1
|
Rosfelter A, de Labbey G, Chenevert J, Dumollard R, Schaub S, Machaty Z, Besnardeau L, Gonzalez Suarez D, Hebras C, Turlier H, Burgess DR, McDougall A. Reduction of cortical pulling at mitotic entry facilitates aster centration. J Cell Sci 2024; 137:jcs262037. [PMID: 38469748 DOI: 10.1242/jcs.262037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 02/23/2024] [Indexed: 03/13/2024] Open
Abstract
Equal cell division relies upon astral microtubule-based centering mechanisms, yet how the interplay between mitotic entry, cortical force generation and long astral microtubules leads to symmetric cell division is not resolved. We report that a cortically located sperm aster displaying long astral microtubules that penetrate the whole zygote does not undergo centration until mitotic entry. At mitotic entry, we find that microtubule-based cortical pulling is lost. Quantitative measurements of cortical pulling and cytoplasmic pulling together with physical simulations suggested that a wavelike loss of cortical pulling at mitotic entry leads to aster centration based on cytoplasmic pulling. Cortical actin is lost from the cortex at mitotic entry coincident with a fall in cortical tension from ∼300pN/µm to ∼100pN/µm. Following the loss of cortical force generators at mitotic entry, long microtubule-based cytoplasmic pulling is sufficient to displace the aster towards the cell center. These data reveal how mitotic aster centration is coordinated with mitotic entry in chordate zygotes.
Collapse
Affiliation(s)
- Anne Rosfelter
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Ghislain de Labbey
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR7241 / INSERM U1050, Université PSL, 75002 Paris, France
| | - Janet Chenevert
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Rémi Dumollard
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Sebastien Schaub
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Zoltan Machaty
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Lydia Besnardeau
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Daniel Gonzalez Suarez
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Céline Hebras
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Hervé Turlier
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR7241 / INSERM U1050, Université PSL, 75002 Paris, France
| | - David R Burgess
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - Alex McDougall
- Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| |
Collapse
|
2
|
Chenevert J, Robert MLV, Sallé J, Cacchia S, Lorca T, Castro A, McDougall A, Minc N, Castagnetti S, Dumont J, Lacroix B. Measuring Mitotic Spindle and Microtubule Dynamics in Marine Embryos and Non-model Organisms. Methods Mol Biol 2024; 2740:187-210. [PMID: 38393477 DOI: 10.1007/978-1-0716-3557-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
During eukaryotic cell division a microtubule-based structure, the mitotic spindle, aligns and segregates chromosomes between daughter cells. Understanding how this cellular structure is assembled and coordinated in space and in time requires measuring microtubule dynamics and visualizing spindle assembly with high temporal and spatial resolution. Visualization is often achieved by the introduction and the detection of molecular probes and fluorescence microscopy. Microtubules and mitotic spindles are highly conserved across eukaryotes; however, several technical limitations have restricted these investigations to only a few species. The ability to monitor microtubule and chromosome choreography in a wide range of species is fundamental to reveal conserved mechanisms or unravel unconventional strategies that certain forms of life have developed to ensure faithful partitioning of chromosomes during cell division. Here, we describe a technique based on injection of purified proteins that enables the visualization of microtubules and chromosomes with a high contrast in several divergent marine embryos. We also provide analysis methods and tools to extract microtubule dynamics and monitor spindle assembly. These techniques can be adapted to a wide variety of species in order to measure microtubule dynamics and spindle assembly kinetics when genetic tools are not available or in parallel to the development of such techniques in non-model organisms.
Collapse
Affiliation(s)
- Janet Chenevert
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Villefranche-sur-mer, France
| | - Morgane L V Robert
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Montpellier Cedex 5, France
| | - Jérémy Sallé
- CNRS, Institut Jacques Monod, Université Paris Cité, Paris, France
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Sébastien Cacchia
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Montpellier Cedex 5, France
| | - Thierry Lorca
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Montpellier Cedex 5, France
| | - Anna Castro
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Montpellier Cedex 5, France
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France
| | - Alex McDougall
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Villefranche-sur-mer, France
| | - Nicolas Minc
- CNRS, Institut Jacques Monod, Université Paris Cité, Paris, France
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Stefania Castagnetti
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Villefranche-sur-mer, France
| | - Julien Dumont
- CNRS, Institut Jacques Monod, Université Paris Cité, Paris, France
| | - Benjamin Lacroix
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, Montpellier Cedex 5, France.
| |
Collapse
|
3
|
Ichbiah S, Delbary F, McDougall A, Dumollard R, Turlier H. Embryo mechanics cartography: inference of 3D force atlases from fluorescence microscopy. Nat Methods 2023; 20:1989-1999. [PMID: 38057527 PMCID: PMC10703677 DOI: 10.1038/s41592-023-02084-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 10/12/2023] [Indexed: 12/08/2023]
Abstract
Tissue morphogenesis results from a tight interplay between gene expression, biochemical signaling and mechanics. Although sequencing methods allow the generation of cell-resolved spatiotemporal maps of gene expression, creating similar maps of cell mechanics in three-dimensional (3D) developing tissues has remained a real challenge. Exploiting the foam-like arrangement of cells, we propose a robust end-to-end computational method called 'foambryo' to infer spatiotemporal atlases of cellular forces from fluorescence microscopy images of cell membranes. Our method generates precise 3D meshes of cells' geometry and successively predicts relative cell surface tensions and pressures. We validate it with 3D foam simulations, study its noise sensitivity and prove its biological relevance in mouse, ascidian and worm embryos. 3D force inference allows us to recover mechanical features identified previously, but also predicts new ones, unveiling potential new insights on the spatiotemporal regulation of cell mechanics in developing embryos. Our code is freely available and paves the way for unraveling the unknown mechanochemical feedbacks that control embryo and tissue morphogenesis.
Collapse
Affiliation(s)
- Sacha Ichbiah
- Center for Interdisciplinary Research in Biology, College of France, CNRS, INSERM, University of PSL, Paris, France
| | - Fabrice Delbary
- Center for Interdisciplinary Research in Biology, College of France, CNRS, INSERM, University of PSL, Paris, France
| | - Alex McDougall
- Laboratory of Developmental Biology of the Villefranche-sur-Mer, Institute of Villefranche-sur-Mer, Sorbonne University, CNRS, Villefranche-sur-Mer, France
| | - Rémi Dumollard
- Laboratory of Developmental Biology of the Villefranche-sur-Mer, Institute of Villefranche-sur-Mer, Sorbonne University, CNRS, Villefranche-sur-Mer, France
| | - Hervé Turlier
- Center for Interdisciplinary Research in Biology, College of France, CNRS, INSERM, University of PSL, Paris, France.
| |
Collapse
|
4
|
Roca M, Besnardeau L, Christians E, McDougall A, Chenevert J, Castagnetti S. Acquisition of the spindle assembly checkpoint and its modulation by cell fate and cell size in a chordate embryo. Development 2023; 150:285941. [PMID: 36515557 DOI: 10.1242/dev.201145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022]
Abstract
The spindle assembly checkpoint (SAC) is a surveillance system that preserves genome integrity by delaying anaphase onset until all chromosomes are correctly attached to spindle microtubules. Recruitment of SAC proteins to unattached kinetochores generates an inhibitory signal that prolongs mitotic duration. Chordate embryos are atypical in that spindle defects do not delay mitotic progression during early development, implying that either the SAC is inactive or the cell-cycle target machinery is unresponsive. Here, we show that in embryos of the chordate Phallusia mammillata, the SAC delays mitotic progression from the 8th cleavage divisions. Unattached kinetochores are not recognized by the SAC machinery until the 7th cell cycle, when the SAC is acquired. After acquisition, SAC strength, which manifests as the degree of mitotic lengthening induced by spindle perturbations, is specific to different cell types and is modulated by cell size, showing similarity to SAC control in early Caenorhabditis elegans embryos. We conclude that SAC acquisition is a process that is likely specific to chordate embryos, while modulation of SAC efficiency in SAC proficient stages depends on cell fate and cell size, which is similar to non-chordate embryos.
