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Zimyanin V, Redemann S. Microtubule length correlates with spindle length in C. elegans meiosis. Cytoskeleton (Hoboken) 2024. [PMID: 38450962 DOI: 10.1002/cm.21849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/24/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024]
Abstract
The accurate segregation of chromosomes during female meiosis relies on the precise assembly and function of the meiotic spindle, a dynamic structure primarily composed of microtubules. Despite the crucial role of microtubule dynamics in this process, the relationship between microtubule length and spindle size remains elusive. Leveraging Caenorhabditis elegans as a model system, we combined electron tomography and live imaging to investigate this correlation. Our analysis revealed significant changes in spindle length throughout meiosis, coupled with alterations in microtubule length. Surprisingly, while spindle size decreases during the initial stages of anaphase, the size of antiparallel microtubule overlap decreased as well. Detailed electron tomography shows a positive correlation between microtubule length and spindle size, indicating a role of microtubule length in determining spindle dimensions. Notably, microtubule numbers displayed no significant association with spindle length, highlighting the dominance of microtubule length regulation in spindle size determination. Depletion of the microtubule depolymerase KLP-7 led to elongated metaphase spindles with increased microtubule length, supporting the link between microtubule length and spindle size. These findings underscore the pivotal role of regulating microtubule dynamics, and thus microtubule length, in governing spindle rearrangements during meiotic division, shedding light on fundamental mechanisms dictating spindle architecture.
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Affiliation(s)
- Vitaly Zimyanin
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Stefanie Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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2
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Zimyanin V, Magaj M, Yu CH, Gibney T, Mustafa B, Horton X, Siller K, Cueff L, Bouvrais H, Pécréaux J, Needleman D, Redemann S. Lack of chromokinesin Klp-19 creates a more rigid midzone and affects force transmission during anaphase in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564275. [PMID: 37961478 PMCID: PMC10634869 DOI: 10.1101/2023.10.26.564275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Recent studies have highlighted the significance of the spindle midzone - the region positioned between chromosomes - in ensuring proper chromosome segregation. By combining advanced 3D electron tomography and cutting-edge light microscopy we have discovered a previously unknown role of the regulation of microtubule dynamics within the spindle midzone of C. elegans. Using Fluorescence recovery after photobleaching and a combination of second harmonic generation and two-photon fluorescence microscopy, we found that the length of the antiparallel microtubule overlap zone in the spindle midzone is constant throughout anaphase, and independent of cortical pulling forces as well as the presence of the microtubule bundling protein SPD-1. Further investigations of SPD-1 and the chromokinesin KLP-19 in C. elegans suggest that KLP-19 regulates the overlap length and functions independently of SPD-1. Our data shows that KLP-19 plays an active role in regulating the length and turn-over of microtubules within the midzone as well as the size of the antiparallel overlap region throughout mitosis. Depletion of KLP-19 in mitosis leads to an increase in microtubule length in the spindle midzone, which also leads to increased microtubule - microtubule interaction, thus building up a more robust microtubule network. The spindle is globally stiffer and more stable, which has implications for the transmission of forces within the spindle affecting chromosome segregation dynamics. Our data shows that by localizing KLP-19 to the spindle midzone in anaphase microtubule dynamics can be locally controlled allowing the formation of a functional midzone.
