1
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Xiao C, Xiong JW. ERK signaling waves via body-wall muscles guide planarian whole-body regeneration across long distances. Cell Regen 2023; 12:36. [PMID: 37938438 PMCID: PMC10632249 DOI: 10.1186/s13619-023-00180-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023]
Abstract
Whole-body regeneration is a multifaceted process that reinstates a body to its initial three-dimension size and structure after resection injury. It is well-known that signaling waves such as calcium and extracellular signal-related kinase (ERK) signaling waves can efficiently transmit information between tissues or cells. However, the mechanisms responsible for coordinating wound responses over long distances are largely unexplored. A recent study has reported that the propagation of ERK signaling waves via longitudinal body-wall muscles play an essential role in wound response and whole-body regeneration in planarians, underscoring the significance of feedback interactions between spatially distinct tissues during whole-body regeneration over long distances. These findings not only address the central questions of regenerative biology but also have potential implications for regenerative medicine.
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Affiliation(s)
- Chenglu Xiao
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
| | - Jing-Wei Xiong
- College of Future Technology, Peking University, Beijing, 100871, China.
- College of Basic Medical Sciences, The Second Affiliated Hospital, Nanchang University, Nanchang, 330031, China.
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2
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Shamipour S, Hofmann L, Steccari I, Kardos R, Heisenberg CP. Yolk granule fusion and microtubule aster formation regulate cortical granule translocation and exocytosis in zebrafish oocytes. PLoS Biol 2023; 21:e3002146. [PMID: 37289834 DOI: 10.1371/journal.pbio.3002146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Dynamic reorganization of the cytoplasm is key to many core cellular processes, such as cell division, cell migration, and cell polarization. Cytoskeletal rearrangements are thought to constitute the main drivers of cytoplasmic flows and reorganization. In contrast, remarkably little is known about how dynamic changes in size and shape of cell organelles affect cytoplasmic organization. Here, we show that within the maturing zebrafish oocyte, the surface localization of exocytosis-competent cortical granules (Cgs) upon germinal vesicle breakdown (GVBD) is achieved by the combined activities of yolk granule (Yg) fusion and microtubule aster formation and translocation. We find that Cgs are moved towards the oocyte surface through radially outward cytoplasmic flows induced by Ygs fusing and compacting towards the oocyte center in response to GVBD. We further show that vesicles decorated with the small Rab GTPase Rab11, a master regulator of vesicular trafficking and exocytosis, accumulate together with Cgs at the oocyte surface. This accumulation is achieved by Rab11-positive vesicles being transported by acentrosomal microtubule asters, the formation of which is induced by the release of CyclinB/Cdk1 upon GVBD, and which display a net movement towards the oocyte surface by preferentially binding to the oocyte actin cortex. We finally demonstrate that the decoration of Cgs by Rab11 at the oocyte surface is needed for Cg exocytosis and subsequent chorion elevation, a process central in egg activation. Collectively, these findings unravel a yet unrecognized role of organelle fusion, functioning together with cytoskeletal rearrangements, in orchestrating cytoplasmic organization during oocyte maturation.
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Affiliation(s)
- Shayan Shamipour
- Institute of Science and Technology Austria, Klosterneuburg, Austria
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Laura Hofmann
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Irene Steccari
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Roland Kardos
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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3
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Swider ZT, Michaud A, Leda M, Landino J, Goryachev AB, Bement WM. Cell cycle and developmental control of cortical excitability in Xenopus laevis. Mol Biol Cell 2022; 33:ar73. [PMID: 35594176 PMCID: PMC9635278 DOI: 10.1091/mbc.e22-01-0025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Interest in cortical excitability—the ability of the cell cortex to generate traveling waves of protein activity—has grown considerably over the past 20 years. Attributing biological functions to cortical excitability requires an understanding of the natural behavior of excitable waves and the ability to accurately quantify wave properties. Here we have investigated and quantified the onset of cortical excitability in Xenopus laevis eggs and embryos and the changes in cortical excitability throughout early development. We found that cortical excitability begins to manifest shortly after egg activation. Further, we identified a close relationship between wave properties—such as wave frequency and amplitude—and cell cycle progression as well as cell size. Finally, we identified quantitative differences between cortical excitability in the cleavage furrow relative to nonfurrow cortical excitability and showed that these wave regimes are mutually exclusive.
