/20/2022] Open
Abstract
Kinetochores drive chromosome segregation by mediating chromosome interactions with the spindle. In higher eukaryotes, sister kinetochores are separately positioned on opposite sides of sister centromeres during mitosis, but associate with each other during meiosis I. Kinetochore association facilitates the attachment of sister chromatids to the same pole, enabling the segregation of homologous chromosomes toward opposite poles. In the fission yeast, Schizosaccharomyces pombe, Rec8-containing meiotic cohesin is suggested to establish kinetochore associations by mediating cohesion of the centromere cores. However, cohesin-mediated kinetochore associations on intact chromosomes have never been demonstrated directly. In the present study, we describe a novel method for the direct evaluation of kinetochore associations on intact chromosomes in live S. pombe cells, and demonstrate that sister kinetochores and the centromere cores are positioned separately on mitotic chromosomes but associate with each other on meiosis I chromosomes. Furthermore, we demonstrate that kinetochore association depends on meiotic cohesin and the cohesin regulators Moa1 and Mrc1, and requires mating-pheromone signaling for its establishment. These results confirm cohesin-mediated kinetochore association and its regulatory mechanisms, along with the usefulness of the developed method for its analysis. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Masashi Nambu
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Atsuki Kishikawa
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Takatomi Yamada
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Kento Ichikawa
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yunosuke Kira
- Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yuta Itabashi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Akira Honda
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kohei Yamada
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Hiroshi Murakami
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Ayumu Yamamoto
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
- Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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9
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Sahay O, Barik GK, Sharma T, Pillai AD, Rapole S, Santra MK. Damsel in distress calling on her knights: Illuminating the pioneering role of E3 ubiquitin ligases in guarding the genome integrity. DNA Repair (Amst) 2021; 109:103261. [PMID: 34920250 DOI: 10.1016/j.dnarep.2021.103261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 11/03/2022]
Abstract
The maintenance of genomic integrity is of utmost importance for the organisms to survive and to accurately inherit traits to their progenies. Any kind of DNA damage either due to defect in DNA duplication and/ or uncontrolled cell division or intracellular insults or environment radiation can result in gene mutation, chromosomal aberration and ultimately genomic instability, which may cause several diseases including cancers. Therefore, cells have evolved machineries for the surveillance of genomic integrity. Enormous exciting studies in the past indicate that ubiquitination (a posttranslational modification of proteins) plays a crucial role in maintaining the genomic integrity by diverse ways. In fact, various E3 ubiquitin ligases catalyse ubiquitination of key proteins to control their central role during cell cycle, DNA damage response (DDR) and DNA repair. Some E3 ligases promote genomic instability while others prevent it, deregulation of both of which leads to several malignancies. In this review, we consolidate the recent findings wherein the role of ubiquitination in conferring genome integrity is highlighted. We also discuss the latest discoveries on the mechanisms utilized by various E3 ligases to preserve genomic stability, with a focus on their actions during cell cycle progression and different types of DNA damage response as well as repair pathways.
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Affiliation(s)
- Osheen Sahay
- National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India; Department of Biotechnology, S.P. Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Ganesh Kumar Barik
- National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India; Department of Biotechnology, S.P. Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Tanisha Sharma
- National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India; Department of Biotechnology, S.P. Pune University, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Ajay D Pillai
- National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Srikanth Rapole
- National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India
| | - Manas Kumar Santra
- National Centre for Cell Science, Ganeshkhind Road, Pune, Maharashtra 411007, India.
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10
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Uzsoy ASM, Zareiesfandabadi P, Jennings J, Kemper AF, Elting MW. Automated tracking of S. pombe spindle elongation dynamics. J Microsc 2021; 284:83-94. [PMID: 34152622 PMCID: PMC8446324 DOI: 10.1111/jmi.13044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 06/18/2021] [Indexed: 01/11/2023]
Abstract
The mitotic spindle is a microtubule-based machine that pulls the two identical sets of chromosomes to opposite ends of the cell during cell division. The fission yeast Schizosaccharomyces pombe is an important model organism for studying mitosis due to its simple, stereotyped spindle structure and well-established genetic toolset. S. pombe spindle length is a useful metric for mitotic progression, but manually tracking spindle ends in each frame to measure spindle length over time is laborious and can limit experimental throughput. We have developed an ImageJ plugin that can automatically track S. pombe spindle length over time and replace manual or semi-automated tracking of spindle elongation dynamics. Using an algorithm that detects the principal axis of the spindle and then finds its ends, we reliably track the length of the spindle as the cell divides. The plugin integrates with existing ImageJ features, exports its data for further analysis outside of ImageJ and does not require any programming by the user. Thus, the plugin provides an accessible tool for quantification of S. pombe spindle length that will allow automatic analysis of large microscopy data sets and facilitate screening for effects of cell biological perturbations on mitotic progression.
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Affiliation(s)
- Ana Sofía M. Uzsoy
- Department of Physics, North Carolina State University, Raleigh, NC 27695
- Department of Computer Science, North Carolina State University, Raleigh, NC 27695
| | | | - Jamie Jennings
- Department of Computer Science, North Carolina State University, Raleigh, NC 27695
| | | | - Mary Williard Elting
- Department of Physics, North Carolina State University, Raleigh, NC 27695
- Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC 27695
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11
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Zareiesfandabadi P, Elting MW. Viscoelastic Relaxation of the Nuclear Envelope Does Not Cause the Collapse of the Spindle After Ablation in S. pombe. JOURNAL OF UNDERGRADUATE REPORTS IN PHYSICS 2021; 31:100013. [PMID: 36110330 PMCID: PMC9472288 DOI: 10.1063/10.0006352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A large molecular machine called the mitotic spindle is responsible for accurate chromosome segregation in eukaryotic cells. The spindle consists of protein filaments known as microtubules and microtubule-associated proteins such as motors and crosslinkers, which help impart its organization. In the case of the fission yeast S. pombe, these form a single bundle inside the nucleus. During spindle elongation, sliding by motor proteins provides an internal source of extensile forces, which are resisted by the compressive forces of the nuclear envelope. To probe the sources of this force balance, we cut the spindle using focused laser light at various stages of spindle elongation. We find that the spindle pole bodies collapse toward each other post-ablation. While this basic behavior has been previously observed, many questions remain about the timing, mechanics, and molecular requirements of this phenomenon. Here, we quantify the time scale of the relaxation and probe its underlying mechanism. We demonstrate that viscoelastic relaxation of the nuclear envelope cannot explain this phenomenon and provide evidence of active forces as the underlying mechanism.
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Affiliation(s)
| | - Mary Williard Elting
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
- Cluster on Quantitative and Computational Developmental Biology, North Carolina State University, Raleigh, NC 27695, USA
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12
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Sevcovicova A, Plava J, Gazdarica M, Szabova E, Huraiova B, Gaplovska-Kysela K, Cipakova I, Cipak L, Gregan J. Mapping and Analysis of Swi5 and Sfr1 Phosphorylation Sites. Genes (Basel) 2021; 12:1014. [PMID: 34208949 PMCID: PMC8305525 DOI: 10.3390/genes12071014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 01/23/2023] Open
Abstract
The evolutionarily conserved Swi5-Sfr1 complex plays an important role in homologous recombination, a process crucial for the maintenance of genomic integrity. Here, we purified Schizosaccharomyces pombe Swi5-Sfr1 complex from meiotic cells and analyzed it by mass spectrometry. Our analysis revealed new phosphorylation sites on Swi5 and Sfr1. We found that mutations that prevent phosphorylation of Swi5 and Sfr1 do not impair their function but swi5 and sfr1 mutants encoding phosphomimetic aspartate at the identified phosphorylation sites are only partially functional. We concluded that during meiosis, Swi5 associates with Sfr1 and both Swi5 and Sfr1 proteins are phosphorylated. However, the functional relevance of Swi5 and Sfr1 phosphorylation remains to be determined.
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Affiliation(s)
- Andrea Sevcovicova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia; (A.S.); (J.P.); (M.G.); (E.S.); (B.H.); (K.G.-K.)
| | - Jana Plava
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia; (A.S.); (J.P.); (M.G.); (E.S.); (B.H.); (K.G.-K.)
- Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, Dubravska Cesta 9, 845 05 Bratislava, Slovakia
| | - Matej Gazdarica
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia; (A.S.); (J.P.); (M.G.); (E.S.); (B.H.); (K.G.-K.)
- Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Eva Szabova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia; (A.S.); (J.P.); (M.G.); (E.S.); (B.H.); (K.G.-K.)
| | - Barbora Huraiova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia; (A.S.); (J.P.); (M.G.); (E.S.); (B.H.); (K.G.-K.)
| | - Katarina Gaplovska-Kysela
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia; (A.S.); (J.P.); (M.G.); (E.S.); (B.H.); (K.G.-K.)
| | - Ingrid Cipakova
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska Cesta 9, 845 05 Bratislava, Slovakia;
| | - Lubos Cipak
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska Cesta 9, 845 05 Bratislava, Slovakia;
| | - Juraj Gregan
- Advanced Microscopy Facility, VBCF and Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
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13
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Krüger LK, Gélin M, Ji L, Kikuti C, Houdusse A, Théry M, Blanchoin L, Tran PT. Kinesin-6 Klp9 orchestrates spindle elongation by regulating microtubule sliding and growth. eLife 2021; 10:67489. [PMID: 34080538 PMCID: PMC8205488 DOI: 10.7554/elife.67489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/02/2021] [Indexed: 11/13/2022] Open
Abstract
Mitotic spindle function depends on the precise regulation of microtubule dynamics and microtubule sliding. Throughout mitosis, both processes have to be orchestrated to establish and maintain spindle stability. We show that during anaphase B spindle elongation in Schizosaccharomyces pombe, the sliding motor Klp9 (kinesin-6) also promotes microtubule growth in vivo. In vitro, Klp9 can enhance and dampen microtubule growth, depending on the tubulin concentration. This indicates that the motor is able to promote and block tubulin subunit incorporation into the microtubule lattice in order to set a well-defined microtubule growth velocity. Moreover, Klp9 recruitment to spindle microtubules is dependent on its dephosphorylation mediated by XMAP215/Dis1, a microtubule polymerase, creating a link between the regulation of spindle length and spindle elongation velocity. Collectively, we unravel the mechanism of anaphase B, from Klp9 recruitment to the motors dual-function in regulating microtubule sliding and microtubule growth, allowing an inherent coordination of both processes.
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Affiliation(s)
- Lara Katharina Krüger
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Matthieu Gélin
- Institut de Recherche Saint Louis,U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France
| | - Liang Ji
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Carlos Kikuti
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Anne Houdusse
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France
| | - Manuel Théry
- Institut de Recherche Saint Louis,U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France.,Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, Paris, France
| | - Laurent Blanchoin
- Institut de Recherche Saint Louis,U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France.,Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, Paris, France
| | - Phong T Tran
- Institut Curie, PSL Research University, Sorbonne Université CNRS, UMR 144, Paris, France.,Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, United States
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14
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Shake It Off: The Elimination of Erroneous Kinetochore-Microtubule Attachments and Chromosome Oscillation. Int J Mol Sci 2021; 22:ijms22063174. [PMID: 33804687 PMCID: PMC8003821 DOI: 10.3390/ijms22063174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/18/2021] [Indexed: 01/17/2023] Open
Abstract
Cell proliferation and sexual reproduction require the faithful segregation of chromosomes. Chromosome segregation is driven by the interaction of chromosomes with the spindle, and the attachment of chromosomes to the proper spindle poles is essential. Initial attachments are frequently erroneous due to the random nature of the attachment process; however, erroneous attachments are selectively eliminated. Proper attachment generates greater tension at the kinetochore than erroneous attachments, and it is thought that attachment selection is dependent on this tension. However, studies of meiotic chromosome segregation suggest that attachment elimination cannot be solely attributed to tension, and the precise mechanism of selective elimination of erroneous attachments remains unclear. During attachment elimination, chromosomes oscillate between the spindle poles. A recent study on meiotic chromosome segregation in fission yeast has suggested that attachment elimination is coupled to chromosome oscillation. In this review, the possible contribution of chromosome oscillation in the elimination of erroneous attachment is discussed in light of the recent finding.
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15
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Escorcia W, Tripathi VP, Yuan JP, Forsburg SL. A visual atlas of meiotic protein dynamics in living fission yeast. Open Biol 2021; 11:200357. [PMID: 33622106 PMCID: PMC8061692 DOI: 10.1098/rsob.200357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Meiosis is a carefully choreographed dynamic process that re-purposes proteins from somatic/vegetative cell division, as well as meiosis-specific factors, to carry out the differentiation and recombination pathway common to sexually reproducing eukaryotes. Studies of individual proteins from a variety of different experimental protocols can make it difficult to compare details between them. Using a consistent protocol in otherwise wild-type fission yeast cells, this report provides an atlas of dynamic protein behaviour of representative proteins at different stages during normal zygotic meiosis in fission yeast. This establishes common landmarks to facilitate comparison of different proteins and shows that initiation of S phase likely occurs prior to nuclear fusion/karyogamy.
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Affiliation(s)
- Wilber Escorcia
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA.,Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 45207, USA
| | - Vishnu P Tripathi
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Ji-Ping Yuan
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Susan L Forsburg
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA
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16
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Wakiya M, Nishi E, Kawai S, Yamada K, Katsumata K, Hirayasu A, Itabashi Y, Yamamoto A. Chiasmata and the kinetochore component Dam1 are crucial for elimination of erroneous chromosome attachments and centromere oscillation at meiosis I. Open Biol 2021; 11:200308. [PMID: 33529549 PMCID: PMC8061696 DOI: 10.1098/rsob.200308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Establishment of proper chromosome attachments to the spindle requires elimination of erroneous attachments, but the mechanism of this process is not fully understood. During meiosis I, sister chromatids attach to the same spindle pole (mono-oriented attachment), whereas homologous chromosomes attach to opposite poles (bi-oriented attachment), resulting in homologous chromosome segregation. Here, we show that chiasmata that link homologous chromosomes and kinetochore component Dam1 are crucial for elimination of erroneous attachments and oscillation of centromeres between the spindle poles at meiosis I in fission yeast. In chiasma-forming cells, Mad2 and Aurora B kinase, which provides time for attachment correction and destabilizes erroneous attachments, respectively, caused elimination of bi-oriented attachments of sister chromatids, whereas in chiasma-lacking cells, they caused elimination of mono-oriented attachments. In chiasma-forming cells, in addition, homologous centromere oscillation was coordinated. Furthermore, Dam1 contributed to attachment elimination in both chiasma-forming and chiasma-lacking cells, and drove centromere oscillation. These results demonstrate that chiasmata alter attachment correction patterns by enabling error correction factors to eliminate bi-oriented attachment of sister chromatids, and suggest that Dam1 induces elimination of erroneous attachments. The coincidental contribution of chiasmata and Dam1 to centromere oscillation also suggests a potential link between centromere oscillation and attachment elimination.
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Affiliation(s)
- Misuzu Wakiya
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Eriko Nishi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Shinnosuke Kawai
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.,Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kohei Yamada
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kazuhiro Katsumata
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Ami Hirayasu
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yuta Itabashi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Ayumu Yamamoto
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.,Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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17
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Schutt KL, Moseley JB. The phosphatase inhibitor Sds23 promotes symmetric spindle positioning in fission yeast. Cytoskeleton (Hoboken) 2020; 77:544-557. [PMID: 33280247 PMCID: PMC8195570 DOI: 10.1002/cm.21648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/05/2020] [Accepted: 12/02/2020] [Indexed: 12/19/2022]
Abstract
A hallmark of cell division in eukaryotic cells is the formation and elongation of a microtubule (MT)-based mitotic spindle. Proper positioning of the spindle is critical to ensure equal segregation of the genetic material to the resulting daughter cells. Both the timing of spindle elongation and constriction of the actomyosin contractile ring must be precisely coordinated to prevent missegregation or damage to the genetic material during cellular division. Here, we show that Sds23, an inhibitor of protein phosphatases, contributes to proper positioning of elongating spindles in fission yeast cells. We found that sds23∆ mutant cells exhibit asymmetric spindles that initially elongate asymmetrically toward one end of the dividing cell. Spindle asymmetry in sds23∆ cells results from a defect that is distinct from previously identified mechanisms, including MT protrusions and enlarged vacuoles. Combined with our previous work, this study demonstrates that Sds23, an inhibitor of PP2A-family protein phosphatases, promotes proper positioning of both the bipolar spindle and cytokinetic ring during fission yeast cell division. These two steps ensure the overall symmetry and fidelity of the cell division process.
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Affiliation(s)
- Katherine L. Schutt
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - James B. Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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18
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Zheng F, Dong F, Yu S, Li T, Jian Y, Nie L, Fu C. Klp2 and Ase1 synergize to maintain meiotic spindle stability during metaphase I. J Biol Chem 2020; 295:13287-13298. [PMID: 32723864 DOI: 10.1074/jbc.ra120.012905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 07/24/2020] [Indexed: 11/06/2022] Open
Abstract
The spindle apparatus segregates bi-oriented sister chromatids during mitosis but mono-oriented homologous chromosomes during meiosis I. It has remained unclear if similar molecular mechanisms operate to regulate spindle dynamics during mitosis and meiosis I. Here, we employed live-cell microscopy to compare the spindle dynamics of mitosis and meiosis I in fission yeast cells and demonstrated that the conserved kinesin-14 motor Klp2 plays a specific role in maintaining metaphase spindle length during meiosis I but not during mitosis. Moreover, the maintenance of metaphase spindle stability during meiosis I requires the synergism between Klp2 and the conserved microtubule cross-linker Ase1, as the absence of both proteins causes exacerbated defects in metaphase spindle stability. The synergism is not necessary for regulating mitotic spindle dynamics. Hence, our work reveals a new molecular mechanism underlying meiotic spindle dynamics and provides insights into understanding differential regulation of meiotic and mitotic events.