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Affiliation(s)
- Vitaly Zimyanin
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Magdalena Magaj
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Che-Hang Yu
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, USA
| | - Theresa Gibney
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Basaran Mustafa
- Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xavier Horton
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Karsten Siller
- IT-Research Computing, University of Virginia, Charlottesville, VA, USA
| | - Louis Cueff
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Hélène Bouvrais
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Jacques Pécréaux
- CNRS, Univ Rennes, IGDR (Institut de Génétique et Dévelopement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Daniel Needleman
- Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
| | - Stefanie Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
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3
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Kiewisz R, Baum D, Müller-Reichert T, Fabig G. Serial-section Electron Tomography and Quantitative Analysis of Microtubule Organization in 3D-reconstructed Mitotic Spindles. Bio Protoc 2023; 13:e4849. [PMID: 37900106 PMCID: PMC10603263 DOI: 10.21769/bioprotoc.4849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 10/31/2023] Open
Abstract
For the analysis of cellular architecture during mitosis, nanometer resolution is needed to visualize the organization of microtubules in spindles. Here, we present a detailed protocol that can be used to produce 3D reconstructions of whole mitotic spindles in cells grown in culture. For this, we attach mammalian cells enriched in mitotic stages to sapphire discs. Our protocol further involves cryo-immobilization by high-pressure freezing, freeze-substitution, and resin embedding. We then use fluorescence light microscopy to stage select mitotic cells in the resin-embedded samples. This is followed by large-scale electron tomography to reconstruct the selected and staged mitotic spindles in 3D. The generated and stitched electron tomograms are then used to semi-automatically segment the microtubules for subsequent quantitative analysis of spindle organization. Thus, by providing a detailed correlative light and electron microscopy (CLEM) approach, we give cell biologists a toolset to streamline the 3D visualization and analysis of spindle microtubules (http://kiewisz.shinyapps.io/asga). In addition, we refer to a recently launched platform that allows for an interactive display of the 3D-reconstructed mitotic spindles (https://cfci.shinyapps.io/ASGA_3DViewer/). Key features • High-throughput screening of mitotic cells by correlative light and electron microscopy (CLEM). • Serial-section electron tomography of selected cells. • Visualization of mitotic spindles in 3D and quantitative analysis of microtubule organization.
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Affiliation(s)
- Robert Kiewisz
- Simons Machine Learning Center, New York Structural Biology Center, New York, NY, USA
- Experimental Center, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Biocomputing Unit, Centro Nacional de Biotechnologia (CNB-CSIC), Darwin, 3, Campus Universidad Autonoma, Cantoblanco, Madrid, Spain
| | - Daniel Baum
- Department of Visual and Data-Centric Computing, Zuse Institute Berlin, Berlin, Germany
| | - Thomas Müller-Reichert
- Experimental Center, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Gunar Fabig
- Experimental Center, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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4
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Köckert M, Okafornta CW, Hill C, Ryndyk A, Striese C, Müller-Reichert T, Paliulis L, Fabig G. Ultrastructure of the nebenkern during spermatogenesis in the praying mantid Hierodula membranacea. PLoS One 2023; 18:e0285073. [PMID: 37498864 PMCID: PMC10374135 DOI: 10.1371/journal.pone.0285073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 07/04/2023] [Indexed: 07/29/2023] Open
Abstract
Spermatogenesis leads to the formation of functional sperm cells. Here we have applied high-pressure freezing in combination with transmission electron microscopy (TEM) to study the ultrastructure of sperm development in subadult males of the praying mantid Hierodula membranacea, a species in which spermatogenesis had not previously been studied. We show the ultrastructure of different stages of sperm development in this species. Thorough examination of TEM data and electron tomographic reconstructions revealed interesting structural features of the nebenkern, an organelle composed of fused mitochondria that has been studied in spermatids of other insect species. We have applied serial-section electron tomography of the nebenkern to demonstrate in three dimensions (3D) that this organelle in H. membranacea is composed of two interwoven mitochondrial derivatives, and that the mitochondrial derivatives are connected by a zipper-like structure at opposing positions. Our approach will enable further ultrastructural analyses of the nebenkern in other organisms.
