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Weiss JD, McVey SL, Stinebaugh SE, Sullivan CF, Dawe RK, Nannas NJ. Frequent Spindle Assembly Errors Require Structural Rearrangement to Complete Meiosis in Zea mays. Int J Mol Sci 2022; 23:ijms23084293. [PMID: 35457112 PMCID: PMC9031645 DOI: 10.3390/ijms23084293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 12/04/2022] Open
Abstract
The success of an organism is contingent upon its ability to faithfully pass on its genetic material. In the meiosis of many species, the process of chromosome segregation requires that bipolar spindles be formed without the aid of dedicated microtubule organizing centers, such as centrosomes. Here, we describe detailed analyses of acentrosomal spindle assembly and disassembly in time-lapse images, from live meiotic cells of Zea mays. Microtubules organized on the nuclear envelope with a perinuclear ring structure until nuclear envelope breakdown, at which point microtubules began bundling into a bipolar form. However, the process and timing of spindle assembly was highly variable, with frequent assembly errors in both meiosis I and II. Approximately 61% of cells formed incorrect spindle morphologies, with the most prevalent being tripolar spindles. The erroneous spindles were actively rearranged to bipolar through a coalescence of poles before proceeding to anaphase. Spindle disassembly occurred as a two-state process with a slow depolymerization, followed by a quick collapse. The results demonstrate that maize meiosis I and II spindle assembly is remarkably fluid in the early assembly stages, but otherwise proceeds through a predictable series of events.
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Affiliation(s)
- Jodi D. Weiss
- Department of Biology, Hamilton College, Clinton, NY 13323, USA; (J.D.W.); (S.L.M.); (S.E.S.); (C.F.S.)
| | - Shelby L. McVey
- Department of Biology, Hamilton College, Clinton, NY 13323, USA; (J.D.W.); (S.L.M.); (S.E.S.); (C.F.S.)
| | - Sarah E. Stinebaugh
- Department of Biology, Hamilton College, Clinton, NY 13323, USA; (J.D.W.); (S.L.M.); (S.E.S.); (C.F.S.)
| | - Caroline F. Sullivan
- Department of Biology, Hamilton College, Clinton, NY 13323, USA; (J.D.W.); (S.L.M.); (S.E.S.); (C.F.S.)
| | - R. Kelly Dawe
- Department of Genetics, University of Georgia, Athens, GA 30602, USA;
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | - Natalie J. Nannas
- Department of Biology, Hamilton College, Clinton, NY 13323, USA; (J.D.W.); (S.L.M.); (S.E.S.); (C.F.S.)
- Correspondence:
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Prusicki MA, Balboni M, Sofroni K, Hamamura Y, Schnittger A. Caught in the Act: Live-Cell Imaging of Plant Meiosis. FRONTIERS IN PLANT SCIENCE 2021; 12:718346. [PMID: 34992616 PMCID: PMC8724559 DOI: 10.3389/fpls.2021.718346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
Live-cell imaging is a powerful method to obtain insights into cellular processes, particularly with respect to their dynamics. This is especially true for meiosis, where chromosomes and other cellular components such as the cytoskeleton follow an elaborate choreography over a relatively short period of time. Making these dynamics visible expands understanding of the regulation of meiosis and its underlying molecular forces. However, the analysis of meiosis by live-cell imaging is challenging; specifically in plants, a temporally resolved understanding of chromosome segregation and recombination events is lacking. Recent advances in live-cell imaging now allow the analysis of meiotic events in plants in real time. These new microscopy methods rely on the generation of reporter lines for meiotic regulators and on the establishment of ex vivo culture and imaging conditions, which stabilize the specimen and keep it alive for several hours or even days. In this review, we combine an overview of the technical aspects of live-cell imaging in plants with a summary of outstanding questions that can now be addressed to promote live-cell imaging in Arabidopsis and other plant species and stimulate ideas on the topics that can be addressed in the context of plant meiotic recombination.