Collapse
Affiliation(s)
- Marianne Roca
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| | - Lydia Besnardeau
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| | - Elisabeth Christians
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| | - Alex McDougall
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| | - Janet Chenevert
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| | - Stefania Castagnetti
- Sorbonne Universités, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| |
Collapse
|
5
|
Godard BG, Dumollard R, Heisenberg CP, McDougall A. Combined effect of cell geometry and polarity domains determines the orientation of unequal division. eLife 2021; 10:75639. [PMID: 34889186 PMCID: PMC8691831 DOI: 10.7554/elife.75639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 11/17/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cell division orientation is thought to result from a competition between cell geometry and polarity domains controlling the position of the mitotic spindle during mitosis. Depending on the level of cell shape anisotropy or the strength of the polarity domain, one dominates the other and determines the orientation of the spindle. Whether and how such competition is also at work to determine unequal cell division (UCD), producing daughter cells of different size, remains unclear. Here, we show that cell geometry and polarity domains cooperate, rather than compete, in positioning the cleavage plane during UCDs in early ascidian embryos. We found that the UCDs and their orientation at the ascidian third cleavage rely on the spindle tilting in an anisotropic cell shape, and cortical polarity domains exerting different effects on spindle astral microtubules. By systematically varying mitotic cell shape, we could modulate the effect of attractive and repulsive polarity domains and consequently generate predicted daughter cell size asymmetries and position. We therefore propose that the spindle position during UCD is set by the combined activities of cell geometry and polarity domains, where cell geometry modulates the effect of cortical polarity domain(s).
Collapse
Affiliation(s)
- Benoit G Godard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, Villefranche sur Mer, France.,Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Remi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, Villefranche sur Mer, France
| | | | - Alex McDougall
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, Villefranche sur Mer, France
| |
Collapse
|
6
|
Gazo I, Gomes IDL, Savy T, Besnardeau L, Hebras C, Benaicha S, Brunet M, Shaliutina O, McDougall A, Peyrieras N, Dumollard R. High-content analysis of larval phenotypes for the screening of xenobiotic toxicity using Phallusia mammillata embryos. Aquat Toxicol 2021; 232:105768. [PMID: 33592501 DOI: 10.1016/j.aquatox.2021.105768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 01/12/2021] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
In recent years, pollution of surface waters with xenobiotic compounds became an issue of concern in society and has been the object of numerous studies. Most of these xenobiotic compounds are man-made molecules and some of them are qualified as endocrine disrupting chemicals (EDCs) when they interfere with hormones actions. Several studies have investigated the teratogenic impacts of EDCs in vertebrates (including marine vertebrates). However, the impact of such EDCs on marine invertebrates is much debated and still largely obscure. In addition, DNA-altering genotoxicants can induce embryonic malformations. The goal of this study is to develop a reliable and effective test for assessing toxicity of chemicals using embryos of the ascidian (Phallusia mammillata) in order to find phenotypic signatures associated with xenobiotics. We evaluated embryonic malformations with high-content analysis of larval phenotypes by scoring several quantitative and qualitative morphometric endpoints on a single image of Phallusia tadpole larvae with semi-automated image analysis. Using this approach we screened different classes of toxicants including genotoxicants, known or suspected EDCs and nuclear receptors (NRs) ligands. The screen presented here reveals a specific phenotypic signature for ligands of retinoic acid receptor/retinoid X receptor. Analysis of larval morphology combined with DNA staining revealed that embryos with DNA aberrations displayed severe malformations affecting multiple aspects of embryonic development. In contrast EDCs exposure induced no or little DNA aberrations and affected mainly neural development. Therefore the ascidian embryo/larval assay presented here can allow to distinguish the type of teratogenicity induced by different classes of toxicants.
Collapse
Affiliation(s)
- Ievgeniia Gazo
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France; University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic.
| | - Isa D L Gomes
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Thierry Savy
- BioEmergences Laboratory, CNRS USR 3695, 91190, Gif-sur-Yvette, France
| | - Lydia Besnardeau
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Celine Hebras
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Sameh Benaicha
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Manon Brunet
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Olena Shaliutina
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Alex McDougall
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Nadine Peyrieras
- BioEmergences Laboratory, CNRS USR 3695, 91190, Gif-sur-Yvette, France
| | - Rémi Dumollard
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| |
Collapse
|
7
|
Godard BG, Dumollard R, Munro E, Chenevert J, Hebras C, McDougall A, Heisenberg CP. Apical Relaxation during Mitotic Rounding Promotes Tension-Oriented Cell Division. Dev Cell 2020; 55:695-706.e4. [PMID: 33207225 DOI: 10.1016/j.devcel.2020.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 09/09/2020] [Accepted: 10/23/2020] [Indexed: 12/16/2022]
Abstract
Global tissue tension anisotropy has been shown to trigger stereotypical cell division orientation by elongating mitotic cells along the main tension axis. Yet, how tissue tension elongates mitotic cells despite those cells undergoing mitotic rounding (MR) by globally upregulating cortical actomyosin tension remains unclear. We addressed this question by taking advantage of ascidian embryos, consisting of a small number of interphasic and mitotic blastomeres and displaying an invariant division pattern. We found that blastomeres undergo MR by locally relaxing cortical tension at their apex, thereby allowing extrinsic pulling forces from neighboring interphasic blastomeres to polarize their shape and thus division orientation. Consistently, interfering with extrinsic forces by reducing the contractility of interphasic blastomeres or disrupting the establishment of asynchronous mitotic domains leads to aberrant mitotic cell division orientations. Thus, apical relaxation during MR constitutes a key mechanism by which tissue tension anisotropy controls stereotypical cell division orientation.
Collapse
Affiliation(s)
- Benoit G Godard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France; Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Rémi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Edwin Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Janet Chenevert
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Céline Hebras
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Alex McDougall
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | | |
Collapse
|
8
|
Gomes IDL, Gazo I, Nabi D, Besnardeau L, Hebras C, McDougall A, Dumollard R. Bisphenols disrupt differentiation of the pigmented cells during larval brain formation in the ascidian. Aquat Toxicol 2019; 216:105314. [PMID: 31561137 DOI: 10.1016/j.aquatox.2019.105314] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/12/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
The endocrine disruptor Bisphenol A (BPA), a widely employed molecule in plastics, has been shown to affect several biological processes in vertebrates, mostly via binding to nuclear receptors. Neurodevelopmental effects of BPA have been documented in vertebrates and linked to neurodevelopmental disorders, probably because some nuclear receptors are present in the vertebrate brain. Similarly, endocrine disruptors have been shown to affect neurodevelopment in marine invertebrates such as ascidians, mollusks or echinoderms, but whether invertebrate nuclear receptors are involved in the mode-of-action is largely unknown. In this study, we assessed the effect of BPA on larval brain development of the ascidian Phallusia mammillata. We found that BPA is toxic to P. mammillata embryos in a dose-dependent manner (EC50: 11.8μM; LC50: 21μM). Furthermore, micromolar doses of BPA impaired differentiation of the ascidian pigmented cells, by inhibiting otolith movement within the sensory vesicle. We further show that this phenotype is specific to other two bisphenols (BPE and BPF) over a bisphenyl (2,2 DPP). Because in vertebrates the estrogen-related receptor gamma (ERRγ) can bind bisphenols with high affinity but not bisphenyls, we tested whether the ascidian ERR participates in the neurodevelopmental phenotype induced by BPA. Interestingly, P. mammillata ERR is expressed in the larval brain, adjacent to the differentiating otolith. Furthermore, antagonists of vertebrate ERRs also inhibited the otolith movement but not pigmentation. Together our observations suggest that BPA may affect ascidian otolith differentiation by altering Pm-ERR activity whereas otolith pigmentation defects might be due to the known inhibitory effect of bisphenols on tyrosinase enzymatic activity.