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Affiliation(s)
- Zachary T Swider
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison Madison, WI 53706.,Center for Quantitative Cell Imaging, University of Wisconsin-Madison Madison, WI 53706
| | - Ani Michaud
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison Madison, WI 53706.,Center for Quantitative Cell Imaging, University of Wisconsin-Madison Madison, WI 53706
| | - Marcin Leda
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Jennifer Landino
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, MI 48109
| | - Andrew B Goryachev
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - William M Bement
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison Madison, WI 53706.,Center for Quantitative Cell Imaging, University of Wisconsin-Madison Madison, WI 53706.,Department of Integrative Biology, University of Wisconsin-Madison Madison, WI 53706
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4
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Bernardello M, Marsal M, Gualda EJ, Loza-Alvarez P. Light-sheet fluorescence microscopy for the in vivo study of microtubule dynamics in the zebrafish embryo. Biomed Opt Express 2021; 12:6237-6254. [PMID: 34745732 PMCID: PMC8547989 DOI: 10.1364/boe.438402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/21/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
During its first hours of development, the zebrafish embryo presents a large microtubule array in the yolk region, essential for its development. Despite of its size and dynamic behavior, this network has been studied only in limited field of views or in fixed samples. We designed and implemented different strategies in Light Sheet Fluorescence microscopy for imaging the entire yolk microtubule (MT) network in vivo. These have allowed us to develop a novel image analysis from which we clearly observe a cyclical re-arrangement of the entire MT network in synchrony with blastoderm mitotic waves. These dynamics also affect a previously unreported microtubule array deep within the yolk, here described. These findings provide a new vision of the zebrafish yolk microtubules arrangement, and offers novel insights in the interaction between mitotic events and microtubules reorganization.
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Affiliation(s)
- Matteo Bernardello
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860, Spain
- equal contribution
| | - Maria Marsal
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860, Spain
- equal contribution
| | - Emilio J. Gualda
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860, Spain
- equal contribution
| | - Pablo Loza-Alvarez
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860, Spain
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5
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Geisterfer ZM, Guilloux G, Gatlin JC, Gibeaux R. The Cytoskeleton and Its Roles in Self-Organization Phenomena: Insights from Xenopus Egg Extracts. Cells 2021; 10:2197. [PMID: 34571847 DOI: 10.3390/cells10092197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 01/11/2023] Open
Abstract
Self-organization of and by the cytoskeleton is central to the biology of the cell. Since their introduction in the early 1980s, cytoplasmic extracts derived from the eggs of the African clawed-frog, Xenopus laevis, have flourished as a major experimental system to study the various facets of cytoskeleton-dependent self-organization. Over the years, the many investigations that have used these extracts uniquely benefited from their simplified cell cycle, large experimental volumes, biochemical tractability and cell-free nature. Here, we review the contributions of egg extracts to our understanding of the cytoplasmic aspects of self-organization by the microtubule and the actomyosin cytoskeletons as well as the importance of cytoskeletal filaments in organizing nuclear structure and function.
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6
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Bordoni B, Walkowski S, Ducoux B, Tobbi F. The Cranial Bowl in the New Millennium and Sutherland's Legacy for Osteopathic Medicine: Part 1. Cureus 2020; 12:e10410. [PMID: 33062527 PMCID: PMC7550223 DOI: 10.7759/cureus.10410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 09/12/2020] [Indexed: 12/12/2022] Open
Abstract
A theoretical model that does not evolve with new information deriving from scientific research, by changing the assumptions from which it was born, becomes a philosophy; the scientist becomes a scholarch. Cranial manual osteopathic medicine is very controversial, although it is commonly practiced, from the clinician to the nonmedical health worker. The article, divided into two parts, reviews the assumptions with which the cranial model was created, highlighting the scientific innovations and new anatomical-physiological reflections. In the first part we will review the synthesis and movement of cerebrospinal fluid (CSF), the movement of the central and peripheral nervous system; we will highlight the mechanical characteristics of the meninges. The aim of the article is to highlight the need to renew the existing cranial model.