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Affiliation(s)
- Fan Zheng
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Fenfen Dong
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Shuo Yu
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Tianpeng Li
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yanze Jian
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Lingyun Nie
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Chuanhai Fu
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
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19
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Loncar A, Rincon SA, Lera Ramirez M, Paoletti A, Tran PT. Kinesin-14 family proteins and microtubule dynamics define S. pombe mitotic and meiotic spindle assembly, and elongation. J Cell Sci 2020; 133:jcs240234. [PMID: 32327557 PMCID: PMC7295595 DOI: 10.1242/jcs.240234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 04/06/2020] [Indexed: 12/18/2022] Open
Abstract
To segregate the chromosomes faithfully during cell division, cells assemble a spindle that captures the kinetochores and pulls them towards opposite poles. Proper spindle function requires correct interplay between microtubule motors and non-motor proteins. Defects in spindle assembly or changes in spindle dynamics are associated with diseases, such as cancer or developmental disorders. Here, we compared mitotic and meiotic spindles in fission yeast. We show that, even though mitotic and meiotic spindles underwent the typical three phases of spindle elongation, they have distinct features. We found that the relative concentration of the kinesin-14 family protein Pkl1 is decreased in meiosis I compared to mitosis, while the concentration of the kinesin-5 family protein Cut7 remains constant. We identified the second kinesin-14 family protein Klp2 and microtubule dynamics as factors necessary for proper meiotic spindle assembly. This work defines the differences between mitotic and meiotic spindles in fission yeast Schizosaccharomyces pombe, and provides prospect for future comparative studies.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ana Loncar
- Institute Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France
| | - Sergio A Rincon
- Instituto de Biología Funcional y Genómica/Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, Salamanca 37007, Spain
| | - Manuel Lera Ramirez
- Institute Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France
| | - Anne Paoletti
- Institute Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France
| | - Phong T Tran
- Institute Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France
- University of Pennsylvania, Department of Cell and Developmental Biology, Philadelphia, PA 19104, USA
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20
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Edelmaier C, Lamson AR, Gergely ZR, Ansari S, Blackwell R, McIntosh JR, Glaser MA, Betterton MD. Mechanisms of chromosome biorientation and bipolar spindle assembly analyzed by computational modeling. eLife 2020; 9:48787. [PMID: 32053104 PMCID: PMC7311174 DOI: 10.7554/elife.48787] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 02/12/2020] [Indexed: 01/19/2023] Open
Abstract
The essential functions required for mitotic spindle assembly and chromosome biorientation and segregation are not fully understood, despite extensive study. To illuminate the combinations of ingredients most important to align and segregate chromosomes and simultaneously assemble a bipolar spindle, we developed a computational model of fission-yeast mitosis. Robust chromosome biorientation requires progressive restriction of attachment geometry, destabilization of misaligned attachments, and attachment force dependence. Large spindle length fluctuations can occur when the kinetochore-microtubule attachment lifetime is long. The primary spindle force generators are kinesin-5 motors and crosslinkers in early mitosis, while interkinetochore stretch becomes important after biorientation. The same mechanisms that contribute to persistent biorientation lead to segregation of chromosomes to the poles after anaphase onset. This model therefore provides a framework to interrogate key requirements for robust chromosome biorientation, spindle length regulation, and force generation in the spindle. Before a cell divides, it must make a copy of its genetic material and then promptly split in two. This process, called mitosis, is coordinated by many different molecular machines. The DNA is copied, then the duplicated chromosomes line up at the middle of the cell. Next, an apparatus called the mitotic spindle latches onto the chromosomes before pulling them apart. The mitotic spindle is a bundle of long, thin filaments called microtubules. It attaches to chromosomes at the kinetochore, the point where two copied chromosomes are cinched together in their middle. Proper cell division is vital for the healthy growth of all organisms, big and small, and yet some parts of the process remain poorly understood despite extensive study. Specifically, there is more to learn about how the mitotic spindle self-assembles, and how microtubules and kinetochores work together to correctly orient and segregate chromosomes into two sister cells. These nanoscale processes are happening a hundred times a minute, so computer simulations are a good way to test what we know. Edelmaier et al. developed a computer model to simulate cell division in fission yeast, a species of yeast often used to study fundamental processes in the cell. The model simulates how the mitotic spindle assembles, how its microtubules attach to the kinetochore and the force required to pull two sister chromosomes apart. Building the simulation involved modelling interactions between the mitotic spindle and kinetochore, their movement and forces applied. To test its accuracy, model simulations were compared to recordings of the mitotic spindle – including its length, structure and position – imaged from dividing yeast cells. Running the simulation, Edelmaier et al. found that several key effects are essential for the proper movement of chromosomes in mitosis. This includes holding chromosomes in the correct orientation as the mitotic spindle assembles and controlling the relative position of microtubules as they attach to the kinetochore. Misaligned attachments must also be readily deconstructed and corrected to prevent any errors. The simulations also showed that kinetochores must begin to exert more force (to separate the chromosomes) once the mitotic spindle is attached correctly. Altogether, these findings improve the current understanding of how the mitotic spindle and its counterparts control cell division. Errors in chromosome segregation are associated with birth defects and cancer in humans, and this new simulation could potentially now be used to help make predictions about how to correct mistakes in the process.
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Affiliation(s)
| | - Adam R Lamson
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - Zachary R Gergely
- Department of Physics, University of Colorado Boulder, Boulder, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Saad Ansari
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - Robert Blackwell
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - J Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Matthew A Glaser
- Department of Physics, University of Colorado Boulder, Boulder, United States
| | - Meredith D Betterton
- Department of Physics, University of Colorado Boulder, Boulder, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
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21
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Schizosaccharomyces pombe Assays to Study Mitotic Recombination Outcomes. Genes (Basel) 2020; 11:genes11010079. [PMID: 31936815 PMCID: PMC7016768 DOI: 10.3390/genes11010079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/07/2020] [Accepted: 01/07/2020] [Indexed: 01/16/2023] Open
Abstract
The fission yeast—Schizosaccharomyces pombe—has emerged as a powerful tractable system for studying DNA damage repair. Over the last few decades, several powerful in vivo genetic assays have been developed to study outcomes of mitotic recombination, the major repair mechanism of DNA double strand breaks and stalled or collapsed DNA replication forks. These assays have significantly increased our understanding of the molecular mechanisms underlying the DNA damage response pathways. Here, we review the assays that have been developed in fission yeast to study mitotic recombination.
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22
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Hercyk BS, Rich-Robinson J, Mitoubsi AS, Harrell MA, Das ME. A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis in fission yeast. J Cell Sci 2019; 132:jcs.236018. [PMID: 31719163 DOI: 10.1242/jcs.229252/video-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 05/23/2023] Open
Abstract
Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. Why the cell needs two GEFs is unclear, given that they are partially redundant and activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis through recruitment of the scaffold protein Scd2, via a Cdc42 feedforward pathway. Similarly, during interphase Gef1 promotes Scd1 recruitment at the new end to enable the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation, and to maintain cell shape during interphase. Our findings reveal an elegant regulatory pattern in which Gef1 primes Cdc42 activation at new sites to initiate Scd1-dependent polarized growth, while Scd1 restricts Gef1 to sites of polarization. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Ahmad S Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Marcus A Harrell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
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23
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Hercyk BS, Rich-Robinson J, Mitoubsi AS, Harrell MA, Das ME. A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis in fission yeast. J Cell Sci 2019; 132:jcs.236018. [PMID: 31719163 DOI: 10.1242/jcs.236018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 12/12/2022] Open
Abstract
Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. Why the cell needs two GEFs is unclear, given that they are partially redundant and activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis through recruitment of the scaffold protein Scd2, via a Cdc42 feedforward pathway. Similarly, during interphase Gef1 promotes Scd1 recruitment at the new end to enable the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation, and to maintain cell shape during interphase. Our findings reveal an elegant regulatory pattern in which Gef1 primes Cdc42 activation at new sites to initiate Scd1-dependent polarized growth, while Scd1 restricts Gef1 to sites of polarization. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Ahmad S Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Marcus A Harrell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
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24
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Ebina H, Ji L, Sato M. CLASP promotes microtubule bundling in metaphase spindle independently of Ase1/PRC1 in fission yeast. Biol Open 2019; 8:bio.045716. [PMID: 31615768 PMCID: PMC6826280 DOI: 10.1242/bio.045716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Microtubules in the mitotic spindle are organised by microtubule-associated proteins. In the late stage of mitosis, spindle microtubules are robustly organised through bundling by the antiparallel microtubule bundler Ase1/PRC1. In early mitosis, however, it is not well characterised as to whether spindle microtubules are actively bundled, as Ase1 does not particularly localise to the spindle at that stage. Here we show that the conserved microtubule-associated protein CLASP (fission yeast Peg1/Cls1) facilitates bundling of spindle microtubules in early mitosis. The peg1 mutant displayed a fragile spindle with unbundled microtubules, which eventually resulted in collapse of the metaphase spindle and abnormal segregation of chromosomes. Peg1 is known to be recruited to the spindle by Ase1 to stabilise antiparallel microtubules in late mitosis. However, we demonstrate that the function of Peg1 in early mitosis does not rely on Ase1. The unbundled spindle phenotype of the peg1 mutant was not seen in the ase1 mutant, and Peg1 preferentially localised to the spindle even in early mitosis unlike Ase1. Moreover, artificial overexpression of Ase1 in the peg1 mutant partially suppressed unbundled microtubules. We thus conclude that Peg1 bundles microtubules in early mitosis, in a distinct manner from its conventional Ase1-dependent functions in other cell cycle stages.