Collapse
Affiliation(s)
- Isa D L Gomes
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France.
| | - Ievgeniia Gazo
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France; University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, Research Institute of Fish Culture and Hydrobiology, Laboratory of Molecular, Cellular and Quantitative Genetics, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Dalileh Nabi
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France
| | - Lydia Besnardeau
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France
| | - Céline Hebras
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France
| | - Alex McDougall
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France
| | - Rémi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France.
| |
Collapse
|
9
|
Gomes IDL, Gazo I, Besnardeau L, Hebras C, McDougall A, Dumollard R. Potential roles of nuclear receptors in mediating neurodevelopmental toxicity of known endocrine-disrupting chemicals in ascidian embryos. Mol Reprod Dev 2019; 86:1333-1347. [PMID: 31215734 DOI: 10.1002/mrd.23219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 05/15/2019] [Accepted: 05/20/2019] [Indexed: 12/17/2022]
Abstract
Endocrine Disrupting Chemicals (EDCs) are molecules able to interfere with the vertebrate hormonal system in different ways, a major one being the modification of the activity of nuclear receptors (NRs). Several NRs are expressed in the vertebrate brain during embryonic development and these NRs are suspected to be responsible for the neurodevelopmental defects induced by exposure to EDCs in fishes or amphibians and to participate in several neurodevelopmental disorders observed in humans. Known EDCs exert toxicity not only on vertebrate forms of marine life but also on marine invertebrates. However, because hormonal systems of invertebrates are poorly understood, it is not clear whether the teratogenic effects of known EDCs are because of endocrine disruption. The most conserved actors of endocrine systems are the NRs which are present in all metazoan genomes but their functions in invertebrate organisms are still insufficiently characterized. EDCs like bisphenol A have recently been shown to affect neurodevelopment in marine invertebrate chordates called ascidians. Because such phenotypes can be mediated by NRs expressed in the ascidian embryo, we review all the information available about NRs expression during ascidian embryogenesis and discuss their possible involvement in the neurodevelopmental phenotypes induced by EDCs.
Collapse
Affiliation(s)
- Isa D L Gomes
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Ievgeniia Gazo
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Lydia Besnardeau
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Céline Hebras
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Alex McDougall
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Rémi Dumollard
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| |
Collapse
|
10
|
Espinoza T, Connell M, Marshall S, Beukeboom R, McDougall A. Nesting behaviour of the endangered Mary River turtle: monitoring and modelling to inform e-flow strategies. AUST J ZOOL 2018. [DOI: 10.1071/zo17044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The Mary River turtle (Elusor macrurus) is an endemic, monotypic species with multiple impacts across its life-history, including overharvesting of eggs, nest predation and habitat degradation. Long-term recruitment failure has led to protection measures established under state, federal and international authority. Previous research has demonstrated that E. macrurus lives instream but nests on river banks, requiring specific habitat for breeding, nesting and recruitment. Ecohydrological rules represent the critical water requirements contributing to a species’ life history and can be used to develop and assess environmental flow strategies for species affected by water resource development. This study investigated the nesting behaviour of E. macrurus, including the environmental drivers that affect nest inundation. Monitoring showed that nesting by E. macrurus peaked in October and November, driven by rainfall events (>10 mm), with potential impacts from flow events (20% of nests established <2.5 m above water level at time of nesting). These ecohydrological rules were modelled against 109 years of simulated natural flow and rainfall data. The ‘potential nesting and nest inundation’ (PNNI) indicator revealed that nesting for E. macrurus was assured in a majority of years under the natural flow scenario. The results of this study will inform the development and assessment of e-flow strategies for nesting by E. macrurus in terms of current, and future water resource development, along with climate change impacts.
Collapse
|
11
|
Costache V, Hebras C, Pruliere G, Besnardeau L, Failla M, Copley RR, Burgess D, Chenevert J, McDougall A. Kif2 localizes to a subdomain of cortical endoplasmic reticulum that drives asymmetric spindle position. Nat Commun 2017; 8:917. [PMID: 29030551 PMCID: PMC5640700 DOI: 10.1038/s41467-017-01048-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/16/2017] [Indexed: 12/22/2022] Open
Abstract
Asymmetric positioning of the mitotic spindle is a fundamental process responsible for creating sibling cell size asymmetry; however, how the cortex causes the depolymerization of astral microtubules during asymmetric spindle positioning has remained elusive. Early ascidian embryos possess a large cortical subdomain of endoplasmic reticulum (ER) that causes asymmetric spindle positioning driving unequal cell division. Here we show that the microtubule depolymerase Kif2 localizes to this subdomain of cortical ER. Rapid live-cell imaging reveals that microtubules are less abundant in the subdomain of cortical ER. Inhibition of Kif2 function prevents the development of mitotic aster asymmetry and spindle pole movement towards the subdomain of cortical ER, whereas locally increasing microtubule depolymerization causes exaggerated asymmetric spindle positioning. This study shows that the microtubule depolymerase Kif2 is localized to a cortical subdomain of endoplasmic reticulum that is involved in asymmetric spindle positioning during unequal cell division. Early ascidian embryos have a cortical subdomain of endoplasmic reticulum (ER) that controls asymmetric spindle positioning driving unequal cell division. Here the authors show that the microtubule depolymerase Kif2 is localized to a cortical subdomain of the ER that is involved in asymmetric spindle positioning.
Collapse
Affiliation(s)
- Vlad Costache
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Celine Hebras
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Gerard Pruliere
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Lydia Besnardeau
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Margaux Failla
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Richard R Copley
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - David Burgess
- Boston College, Biology Department, 528 Higgins Hall, 140 Commonwealth Ave, Chestnut Hill, MA, 0246, USA
| | - Janet Chenevert
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France.
| | - Alex McDougall
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France.
| |
Collapse
|
12
|
Dumollard R, Gazo I, Gomes IDL, Besnardeau L, McDougall A. Ascidians: An Emerging Marine Model for Drug Discovery and Screening. Curr Top Med Chem 2017; 17:2056-2066. [DOI: 10.2174/1568026617666170130104922] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 11/22/2022]
Affiliation(s)
- Remi Dumollard
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Dévelopement de Villefranche- sur-mer (LBDV), Observatoire Oceanologique, 06230, Villefranche sur-mer, France
| | - Ievgeniia Gazo
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zatisí 728/II, 389 25, Vodnany, Czech Republic
| | - Isa D. L. Gomes
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Dévelopement de Villefranche-surmer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Lydia Besnardeau
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Dévelopement de Villefranche-surmer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| | - Alex McDougall
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Dévelopement de Villefranche-surmer (LBDV), Observatoire Océanologique, 06230 Villefranche sur-mer, France
| |
Collapse
|
13
|
Dumollard R, Minc N, Salez G, Aicha SB, Bekkouche F, Hebras C, Besnardeau L, McDougall A. The invariant cleavage pattern displayed by ascidian embryos depends on spindle positioning along the cell's longest axis in the apical plane and relies on asynchronous cell divisions. eLife 2017; 6. [PMID: 28121291 PMCID: PMC5319837 DOI: 10.7554/elife.19290] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [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: 06/30/2016] [Accepted: 01/24/2017] [Indexed: 12/24/2022] Open