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Affiliation(s)
- Maria Köckert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | - Charlice Hill
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Anne Ryndyk
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Cynthia Striese
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Leocadia Paliulis
- Biology Department, Bucknell University, Lewisburg, PA, United States of America
| | - Gunar Fabig
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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5
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Kiewisz R, Fabig G, Müller-Reichert T, Bepler T. Automated Segmentation of 3D Cytoskeletal Filaments from Electron Micrographs with TARDIS. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:970-972. [PMID: 37613687 DOI: 10.1093/micmic/ozad067.485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Robert Kiewisz
- Simons Machine Learning Center/New York Structural Biology Center, New York, New York, USA
- Biocomputing Unit/Centro Nacional de Biotecnologia, Madrid, Cantoblanco, Spain
| | - Gunar Fabig
- Faculty of Medicine Carl Gustav Carus/Technische Universität Dresden, Dresden, Saxony, Germany
| | - Thomas Müller-Reichert
- Faculty of Medicine Carl Gustav Carus/Technische Universität Dresden, Dresden, Saxony, Germany
| | - Tristan Bepler
- Simons Machine Learning Center/New York Structural Biology Center, New York, New York, USA
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6
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de Teresa-Trueba I, Goetz SK, Mattausch A, Stojanovska F, Zimmerli CE, Toro-Nahuelpan M, Cheng DWC, Tollervey F, Pape C, Beck M, Diz-Muñoz A, Kreshuk A, Mahamid J, Zaugg JB. Convolutional networks for supervised mining of molecular patterns within cellular context. Nat Methods 2023; 20:284-294. [PMID: 36690741 PMCID: PMC9911354 DOI: 10.1038/s41592-022-01746-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 12/02/2022] [Indexed: 01/24/2023]
Abstract
Cryo-electron tomograms capture a wealth of structural information on the molecular constituents of cells and tissues. We present DeePiCt (deep picker in context), an open-source deep-learning framework for supervised segmentation and macromolecular complex localization in cryo-electron tomography. To train and benchmark DeePiCt on experimental data, we comprehensively annotated 20 tomograms of Schizosaccharomyces pombe for ribosomes, fatty acid synthases, membranes, nuclear pore complexes, organelles, and cytosol. By comparing DeePiCt to state-of-the-art approaches on this dataset, we show its unique ability to identify low-abundance and low-density complexes. We use DeePiCt to study compositionally distinct subpopulations of cellular ribosomes, with emphasis on their contextual association with mitochondria and the endoplasmic reticulum. Finally, applying pre-trained networks to a HeLa cell tomogram demonstrates that DeePiCt achieves high-quality predictions in unseen datasets from different biological species in a matter of minutes. The comprehensively annotated experimental data and pre-trained networks are provided for immediate use by the community.
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Affiliation(s)
- Irene de Teresa-Trueba
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,Present Address: Computer Science and Artificial Intelligence Lab, ENGIE Lab Crigen, Stains, France
| | - Sara K. Goetz
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Alexander Mattausch
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Frosina Stojanovska
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Christian E. Zimmerli
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.419494.50000 0001 1018 9466Present Address: Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Mauricio Toro-Nahuelpan
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,Present Address: Santiago GmbH & Co. KG, Willich, Germany
| | - Dorothy W. C. Cheng
- grid.7700.00000 0001 2190 4373Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany ,grid.4709.a0000 0004 0495 846XCell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Fergus Tollervey
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Constantin Pape
- grid.4709.a0000 0004 0495 846XCell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.7450.60000 0001 2364 4210Present Address: Institute for Computer Science, Universität Göttingen, Göttingen, Germany
| | - Martin Beck
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.4709.a0000 0004 0495 846XCell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.419494.50000 0001 1018 9466Present Address: Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Alba Diz-Muñoz
- grid.4709.a0000 0004 0495 846XCell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Anna Kreshuk
- grid.4709.a0000 0004 0495 846XCell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany. .,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Judith B. Zaugg
- grid.4709.a0000 0004 0495 846XStructural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany ,grid.4709.a0000 0004 0495 846XGenome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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7
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Laguillo-Diego A, Kiewisz R, Martí-Gómez C, Baum D, Müller-Reichert T, Vernos I. MCRS1 modulates the heterogeneity of microtubule minus-end morphologies in mitotic spindles. Mol Biol Cell 2022; 34:ar1. [PMID: 36350698 PMCID: PMC9816640 DOI: 10.1091/mbc.e22-08-0306-t] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Faithful chromosome segregation requires the assembly of a bipolar spindle, consisting of two antiparallel microtubule (MT) arrays having most of their minus ends focused at the spindle poles and their plus ends overlapping in the spindle midzone. Spindle assembly, chromosome alignment, and segregation require highly dynamic MTs. The plus ends of MTs have been extensively investigated but their minus-end structure remains poorly characterized. Here, we used large-scale electron tomography to study the morphology of the MT minus ends in three dimensionally reconstructed metaphase spindles in HeLa cells. In contrast to the homogeneous open morphology of the MT plus ends at the kinetochores, we found that MT minus ends are heterogeneous, showing either open or closed morphologies. Silencing the minus end-specific stabilizer, MCRS1 increased the proportion of open MT minus ends. Altogether, these data suggest a correlation between the morphology and the dynamic state of the MT ends. Taking this heterogeneity of the MT minus-end morphologies into account, our work indicates an unsynchronized behavior of MTs at the spindle poles, thus laying the groundwork for further studies on the complexity of MT dynamics regulation.