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Affiliation(s)
- Bruno Bordoni
- Physical Medicine and Rehabilitation, Foundation Don Carlo Gnocchi, Milan, ITA
| | - Stevan Walkowski
- Osteopathic Manipulative Medicine, Heritage College of Osteopathic Medicine-Dublin, Ohio, USA
| | - Bruno Ducoux
- Osteopathy, Formation Recherche Osteopathie Prévention, Bordeaux, FRA
| | - Filippo Tobbi
- Osteopathy, Poliambulatorio Medico e Odontoiatrico, Varese, ITA
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7
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Nolet FE, Vandervelde A, Vanderbeke A, Piñeros L, Chang JB, Gelens L. Nuclei determine the spatial origin of mitotic waves. eLife 2020; 9:52868. [PMID: 32452767 PMCID: PMC7314552 DOI: 10.7554/elife.52868] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/22/2020] [Indexed: 12/11/2022] Open
Abstract
Traveling waves play an essential role in coordinating mitosis over large distances, but what determines the spatial origin of mitotic waves remains unclear. Here, we show that such waves initiate at pacemakers, regions that oscillate faster than their surroundings. In cell-free extracts of Xenopus laevis eggs, we find that nuclei define such pacemakers by concentrating cell cycle regulators. In computational models of diffusively coupled oscillators that account for nuclear import, nuclear positioning determines the pacemaker location. Furthermore, we find that the spatial dimensions of the oscillatory medium change the nuclear positioning and strongly influence whether a pacemaker is more likely to be at a boundary or an internal region. Finally, we confirm experimentally that increasing the system width increases the proportion of pacemakers at the boundary. Our work provides insight into how nuclei and spatial system dimensions can control local concentrations of regulators and influence the emergent behavior of mitotic waves.
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Affiliation(s)
- Felix E Nolet
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Alexandra Vandervelde
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Arno Vanderbeke
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium.,MeBioS - Biosensors Group, Department of Biosystems, KU Leuven, Leuven, Belgium
| | - Liliana Piñeros
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Jeremy B Chang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, United States
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
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8
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Basu S, Roberts EL, Jones AW, Swaffer MP, Snijders AP, Nurse P. The Hydrophobic Patch Directs Cyclin B to Centrosomes to Promote Global CDK Phosphorylation at Mitosis. Curr Biol 2020; 30:883-892.e4. [PMID: 32084401 PMCID: PMC7063568 DOI: 10.1016/j.cub.2019.12.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/20/2019] [Accepted: 12/17/2019] [Indexed: 11/15/2022]
Abstract
The cyclin-dependent kinases (CDKs) are the major cell-cycle regulators that phosphorylate hundreds of substrates, controlling the onset of S phase and M phase [1, 2, 3]. However, the patterns of substrate phosphorylation increase are not uniform, as different substrates become phosphorylated at different times as cells proceed through the cell cycle [4, 5]. In fission yeast, the correct ordering of CDK substrate phosphorylation can be established by the activity of a single mitotic cyclin-CDK complex [6, 7]. Here, we investigate the substrate-docking region, the hydrophobic patch, on the fission yeast mitotic cyclin Cdc13 as a potential mechanism to correctly order CDK substrate phosphorylation. We show that the hydrophobic patch targets Cdc13 to the yeast centrosome equivalent, the spindle pole body (SPB), and disruption of this motif prevents both centrosomal localization of Cdc13 and the onset of mitosis but does not prevent S phase. CDK phosphorylation in mitosis is compromised for approximately half of all mitotic CDK substrates, with substrates affected generally being those that require the highest levels of CDK activity to become phosphorylated and those that are located at the SPB. Our experiments suggest that the hydrophobic patch of mitotic cyclins contributes to CDK substrate selection by directing the localization of Cdc13-CDK to centrosomes and that this localization of CDK contributes to the CDK substrate phosphorylation necessary to ensure proper entry into mitosis. Finally, we show that mutation of the hydrophobic patch prevents cyclin B1 localization to centrosomes in human cells, suggesting that this mechanism of cyclin-CDK spatial regulation may be conserved across eukaryotes. The hydrophobic patch of human and yeast cyclin B directs it to the centrosome Loss of the yeast cyclin B hydrophobic patch allows S phase but prevents mitosis Compartmentalized mitotic CDK phosphorylation relies on the hydrophobic patch
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Affiliation(s)
- Souradeep Basu
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | - Emma L Roberts
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Andrew W Jones
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Protein Analysis and Proteomics Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Matthew P Swaffer
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Ambrosius P Snijders
- Protein Analysis and Proteomics Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Laboratory of Yeast Genetics and Cell Biology, Rockefeller University, New York, NY 10065, USA
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9