Abstract
The ascidian embryo is an ideal system to investigate how cell position is determined during embryogenesis. Using 3D timelapse imaging and computational methods we analyzed the planar cell divisions in ascidian early embryos and found that spindles in every cell tend to align at metaphase in the long length of the apical surface except in cells undergoing unequal cleavage. Furthermore, the invariant and conserved cleavage pattern of ascidian embryos was found to consist in alternate planar cell divisions between ectoderm and endomesoderm. In order to test the importance of alternate cell divisions we manipulated zygotic transcription induced by β-catenin or downregulated wee1 activity, both of which abolish this cell cycle asynchrony. Crucially, abolishing cell cycle asynchrony consistently disrupted the spindle orienting mechanism underpinning the invariant cleavage pattern. Our results demonstrate how an evolutionary conserved cell cycle asynchrony maintains the invariant cleavage pattern driving morphogenesis of the ascidian blastula. DOI:http://dx.doi.org/10.7554/eLife.19290.001 The position of cells within an embryo early in development determines what type of cells they will become in the fully formed embryo. The embryos of ascidians, commonly known as sea squirts, are ideal for studying what influences cell positioning. These embryos consist of a small number of cells that divide according to an “invariant cleavage pattern”, which means that the positioning and timing of the cell divisions is identical between different individuals of the same species. The pattern of cell division is also largely the same across different ascidian species, which raises questions about how it is controlled. When a cell divides, a structure called the spindle forms inside it to distribute copies of the cell’s genetic material between the new cells. The orientation of the spindle determines the direction in which the cell will divide. Now, by combining 3D imaging of living ascidian embryos with computational modeling, Dumollard et al. show that the spindles in every equally dividing cell tend to all align in the long length of the cell’s “apical” surface. Such alignment allows the cells to be on the outside of the embryo and implements the ascidian invariant cleavage pattern. The cells in the embryo do not all divide at the same time. Indeed, the shape of the cells (and especially their apical surface) depends on two layers of cells in the embryo not dividing at the same time; instead, periods of cell division alternate between the layers. A network of genes in the embryo regulates the timing of these cell divisions and makes it possible for the cells to divide according to an invariant cleavage pattern. However, this network of genes is not the only control mechanism that shapes the early embryo. A structure found in egg cells (and hence produced by the embryo’s mother) causes cells at the rear of the embryo to divide unequally, and this influences the shape of all the cells in the embryo. Thus it appears that maternal mechanisms work alongside the embryo’s gene network to shape the early embryo. The next step will be to determine how physical forces – for example, from the cells pressing against each other – influence the position of the embryo’s cells. How do gene networks relay the biomechanical properties of the embryo to help it take shape? DOI:http://dx.doi.org/10.7554/eLife.19290.002
Collapse
Affiliation(s)
- Rémi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Nicolas Minc
- Institut Jacques Monod, UMR7592 CNRS, Paris, France
| | - Gregory Salez
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Sameh Ben Aicha
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Faisal Bekkouche
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Céline Hebras
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Lydia Besnardeau
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Alex McDougall
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| |
Collapse
|
14
|
McDougall A, Goldszmidt M, Kinsella EA, Smith S, Lingard L. Collaboration and entanglement: An actor-network theory analysis of team-based intraprofessional care for patients with advanced heart failure. Soc Sci Med 2016; 164:108-117. [PMID: 27490299 PMCID: PMC5650482 DOI: 10.1016/j.socscimed.2016.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 06/30/2016] [Accepted: 07/11/2016] [Indexed: 11/17/2022]
Abstract
Despite calls for more interprofessional and intraprofessional team-based approaches in healthcare, we lack sufficient understanding of how this happens in the context of patient care teams. This multi-perspective, team-based interview study examined how medical teams negotiated collaborative tensions. From 2011 to 2013, 50 patients across five sites in three Canadian provinces were interviewed about their care experiences and were asked to identify members of their health care teams. Patient-identified team members were subsequently interviewed to form 50 "Team Sampling Units" (TSUs), consisting of 209 interviews with patients, caregivers and healthcare providers. Results are gathered from a focused analysis of 13 TSUs where intraprofessional collaborative tensions involved treating fluid overload, or edema, a common HF symptom. Drawing on actor-network theory (ANT), the analysis focused on intraprofessional collaboration between specialty care teams in cardiology and nephrology. The study found that despite a shared narrative of common purpose between cardiology teams and nephrology teams, fluid management tools and techniques formed sites of collaborative tension. In particular, care activities involved asynchronous clinical interpretations, geographically distributed specialist care, fragmented forms of communication, and uncertainty due to clinical complexity. Teams 'disentangled' fluid in order to focus on its physiological function and mobilisation. Teams also used distinct 'framings' of fluid management that created perceived collaborative tensions. This study advances collaborative entanglement as a conceptual framework for understanding, teaching, and potentially ameliorating some of the tensions that manifest during intraprofessional care for patients with complex, chronic disease.
Collapse
Affiliation(s)
- A McDougall
- Health & Rehabilitation Sciences-Health Professional Education, Western University, London, ON, Canada; Centre for Education Research & Innovation, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada.
| | - M Goldszmidt
- Centre for Education Research & Innovation, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada; Dept. of Medicine, Division of Internal Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - E A Kinsella
- Health & Rehabilitation Sciences-Occupational Therapy/Health Professional Education, Western University, London, ON, Canada; Centre for Education Research & Innovation, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - S Smith
- Dept. of Medicine, Division of Cardiology, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - L Lingard
- Centre for Education Research & Innovation, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada; Dept. of Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| |
Collapse
|
15
|
Brozovic M, Martin C, Dantec C, Dauga D, Mendez M, Simion P, Percher M, Laporte B, Scornavacca C, Di Gregorio A, Fujiwara S, Gineste M, Lowe EK, Piette J, Racioppi C, Ristoratore F, Sasakura Y, Takatori N, Brown TC, Delsuc F, Douzery E, Gissi C, McDougall A, Nishida H, Sawada H, Swalla BJ, Yasuo H, Lemaire P. ANISEED 2015: a digital framework for the comparative developmental biology of ascidians. Nucleic Acids Res 2016; 44:D808-18. [PMID: 26420834 PMCID: PMC4702943 DOI: 10.1093/nar/gkv966] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/14/2015] [Indexed: 11/24/2022] Open
Abstract
Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010. Over the past five years, we refactored the system from an initial custom schema to an extended version of the Chado schema and redesigned all user and back end interfaces. This new architecture was used to improve and enrich the description of Ciona intestinalis embryonic development, based on an improved genome assembly and gene model set, refined functional gene annotation, and anatomical ontologies, and a new collection of full ORF cDNAs. The genomes of nine ascidian species have been sequenced since the release of the C. intestinalis genome. In ANISEED 2015, all nine new ascidian species can be explored via dedicated genome browsers, and searched by Blast. In addition, ANISEED provides full functional gene annotation, anatomical ontologies and some gene expression data for the six species with highest quality genomes. ANISEED is publicly available at: http://www.aniseed.cnrs.fr.