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Affiliation(s)
- Hirohisa Ebina
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Liang Ji
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan.,Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masamitsu Sato
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan .,Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Institute for Medical-Oriented Structural Biology Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan.,Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan
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25
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Two XMAP215/TOG Microtubule Polymerases, Alp14 and Dis1, Play Non-Exchangeable, Distinct Roles in Microtubule Organisation in Fission Yeast. Int J Mol Sci 2019; 20:ijms20205108. [PMID: 31618856 PMCID: PMC6834199 DOI: 10.3390/ijms20205108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/12/2019] [Accepted: 10/12/2019] [Indexed: 12/29/2022] Open
Abstract
Proper bipolar spindle assembly underlies accurate chromosome segregation. A cohort of microtubule-associated proteins orchestrates spindle microtubule formation in a spatiotemporally coordinated manner. Among them, the conserved XMAP215/TOG family of microtubule polymerase plays a central role in spindle assembly. In fission yeast, two XMAP215/TOG members, Alp14 and Dis1, share essential roles in cell viability; however how these two proteins functionally collaborate remains undetermined. Here we show the functional interplay and specification of Alp14 and Dis1. Creation of new mutant alleles of alp14, which display temperature sensitivity in the absence of Dis1, enabled us to conduct detailed analyses of a double mutant. We have found that simultaneous inactivation of Alp14 and Dis1 results in early mitotic arrest with very short, fragile spindles. Intriguingly, these cells often undergo spindle collapse, leading to a lethal “cut” phenotype. By implementing an artificial targeting system, we have shown that Alp14 and Dis1 are not functionally exchangeable and as such are not merely redundant paralogues. Interestingly, while Alp14 promotes microtubule nucleation, Dis1 does not. Our results uncover that the intrinsic specification, not the spatial regulation, between Alp14 and Dis1 underlies the collaborative actions of these two XMAP215/TOG members in mitotic progression, spindle integrity and genome stability.
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26
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Pinder C, Matsuo Y, Maurer SP, Toda T. Kinesin-8 and Dis1/TOG collaborate to limit spindle elongation from prophase to anaphase A for proper chromosome segregation in fission yeast. J Cell Sci 2019; 132:jcs232306. [PMID: 31427431 PMCID: PMC6765184 DOI: 10.1242/jcs.232306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022] Open
Abstract
High-fidelity chromosome segregation relies on proper microtubule regulation. Kinesin-8 has been shown to destabilise microtubules to reduce metaphase spindle length and chromosome movements in multiple species. XMAP215/chTOG polymerases catalyse microtubule growth for spindle assembly, elongation and kinetochore-microtubule attachment. Understanding of their biochemical activity has advanced, but little work directly addresses the functionality and interplay of these conserved factors. We utilised the synthetic lethality of fission yeast kinesin-8 (Klp5-Klp6) and XMAP215/chTOG (Dis1) to study their individual and overlapping roles. We found that the non-motor kinesin-8 tailbox is essential for mitotic function; mutation compromises plus-end-directed processivity. Klp5-Klp6 induces catastrophes to control microtubule length and, surprisingly, Dis1 collaborates with kinesin-8 to slow spindle elongation. Together, they enforce a maximum spindle length for a viable metaphase-anaphase transition and limit elongation during anaphase A to prevent lagging chromatids. Our work provides mechanistic insight into how kinesin-8 negatively regulates microtubules and how this functionally overlaps with Dis1 and highlights the importance of spindle length control in mitosis.
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Affiliation(s)
- Corinne Pinder
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Division of Biological and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Yuzy Matsuo
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Sebastian P Maurer
- Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
| | - Takashi Toda
- Cell Regulation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Division of Biological and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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27
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Galander S, Barton RE, Kelly DA, Marston AL. Spo13 prevents premature cohesin cleavage during meiosis. Wellcome Open Res 2019; 4:29. [PMID: 30906881 PMCID: PMC6426077 DOI: 10.12688/wellcomeopenres.15066.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2019] [Indexed: 01/21/2024] Open
Abstract
Background: Meiosis produces gametes through two successive nuclear divisions, meiosis I and meiosis II. In contrast to mitosis and meiosis II, where sister chromatids are segregated, during meiosis I, homologous chromosomes are segregated. This requires the monopolar attachment of sister kinetochores and the loss of cohesion from chromosome arms, but not centromeres, during meiosis I. The establishment of both sister kinetochore mono-orientation and cohesion protection rely on the budding yeast meiosis I-specific Spo13 protein, the functional homolog of fission yeast Moa1 and mouse MEIKIN. Methods: Here we investigate the effects of loss of SPO13 on cohesion during meiosis I using a live-cell imaging approach. Results: Unlike wild type, cells lacking SPO13 fail to maintain the meiosis-specific cohesin subunit, Rec8, at centromeres and segregate sister chromatids to opposite poles during anaphase I. We show that the cohesin-destabilizing factor, Wpl1, is not primarily responsible for the loss of cohesion during meiosis I. Instead, premature loss of centromeric cohesin during anaphase I in spo13 Δ cells relies on separase-dependent cohesin cleavage. Further, cohesin loss in spo13 Δ anaphase I cells is blocked by forcibly tethering the regulatory subunit of protein phosphatase 2A, Rts1, to Rec8. Conclusions: Our findings indicate that separase-dependent cleavage of phosphorylated Rec8 causes premature cohesin loss in spo13 Δ cells.
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Affiliation(s)
- Stefan Galander
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Rachael E. Barton
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - David A. Kelly
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Adèle L. Marston
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
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28
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Galander S, Barton RE, Kelly DA, Marston AL. Spo13 prevents premature cohesin cleavage during meiosis. Wellcome Open Res 2019; 4:29. [PMID: 30906881 PMCID: PMC6426077 DOI: 10.12688/wellcomeopenres.15066.2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2019] [Indexed: 01/11/2023] Open
Abstract
Background: Meiosis produces gametes through two successive nuclear divisions, meiosis I and meiosis II. In contrast to mitosis and meiosis II, where sister chromatids are segregated, during meiosis I, homologous chromosomes are segregated. This requires the monopolar attachment of sister kinetochores and the loss of cohesion from chromosome arms, but not centromeres, during meiosis I. The establishment of both sister kinetochore mono-orientation and cohesion protection rely on the budding yeast meiosis I-specific Spo13 protein, the functional homolog of fission yeast Moa1 and mouse MEIKIN. Methods: Here we investigate the effects of loss of
SPO13 on cohesion during meiosis I using a live-cell imaging approach. Results: Unlike wild type, cells lacking
SPO13 fail to maintain the meiosis-specific cohesin subunit, Rec8, at centromeres and segregate sister chromatids to opposite poles during anaphase I. We show that the cohesin-destabilizing factor, Wpl1, is not primarily responsible for the loss of cohesion during meiosis I. Instead, premature loss of centromeric cohesin during anaphase I in
spo13Δ cells relies on separase-dependent cohesin cleavage. Further, cohesin loss in
spo13Δ anaphase I cells is blocked by forcibly tethering the regulatory subunit of protein phosphatase 2A, Rts1, to Rec8. Conclusions: Our findings indicate that separase-dependent cleavage of phosphorylated Rec8 causes premature cohesin loss in
spo13Δ cells.