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Affiliation(s)
- Alejandra Laguillo-Diego
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Robert Kiewisz
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Carlos Martí-Gómez
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Daniel Baum
- Department of Visual and Data-Centric Computing, Zuse Institute Berlin, 14195 Berlin, Germany
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Isabelle Vernos
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona 08003, Spain,Universitat Pompeu Fabra, Barcelona 08003, Spain,ICREA, Barcelona 08010, Spain,*Address correspondence to: Isabelle Vernos ()
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8
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Kiewisz R, Fabig G, Conway W, Baum D, Needleman DJ, Müller-Reichert T. Three-dimensional structure of kinetochore-fibers in human mitotic spindles. eLife 2022; 11:75459. [PMID: 35894209 PMCID: PMC9365394 DOI: 10.7554/elife.75459] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 07/24/2022] [Indexed: 11/13/2022] Open
Abstract
During cell division, kinetochore microtubules (KMTs) provide a physical linkage between the chromosomes and the rest of the spindle. KMTs in mammalian cells are organized into bundles, so-called kinetochore-fibers (k-fibers), but the ultrastructure of these fibers is currently not well characterized. Here, we show by large-scale electron tomography that each k-fiber in HeLa cells in metaphase is composed of approximately nine KMTs, only half of which reach the spindle pole. Our comprehensive reconstructions allowed us to analyze the three-dimensional (3D) morphology of k-fibers and their surrounding MTs in detail. We found that k-fibers exhibit remarkable variation in circumference and KMT density along their length, with the pole-proximal side showing a broadening. Extending our structural analysis then to other MTs in the spindle, we further observed that the association of KMTs with non-KMTs predominantly occurs in the spindle pole regions. Our 3D reconstructions have implications for KMT growth and k-fiber self-organization models as covered in a parallel publication applying complementary live-cell imaging in combination with biophysical modeling (Conway et al., 2022). Finally, we also introduce a new visualization tool allowing an interactive display of our 3D spindle data that will serve as a resource for further structural studies on mitosis in human cells.
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Affiliation(s)
- Robert Kiewisz
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Gunar Fabig
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - William Conway
- Department of Physics, Harvard University, Cambridge, United States
| | - Daniel Baum
- Department of Visual and Data-Centric Computing, Zuse Institute Berlin, Berlin, Germany
| | - Daniel J Needleman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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9
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Katzke J, Puchenkov P, Stark H, Economo EP. A Roadmap to Reconstructing Muscle Architecture from CT Data. INTEGRATIVE ORGANISMAL BIOLOGY (OXFORD, ENGLAND) 2022; 4:obac001. [PMID: 35211665 PMCID: PMC8857456 DOI: 10.1093/iob/obac001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Indexed: 02/02/2023]
Abstract
Skeletal muscle is responsible for voluntary force generation across animals, and muscle architecture largely determines the parameters of mechanical output. The ability to analyze muscle performance through muscle architecture is thus a key step towards better understanding the ecology and evolution of movements and morphologies. In pennate skeletal muscle, volume, fiber lengths, and attachment angles to force transmitting structures comprise the most relevant parameters of muscle architecture. Measuring these features through tomographic techniques offers an alternative to tedious and destructive dissections, particularly as the availability of tomographic data is rapidly increasing. However, there is a need for streamlined computational methods to access this information efficiently. Here, we establish and compare workflows using partially automated image analysis for fast and accurate estimation of animal muscle architecture. After isolating a target muscle through segmentation, we evaluate freely available and proprietary fiber tracing algorithms to reconstruct muscle fibers. We then present a script using the Blender Python API to estimate attachment angles, fiber lengths, muscle volume, and physiological cross-sectional area. We apply these methods to insect and vertebrate muscle and provide guided workflows. Results from fiber tracing are consistent compared to manual measurements but much less time-consuming. Lastly, we emphasize the capabilities of the open-source three-dimensional software Blender as both a tool for visualization and a scriptable analytic tool to process digitized anatomical data. Across organisms, it is feasible to extract, analyze, and visualize muscle architecture from tomography data by exploiting the spatial features of scans and the geometric properties of muscle fibers. As digital libraries of anatomies continue to grow, the workflows and approach presented here can be part of the open-source future of digital comparative analysis.