Collapse
Affiliation(s)
- Matija Brozovic
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Cyril Martin
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Christelle Dantec
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Delphine Dauga
- Institut de Biologie du Développement de Marseille (IBDM), UMR7288 CNRS-Aix Marseille Université, Parc Scientifique de Luminy, Case 907, F-13288 Marseille Cedex 9, France Bioself Communication, 28 rue de la Bibliothèque, F-13001 Marseille, France
| | - Mickaël Mendez
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Paul Simion
- Institut des Sciences de l'Evolution de Montpellier (ISE-M), UMR 5554 CNRS-IRD-Université de Montpellier, F-34090 Montpellier, France
| | - Madeline Percher
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Baptiste Laporte
- Institut de Biologie du Développement de Marseille (IBDM), UMR7288 CNRS-Aix Marseille Université, Parc Scientifique de Luminy, Case 907, F-13288 Marseille Cedex 9, France
| | - Céline Scornavacca
- Institut des Sciences de l'Evolution de Montpellier (ISE-M), UMR 5554 CNRS-IRD-Université de Montpellier, F-34090 Montpellier, France
| | - Anna Di Gregorio
- Department of Basic Science and Craniofacial Biology New York University College of Dentistry, 345 E 24th Street, New York, NY 10010, USA
| | - Shigeki Fujiwara
- Department of Applied Science, Kochi University, Kochi-shi, Kochi 780-8520, Japan
| | - Mathieu Gineste
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Elijah K Lowe
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, I-80121 Napoli, Italy BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, USA
| | - Jacques Piette
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France
| | - Claudia Racioppi
- Center for Developmental Genetics, Department of Biology, New York University, New York, NY 10003, USA
| | - Filomena Ristoratore
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, I-80121 Napoli, Italy
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan
| | - Naohito Takatori
- Developmental Biology Laboratory, Department of Biological Sciences, School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiooji, Tokyo 192-0397, Japan Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Titus C Brown
- Population Health and Reproduction, UC Davis, Davis, CA 95616, USA
| | - Frédéric Delsuc
- Institut des Sciences de l'Evolution de Montpellier (ISE-M), UMR 5554 CNRS-IRD-Université de Montpellier, F-34090 Montpellier, France
| | - Emmanuel Douzery
- Institut des Sciences de l'Evolution de Montpellier (ISE-M), UMR 5554 CNRS-IRD-Université de Montpellier, F-34090 Montpellier, France
| | - Carmela Gissi
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, Milano 20133, Italy
| | - Alex McDougall
- Sorbonne Universités, Université Pierre et Marie Curie, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer, Observatoire Océanologique, F-06230 Villefranche-sur-mer, France
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Hitoshi Sawada
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, 429-63 Sugashima, Toba 517-0004, Japan
| | - Billie J Swalla
- Friday Harbor Laboratories, 620 University Road, Friday Harbor, WA 98250-9299, USA
| | - Hitoyoshi Yasuo
- Sorbonne Universités, Université Pierre et Marie Curie, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer, Observatoire Océanologique, F-06230 Villefranche-sur-mer, France
| | - Patrick Lemaire
- Centre de Recherches de Biochimie Macromoléculaire (CRBM), UMR5237, CNRS-Université de Montpellier, 1919 route de Mende, F-34090 Montpellier, France Institut de Biologie du Développement de Marseille (IBDM), UMR7288 CNRS-Aix Marseille Université, Parc Scientifique de Luminy, Case 907, F-13288 Marseille Cedex 9, France
| |
Collapse
|
16
|
Moorhouse KS, Gudejko HF, McDougall A, Burgess DR. Influence of cell polarity on early development of the sea urchin embryo. Dev Dyn 2015; 244:1469-84. [PMID: 26293695 PMCID: PMC4715636 DOI: 10.1002/dvdy.24337] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Establishment and maintenance of cell polarity is critical for normal embryonic development. Previously, it was thought that the echinoderm embryo remained relatively unpolarized until the first asymmetric division at the 16-cell stage. Here, we analyzed roles of the cell polarity regulators, the PAR complex proteins, and how their disruption in early development affects later developmental milestones. RESULTS We found that PAR6, aPKC, and CDC42 localize to the apical cortex as early as the 2-cell stage and that this localization is retained through the gastrula stage. Of interest, PAR1 also colocalizes with these apical markers through the gastrula stage. Additionally, PAR1 was found to be in complex with aPKC, but not PAR6. PAR6, aPKC, and CDC42 are anchored in the cortical actin cytoskeleton by assembled myosin. Furthermore, assembled myosin was found to be necessary to maintain proper PAR6 localization through subsequent cleavage divisions. Interference with myosin assembly prevented the embryos from reaching the blastula stage, while transient disruptions of either actin or microtubules did not have this effect. CONCLUSIONS These observations suggest that disruptions of the polarity in the early embryo can have a significant impact on the ability of the embryo to reach later critical stages in development.
Collapse
Affiliation(s)
- Kathleen S. Moorhouse
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Heather F.M. Gudejko
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Alex McDougall
- UMR 7009, UPMC Sorbonne Universités, Centre National de la Recherche (CNRS), Observatoire Océanologique, 181 Chemin du Lazaret, 06230 Villefranche-sur-Mer, France
| | - David R. Burgess
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| |
Collapse
|
17
|
Levasseur M, McDougall A. IP3 Responsiveness Is Regulated in a Meiotic Cell Cycle Dependent Manner: Implications for Fertilization Induced Calcium Signalling. Cell Cycle 2014. [DOI: 10.4161/cc.2.6.504] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
18
|
Costache V, McDougall A, Dumollard R. Cell cycle arrest and activation of development in marine invertebrate deuterostomes. Biochem Biophys Res Commun 2014; 450:1175-81. [DOI: 10.1016/j.bbrc.2014.03.155] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 03/31/2014] [Indexed: 11/24/2022]
|
19
|
Levasseur M, Dumollard R, Chambon JP, Hebras C, Sinclair M, Whitaker M, McDougall A. Release from meiotic arrest in ascidian eggs requires the activity of two phosphatases but not CaMKII. Development 2014; 140:4583-93. [PMID: 24194472 DOI: 10.1242/dev.096578] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The fertilising sperm triggers a transient Ca(2+) increase that releases eggs from cell cycle arrest in the vast majority of animal eggs. In vertebrate eggs, Erp1, an APC/C(cdc20) inhibitor, links release from metaphase II arrest with the Ca(2+) transient and its degradation is triggered by the Ca(2+)-induced activation of CaMKII. By contrast, many invertebrate groups have mature eggs that arrest at metaphase I, and these species do not possess the CaMKII target Erp1 in their genomes. As a consequence, it is unknown exactly how cell cycle arrest at metaphase I is achieved and how the fertilisation Ca(2+) transient overcomes the arrest in the vast majority of animal species. Using live-cell imaging with a novel cyclin reporter to study cell cycle arrest and its release in urochordate ascidians, the closest living invertebrate group to the vertebrates, we have identified a new signalling pathway for cell cycle resumption in which CaMKII plays no part. Instead, we find that the Ca(2+)-activated phosphatase calcineurin (CN) is required for egg activation. Moreover, we demonstrate that parthenogenetic activation of metaphase I-arrested eggs by MEK inhibition, independent of a Ca(2+) increase, requires the activity of a second egg phosphatase: PP2A. Furthermore, PP2A activity, together with CN, is required for normal egg activation during fertilisation. As ascidians are a sister group of the vertebrates, we discuss these findings in relation to cell cycle arrest and egg activation in chordates.
Collapse
Affiliation(s)
- Mark Levasseur
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | | | | | | | | | | | | |
Collapse
|
20
|
Levasseur M, Dumollard R, Chambon JP, Hebras C, Sinclair M, Whitaker M, McDougall A. Release from meiotic arrest in ascidian eggs requires the activity of two phosphatases but not CaMKII. J Cell Sci 2013. [DOI: 10.1242/jcs.145144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
21
|
Dumollard R, Hebras C, Besnardeau L, McDougall A. Beta-catenin patterns the cell cycle during maternal-to-zygotic transition in urochordate embryos. Dev Biol 2013; 384:331-42. [PMID: 24140189 DOI: 10.1016/j.ydbio.2013.10.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/18/2013] [Accepted: 10/03/2013] [Indexed: 11/18/2022]
Abstract
During the transition from maternal to zygotic control of development, cell cycle length varies in different lineages, and this is important for their fates and functions. The maternal to zygotic transition (MZT) in metazoan embryos involves a profound remodeling of the cell cycle: S phase length increases then G2 is introduced. Although β-catenin is the master regulator of endomesoderm patterning at MZT in all metazoans, the influence of maternal β-catenin on the cell cycle at MZT remains poorly understood. By studying urochordate embryogenesis we found that cell cycle remodeling during MZT begins with the formation of 3 mitotic domains at the 16-cell stage arising from differential S phase lengthening, when endomesoderm is specified. Then, at the 64-cell stage, a G2 phase is introduced in the endoderm lineage during its specification. Strikingly, these two phases of cell cycle remodeling are patterned by β-catenin-dependent transcription. Functional analysis revealed that, at the 16-cell stage, β-catenin speeds up S phase in the endomesoderm. In contrast, two cell cycles later at gastrulation, nuclear β-catenin induces endoderm fate and delays cell division. Such interphase lengthening in invaginating cells is known to be a requisite for gastrulation movements. Therefore, in basal chordates β-catenin has a dual role to specify germ layers and remodel the cell cycle.
Collapse
Affiliation(s)
- Rémi Dumollard
- UMR 7009, UPMC University, Paris 06, France; Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France.
| | | | | | | |
Collapse
|
22
|
Negishi T, McDougall A, Yasuo H. Practical tips for imaging ascidian embryos. Dev Growth Differ 2013; 55:446-53. [PMID: 23611302 DOI: 10.1111/dgd.12059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 03/06/2013] [Accepted: 03/15/2013] [Indexed: 01/12/2023]
Abstract
Decades of studies on ascidian embryogenesis have culminated in deciphering the first gene regulatory "blueprint" for the generation of all major larval tissue types in chordates. However, the current gene regulatory network (GRN) is not well integrated with the morphogenetic and cellular processes that are also taking place during embryogenesis. Describing these processes represents a major on-going challenge, aided by recent advances in imaging and fluorescent protein (FP) technologies. In this report, we describe the application of these technologies to the developmental biology of ascidians and provide a detailed practical guide on the preparation of ascidian embryos for imaging.