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Affiliation(s)
- Stefan Galander
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Rachael E Barton
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - David A Kelly
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Adèle L Marston
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
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29
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Salas-Pino S, Daga RR. Spatiotemporal control of spindle disassembly in fission yeast. Cell Mol Life Sci 2019; 76:3543-3551. [PMID: 31129857 PMCID: PMC11105212 DOI: 10.1007/s00018-019-03139-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 12/20/2022]
Abstract
Maintenance of genomic stability during cell division is one of the most important cellular tasks, and it critically depends on the faithful replication of the genetic material and its equal partitioning into daughter cells, gametes, or spores in the case of yeasts. Defective mitotic spindle assembly and disassembly both result in changes in cellular ploidy that ultimately impinge proliferation fitness and might increase tumor malignancy. Although a great progress has been made in understanding how spindles are assembled to orchestrate chromosome segregation, much less is known about how they are disassembled once completed their function. Here, we review two recently uncovered mechanisms of spindle disassembly that operate at different stages of the fission yeast life cycle.
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Affiliation(s)
- Silvia Salas-Pino
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucia, Carretera de Utrera, km1, 41013, Seville, Spain.
| | - Rafael R Daga
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucia, Carretera de Utrera, km1, 41013, Seville, Spain.
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30
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Kashiwazaki J, Yoneda Y, Mutoh T, Arai R, Yoshida M, Mabuchi I. A unique kinesin-like protein, Klp8, is involved in mitosis and cell morphology through microtubule stabilization. Cytoskeleton (Hoboken) 2019; 76:355-367. [PMID: 31276301 DOI: 10.1002/cm.21551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/23/2019] [Accepted: 07/01/2019] [Indexed: 11/10/2022]
Abstract
Kinesins are microtubule (MT)-based motors involved in various cellular functions including intracellular transport of vesicles and organelles, and dynamics of chromosomes during cell division. The fission yeast Schizosaccharomyces pombe expresses nine kinesin-like proteins (klps). Klp8 is one of them and has not been characterized yet though it has been reported to localize at the division site. Here, we studied function and localization of Klp8 in S. pombe cells. The gene klp8+ was not essential for both viability and cytoskeletal organization. Klp8-YFP was concentrated as medial cortical dots during interphase, and organized into a ring at the division site during mitosis. The Klp8 ring seemed to be localized in the space between the actomyosin contractile ring and the plasma membrane. The Klp8 ring shrank as cytokinesis proceeded. In klp8-deleted (Δ) cells, the speed of spindle elongation during anaphase B was slowed down. Overproduction of Klp8 caused bent or elongated cells, in which MTs were abnormally elongated and less dynamic than those in normal cells. Deletion of klp8+ gene suppressed the delay in mitotic entry in blt1Δ cells. These results suggest that Klp8 is involved in mitosis and cell morphology through MT stabilization.
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Affiliation(s)
- Jun Kashiwazaki
- Department of Life Science, Gakushuin University, Tokyo, Japan
| | - Yumi Yoneda
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Tadashi Mutoh
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Ritsuko Arai
- Chemical Genetics Laboratory, RIKEN, Wako, Japan
| | - Minoru Yoshida
- Chemical Genetics Laboratory, RIKEN, Wako, Japan.,CREST Research Project, Japan Science and Technology Corporation, Wako, Japan
| | - Issei Mabuchi
- Department of Life Science, Gakushuin University, Tokyo, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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31
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Winters L, Ban I, Prelogović M, Kalinina I, Pavin N, Tolić IM. Pivoting of microtubules driven by minus-end-directed motors leads to spindle assembly. BMC Biol 2019; 17:42. [PMID: 31122217 PMCID: PMC6533735 DOI: 10.1186/s12915-019-0656-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/16/2019] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND At the beginning of mitosis, the cell forms a spindle made of microtubules and associated proteins to segregate chromosomes. An important part of spindle architecture is a set of antiparallel microtubule bundles connecting the spindle poles. A key question is how microtubules extending at arbitrary angles form an antiparallel interpolar bundle. RESULTS Here, we show in fission yeast that microtubules meet at an oblique angle and subsequently rotate into antiparallel alignment. Our live-cell imaging approach provides a direct observation of interpolar bundle formation. By combining experiments with theory, we show that microtubules from each pole search for those from the opposite pole by performing random angular movement. Upon contact, two microtubules slide sideways along each other in a directed manner towards the antiparallel configuration. We introduce the contour length of microtubules as a measure of activity of motors that drive microtubule sliding, which we used together with observation of Cut7/kinesin-5 motors and our theory to reveal the minus-end-directed motility of this motor in vivo. CONCLUSION Random rotational motion helps microtubules from the opposite poles to find each other and subsequent accumulation of motors allows them to generate forces that drive interpolar bundle formation.
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Affiliation(s)
- Lora Winters
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307, Dresden, Germany
| | - Ivana Ban
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000, Zagreb, Croatia
| | - Marcel Prelogović
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000, Zagreb, Croatia
| | - Iana Kalinina
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307, Dresden, Germany
| | - Nenad Pavin
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000, Zagreb, Croatia.
| | - Iva M Tolić
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307, Dresden, Germany.
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia.
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32
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Yamamoto TG, Ding DQ, Nagahama Y, Chikashige Y, Haraguchi T, Hiraoka Y. Histone H2A insufficiency causes chromosomal segregation defects due to anaphase chromosome bridge formation at rDNA repeats in fission yeast. Sci Rep 2019; 9:7159. [PMID: 31073221 PMCID: PMC6509349 DOI: 10.1038/s41598-019-43633-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/28/2019] [Indexed: 11/16/2022] Open
Abstract
The nucleosome, composed of DNA and a histone core, is the basic structural unit of chromatin. The fission yeast Schizosaccharomyces pombe has two genes of histone H2A, hta1+ and hta2+; these genes encode two protein species of histone H2A (H2Aα and H2Aβ, respectively), which differ in three amino acid residues, and only hta2+ is upregulated during meiosis. However, it is unknown whether S. pombe H2Aα and H2Aβ have functional differences. Therefore, in this study, we examined the possible functional differences between H2Aα and H2Aβ during meiosis in S. pombe. We found that deletion of hta2+, but not hta1+, causes defects in chromosome segregation and spore formation during meiosis. Meiotic defects in hta2+ deletion cells were rescued by expressing additional copies of hta1+ or by expressing hta1+ from the hta2 promoter. This indicated that the defects were caused by insufficient amounts of histone H2A, and not by the amino acid residue differences between H2Aα and H2Aβ. Microscopic observation attributed the chromosome segregation defects to anaphase bridge formation in a chromosomal region at the repeats of ribosomal RNA genes (rDNA repeats). These results suggest that histone H2A insufficiency affects the chromatin structures of rDNA repeats, leading to chromosome missegregation in S. pombe.
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Affiliation(s)
- Takaharu G Yamamoto
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Da-Qiao Ding
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yuki Nagahama
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Tokuko Haraguchi
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan.,Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan. .,Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.
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33
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Okada H, Wloka C, Wu JQ, Bi E. Distinct Roles of Myosin-II Isoforms in Cytokinesis under Normal and Stressed Conditions. iScience 2019; 14:69-87. [PMID: 30928696 PMCID: PMC6441717 DOI: 10.1016/j.isci.2019.03.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 01/30/2019] [Accepted: 03/12/2019] [Indexed: 12/31/2022] Open
Abstract
To address the question of why more than one myosin-II isoform is expressed in a single cell to drive cytokinesis, we analyzed the roles of the myosin-II isoforms, Myo2 and Myp2, of the fission yeast Schizosaccharomyces pombe, in cytokinesis under normal and stressed conditions. We found that Myp2 controls the disassembly, stability, and constriction initiation of the Myo2 ring in response to high-salt stress. A C-terminal coiled-coil domain of Myp2 is required for its immobility and contractility during cytokinesis, and when fused to the tail of the dynamic Myo2, renders the chimera the low-turnover property. We also found, by following distinct processes in real time at the single-cell level, that Myo2 and Myp2 are differentially required but collectively essential for guiding extracellular matrix remodeling during cytokinesis. These results suggest that the dynamic and immobile myosin-II isoforms are evolved to carry out cytokinesis with robustness under different growth conditions. The myosin-II isoforms Myo2 and Myp2 display distinct responses to cellular stress Myp2 controls the constriction initiation of Myo2 during stress response A C-terminal region of Myp2 is required for its immobility during cytokinesis Myo2 and Myp2 are differentially required for guiding ECM remodeling during cytokinesis
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Affiliation(s)
- Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Carsten Wloka
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AE Groningen, The Netherlands
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
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34
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Loiodice I, Janson ME, Tavormina P, Schaub S, Bhatt D, Cochran R, Czupryna J, Fu C, Tran PT. Quantifying Tubulin Concentration and Microtubule Number Throughout the Fission Yeast Cell Cycle. Biomolecules 2019; 9:biom9030086. [PMID: 30836700 PMCID: PMC6468777 DOI: 10.3390/biom9030086] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 02/26/2019] [Indexed: 11/16/2022] Open
Abstract
The fission yeast Schizosaccharomyces pombe serves as a good genetic model organism for the molecular dissection of the microtubule (MT) cytoskeleton. However, analysis of the number and distribution of individual MTs throughout the cell cycle, particularly during mitosis, in living cells is still lacking, making quantitative modelling imprecise. We use quantitative fluorescent imaging and analysis to measure the changes in tubulin concentration and MT number and distribution throughout the cell cycle at a single MT resolution in living cells. In the wild-type cell, both mother and daughter spindle pole body (SPB) nucleate a maximum of 23 ± 6 MTs at the onset of mitosis, which decreases to a minimum of 4 ± 1 MTs at spindle break down. Interphase MT bundles, astral MT bundles, and the post anaphase array (PAA) microtubules are composed primarily of 1 ± 1 individual MT along their lengths. We measure the cellular concentration of αβ-tubulin subunits to be ~5 µM throughout the cell cycle, of which one-third is in polymer form during interphase and one-quarter is in polymer form during mitosis. This analysis provides a definitive characterization of αβ-tubulin concentration and MT number and distribution in fission yeast and establishes a foundation for future quantitative comparison of mutants defective in MTs.