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Wesley CC, Mishra S, Levy DL. Organelle size scaling over embryonic development. Wiley Interdiscip Rev Dev Biol 2020; 9:e376. [PMID: 32003549 DOI: 10.1002/wdev.376] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/19/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Cell division without growth results in progressive cell size reductions during early embryonic development. How do the sizes of intracellular structures and organelles scale with cell size and what are the functional implications of such scaling relationships? Model organisms, in particular Caenorhabditis elegans worms, Drosophila melanogaster flies, Xenopus laevis frogs, and Mus musculus mice, have provided insights into developmental size scaling of the nucleus, mitotic spindle, and chromosomes. Nuclear size is regulated by nucleocytoplasmic transport, nuclear envelope proteins, and the cytoskeleton. Regulators of microtubule dynamics and chromatin compaction modulate spindle and mitotic chromosome size scaling, respectively. Developmental scaling relationships for membrane-bound organelles, like the endoplasmic reticulum, Golgi, mitochondria, and lysosomes, have been less studied, although new imaging approaches promise to rectify this deficiency. While models that invoke limiting components and dynamic regulation of assembly and disassembly can account for some size scaling relationships in early embryos, it will be exciting to investigate the contribution of newer concepts in cell biology such as phase separation and interorganellar contacts. With a growing understanding of the underlying mechanisms of organelle size scaling, future studies promise to uncover the significance of proper scaling for cell function and embryonic development, as well as how aberrant scaling contributes to disease. This article is categorized under: Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Early Embryonic Development > Fertilization to Gastrulation Comparative Development and Evolution > Model Systems.
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Affiliation(s)
- Chase C Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
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10
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Abstract
The notion that graded distributions of signals underlie the spatial organization of biological systems has long been a central pillar in the fields of cell and developmental biology. During morphogenesis, morphogens spread across tissues to guide development of the embryo. Similarly, a variety of dynamic gradients and pattern-forming networks have been discovered that shape subcellular organization. Here we discuss the principles of intracellular pattern formation by these intracellular morphogens and relate them to conceptually similar processes operating at the tissue scale. We will specifically review mechanisms for generating cellular asymmetry and consider how intracellular patterning networks are controlled and adapt to cellular geometry. Finally, we assess the general concept of intracellular gradients as a mechanism for positional control in light of current data, highlighting how the simple readout of fixed concentration thresholds fails to fully capture the complexity of spatial patterning processes occurring inside cells.
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Affiliation(s)
- Lars Hubatsch
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Nathan W Goehring
- The Francis Crick Institute, London, United Kingdom; Institute for the Physics of Living Systems, University College London, London, United Kingdom; MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom.
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11
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Abstract
Emergence of dynamic patterns in the form of oscillations and waves on the cortex of single cells is a fascinating and enigmatic phenomenon. Here we outline various theoretical frameworks used to model pattern formation with the goal of reducing complex, heterogeneous patterns into key parameters that are biologically tractable. We also review progress made in recent years on the quantitative and molecular definitions of these terms, which we believe have begun to transform single-cell dynamic patterns from a purely observational and descriptive subject to more mechanistic studies. Specifically, we focus on the nature of local excitable and oscillation events, their spatial couplings leading to propagating waves and the role of active membrane. Instead of arguing for their functional importance, we prefer to consider such patterns as basic properties of dynamic systems. We discuss how knowledge of these patterns could be used to dissect the structure of cellular organization and how the network-centric view could help define cellular functions as transitions between different dynamical states. Last, we speculate on how these patterns could encode temporal and spatial information. This article is part of the theme issue ‘Self-organization in cell biology’.
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Affiliation(s)
- Yang Yang
- Department of Biological Sciences, Centre for Bioimaging Sciences, Mechanobiology Institute, National University of Singapore, Singapore
| | - Min Wu
- Department of Biological Sciences, Centre for Bioimaging Sciences, Mechanobiology Institute, National University of Singapore, Singapore
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12
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Namigai† EKO, Shimeld SM. Live Imaging of Cleavage Variability and Vesicle Flow Dynamics in Dextral and Sinistral Spiralian Embryos. Zoolog Sci 2019; 36:5-16. [DOI: 10.2108/zs180088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/13/2018] [Indexed: 11/17/2022]
Affiliation(s)
- Erica K. O. Namigai†
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, U. K
| | - Sebastian M. Shimeld
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, U. K
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13
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Abstract
For over a century, the centrosome has been an organelle more easily tracked than understood, and the study of its peregrinations within the cell remains a chief underpinning of its functional investigation. Increasing attention and new approaches have been brought to bear on mechanisms that control centrosome localization in the context of cleavage plane determination, ciliogenesis, directional migration, and immunological synapse formation, among other cellular and developmental processes. The Golgi complex, often linked with the centrosome, presents a contrasting case of a pleiomorphic organelle for which functional studies advanced somewhat more rapidly than positional tracking. However, Golgi orientation and distribution has emerged as an area of considerable interest with respect to polarized cellular function. This chapter will review our current understanding of the mechanism and significance of the positioning of these organelles.