Collapse
Affiliation(s)
- Takefumi Negishi
- UPMC Univ Paris 06 and Centre National de la Recherche Scientifique, Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Observatoire Océanologique, 06234, Villefranche-sur-mer, France
| | | | | |
Collapse
|
23
|
Hebras C, McDougall A. Urochordate ascidians possess a single isoform of Aurora kinase that localizes to the midbody via TPX2 in eggs and cleavage stage embryos. PLoS One 2012; 7:e45431. [PMID: 23029005 PMCID: PMC3447887 DOI: 10.1371/journal.pone.0045431] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/17/2012] [Indexed: 01/09/2023] Open
Abstract
Aurora kinases are key proteins found throughout the eukaryotes that control mitotic progression. Vertebrate Aurora-A and B kinases are thought to have evolved from a single Aurora-kinase isoform closest to that found in present day urochordates. In urochordate ascidians Aurora binds both TPX2 (a vertebrate AURKA partner) and INCENP (a vertebrate AURKB partner) and localizes to centrosomes and spindle microtubules as well as chromosomes and midbody during both meiosis and mitosis. Ascidian Aurora also displays this localization pattern during mitosis in echinoderms, strengthening the idea that non-vertebrate deuterostomes such as the urochordates and echinoderms possess a single form of Aurora kinase that has properties of vertebrate Aurora-kinase A and B. In the ascidian, TPX2 localizes to the centrosome and the spindle poles also as in vertebrates. However, we were surprised to find that TPX2 also localized strongly to the midbody in ascidian eggs and embryos. We thus examined more closely Aurora localization to the midbody by creating two separate point mutations of ascidian Aurora predicted to perturb binding to TPX2. Both forms of mutated Aurora behaved as predicted: neither localized to spindle poles where TPX2 is enriched. Interestingly, neither form of mutated Aurora localized to the midbody where TPX2 is also enriched, suggesting that ascidian Aurora midbody localization required TPX2 binding in ascidians. Functional analysis revealed that inhibition of Aurora kinase with a pharmacological inhibitor or with a dominant negative kinase dead form of Aurora caused cytokinesis failure and perturbed midbody formation during polar body extrusion. Our data support the view that vertebrate Aurora-A and B kinases evolved from a single non-vertebrate deuterostome ancestor. Moreover, since TPX2 localizes to the midbody in ascidian eggs and cleavage stage embryos it may be worthwhile re-assessing whether Aurora A kinase or TPX2 localize to the midbody in eggs and cleavage stage embryos.
Collapse
Affiliation(s)
- Celine Hebras
- Université Pierre et Marie Curie and CNRS, Developmental Biology Unit, Villefranche-sur-Mer, France
| | - Alex McDougall
- Université Pierre et Marie Curie and CNRS, Developmental Biology Unit, Villefranche-sur-Mer, France
- * E-mail:
| |
Collapse
|
24
|
Ghia D, Thomas P, Cordato D, Epstein D, Beran RG, Cappelen-Smith C, Griffith N, Hanna I, McDougall A, Hodgkinson SJ, Worthington JM. Low positive predictive value of the ABCD2 score in emergency department transient ischaemic attack diagnoses: the South Western Sydney transient ischaemic attack study. Intern Med J 2012; 42:913-8. [PMID: 21790923 DOI: 10.1111/j.1445-5994.2011.02564.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The ABCD(2) stroke risk score is recommended in national guidelines for stratifying care in transient ischaemic attack (TIA) patients, based on its prediction of early stroke risk. We had become concerned about the score accuracy and its clinical value in modern TIA cohorts. METHODS We identified emergency department-diagnosed TIA at two hospitals over 3 years (2004-2006). Cases were followed for stroke occurrence and ABCD(2) scores were determined from expert record review. Sensitivity, specificity and positive predictive values (PPV) of moderate-high ABCD(2) scores were determined. RESULTS There were 827 indexed TIA diagnoses and record review was possible in 95.4%. Admitted patients had lower 30-day stroke risk (n = 0) than discharged patients (n = 7; 3.1%) (P < 0.0001). There was no significant difference in proportion of strokes between those with a low or moderate-high ABCD(2) score at 30 (1.2 vs 0.8%), 90 (2.0 vs 1.9%) and 365 days (2.4 vs 2.4%) respectively. At 30 days the sensitivity, specificity and PPV of a moderate-high score were 57% (95% confidence interval (CI) 25.0-84.2), 32.2% (95% CI 29.1-35.6) and 0.75% (95% CI 0.29-1.91) respectively. CONCLUSIONS Early stroke risk was low after an emergency diagnosis of TIA and significantly lower in admitted patients. Moderate-high ABCD(2) scores did not predict early stroke risk. We suggest local validation of ABCD(2) before its clinical use and a review of its place in national guidelines.
Collapse
Affiliation(s)
- D Ghia
- Neurology Department, Liverpool Hospital, Sydney, New South Wales, Australia
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
The egg of ascidians (urochordate), as virtually all animal and plant species, displays Ca2+ signals upon fertilisation. These Ca2+ signals are repetitive Ca2+ waves that initiate in the cortex of the egg and spread through the whole egg interior. Two series of Ca2+ waves triggered from two distinct Ca2+ wave pacemakers entrain the two meiotic divisions preceding entry into the first interphase. The second messenger inositol (1,4,5) trisphosphate (IP3) is the main mediator of these global Ca2+ waves. Other Ca2+ signalling pathways (RyR and NAADPR) are functional in the egg but they mediate localised cortical Ca2+ signals whose physiological significance remains unclear. The meiosis I Ca2+ wave pacemaker is mobile and relies on intracellular Ca2+ release from the endoplasmic reticulum (ER) induced by a large production of IP3 at the sperm aster site. The meiosis II Ca2+ wave pacemaker is stably localised in a vegetal protrusion called the contraction pole. It is probable that a local production of IP3 in the contraction pole determines the site of this second pacemaker while functional interactions between ER and mitochondria regulate its activity. Finally, a third ectopic pacemaker can be induced by a global increase in IP3, making the ascidian egg a unique system where three different Ca2+ wave pacemakers coexist in the same cell.
Collapse
Affiliation(s)
- Rémi Dumollard
- Department of Physiology, University College London, Gower Street, London, WC1E 6BT, UK.
| | | | | | | |
Collapse
|
26
|
Tait GR, Schryer C, McDougall A, Lingard L. Exploring the therapeutic power of narrative at the end of life: a qualitative analysis of narratives emerging in dignity therapy. BMJ Support Palliat Care 2011; 1:296-300. [DOI: 10.1136/bmjspcare-2011-000051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
27
|
Dumollard R, Levasseur M, Hebras C, Huitorel P, Carroll M, Chambon JP, McDougall A. Mos limits the number of meiotic divisions in urochordate eggs. Development 2011; 138:885-95. [DOI: 10.1242/dev.057133] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mos kinase is a universal mediator of oocyte meiotic maturation and is produced during oogenesis and destroyed after fertilization. The hallmark of maternal meiosis is that two successive M phases (meiosis I and II) drive two rounds of asymmetric cell division (ACD). However, how the egg limits the number of meioses to just two, thereby preventing gross aneuploidy, is poorly characterized. Here, in urochordate eggs, we show that loss of Mos/MAPK activity is necessary to prevent entry into meiosis III. Remarkably, maintaining the Mos/MAPK pathway active after fertilization at near physiological levels induces additional rounds of meiotic M phase (meiosis III, IV and V). During these additional rounds of meiosis, the spindle is positioned asymmetrically resulting in further rounds of ACD. In addition, inhibiting meiotic exit with Mos prevents pronuclear formation, cyclin A accumulation and maintains sperm-triggered Ca2+ oscillations, all of which are hallmarks of the meiotic cell cycle in ascidians. It will be interesting to determine whether Mos availability in mammals can also control the number of meioses as it does in the urochordates. Our results demonstrate the power of urochordate eggs as a model to dissect the egg-to-embryo transition.