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Affiliation(s)
- Isabelle Loiodice
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marcel E Janson
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Sebastien Schaub
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France
| | - Divya Bhatt
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ryan Cochran
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Julie Czupryna
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Chuanhai Fu
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Phong T Tran
- Cell & Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005 Paris, France.
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35
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Li D, Roca M, Yuecel R, Lorenz A. Immediate visualization of recombination events and chromosome segregation defects in fission yeast meiosis. Chromosoma 2019; 128:385-396. [PMID: 30739171 PMCID: PMC6823302 DOI: 10.1007/s00412-019-00691-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 02/07/2023]
Abstract
Schizosaccharomyces pombe, also known as fission yeast, is an established model for studying chromosome biological processes. Over the years, research employing fission yeast has made important contributions to our knowledge about chromosome segregation during meiosis, as well as meiotic recombination and its regulation. Quantification of meiotic recombination frequency is not a straightforward undertaking, either requiring viable progeny for a genetic plating assay, or relying on laborious Southern blot analysis of recombination intermediates. Neither of these methods lends itself to high-throughput screens to identify novel meiotic factors. Here, we establish visual assays novel to Sz. pombe for characterizing chromosome segregation and meiotic recombination phenotypes. Genes expressing red, yellow, and/or cyan fluorophores from spore-autonomous promoters have been integrated into the fission yeast genomes, either close to the centromere of chromosome 1 to monitor chromosome segregation, or on the arm of chromosome 3 to form a genetic interval at which recombination frequency can be determined. The visual recombination assay allows straightforward and immediate assessment of the genetic outcome of a single meiosis by epi-fluorescence microscopy without requiring tetrad dissection. We also demonstrate that the recombination frequency analysis can be automatized by utilizing imaging flow cytometry to enable high-throughput screens. These assays have several advantages over traditional methods for analyzing meiotic phenotypes.
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Affiliation(s)
- Dmitriy Li
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Iain Fraser Cytometry Centre (IFCC), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Marianne Roca
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Sorbonne Université, 06230, Villefranche-sur-Mer, France
| | - Raif Yuecel
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Iain Fraser Cytometry Centre (IFCC), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Alexander Lorenz
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
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36
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O’Shaughnessy B, Thiyagarajan S. Mechanisms of contractile ring tension production and constriction. Biophys Rev 2018; 10:1667-1681. [PMID: 30456601 PMCID: PMC6297097 DOI: 10.1007/s12551-018-0476-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 10/23/2018] [Indexed: 12/24/2022] Open
Abstract
The contractile ring is a remarkable tension-generating cellular machine that constricts and divides cells into two during cytokinesis, the final stage of the cell cycle. Since the ring's discovery, the parallels with muscle have been emphasized. Both are contractile actomyosin machineries, and long ago, a muscle-like sliding filament mechanism was proposed for the ring. This review focuses on the mechanisms that generate ring tension and constrict contractile rings. The emphasis is on fission yeast, whose contractile ring is sufficiently well characterized that realistic mathematical models are feasible, and possible lessons from fission yeast that may apply to animal cells are discussed. Recent discoveries relevant to the organization in fission yeast rings suggest a stochastic steady-state version of the classic sliding filament mechanism for tension. The importance of different modes of anchoring for tension production and for organizational stability of constricting rings is discussed. Possible mechanisms are discussed that set the constriction rate and enable the contractile ring to meet the technical challenge of maintaining structural integrity and tension-generating capacity while continuously disassembling throughout constriction.
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Affiliation(s)
- Ben O’Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, NY 10027 USA
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37
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Ueda EI, Kashiwazaki J, Inoué S, Mabuchi I. Fission yeast Adf1 is necessary for reassembly of actin filaments into the contractile ring during cytokinesis. Biochem Biophys Res Commun 2018; 506:330-338. [DOI: 10.1016/j.bbrc.2018.07.156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/31/2018] [Indexed: 01/27/2023]
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38
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Vještica A, Merlini L, Nkosi PJ, Martin SG. Gamete fusion triggers bipartite transcription factor assembly to block re-fertilization. Nature 2018; 560:397-400. [PMID: 30089908 DOI: 10.1038/s41586-018-0407-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/25/2018] [Indexed: 02/08/2023]
Abstract
The ploidy cycle, which is integral to sexual reproduction, requires meiosis to halve chromosome numbers as well as mechanisms that ensure zygotes are formed by exactly two partners1-4. During sexual reproduction of the fungal model organism Schizosaccharomyces pombe, haploid P and M cells fuse to form a diploid zygote that immediately enters meiosis5. Here we reveal that rapid post-fusion reconstitution of a bipartite transcription factor blocks re-fertilization. We first identify mutants that undergo transient cell fusion involving cytosol exchange but not karyogamy, and show that this drives distinct cell fates in the two gametes. The P partner undergoes lethal haploid meiosis, whereas the M cell persists in mating. The zygotic transcription that drives meiosis is rapidly initiated first from the P parental genome, even in wild-type cells. This asymmetric gene expression depends on a bipartite complex formed post-fusion between the cytosolic M-cell-specific peptide Mi and the nuclear P-cell-specific homeobox protein Pi6,7, which captures Mi in the P nucleus. Zygotic transcription is thus poised to initiate in the P nucleus as fast as Mi reaches it after fusion, a design that we reconstruct using two synthetic interactors localized to the nucleus and the cytosol of two respective partner cells. Notably, delaying zygotic transcription-by postponing Mi expression or deleting its transcriptional target in the P genome-leads to zygotes fusing with additional gametes, thus forming polyploids and eventually aneuploid progeny. The signalling cascade to block re-fertilization shares components with, but bifurcates from, meiotic induction8-10. Thus, a cytoplasmic connection upon gamete fusion leads to asymmetric reconstitution of a bipartite transcription factor to rapidly block re-fertilization and induce meiosis, ensuring genome maintenance during sexual reproduction.
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Affiliation(s)
- Aleksandar Vještica
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Pedro Junior Nkosi
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
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39
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Ogawa S, Kido S, Handa T, Ogawa H, Asakawa H, Takahashi TS, Nakagawa T, Hiraoka Y, Masukata H. Shelterin promotes tethering of late replication origins to telomeres for replication-timing control. EMBO J 2018; 37:embj.201898997. [PMID: 29997179 DOI: 10.15252/embj.201898997] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/19/2018] [Accepted: 06/19/2018] [Indexed: 12/12/2022] Open
Abstract
DNA replication initiates at many discrete loci on eukaryotic chromosomes, and individual replication origins are regulated under a spatiotemporal program. However, the underlying mechanisms of this regulation remain largely unknown. In the fission yeast Schizosaccharomyces pombe, the telomere-binding protein Taz1, ortholog of human TRF1/TRF2, regulates a subset of late replication origins by binding to the telomere-like sequence near the origins. Here, we showed using a lacO/LacI-GFP system that Taz1-dependent late origins were predominantly localized at the nuclear periphery throughout interphase, and were localized adjacent to the telomeres in the G1/S phase. The peripheral localization that depended on the nuclear membrane protein Bqt4 was not necessary for telomeric association and replication-timing control of the replication origins. Interestingly, the shelterin components Rap1 and Poz1 were required for replication-timing control and telomeric association of Taz1-dependent late origins, and this requirement was bypassed by a minishelterin Tpz1-Taz1 fusion protein. Our results suggest that Taz1 suppresses replication initiation through shelterin-mediated telomeric association of the origins at the onset of S phase.