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14
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Abstract
Mitosis is controlled by reversible protein phosphorylation involving specific kinases and phosphatases. A handful of major mitotic protein kinases, such as the cyclin B-CDK1 complex, the Aurora kinases, and Polo-like kinase 1 (PLK1), cooperatively regulate distinct mitotic processes. Research has identified proteins and mechanisms that integrate these kinases into signaling cascades that guide essential mitotic events. These findings have important implications for our understanding of the mechanisms of mitotic regulation and may advance the development of novel antimitotic drugs. We review collected evidence that in vertebrates, the Aurora kinases serve as catalytic subunits of distinct complexes formed with the four scaffold proteins Bora, CEP192, INCENP, and TPX2, which we deem "core" Aurora cofactors. These complexes and the Aurora-PLK1 cascades organized by Bora, CEP192, and INCENP control crucial aspects of mitosis and all pathways of spindle assembly. We compare the mechanisms of Aurora activation in relation to the different spindle assembly pathways and draw a functional analogy between the CEP192 complex and the chromosomal passenger complex that may reflect the coevolution of centrosomes, kinetochores, and the actomyosin cleavage apparatus. We also analyze the roles and mechanisms of Aurora-PLK1 signaling in the cell and centrosome cycles and in the DNA damage response.
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Affiliation(s)
- Vladimir Joukov
- N.N. Petrov National Medical Research Center of Oncology, Saint-Petersburg 197758, Russian Federation.
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15
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Bornens M. Cell polarity: having and making sense of direction-on the evolutionary significance of the primary cilium/centrosome organ in Metazoa. Open Biol 2018; 8:180052. [PMID: 30068565 PMCID: PMC6119866 DOI: 10.1098/rsob.180052] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/05/2018] [Indexed: 12/13/2022] Open
Abstract
Cell-autonomous polarity in Metazoans is evolutionarily conserved. I assume that permanent polarity in unicellular eukaryotes is required for cell motion and sensory reception, integration of these two activities being an evolutionarily constrained function. Metazoans are unique in making cohesive multicellular organisms through complete cell divisions. They evolved a primary cilium/centrosome (PC/C) organ, ensuring similar functions to the basal body/flagellum of unicellular eukaryotes, but in different cells, or in the same cell at different moments. The possibility that this innovation contributed to the evolution of individuality, in being instrumental in the early specification of the germ line during development, is further discussed. Then, using the example of highly regenerative organisms like planarians, which have lost PC/C organ in dividing cells, I discuss the possibility that part of the remodelling necessary to reach a new higher-level unit of selection in multi-cellular organisms has been triggered by conflicts among individual cell polarities to reach an organismic polarity. Finally, I briefly consider organisms with a sensorimotor organ like the brain that requires exceedingly elongated polarized cells for its activity. I conclude that beyond critical consequences for embryo development, the conservation of cell-autonomous polarity in Metazoans had far-reaching implications for the evolution of individuality.
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Affiliation(s)
- Michel Bornens
- Institut Curie, PSL Research University, CNRS - UMR 144, 75005 Paris, France
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16
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Abstract
Many biological events, such as the propagation of nerve impulses, the synchronized cell cycles of early embryogenesis, and collective cell migration, must be coordinated with remarkable speed across very large distances. Such rapid coordination cannot be achieved by simple diffusion of molecules alone and requires specialized mechanisms. Although active transport can provide a directed and efficient way to travel across subcellular structures, it cannot account for the most rapid examples of coordination found in biology. Rather, these appear to be driven by mechanisms involving traveling waves of chemical activities that are able to propagate information rapidly across biological or physical systems. Indeed, recent advances in our ability to probe the dynamics of signaling pathways are revealing many examples of coordination of cellular and developmental processes through traveling chemical waves. Here, we will review the theoretical principles underlying such waves; highlight recent literature on their role in different contexts, ranging from chemotaxis to development; and discuss open questions and future perspectives on the study of chemical waves as an essential feature of cell and tissue physiology.