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Affiliation(s)
| | | | | | | | - Arp Schnittger
- Department of Developmental Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
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Sofroni K, Takatsuka H, Yang C, Dissmeyer N, Komaki S, Hamamura Y, Böttger L, Umeda M, Schnittger A. CDKD-dependent activation of CDKA;1 controls microtubule dynamics and cytokinesis during meiosis. J Cell Biol 2021; 219:151917. [PMID: 32609301 PMCID: PMC7401817 DOI: 10.1083/jcb.201907016] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 02/17/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Precise control of cytoskeleton dynamics and its tight coordination with chromosomal events are key to cell division. This is exemplified by formation of the spindle and execution of cytokinesis after nuclear division. Here, we reveal that the central cell cycle regulator CYCLIN DEPENDENT KINASE A;1 (CDKA;1), the Arabidopsis homologue of Cdk1 and Cdk2, partially in conjunction with CYCLIN B3;1 (CYCB3;1), is a key regulator of the microtubule cytoskeleton in meiosis. For full CDKA;1 activity, the function of three redundantly acting CDK-activating kinases (CAKs), CDKD;1, CDKD;2, and CDKD;3, is necessary. Progressive loss of these genes in combination with a weak loss-of-function mutant in CDKA;1 allowed a fine-grained dissection of the requirement of cell-cycle kinase activity for meiosis. Notably, a moderate reduction of CDKA;1 activity converts the simultaneous cytokinesis in Arabidopsis, i.e., one cytokinesis separating all four meiotic products concurrently into two successive cytokineses with cell wall formation after the first and second meiotic division, as found in many monocotyledonous species.
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Affiliation(s)
- Kostika Sofroni
- University of Hamburg, Department of Developmental Biology, Hamburg, Germany
| | - Hirotomo Takatsuka
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Nara, Japan
| | - Chao Yang
- University of Hamburg, Department of Developmental Biology, Hamburg, Germany
| | - Nico Dissmeyer
- Department of Plant Physiology, University of Osnabrück, Osnabrück, Germany
| | - Shinichiro Komaki
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Nara, Japan
| | - Yuki Hamamura
- University of Hamburg, Department of Developmental Biology, Hamburg, Germany
| | - Lev Böttger
- University of Hamburg, Department of Developmental Biology, Hamburg, Germany
| | - Masaaki Umeda
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Nara, Japan
| | - Arp Schnittger
- University of Hamburg, Department of Developmental Biology, Hamburg, Germany
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Aguilar M, Prieto P. Telomeres and Subtelomeres Dynamics in the Context of Early Chromosome Interactions During Meiosis and Their Implications in Plant Breeding. FRONTIERS IN PLANT SCIENCE 2021; 12:672489. [PMID: 34149773 PMCID: PMC8212018 DOI: 10.3389/fpls.2021.672489] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/06/2021] [Indexed: 05/08/2023]
Abstract
Genomic architecture facilitates chromosome recognition, pairing, and recombination. Telomeres and subtelomeres play an important role at the beginning of meiosis in specific chromosome recognition and pairing, which are critical processes that allow chromosome recombination between homologs (equivalent chromosomes in the same genome) in later stages. In plant polyploids, these terminal regions are even more important in terms of homologous chromosome recognition, due to the presence of homoeologs (equivalent chromosomes from related genomes). Although telomeres interaction seems to assist homologous pairing and consequently, the progression of meiosis, other chromosome regions, such as subtelomeres, need to be considered, because the DNA sequence of telomeres is not chromosome-specific. In addition, recombination operates at subtelomeres and, as it happens in rye and wheat, homologous recognition and pairing is more often correlated with recombining regions than with crossover-poor regions. In a plant breeding context, the knowledge of how homologous chromosomes initiate pairing at the beginning of meiosis can contribute to chromosome manipulation in hybrids or interspecific genetic crosses. Thus, recombination in interspecific chromosome associations could be promoted with the aim of transferring desirable agronomic traits from related genetic donor species into crops. In this review, we summarize the importance of telomeres and subtelomeres on chromatin dynamics during early meiosis stages and their implications in recombination in a plant breeding framework.