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Affiliation(s)
- Shiho Ogawa
- Graduate School of Science, Osaka University, Toyonaka Osaka, Japan
| | - Sayuri Kido
- Graduate School of Science, Osaka University, Toyonaka Osaka, Japan
| | - Tetsuya Handa
- Graduate School of Science, Osaka University, Toyonaka Osaka, Japan
| | - Hidesato Ogawa
- Graduate School of Frontier Biosciences, Osaka University, Suita Osaka, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, Suita Osaka, Japan
| | | | - Takuro Nakagawa
- Graduate School of Science, Osaka University, Toyonaka Osaka, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita Osaka, Japan
| | - Hisao Masukata
- Graduate School of Science, Osaka University, Toyonaka Osaka, Japan .,Graduate School of Frontier Biosciences, Osaka University, Suita Osaka, Japan
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40
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Asp1 Bifunctional Activity Modulates Spindle Function via Controlling Cellular Inositol Pyrophosphate Levels in Schizosaccharomyces pombe. Mol Cell Biol 2018; 38:MCB.00047-18. [PMID: 29440310 DOI: 10.1128/mcb.00047-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/01/2018] [Indexed: 11/20/2022] Open
Abstract
The generation of two daughter cells with the same genetic information requires error-free chromosome segregation during mitosis. Chromosome transmission fidelity is dependent on spindle structure/function, which requires Asp1 in the fission yeast Schizosaccharomyces pombe Asp1 belongs to the diphosphoinositol pentakisphosphate kinase (PPIP5K)/Vip1 family which generates high-energy inositol pyrophosphate (IPP) molecules. Here, we show that Asp1 is a bifunctional enzyme in vivo: Asp1 kinase generates specific IPPs which are the substrates of the Asp1 pyrophosphatase. Intracellular levels of these IPPs directly correlate with microtubule stability: pyrophosphatase loss-of-function mutants raised Asp1-made IPP levels 2-fold, thus increasing microtubule stability, while overexpression of the pyrophosphatase decreased microtubule stability. Absence of Asp1-generated IPPs resulted in an aberrant, increased spindle association of the S. pombe kinesin-5 family member Cut7, which led to spindle collapse. Thus, chromosome transmission is controlled via intracellular IPP levels. Intriguingly, identification of the mitochondrion-associated Met10 protein as the first pyrophosphatase inhibitor revealed that IPPs also regulate mitochondrial distribution.
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41
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Klemm AH, Bosilj A, Gluncˇic M, Pavin N, Tolic IM. Metaphase kinetochore movements are regulated by kinesin-8 motors and microtubule dynamic instability. Mol Biol Cell 2018; 29:1332-1345. [PMID: 29851559 PMCID: PMC5994901 DOI: 10.1091/mbc.e17-11-0667] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During metaphase, sister chromatids are connected to microtubules extending from the opposite spindle poles via kinetochores to protein complexes on the chromosome. Kinetochores congress to the equatorial plane of the spindle and oscillate around it, with kinesin-8 motors restricting these movements. Yet, the physical mechanism underlying kinetochore movements is unclear. We show that kinetochore movements in the fission yeast Schizosaccharomyces pombe are regulated by kinesin-8-promoted microtubule catastrophe, force-induced rescue, and microtubule dynamic instability. A candidate screen showed that among the selected motors only kinesin-8 motors Klp5/Klp6 are required for kinetochore centering. Kinesin-8 accumulates at the end of microtubules, where it promotes catastrophe. Laser ablation of the spindle resulted in kinetochore movement toward the intact spindle pole in wild-type and klp5Δ cells, suggesting that kinetochore movement is driven by pulling forces. Our theoretical model with Langevin description of microtubule dynamic instability shows that kinesin-8 motors are required for kinetochore centering, whereas sensitivity of rescue to force is necessary for the generation of oscillations. We found that irregular kinetochore movements occur for a broader range of parameters than regular oscillations. Thus, our work provides an explanation for how regulation of microtubule dynamic instability contributes to kinetochore congression and the accompanying movements around the spindle center.
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Affiliation(s)
- Anna H Klemm
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Agneza Bosilj
- Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
| | - Matko Gluncˇic
- Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
| | - Nenad Pavin
- Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
| | - Iva M Tolic
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.,Division of Molecular Biology, Rud¯er Boškovic´ Institute, 10000 Zagreb, Croatia
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42
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Yukawa M, Yamada Y, Yamauchi T, Toda T. Two spatially distinct kinesin-14 proteins, Pkl1 and Klp2, generate collaborative inward forces against kinesin-5 Cut7 in S. pombe. J Cell Sci 2018; 131:jcs.210740. [PMID: 29167352 DOI: 10.1242/jcs.210740] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 11/16/2017] [Indexed: 01/15/2023] Open
Abstract
Kinesin motors play central roles in bipolar spindle assembly. In many eukaryotes, spindle pole separation is driven by kinesin-5, which generates outward force. This outward force is balanced by antagonistic inward force elicited by kinesin-14 and/or dynein. In fission yeast, two kinesin-14 proteins, Pkl1 and Klp2, play an opposing role against the kinesin-5 motor protein Cut7. However, how the two kinesin-14 proteins coordinate individual activities remains elusive. Here, we show that although deletion of either pkl1 or klp2 rescues temperature-sensitive cut7 mutants, deletion of only pkl1 can bypass the lethality caused by cut7 deletion. Pkl1 is tethered to the spindle pole body, whereas Klp2 is localized along the spindle microtubule. Forced targeting of Klp2 to the spindle pole body, however, compensates for Pkl1 functions, indicating that cellular localizations, rather than individual motor specificities, differentiate between the two kinesin-14 proteins. Interestingly, human kinesin-14 (KIFC1 or HSET) can replace either Pkl1 or Klp2. Moreover, overproduction of HSET induces monopolar spindles, reminiscent of the phenotype of Cut7 inactivation. Taken together, this study has uncovered the biological mechanism whereby two different Kinesin-14 motor proteins exert their antagonistic roles against kinesin-5 in a spatially distinct manner.
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Affiliation(s)
- Masashi Yukawa
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Yusuke Yamada
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Tomoaki Yamauchi
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takashi Toda
- Hiroshima Research Center for Healthy Aging, and Laboratory of Molecular and Chemical Cell Biology, Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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43
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Schizosaccharomyces japonicus: A Distinct Dimorphic Yeast among the Fission Yeasts. Cold Spring Harb Protoc 2017; 2017:pdb.top082651. [PMID: 28733412 DOI: 10.1101/pdb.top082651] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genomic sequencing data and morphological properties demonstrate evolutionary relationships among groups of the fission yeast, Schizosaccharomyces Phylogenetically, S. japonicus is the furthest removed from other species of fission yeast. The basic characteristics of cell proliferation are shared among all fission yeast, including the process of binary fission during vegetative growth, conjugation and karyogamy with horsetail movement, mating-type switching, and sporulation. However, S. japonicus also exhibits characteristics that are unique to filamentous fungi. S. japonicus is a nonpathogenic yeast that exhibits dimorphism. Depending on the environmental conditions, S. japonicus transforms from yeast cells into filamentous cells (hyphae), and blue light triggers synchronous septation of hyphal cells. A rough version of the whole-genome sequence is now available, facilitating genetic manipulation of S. japonicus. Furthermore, the extensive genetic knowledge available for S. pombe is aiding the development of genetic tools for analyzing S. japonicus. S. japonicus will help shed light on the evolutionary relationships among the fission yeast.
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44
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Ding DQ, Hiraoka Y. Visualization of a Specific Genome Locus by the lacO/LacI-GFP System. Cold Spring Harb Protoc 2017; 2017:pdb.prot091934. [PMID: 28733400 DOI: 10.1101/pdb.prot091934] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Observing the dynamics of a specific chromosome locus in living cells can provide important information as to the molecular mechanisms underlying events such as chromosome segregation, homologous chromosome pairing, chromosome arrangement, and gene expression. The lacO/LacI-GFP system provides a simple and useful method in which a chromosome locus is visualized by inserting lacO repeat arrays and then expressing an LacI-GFP fusion that specifically binds to the lacO sequence. This system has been adapted for use in Schizosaccharomyces pombe by expressing the LacI-GFP under a promoter of the dis1+ gene. Furthermore, a two-step integration method has been developed that ensures high-efficiency integration of lacO arrays to a desired target position.
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Affiliation(s)
- Da-Qiao Ding
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan; .,Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
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45
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Salas-Pino S, Gallardo P, Barrales RR, Braun S, Daga RR. The fission yeast nucleoporin Alm1 is required for proteasomal degradation of kinetochore components. J Cell Biol 2017; 216:3591-3608. [PMID: 28974540 PMCID: PMC5674884 DOI: 10.1083/jcb.201612194] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 05/28/2017] [Accepted: 08/16/2017] [Indexed: 02/06/2023] Open
Abstract
TPR nucleoporins form the nuclear pore complex basket. The fission yeast TPR Alm1 is required for localization of the proteasome to the nuclear envelope, which is in turn required for kinetochore homeostasis and proper chromosome segregation. Kinetochores (KTs) are large multiprotein complexes that constitute the interface between centromeric chromatin and the mitotic spindle during chromosome segregation. In spite of their essential role, little is known about how centromeres and KTs are assembled and how their precise stoichiometry is regulated. In this study, we show that the nuclear pore basket component Alm1 is required to maintain both the proteasome and its anchor, Cut8, at the nuclear envelope, which in turn regulates proteostasis of certain inner KT components. Consistently, alm1-deleted cells show increased levels of KT proteins, including CENP-CCnp3, spindle assembly checkpoint activation, and chromosome segregation defects. Our data demonstrate a novel function of the nucleoporin Alm1 in proteasome localization required for KT homeostasis.