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Affiliation(s)
- Victoria E Deneke
- Department of Cell Biology, Duke University Medical Center, Durham, NC
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, NC
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17
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Affiliation(s)
- Patrick L. Ferree
- Department of Cell Biology; Duke University Medical Center; Durham NC USA
| | - Stefano Di Talia
- Department of Cell Biology; Duke University Medical Center; Durham NC USA
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18
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Decker F, Oriola D, Dalton B, Brugués J. Autocatalytic microtubule nucleation determines the size and mass of Xenopus laevis egg extract spindles. eLife 2018; 7:31149. [PMID: 29323637 PMCID: PMC5814149 DOI: 10.7554/elife.31149] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/09/2018] [Indexed: 01/27/2023] Open
Abstract
Regulation of size and growth is a fundamental problem in biology. A prominent example is the formation of the mitotic spindle, where protein concentration gradients around chromosomes are thought to regulate spindle growth by controlling microtubule nucleation. Previous evidence suggests that microtubules nucleate throughout the spindle structure. However, the mechanisms underlying microtubule nucleation and its spatial regulation are still unclear. Here, we developed an assay based on laser ablation to directly probe microtubule nucleation events in Xenopus laevis egg extracts. Combining this method with theory and quantitative microscopy, we show that the size of a spindle is controlled by autocatalytic growth of microtubules, driven by microtubule-stimulated microtubule nucleation. The autocatalytic activity of this nucleation system is spatially regulated by the limiting amounts of active microtubule nucleators, which decrease with distance from the chromosomes. This mechanism provides an upper limit to spindle size even when resources are not limiting.
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Affiliation(s)
- Franziska Decker
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany,Center for Systems Biology DresdenDresdenGermany,Max Planck Institute for the Physics of Complex SystemsDresdenGermany
| | - David Oriola
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany,Center for Systems Biology DresdenDresdenGermany,Max Planck Institute for the Physics of Complex SystemsDresdenGermany
| | - Benjamin Dalton
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany,Center for Systems Biology DresdenDresdenGermany,Max Planck Institute for the Physics of Complex SystemsDresdenGermany
| | - Jan Brugués
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany,Center for Systems Biology DresdenDresdenGermany,Max Planck Institute for the Physics of Complex SystemsDresdenGermany
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Presler M, Van Itallie E, Klein AM, Kunz R, Coughlin ML, Peshkin L, Gygi SP, Wühr M, Kirschner MW. Proteomics of phosphorylation and protein dynamics during fertilization and meiotic exit in the Xenopus egg. Proc Natl Acad Sci U S A 2017; 114:E10838-47. [PMID: 29183978 DOI: 10.1073/pnas.1709207114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fertilization releases the meiotic arrest and initiates the events that prepare the egg for the ensuing developmental program. Protein degradation and phosphorylation are known to regulate protein activity during this process. However, the full extent of protein loss and phosphoregulation is still unknown. We examined absolute protein and phosphosite dynamics of the fertilization response by mass spectrometry-based proteomics in electroactivated eggs. To do this, we developed an approach for calculating the stoichiometry of phosphosites from multiplexed proteomics that is compatible with dynamic, stable, and multisite phosphorylation. Overall, the data suggest that degradation is limited to a few low-abundance proteins. However, this degradation promotes extensive dephosphorylation that occurs over a wide range of abundances during meiotic exit. We also show that eggs release a large amount of protein into the medium just after fertilization, most likely related to the blocks to polyspermy. Concomitantly, there is a substantial increase in phosphorylation likely tied to calcium-activated kinases. We identify putative degradation targets and components of the slow block to polyspermy. The analytical approaches demonstrated here are broadly applicable to studies of dynamic biological systems.