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Affiliation(s)
| | - Pavel Puchenkov
- Scientific Computing and Data Analysis Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University, Onna, 904-0495 Okinawa, Japan
| | - Heiko Stark
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Fürstengraben 1,07743 Jena, Germany
| | - Evan P Economo
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, 904-0495 Okinawa, Japan
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10
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Lim YW, Wen FL, Shankar P, Shibata T, Motegi F. A balance between antagonizing PAR proteins specifies the pattern of asymmetric and symmetric divisions in C. elegans embryogenesis. Cell Rep 2021; 36:109326. [PMID: 34233197 DOI: 10.1016/j.celrep.2021.109326] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/05/2021] [Accepted: 06/08/2021] [Indexed: 10/20/2022] Open
Abstract
Coordination between cell differentiation and proliferation during development requires the balance between asymmetric and symmetric modes of cell division. However, the cellular intrinsic cue underlying the choice between these two division modes remains elusive. Here, we show evidence in Caenorhabditis elegans that the invariable lineage of the division modes is specified by the balance between antagonizing complexes of partitioning-defective (PAR) proteins. By uncoupling unequal inheritance of PAR proteins from that of fate determinants during cell division, we demonstrate that changes in the balance between PAR-2 and PAR-6 can be sufficient to re-program the division modes from symmetric to asymmetric and vice versa in two daughter cells. The division mode adopted occurs independently of asymmetry in cytoplasmic fate determinants, cell-size asymmetry, and cell-cycle asynchrony between sister cells. We propose that the balance between PAR proteins represents an intrinsic self-organizing cue for the specification of the two division modes during development.
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Affiliation(s)
- Yen Wei Lim
- Temasek Life-sciences Laboratory, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117583, Singapore
| | - Fu-Lai Wen
- RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Prabhat Shankar
- RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Tatsuo Shibata
- RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan.
| | - Fumio Motegi
- Temasek Life-sciences Laboratory, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117583, Singapore; Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore; Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
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11
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Lantzsch I, Yu CH, Chen YZ, Zimyanin V, Yazdkhasti H, Lindow N, Szentgyoergyi E, Pani AM, Prohaska S, Srayko M, Fürthauer S, Redemann S. Microtubule reorganization during female meiosis in C. elegans. eLife 2021; 10:58903. [PMID: 34114562 PMCID: PMC8225387 DOI: 10.7554/elife.58903] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 05/24/2021] [Indexed: 02/01/2023] Open
Abstract
Most female meiotic spindles undergo striking morphological changes while transitioning from metaphase to anaphase. The ultra-structure of meiotic spindles, and how changes to this structure correlate with such dramatic spindle rearrangements remains largely unknown. To address this, we applied light microscopy, large-scale electron tomography and mathematical modeling of female meiotic Caenorhabditis elegans spindles. Combining these approaches, we find that meiotic spindles are dynamic arrays of short microtubules that turn over within seconds. The results show that the metaphase to anaphase transition correlates with an increase in microtubule numbers and a decrease in their average length. Detailed analysis of the tomographic data revealed that the microtubule length changes significantly during the metaphase-to-anaphase transition. This effect is most pronounced for microtubules located within 150 nm of the chromosome surface. To understand the mechanisms that drive this transition, we developed a mathematical model for the microtubule length distribution that considers microtubule growth, catastrophe, and severing. Using Bayesian inference to compare model predictions and data, we find that microtubule turn-over is the major driver of the spindle reorganizations. Our data suggest that in metaphase only a minor fraction of microtubules, those closest to the chromosomes, are severed. The large majority of microtubules, which are not in close contact with chromosomes, do not undergo severing. Instead, their length distribution is fully explained by growth and catastrophe. This suggests that the most prominent drivers of spindle rearrangements are changes in nucleation and catastrophe rate. In addition, we provide evidence that microtubule severing is dependent on katanin.