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Affiliation(s)
- Silvia Salas-Pino
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Junta de Andalucia, Seville, Spain
| | - Paola Gallardo
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Junta de Andalucia, Seville, Spain
| | - Ramón R Barrales
- Department of Physiological Chemistry, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martiensried, Germany
| | - Sigurd Braun
- Department of Physiological Chemistry, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martiensried, Germany.,International Max Planck Research School for Molecular and Cellular Life Sciences, Planegg-Martinsried, Germany
| | - Rafael R Daga
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Junta de Andalucia, Seville, Spain
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46
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Lin L, Chen L, Tran PT. Fission yeast neddylation ligase Dcn1 facilitates cohesin cleavage and chromosome segregation at anaphase. Biol Open 2017; 6:844-849. [PMID: 28455357 PMCID: PMC5483010 DOI: 10.1242/bio.021238] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Post-translational protein modification such as phosphorylation and ubiquitination are critical during mitosis to ensure proper timing and progression of chromosome segregation. It has been recently recognized that another type of protein modification – neddylation – may also regulate mitosis and chromosome segregation. The conserved protein DCN1 (defective cullin neddylation 1) has been shown, when knocked-down by RNAi, to result in multinucleated cells and/or blockage of cell proliferation. However, how DCN1 functions in mitosis and chromosome segregation is not known. We report here the fission yeast dcn1+ and its role in mitosis and chromosome segregation. Dcn1-GFP localizes to the nucleus throughout the cell cycle. dcn1-deletion (dcn1Δ) leads to chromosome and kinetochore lagging at anaphase, resulting from delayed and attenuated cohesin cleavage and sister chromatids separation. These results put Dcn1 upstream of the anaphase promoting complex/cyclosome (APC/C) pathway. We propose a mechanism for Dcn1 function at mitosis. Summary: The fission yeast neddylation ligase Dcn1 plays a role in chromosome segregation. dcn1-deletion results in activation of the Mad2-dependent spindle assembly checkpoint, and lagging chromosomes at anaphase.
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Affiliation(s)
- Lan Lin
- School of Medicine, Southeast University, Nanjing, Jiangsu 210009, People's Republic of China.,Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Li Chen
- Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Phong T Tran
- Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA .,Institut Curie, PSL Research Universities, CNRS, UMR144, Paris F-75005, France
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47
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Li T, Mary H, Grosjean M, Fouchard J, Cabello S, Reyes C, Tournier S, Gachet Y. MAARS: a novel high-content acquisition software for the analysis of mitotic defects in fission yeast. Mol Biol Cell 2017; 28:1601-1611. [PMID: 28450455 PMCID: PMC5469604 DOI: 10.1091/mbc.e16-10-0723] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/14/2017] [Accepted: 04/20/2017] [Indexed: 01/08/2023] Open
Abstract
Faithful segregation of chromosomes during cell division relies on multiple processes such as chromosome attachment and correct spindle positioning. Yet mitotic progression is defined by multiple parameters, which need to be quantitatively evaluated. To study the spatiotemporal control of mitotic progression, we developed a high-content analysis (HCA) approach that combines automated fluorescence microscopy with real-time quantitative image analysis and allows the unbiased acquisition of multiparametric data at the single-cell level for hundreds of cells simultaneously. The Mitotic Analysis and Recording System (MAARS) provides automatic and quantitative single-cell analysis of mitotic progression on an open-source platform. It can be used to analyze specific characteristics such as cell shape, cell size, metaphase/anaphase delays, and mitotic abnormalities including spindle mispositioning, spindle elongation defects, and chromosome segregation defects. Using this HCA approach, we were able to visualize rare and unexpected events of error correction during anaphase in wild-type or mutant cells. Our study illustrates that such an expert system of mitotic progression is able to highlight the complexity of the mechanisms required to prevent chromosome loss during cell division.
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Affiliation(s)
- Tong Li
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Hadrien Mary
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Marie Grosjean
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Jonathan Fouchard
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Simon Cabello
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Céline Reyes
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Sylvie Tournier
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Yannick Gachet
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
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48
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Wei B, Hercyk BS, Habiyaremye J, Das M. Spatiotemporal Analysis of Cytokinetic Events in Fission Yeast. J Vis Exp 2017. [PMID: 28287547 DOI: 10.3791/55109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cytokinesis, the final step in cell division is critical for maintaining genome integrity. Proper cytokinesis is important for cell differentiation and development. Cytokinesis involves a series of events that are well coordinated in time and space. Cytokinesis involves the formation of an actomyosin ring at the division site, followed by ring constriction, membrane furrow formation and extra cellular matrix remodeling. The fission yeast, Schizosaccharomyces pombe (S. pombe) is a well-studied model system that has revealed with substantial clarity the initial events in cytokinesis. However, we do not understand clearly how different cytokinetic events are coordinated spatiotemporally. To determine this, one needs to analyze the different cytokinetic events in great details in both time and in space. Here we describe a microscopy approach to examine different cytokinetic events in live cells. With this approach it is possible to time different cytokinetic events and determine the time of recruitment of different proteins during cytokinesis. In addition, we describe protocols to compare protein localization, and distribution at the site of cell division. This is a basic protocol to study cytokinesis in fission yeast and can also be used for other yeasts and fungal systems.
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Affiliation(s)
- Bin Wei
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee
| | - Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee
| | - Julius Habiyaremye
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee
| | - Maitreyi Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee;
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49
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Folco HD, Chalamcharla VR, Sugiyama T, Thillainadesan G, Zofall M, Balachandran V, Dhakshnamoorthy J, Mizuguchi T, Grewal SIS. Untimely expression of gametogenic genes in vegetative cells causes uniparental disomy. Nature 2017; 543:126-130. [PMID: 28199302 PMCID: PMC5567995 DOI: 10.1038/nature21372] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 12/28/2016] [Indexed: 01/03/2023]
Affiliation(s)
- H Diego Folco
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Venkata R Chalamcharla
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Tomoyasu Sugiyama
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Gobi Thillainadesan
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Martin Zofall
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Vanivilasini Balachandran
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jothy Dhakshnamoorthy
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Takeshi Mizuguchi
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Shiv I S Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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50
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Blackwell R, Edelmaier C, Sweezy-Schindler O, Lamson A, Gergely ZR, O’Toole E, Crapo A, Hough LE, McIntosh JR, Glaser MA, Betterton MD. Physical determinants of bipolar mitotic spindle assembly and stability in fission yeast. SCIENCE ADVANCES 2017; 3:e1601603. [PMID: 28116355 PMCID: PMC5249259 DOI: 10.1126/sciadv.1601603] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/05/2016] [Indexed: 05/10/2023]
Abstract
Mitotic spindles use an elegant bipolar architecture to segregate duplicated chromosomes with high fidelity. Bipolar spindles form from a monopolar initial condition; this is the most fundamental construction problem that the spindle must solve. Microtubules, motors, and cross-linkers are important for bipolarity, but the mechanisms necessary and sufficient for spindle assembly remain unknown. We describe a physical model that exhibits de novo bipolar spindle formation. We began with physical properties of fission-yeast spindle pole body size and microtubule number, kinesin-5 motors, kinesin-14 motors, and passive cross-linkers. Our model results agree quantitatively with our experiments in fission yeast, thereby establishing a minimal system with which to interrogate collective self-assembly. By varying the features of our model, we identify a set of functions essential for the generation and stability of spindle bipolarity. When kinesin-5 motors are present, their bidirectionality is essential, but spindles can form in the presence of passive cross-linkers alone. We also identify characteristic failed states of spindle assembly-the persistent monopole, X spindle, separated asters, and short spindle, which are avoided by the creation and maintenance of antiparallel microtubule overlaps. Our model can guide the identification of new, multifaceted strategies to induce mitotic catastrophes; these would constitute novel strategies for cancer chemotherapy.
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Affiliation(s)
- Robert Blackwell
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- PULS Group, Department of Physics and Cluster of Excellence: Engineering of Advanced Materials, Friedrich-Alexander University Erlangen-Nurnberg, Nagelsbachstr. 49b, Erlangen, Germany
| | | | | | - Adam Lamson
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Zachary R. Gergely
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Eileen O’Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Ammon Crapo
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Loren E. Hough
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - J. Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Matthew A. Glaser
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Meredith D. Betterton
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
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