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Bischof J, Brand CA, Somogyi K, Májer I, Thome S, Mori M, Schwarz US, Lénárt P. A cdk1 gradient guides surface contraction waves in oocytes. Nat Commun 2017; 8:849. [PMID: 29021609 PMCID: PMC5636809 DOI: 10.1038/s41467-017-00979-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/09/2017] [Indexed: 11/29/2022] Open
Abstract
Surface contraction waves (SCWs) in oocytes and embryos lead to large-scale shape changes coupled to cell cycle transitions and are spatially coordinated with the cell axis. Here, we show that SCWs in the starfish oocyte are generated by a traveling band of myosin II-driven cortical contractility. At the front of the band, contractility is activated by removal of cdk1 inhibition of the RhoA/RhoA kinase/myosin II signaling module, while at the rear, contractility is switched off by negative feedback originating downstream of RhoA kinase. The SCW's directionality and speed are controlled by a spatiotemporal gradient of cdk1-cyclinB. This gradient is formed by the release of cdk1-cyclinB from the asymmetrically located nucleus, and progressive degradation of cyclinB. By combining quantitative imaging, biochemical and mechanical perturbations with mathematical modeling, we demonstrate that the SCWs result from the spatiotemporal integration of two conserved regulatory modules, cdk1-cyclinB for cell cycle regulation and RhoA/Rok/NMYII for actomyosin contractility.Surface contraction waves (SCWs) are prominent shape changes coupled to cell cycle transitions in oocytes. Here the authors show that SCWs are patterned by the spatiotemporal integration of two conserved modules, cdk1-cyclinB for cell cycle regulation and RhoA/Rok/NMYII for actomyosin contractility.
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Affiliation(s)
- Johanna Bischof
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Christoph A Brand
- Institute for Theoretical Physics and BioQuant, Heidelberg University, Philosophenweg 19, 69120, Heidelberg, Germany
| | - Kálmán Somogyi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Imre Májer
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Sarah Thome
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Masashi Mori
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Ulrich S Schwarz
- Institute for Theoretical Physics and BioQuant, Heidelberg University, Philosophenweg 19, 69120, Heidelberg, Germany
| | - Péter Lénárt
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany.
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Deneke VE, Melbinger A, Vergassola M, Di Talia S. Waves of Cdk1 Activity in S Phase Synchronize the Cell Cycle in Drosophila Embryos. Dev Cell 2017; 38:399-412. [PMID: 27554859 DOI: 10.1016/j.devcel.2016.07.023] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/13/2016] [Accepted: 07/26/2016] [Indexed: 01/16/2023]
Abstract
Embryos of most metazoans undergo rapid and synchronous cell cycles following fertilization. While diffusion is too slow for synchronization of mitosis across large spatial scales, waves of Cdk1 activity represent a possible process of synchronization. However, the mechanisms regulating Cdk1 waves during embryonic development remain poorly understood. Using biosensors of Cdk1 and Chk1 activities, we dissect the regulation of Cdk1 waves in the Drosophila syncytial blastoderm. We show that Cdk1 waves are not controlled by the mitotic switch but by a double-negative feedback between Cdk1 and Chk1. Using mathematical modeling and surgical ligations, we demonstrate a fundamental distinction between S phase Cdk1 waves, which propagate as active trigger waves in an excitable medium, and mitotic Cdk1 waves, which propagate as passive phase waves. Our findings show that in Drosophila embryos, Cdk1 positive feedback serves primarily to ensure the rapid onset of mitosis, while wave propagation is regulated by S phase events.
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Affiliation(s)
- Victoria E Deneke
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Anna Melbinger
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Massimo Vergassola
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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22
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Abstract
Microtubule asters - radial arrays of microtubules organized by centrosomes - play a fundamental role in the spatial coordination of animal cells. The standard model of aster growth assumes a fixed number of microtubules originating from the centrosomes. However, aster morphology in this model does not scale with cell size, and we recently found evidence for non-centrosomal microtubule nucleation. Here, we combine autocatalytic nucleation and polymerization dynamics to develop a biophysical model of aster growth. Our model predicts that asters expand as traveling waves and recapitulates all major aspects of aster growth. With increasing nucleation rate, the model predicts an explosive transition from stationary to growing asters with a discontinuous jump of the aster velocity to a nonzero value. Experiments in frog egg extract confirm the main theoretical predictions. Our results suggest that asters observed in large fish and amphibian eggs are a meshwork of short, unstable microtubules maintained by autocatalytic nucleation and provide a paradigm for the assembly of robust and evolvable polymer networks. DOI:http://dx.doi.org/10.7554/eLife.19145.001 Cells must carefully organize their contents in order to work effectively. Protein filaments called microtubules often play important roles in this organization, as well as giving structure to the cell. Many cells contain structures called asters that