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Affiliation(s)
- Ina Lantzsch
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität DresdenDresdenGermany
| | - Che-Hang Yu
- Department of Electrical and Computer Engineering, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Yu-Zen Chen
- Center for Membrane and Cell Physiology, University of Virginia School of MedicineCharlottesvilleUnited States,Department of Molecular Physiology and Biological Physics, University of Virginia, School of MedicineCharlottesvilleUnited States
| | - Vitaly Zimyanin
- Center for Membrane and Cell Physiology, University of Virginia School of MedicineCharlottesvilleUnited States,Department of Molecular Physiology and Biological Physics, University of Virginia, School of MedicineCharlottesvilleUnited States
| | - Hossein Yazdkhasti
- Center for Membrane and Cell Physiology, University of Virginia School of MedicineCharlottesvilleUnited States,Department of Molecular Physiology and Biological Physics, University of Virginia, School of MedicineCharlottesvilleUnited States
| | | | - Erik Szentgyoergyi
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität DresdenDresdenGermany
| | - Ariel M Pani
- Department of Biology, University of VirginiaCharlottesvilleUnited States,Department of Cell Biology, University of Virginia School of MedicineCharlottesvilleUnited States
| | | | - Martin Srayko
- Department of Biological Sciences, University of AlbertaEdmontonCanada
| | | | - Stefanie Redemann
- Center for Membrane and Cell Physiology, University of Virginia School of MedicineCharlottesvilleUnited States,Department of Molecular Physiology and Biological Physics, University of Virginia, School of MedicineCharlottesvilleUnited States,Department of Cell Biology, University of Virginia School of MedicineCharlottesvilleUnited States
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12
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Fabig G, Kiewisz R, Lindow N, Powers JA, Cota V, Quintanilla LJ, Brugués J, Prohaska S, Chu DS, Müller-Reichert T. Male meiotic spindle features that efficiently segregate paired and lagging chromosomes. eLife 2020; 9:50988. [PMID: 32149606 PMCID: PMC7101234 DOI: 10.7554/elife.50988] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 03/08/2020] [Indexed: 01/25/2023] Open
Abstract
Chromosome segregation during male meiosis is tailored to rapidly generate multitudes of sperm. Little is known about mechanisms that efficiently partition chromosomes to produce sperm. Using live imaging and tomographic reconstructions of spermatocyte meiotic spindles in Caenorhabditis elegans, we find the lagging X chromosome, a distinctive feature of anaphase I in C. elegans males, is due to lack of chromosome pairing. The unpaired chromosome remains tethered to centrosomes by lengthening kinetochore microtubules, which are under tension, suggesting that a ‘tug of war’ reliably resolves lagging. We find spermatocytes exhibit simultaneous pole-to-chromosome shortening (anaphase A) and pole-to-pole elongation (anaphase B). Electron tomography unexpectedly revealed spermatocyte anaphase A does not stem solely from kinetochore microtubule shortening. Instead, movement of autosomes is largely driven by distance change between chromosomes, microtubules, and centrosomes upon tension release during anaphase. Overall, we define novel features that segregate both lagging and paired chromosomes for optimal sperm production.
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Affiliation(s)
- Gunar Fabig
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Robert Kiewisz
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | - James A Powers
- Light Microscopy Imaging Center, Indiana University, Bloomington, United States
| | - Vanessa Cota
- Department of Biology, San Francisco State University, San Francisco, United States
| | - Luis J Quintanilla
- Department of Biology, San Francisco State University, San Francisco, United States
| | - Jan Brugués
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Centre for Systems Biology Dresden, Dresden, Germany
| | | | - Diana S Chu
- Department of Biology, San Francisco State University, San Francisco, United States
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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13
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Redemann S, Fürthauer S, Shelley M, Müller-Reichert T. Current approaches for the analysis of spindle organization. Curr Opin Struct Biol 2019; 58:269-277. [DOI: 10.1016/j.sbi.2019.05.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 01/06/2023]
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14
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15
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Redemann S, Lantzsch I, Lindow N, Prohaska S, Srayko M, Müller-Reichert T. A Switch in Microtubule Orientation during C. elegans Meiosis. Curr Biol 2018; 28:2991-2997.e2. [PMID: 30197085 DOI: 10.1016/j.cub.2018.07.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 06/29/2018] [Accepted: 07/05/2018] [Indexed: 11/26/2022]
Abstract
In oocytes of many organisms, meiotic spindles form in the absence of centrosomes [1-5]. Such female meiotic spindles have a pointed appearance in metaphase with microtubules focused at acentrosomal spindle poles. At anaphase, the microtubules of acentrosomal spindles then transition to an inter-chromosomal array, while the spindle poles disappear. This transition is currently not understood. Previous studies have focused on this inter-chromosomal microtubule array and proposed a pushing model to drive chromosome segregation [6, 7]. This model includes an end-on orientation of microtubules with chromosomes. Alternatively, chromosomes were thought to associate along bundles of microtubules [8, 9]. Starting with metaphase, this second model proposed a pure lateral chromosome-to-microtubule association up to the final meiotic stages of anaphase. Here, we applied large-scale electron tomography [10] of staged C. elegans oocytes in meiosis to analyze the orientation of microtubules in respect to chromosomes. We show that microtubules at metaphase I are primarily oriented laterally to the chromosomes and that microtubules switch to an end-on orientation during progression through anaphase. We further show that this switch in microtubule orientation involves a kinesin-13 microtubule depolymerase, KLP-7, which removes laterally associated microtubules around chromosomes. From this, we conclude that both lateral and end-on modes of microtubule-to-chromosome orientations are successively used in C. elegans oocytes to segregate meiotic chromosomes.