Collapse
Affiliation(s)
- Rémi Dumollard
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Mark Levasseur
- Institute of Cell and Molecular Bioscences, The Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK
| | - Céline Hebras
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Philippe Huitorel
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Michael Carroll
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Jean-Philippe Chambon
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Alex McDougall
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| |
Collapse
|
28
|
Sardet C, McDougall A, Yasuo H, Chenevert J, Pruliere G, Dumollard R, Hudson C, Hebras C, Le Nguyen N, Paix A. Embryological methods in ascidians: the Villefranche-sur-Mer protocols. Methods Mol Biol 2011; 770:365-400. [PMID: 21805272 DOI: 10.1007/978-1-61779-210-6_14] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Ascidians (marine invertebrates: urochordates) are thought to be the closest sister groups of vertebrates. They are particularly attractive models because of their non-duplicated genome and the fast and synchronous development of large populations of eggs into simple tadpoles made of about 3,000 cells. As a result of stereotyped asymmetric cleavage patterns all blastomeres become fate restricted between the 16- and 110 cell stage through inheritance of maternal determinants and/or cellular interactions. These advantageous features have allowed advances in our understanding of the nature and role of maternal determinants, inductive interactions, and gene networks that are involved in cell lineage specification and differentiation of embryonic tissues. Ascidians have also contributed to our understanding of fertilization, cell cycle control, self-recognition, metamorphosis, and regeneration. In this chapter we provide basic protocols routinely used at the marine station in Villefranche-sur-Mer using the cosmopolitan species of reference Ciona intestinalis and the European species Phallusia mammillata. These two models present complementary advantages with regard to molecular, functional, and imaging approaches. We describe techniques for basic culture of embryos, micro-injection, in vivo labelling, micro-manipulations, fixation, and immuno-labelling. These methods allow analysis of calcium signals, reorganizations of cytoplasmic and cortical domains, meiotic and mitotic cell cycle and cleavages as well as the roles of specific genes and cellular interactions. Ascidians eggs and embryos are also an ideal material to isolate cortical fragments and to isolate and re-associate individual blastomeres. We detail the experimental manipulations which we have used to understand the structure and role of the egg cortex and of specific blastomeres during development.
Collapse
Affiliation(s)
- Christian Sardet
- Biologie du Développement, UMR 7009 CNRS/UPMC, Observatoire Océanologique, Villefranche sur Mer 06230, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
In ascidians the cell cycle machinery has been studied mainly in oocytes while ascidian embryos have been used to dissect the mechanism that controls asymmetric cell division (ACD). Here we overview the most specific and often exceptional points and events in cell cycle control in ascidian oocytes and early embryos. Mature stage IV eggs are arrested at metaphase I due to cytostatic factor (CSF). In vertebrates, unfertilized eggs are arrested at metaphase II by CSF. Meta II-CSF is mediated by the Mos/MEK/MAPK/Erp1 pathway, which inhibits the ubiquitin ligase APC/C(cdc20) preventing cyclin B destruction thus stabilizing MPF activity. CSF is inactivated by the fertilization Ca(2+) transient that stimulates the destruction of Erp1 thus releasing APC/C(cdc20) from inhibition. Although many of the components of CSF are conserved between the ascidian and the vertebrates, the lack of Erp1 in the ascidians (and indeed other invertebrates) is notable since the Mos/MAPK pathway nonetheless mediates Meta I-CSF. Moreover, since the fertilization Ca(2+) transient targets Erp1, it is not clear how the sperm-triggered Ca(2+) transient in ascidians (and again other invertebrates) stimulates cyclin B destruction in the absence of Erp1. Nonetheless, like mammalian eggs, sperm trigger a series of Ca(2+) oscillations that increases the rate of cyclin B destruction and the subsequent loss of MAPK activity leading to meiotic exit in ascidians. Positive feedback from MPF maintains the Ca(2+) oscillations in fertilized ascidian eggs ensuring the eventual loss of MPF stimulating the egg-to-embryo transition. Embryonic cell cycles in the ascidian are highly stereotyped where both the rate of cell division and the orientation of cell division planes are precisely controlled. Three successive rounds of ACD generate two small posterior germ cell precursors at the 64 cell stage. The centrosome-attracting body (CAB) is a macroscopic cortical structure visible by light microscopy that causes these three rounds of ACD. Entry into mitosis activates the CAB causing the whole mitotic spindle to rotate and migrate toward the cortical CAB leading to a highly ACD whereby one small cell is formed that inherits the CAB and approximately 40 maternal postplasmic/PEM RNAs including the germ cell marker vasa.
Collapse
Affiliation(s)
- Alex McDougall
- Developmental Biology Unit UMR 7009, UMPC Univ. Paris 06 and Center National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France.
| | | | | | | | | |
Collapse
|
30
|
Prodon F, Chenevert J, Hébras C, Dumollard R, Faure E, Gonzalez-Garcia J, Nishida H, Sardet C, McDougall A. Dual mechanism controls asymmetric spindle position in ascidian germ cell precursors. Development 2010; 137:2011-21. [DOI: 10.1242/dev.047845] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mitotic spindle orientation with respect to cortical polarity cues generates molecularly distinct daughter cells during asymmetric cell division (ACD). However, during ACD it remains unknown how the orientation of the mitotic spindle is regulated by cortical polarity cues until furrowing begins. In ascidians, the cortical centrosome-attracting body (CAB) generates three successive unequal cleavages and the asymmetric segregation of 40 localized postplasmic/PEM RNAs in germ cell precursors from the 8-64 cell stage. By combining fast 4D confocal fluorescence imaging with gene-silencing and classical blastomere isolation experiments, we show that spindle repositioning mechanisms are active from prometaphase until anaphase, when furrowing is initiated in B5.2 cells. We show that the vegetal-most spindle pole/centrosome is attracted towards the CAB during prometaphase, causing the spindle to position asymmetrically near the cortex. Next, during anaphase, the opposite spindle pole/centrosome is attracted towards the border with neighbouring B5.1 blastomeres, causing the spindle to rotate (10°/minute) and migrate (3 μm/minute). Dynamic 4D fluorescence imaging of filamentous actin and plasma membrane shows that precise orientation of the cleavage furrow is determined by this second phase of rotational spindle displacement. Furthermore, in pairs of isolated B5.2 blastomeres, the second phase of rotational spindle displacement was lost. Finally, knockdown of PEM1, a protein localized in the CAB and required for unequal cleavage in B5.2 cells, completely randomizes spindle orientation. Together these data show that two separate mechanisms active during mitosis are responsible for spindle positioning, leading to precise orientation of the cleavage furrow during ACD in the cells that give rise to the germ lineage in ascidians.
Collapse
Affiliation(s)
- François Prodon
- Developmental Biology Unit UMR 7009, UPMC (University of Paris 06) and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Janet Chenevert
- Developmental Biology Unit UMR 7009, UPMC (University of Paris 06) and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Céline Hébras
- Developmental Biology Unit UMR 7009, UPMC (University of Paris 06) and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Rémi Dumollard
- Developmental Biology Unit UMR 7009, UPMC (University of Paris 06) and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Emmanuel Faure
- ISCPIF-CREA, Ecole Polytechnique–CNRS, 75015 Paris, France
| | - Jose Gonzalez-Garcia
- Department of Obstetrics and Gynaecology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Christian Sardet
- Developmental Biology Unit UMR 7009, UPMC (University of Paris 06) and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| | - Alex McDougall
- Developmental Biology Unit UMR 7009, UPMC (University of Paris 06) and Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
| |
Collapse
|
31
|
Sardet C, Roegiers F, Dumollard R, Rouviere C, McDougall A. Calcium waves and oscillations in eggs. Biophys Chem 2007; 72:131-40. [PMID: 17029706 DOI: 10.1016/s0301-4622(98)00129-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/16/1998] [Accepted: 02/13/1998] [Indexed: 11/24/2022]
Abstract
Eggs from several protostomes (molluscs, annelids, nemerteans, etc.) and two deuterostomes (mammals and ascidians) display repetitive calcium signals. Oscillations in the level of intracellular calcium concentration are occasionally triggered by maturing hormones (as in some molluscs) and mostly observed after fertilization which occurs at different stages of the meiotic cell cycle (oocytes are arrested in prophase, metaphase I or metaphase II). In most eggs examined so far, calcium oscillations last until the end of meiosis just before male and female pronuclei form. This ability depends on the sensitivity of InsP3 channels and on the permeability of the plasma membrane to extracellular calcium. In eggs that undergo cytoplasmic reorganization at fertilization (annelids, nemerteans, ascidians, etc.) the repetitive calcium signals are waves that originate from localized cortical sites that become calcium waves pacemakers. In ascidians we have identified the site of initiation of repetitive calcium waves as an accumulation of endoplasmic reticulum sandwiched between the plasma membrane and an accumulation of mitochondria. We compare and discuss the generation of calcium signals in the different eggs, their relationship with the cell cycle and the possible roles they play during development.