are formed of microtubules that radiate out from a central point (much like a star shape). Textbooks generally state that all microtubules in the aster grow outward from its center. If this was the case, the microtubules at the edge of large asters – such as those found in frog egg cells and other extremely large cells – would be spread relatively far apart from each other. However, even at the edges of large asters, the microtubules are quite densely packed. In 2014, a group of researchers proposed that new microtubules could form throughout the aster instead of all originating from the center. This model had not been tested; it was also unclear under what conditions an aster would be able to grow to fill a large cell. Ishihara et al. – including some of the researchers involved in the 2014 work – have now developed a mathematical theory of aster growth that is based on the assumption that microtubules stimulate the generation of new microtubules. The theory reproduces the key features seen during the growth of asters in large cells, and predicts that the asters may stay at a constant size or grow continuously. The condition required for the aster to grow is simple: each microtubule in it has to trigger the generation of at least one new microtubule during its lifetime. Ishihara et al. have named this process “collective growth”. Experiments performed using microtubules taken from crushed frog eggs and assembled under a cover slip provided further evidence that asters grow via a collective growth process. Future studies could now investigate whether collective growth also underlies the formation of other cellular structures. DOI:http://dx.doi.org/10.7554/eLife.19145.002
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Affiliation(s)
- Keisuke Ishihara
- Department of Systems Biology, Harvard Medical School, Boston, United States.,Cell Division Group, Marine Biological Laboratory, Woods Hole, United Sates
| | - Kirill S Korolev
- Department of Physics and Graduate Program in Bioinformatics, Boston University, Boston, United States
| | - Timothy J Mitchison
- Department of Systems Biology, Harvard Medical School, Boston, United States.,Cell Division Group, Marine Biological Laboratory, Woods Hole, United Sates
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23
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Abstract
Embryos of most metazoans undergo rapid and synchronous cell cycles following fertilization. While diffusion is too slow for synchronization of mitosis across large spatial scales, waves of Cdk1 activity represent a possible process of synchronization. However, the mechanisms regulating Cdk1 waves during embryonic development remain poorly understood. Using biosensors of Cdk1 and Chk1 activities, we dissect the regulation of Cdk1 waves in the Drosophila syncytial blastoderm. We show that Cdk1 waves are not controlled by the mitotic switch but by a double-negative feedback between Cdk1 and Chk1. Using mathematical modeling and surgical ligations, we demonstrate a fundamental distinction between S phase Cdk1 waves, which propagate as active trigger waves in an excitable medium, and mitotic Cdk1 waves, which propagate as passive phase waves. Our findings show that in Drosophila embryos, Cdk1 positive feedback serves primarily to ensure the rapid onset of mitosis, while wave propagation is regulated by S phase events.
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Affiliation(s)
- Victoria E Deneke
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Anna Melbinger
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Massimo Vergassola
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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Affiliation(s)
- Michel Bornens
- UMR 144 CNRS-Institut CURIE, 26 rue d'Ulm 75 248, PARIS Cedex 05, France
| | - Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL) Lausanne, Switzerland
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Ishihara K, Nguyen PA, Groen AC, Field CM, Mitchison TJ. Microtubule nucleation remote from centrosomes may explain how asters span large cells. Proc Natl Acad Sci U S A 2014; 111:17715-22. [PMID: 25468969 DOI: 10.1073/pnas.1418796111] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A major challenge in cell biology is to understand how nanometer-sized molecules can organize micrometer-sized cells in space and time. One solution in many animal cells is a radial array of microtubules called an aster, which is nucleated by a central organizing center and spans the entire cytoplasm. Frog (here Xenopus laevis) embryos are more than 1 mm in diameter and divide with a defined geometry every 30 min. Like smaller cells, they are organized by asters, which grow, interact, and move to precisely position the cleavage planes. It has been unclear whether asters grow to fill the enormous egg by the same mechanism used in smaller somatic cells, or whether special mechanisms are required. We addressed this question by imaging growing asters in a cell-free system derived from eggs, where asters grew to hundreds of microns in diameter. By tracking marks on the lattice, we found that microtubules could slide outward, but this was not essential for rapid aster growth. Polymer treadmilling did not occur. By measuring the number and positions of microtubule ends over time, we found that most microtubules were nucleated away from the centrosome and that interphase egg cytoplasm supported spontaneous nucleation after a time lag. We propose that aster growth is initiated by centrosomes but that asters grow by propagating a wave of microtubule nucleation stimulated by the presence of preexisting microtubules.
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