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Affiliation(s)
- Miguel Aguilar
- Área de Fisiología Vegetal, Universidad de Córdoba, Córdoba, Spain
| | - Pilar Prieto
- Plant Breeding Department, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain
- *Correspondence: Pilar Prieto, ; orcid.org/0000-0002-8160-808X
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Prusicki MA, Keizer EM, Van Rosmalen RP, Fleck C, Schnittger A. Live Cell Imaging of Male Meiosis in Arabidopsis by a Landmark-based System. Bio Protoc 2020; 10:e3611. [PMID: 33659575 DOI: 10.21769/bioprotoc.3611] [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: 01/22/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 12/19/2022] Open
Abstract
Live cell imaging has tremendously promoted our understanding of cellular and subcellular processes such as cell division. Here, we present a step-by-step protocol for a robust and easy-to-use live cell imaging approach to study male meiosis in the plant Arabidopsis thaliana as recently established. Our method relies on the concomitant analysis of two reporter genes that highlight chromosome configurations and microtubule dynamics. In combination, these reporter genes allowed the discrimination of five cellular parameters: cell shape, microtubule array, nucleus position, nucleolus position, and chromatin condensation. These parameters can adopt different states, e.g., the nucleus position can be central or lateral. Analyzing how tightly these states are associated gives rise to landmark stages that in turn allow a quantitative and qualitative dissection of meiotic progression. We envision that such an approach can also provide valuable criteria for the analysis of cell differentiation processes outside of meiosis.
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Affiliation(s)
- Maria Ada Prusicki
- Department of Developmental Biology, University of Hamburg, Hamburg, Germany
| | - Emma Mathilde Keizer
- Department of Mathematical and Statistical Methods, Wageningen University and Research, Wageningen, The Netherlands
| | - Rik Peter Van Rosmalen
- Department of Agrotechnology and Food Sciences, Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, The Netherlands
| | - Christian Fleck
- Department of Agrotechnology and Food Sciences, Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, The Netherlands
| | - Arp Schnittger
- Department of Developmental Biology, University of Hamburg, Hamburg, Germany
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Prusicki MA, Keizer EM, van Rosmalen RP, Komaki S, Seifert F, Müller K, Wijnker E, Fleck C, Schnittger A. Live cell imaging of meiosis in Arabidopsis thaliana. eLife 2019; 8:e42834. [PMID: 31107238 PMCID: PMC6559805 DOI: 10.7554/elife.42834] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 05/17/2019] [Indexed: 11/13/2022] Open
Abstract
To follow the dynamics of meiosis in the model plant Arabidopsis, we have established a live cell imaging setup to observe male meiocytes. Our method is based on the concomitant visualization of microtubules (MTs) and a meiotic cohesin subunit that allows following five cellular parameters: cell shape, MT array, nucleus position, nucleolus position, and chromatin condensation. We find that the states of these parameters are not randomly associated and identify 11 cellular states, referred to as landmarks, which occur much more frequently than closely related ones, indicating that they are convergence points during meiotic progression. As a first application of our system, we revisited a previously identified mutant in the meiotic A-type cyclin TARDY ASYNCHRONOUS MEIOSIS (TAM). Our imaging system enabled us to reveal both qualitatively and quantitatively altered landmarks in tam, foremost the formation of previously not recognized ectopic spindle- or phragmoplast-like structures that arise without attachment to chromosomes.