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Affiliation(s)
- Stefanie Redemann
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
| | - Ina Lantzsch
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | | | - Martin Srayko
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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16
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Tracing Actin Filament Bundles in Three-Dimensional Electron Tomography Density Maps of Hair Cell Stereocilia. Molecules 2018; 23:molecules23040882. [PMID: 29641472 PMCID: PMC6017643 DOI: 10.3390/molecules23040882] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/14/2018] [Accepted: 03/22/2018] [Indexed: 12/20/2022] Open
Abstract
Cryo-electron tomography (cryo-ET) is a powerful method of visualizing the three-dimensional organization of supramolecular complexes, such as the cytoskeleton, in their native cell and tissue contexts. Due to its minimal electron dose and reconstruction artifacts arising from the missing wedge during data collection, cryo-ET typically results in noisy density maps that display anisotropic XY versus Z resolution. Molecular crowding further exacerbates the challenge of automatically detecting supramolecular complexes, such as the actin bundle in hair cell stereocilia. Stereocilia are pivotal to the mechanoelectrical transduction process in inner ear sensory epithelial hair cells. Given the complexity and dense arrangement of actin bundles, traditional approaches to filament detection and tracing have failed in these cases. In this study, we introduce BundleTrac, an effective method to trace hundreds of filaments in a bundle. A comparison between BundleTrac and manually tracing the actin filaments in a stereocilium showed that BundleTrac accurately built 326 of 330 filaments (98.8%), with an overall cross-distance of 1.3 voxels for the 330 filaments. BundleTrac is an effective semi-automatic modeling approach in which a seed point is provided for each filament and the rest of the filament is computationally identified. We also demonstrate the potential of a denoising method that uses a polynomial regression to address the resolution and high-noise anisotropic environment of the density map.
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17
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Müller-Reichert T, Kiewisz R, Redemann S. Mitotic spindles revisited – new insights from 3D electron microscopy. J Cell Sci 2018; 131:131/3/jcs211383. [DOI: 10.1242/jcs.211383] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
ABSTRACT
The mitotic spindle is a complex three-dimensional (3D) apparatus that functions to ensure the faithful segregation of chromosomes during cell division. Our current understanding of spindle architecture is mainly based on a plethora of information derived from light microscopy with rather few insights about spindle ultrastructure obtained from electron microscopy. In this Review, we will provide insights into the history of imaging of mitotic spindles and highlight recent technological advances in electron tomography and data processing, which have delivered detailed 3D reconstructions of mitotic spindles in the early embryo of the nematode Caenorhabditis elegans. Tomographic reconstructions provide novel views on spindles and will enable us to revisit and address long-standing questions in the field of mitosis.
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Affiliation(s)
- Thomas Müller-Reichert
- Technische Universität Dresden, Experimental Center, Medical Faculty Carl Gustav Carus, Fiedlerstraße 42, 01307 Dresden, Germany
| | - Robert Kiewisz
- Technische Universität Dresden, Experimental Center, Medical Faculty Carl Gustav Carus, Fiedlerstraße 42, 01307 Dresden, Germany
| | - Stefanie Redemann
- Technische Universität Dresden, Experimental Center, Medical Faculty Carl Gustav Carus, Fiedlerstraße 42, 01307 Dresden, Germany
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18
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Clarke NI, Royle SJ. Correlating light microscopy with serial block face scanning electron microscopy to study mitotic spindle architecture. Methods Cell Biol 2018; 145:29-43. [PMID: 29957210 DOI: 10.1016/bs.mcb.2018.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mitotic spindle is a complex structure that coordinates the accurate segregation of chromosomes during cell division. To understand how the mitotic spindle operates at the molecular level, high resolution imaging is needed. Serial block face-scanning electron microscopy (SBF-SEM) is a technique that can be used to visualize the ultrastructure of entire cells, including components of the mitotic spindle such as microtubules, kinetochores, centrosomes, and chromosomes. Although transmission electron microscopy (TEM) has higher resolution, the reconstruction of large volumes using TEM and tomography is labor intensive, whereas SBF-SEM takes only days to process, image, and segment samples. SBF-SEM fills the resolution gap between light microscopy (LM) and TEM. When combined with LM, SBF-SEM provides a platform where dynamic cellular events can be selected and imaged at high resolution. Here we outline methods to use correlation and SBF-SEM to study mitotic spindle architecture in 3D with high resolution.
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Affiliation(s)
- Nicholas I Clarke
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom
| | - Stephen J Royle
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom.
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19
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Winter ES, Schwarz A, Fabig G, Feldman JL, Pires-daSilva A, Müller-Reichert T, Sadler PL, Shakes DC. Cytoskeletal variations in an asymmetric cell division support diversity in nematode sperm size and sex ratios. Development 2017; 144:3253-3263. [PMID: 28827395 DOI: 10.1242/dev.153841] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/14/2017] [Indexed: 12/18/2022]
Abstract
Asymmetric partitioning is an essential component of many developmental processes. As spermatogenesis concludes, sperm are streamlined by discarding unnecessary cellular components into cellular wastebags called residual bodies (RBs). During nematode spermatogenesis, this asymmetric partitioning event occurs shortly after anaphase II, and both microtubules and actin partition into a central RB. Here, we use fluorescence and transmission electron microscopy to elucidate and compare the intermediate steps of RB formation in Caenorhabditis elegans, Rhabditis sp. SB347 (recently named Auanema rhodensis) and related nematodes. In all cases, intact microtubules reorganize and move from centrosomal to non-centrosomal sites at the RB-sperm boundary whereas actin reorganizes through cortical ring expansion and clearance from the poles. However, in species with tiny spermatocytes, these cytoskeletal changes are restricted to one pole. Consequently, partitioning yields one functional sperm with the X-bearing chromosome complement and an RB with the other chromosome set. Unipolar partitioning may not require an unpaired X, as it also occurs in XX spermatocytes. Instead, constraints related to spermatocyte downsizing may have contributed to the evolution of a sperm cell equivalent to female polar bodies.
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Affiliation(s)
- Ethan S Winter
- Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA
| | - Anna Schwarz
- Experimental Center, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Gunar Fabig
- Experimental Center, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Jessica L Feldman
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | | | - Thomas Müller-Reichert
- Experimental Center, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Penny L Sadler
- Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA.,Department of Biology & Biochemistry, University of Houston, Houston, TX, 77204, USA
| | - Diane C Shakes
- Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA
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20
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Gibson KH, Vorkel D, Meissner J, Verbavatz JM. Fluorescing the electron: strategies in correlative experimental design. Methods Cell Biol 2014; 124:23-54. [PMID: 25287835 DOI: 10.1016/b978-0-12-801075-4.00002-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Correlative light and electron microscopy (CLEM) encompasses a growing number of imaging techniques aiming to combine the benefits of light microscopy, which allows routine labeling of molecules and live-cell imaging of fluorescently tagged proteins with the resolution and ultrastructural detail provided by electron microscopy (EM). Here we review three different strategies that are commonly used in CLEM and we illustrate each approach with one detailed example of their application. The focus is on different options for sample preparation with their respective benefits as well as on the imaging workflows that can be used. The three strategies cover: (1) the combination of live-cell imaging with the high resolution of EM (time-resolved CLEM), (2) the need to identify a fluorescent cell of interest for further exploration by EM (cell sorting), and (3) the subcellular correlation of a fluorescent feature in a cell with its associated ultrastructural features (spatial CLEM). Finally, we discuss future directions for CLEM exploring the possibilities for combining super-resolution microscopy with EM.
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Affiliation(s)
- Kimberley H Gibson
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Daniela Vorkel
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jana Meissner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jean-Marc Verbavatz
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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