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Affiliation(s)
- Maria A Prusicki
- Department of Developmental BiologyUniversity of HamburgHamburgGermany
| | - Emma M Keizer
- Department of Agrotechnology and Food SciencesWageningen UniversityWageningenThe Netherlands
| | - Rik P van Rosmalen
- Department of Agrotechnology and Food SciencesWageningen UniversityWageningenThe Netherlands
| | - Shinichiro Komaki
- Department of Developmental BiologyUniversity of HamburgHamburgGermany
| | - Felix Seifert
- Department of Developmental BiologyUniversity of HamburgHamburgGermany
| | - Katja Müller
- Department of Developmental BiologyUniversity of HamburgHamburgGermany
| | - Erik Wijnker
- Department of Plant Science, Laboratory of GeneticsWageningen University and ResearchWageningenThe Netherlands
| | - Christian Fleck
- Department of Agrotechnology and Food SciencesWageningen UniversityWageningenThe Netherlands
| | - Arp Schnittger
- Department of Developmental BiologyUniversity of HamburgHamburgGermany
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Lambing C, Heckmann S. Tackling Plant Meiosis: From Model Research to Crop Improvement. FRONTIERS IN PLANT SCIENCE 2018; 9:829. [PMID: 29971082 PMCID: PMC6018109 DOI: 10.3389/fpls.2018.00829] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/28/2018] [Indexed: 05/04/2023]
Abstract
Genetic engineering and traditional plant breeding, which harnesses the natural genetic variation that arises during meiosis, will have key roles to improve crop varieties and thus deliver Food Security in the future. Meiosis, a specialized cell division producing haploid gametes to maintain somatic diploidy following their fusion, assures genetic variation by regulated genetic exchange through homologous recombination. However, meiotic recombination events are restricted in their total number and their distribution along chromosomes limiting allelic variations in breeding programs. Thus, modifying the number and distribution of meiotic recombination events has great potential to improve and accelerate plant breeding. In recent years much progress has been made in understanding meiotic progression and recombination in plants. Many genes and factors involved in these processes have been identified primarily in Arabidopsis thaliana but also more recently in crops such as Brassica, rice, barley, maize, or wheat. These advances put researchers in the position to translate acquired knowledge to various crops likely improving and accelerating breeding programs. However, although fundamental aspects of meiotic progression and recombination are conserved between species, differences in genome size and organization (due to repetitive DNA content and ploidy level) exist, particularly among plants, that likely account for differences in meiotic progression and recombination patterns found between species. Thus, tools and approaches are needed to better understand differences and similarities in meiotic progression and recombination among plants, to study fundamental aspects of meiosis in a variety of plants including crops and non-model species, and to transfer knowledge into crop species. In this article, we provide an overview of tools and approaches available to study plant meiosis, highlight new techniques, give examples of areas of future research and review distinct aspects of meiosis in non-model species.
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Affiliation(s)
- Christophe Lambing
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Christophe Lambing, Stefan Heckmann,
| | - Stefan Heckmann
- Independent Research Group Meiosis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany
- *Correspondence: Christophe Lambing, Stefan Heckmann,
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Cooperation Between Kinesin Motors Promotes Spindle Symmetry and Chromosome Organization in Oocytes. Genetics 2016; 205:517-527. [PMID: 27932541 DOI: 10.1534/genetics.116.194647] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/29/2016] [Indexed: 11/18/2022] Open
Abstract
The oocyte spindle in most animal species is assembled in the absence of the microtubule-organizing centers called centrosomes. Without the organization provided by centrosomes, acentrosomal meiotic spindle organization may rely heavily on the bundling of microtubules by kinesin motor proteins. Indeed, the minus-end directed kinesin-14 NCD, and the plus-end directed kinesin-6 Subito are known to be required for oocyte spindle organization in Drosophila melanogaster How multiple microtubule-bundling kinesins interact to produce a functional acentrosomal spindle is not known. In addition, there have been few studies on the meiotic function of one of the most important microtubule-bundlers in mitotic cells, the kinesin-5 KLP61F. We have found that the kinesin-5 KLP61F is required for spindle and centromere symmetry in oocytes. The asymmetry observed in the absence of KLP61F depends on NCD, the kinesin-12 KLP54D, and the microcephaly protein ASP. In contrast, KLP61F and Subito work together in maintaining a bipolar spindle. We propose that the prominent central spindle, stabilized by Subito, provides the framework for the coordination of multiple microtubule-bundling activities. The activities of several proteins, including NCD, KLP54D, and ASP, generate asymmetries within the acentrosomal spindle, while KLP61F and Subito balance these forces, resulting in the capacity to accurately segregate chromosomes.
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