Collapse
Affiliation(s)
- C Sardet
- Unité de Biologie Cellulaire Marine, URA 671, CNRS/UPMC, Observatoire, Station Zoologique, 06230 Villefranche-sur-Mer, France.
| | | | | | | | | |
Collapse
|
32
|
Chambon JP, Nakayama A, Takamura K, McDougall A, Satoh N. ERK- and JNK-signalling regulate gene networks that stimulate metamorphosis and apoptosis in tail tissues of ascidian tadpoles. Development 2007; 134:1203-19. [PMID: 17332536 DOI: 10.1242/dev.002220] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In ascidian tadpoles, metamorphosis is triggered by a polarized wave of apoptosis, via mechanisms that are largely unknown. We demonstrate that the MAP kinases ERK and JNK are both required for the wave of apoptosis and metamorphosis. By employing a gene-profiling-based approach, we identified the network of genes controlled by either ERK or JNK activity that stimulate the onset of apoptosis. This approach identified a gene network involved in hormonal signalling, in innate immunity, in cell-cell communication and in the extracellular matrix. Through gene silencing, we show that Ci-sushi, a cell-cell communication protein controlled by JNK activity, is required for the wave of apoptosis that precedes tail regression. These observations lead us to propose a model of metamorphosis whereby JNK activity in the CNS induces apoptosis in several adjacent tissues that compose the tail by inducing the expression of genes such as Ci-sushi.
Collapse
Affiliation(s)
- Jean-Philippe Chambon
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
| | | | | | | | | |
Collapse
|
33
|
Levasseur M, Carroll M, Jones KT, McDougall A. A novel mechanism controls the Ca2+ oscillations triggered by activation of ascidian eggs and has an absolute requirement for Cdk1 activity. J Cell Sci 2007; 120:1763-71. [PMID: 17502483 DOI: 10.1242/jcs.003012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fertilisation in ascidians triggers a series of periodic rises in cytosolic Ca2+ that are essential for release from metaphase I arrest and progression through meiosis II. These sperm-triggered Ca2+ oscillations are switched off at exit from meiosis II. Ascidian zygotes provided the first demonstration of the positive feedback loop whereby elevated Cdk1 activity maintained these Ca2+ oscillations. Since then it has been reported that Cdk1 sensitises the type I inositol trisphosphate [Ins(1,4,5)P3] receptor in somatic cells, and that sperm-triggered Ca2+ oscillations in mouse zygotes stop because the forming pronuclei sequester phospholipase C zeta that was delivered to the egg by the fertilising sperm.Here, using enucleation, we demonstrate in ascidian eggs that Ca2+ spiking stops at the correct time in the absence of pronuclei. Sequestration of sperm factor is therefore not involved in terminating Ca2+ spiking for these eggs. Instead we found that microinjection of the Cdk1 inhibitor p21 blocked Ca2+ spiking induced by ascidian sperm extract (ASE). However, such eggs were still capable of releasing Ca2+ in response to Ins(1,4,5)P3 receptor agonists, indicating that ASE-triggered Ca2+ oscillations can stop even though the response to Ins(1,4,5)P3 remained elevated. These data suggest that Cdk1 activity promotes Ins(1,4,5)P3 production in the presence of the sperm factor, rather than sensitising the Ca2+ releasing machinery to Ins(1,4,5)P3. These findings suggest a new link between this cell cycle kinase and the Ins(1,4,5)P3 pathway.
Collapse
Affiliation(s)
- Mark Levasseur
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Newcastle upon Tyne, UK.
| | | | | | | |
Collapse
|
34
|
Parry H, McDougall A, Whitaker M. Endoplasmic reticulum generates calcium signalling microdomains around the nucleus and spindle in syncytial Drosophila embryos. Biochem Soc Trans 2006; 34:385-8. [PMID: 16709168 DOI: 10.1042/bst0340385] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cell cycle calcium signals are generated by inositol trisphosphate-mediated release of calcium from internal stores [Ciapa, Pesando, Wilding and Whitaker (1994) Nature (London) 368, 875–878; Groigno and Whitaker (1998) Cell 92, 193–204]. The major internal calcium store is the ER (endoplasmic reticulum): the spatial organization of the ER during mitosis is important in defining a microdomain around the nucleus and mitotic spindle in early Drosophila embryos [Parry, McDougall and Whitaker (2005) J. Cell Biol. 171, 47–59]. Nuclear divisions in syncytial Drosophila embryos are accompanied by both cortical and nuclear localized calcium transients. Mitosis is prevented by the InsP3 antagonists Xestospongin C and heparin. Nuclear-localized transients and cortical transients rely on extraembryonic calcium, suggesting that ER calcium levels are maintained by calcium influx.
Collapse
Affiliation(s)
- H Parry
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, UK
| | | | | |
Collapse
|
35
|
Abstract
Predator-induced defenses are well-known adaptive responses found in many marine and freshwater organisms. These responses usually occur in juveniles or actively growing adults and reduce the ability of a predator to consume its prey. We report a predator-induced response occurring in utero in the viviparid snail Bellamya chinensis (Gray, 1863) that results in significant changes in offspring number, shell size variability of released juveniles, and juvenile shell organic content. Water-borne cues derived from a predatory crayfish ( Orconectes limosus (Rafinesque, 1817)) induced a doubling of the number of offspring released; these newly born snails were generally smaller, though more variable in size, and possessed a greater shell organic content than controls. The generally smaller size of juveniles released in the presence of a predator reflects a faster rate of generation and passage through the uterus. These responses to the presence of a predator could be adaptive by decreasing predation pressure within a population or by reducing mortality following failed attacks.
Collapse
Affiliation(s)
- R.S. Prezant
- Department of Biology and Molecular Biology, College of Science and Mathematics, Montclair State University, Montclair, NJ 07043, USA
- Department of Mathematical Sciences, College of Science and Mathematics, Montclair State University, Montclair, NJ 07043, USA
| | - E.J. Chapman
- Department of Biology and Molecular Biology, College of Science and Mathematics, Montclair State University, Montclair, NJ 07043, USA
- Department of Mathematical Sciences, College of Science and Mathematics, Montclair State University, Montclair, NJ 07043, USA
| | - A. McDougall
- Department of Biology and Molecular Biology, College of Science and Mathematics, Montclair State University, Montclair, NJ 07043, USA
- Department of Mathematical Sciences, College of Science and Mathematics, Montclair State University, Montclair, NJ 07043, USA
| |
Collapse
|
36
|
Homer HA, McDougall A, Levasseur M, Murdoch AP, Herbert M. Mad2 is required for inhibiting securin and cyclin B degradation following spindle depolymerisation in meiosis I mouse oocytes. Reproduction 2006; 130:829-43. [PMID: 16322543 DOI: 10.1530/rep.1.00856] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mad2 is a pivotal component of the spindle assembly checkpoint (SAC) which inhibits anaphase promoting complex/cyclo-some (APC/C) activity by sequestering Cdc20 thereby regulating the destruction of securin and cyclin B. During mitosis, spindle depolymerisation induces a robust Mad2-dependent arrest due to inhibition of securin and cyclin B destruction. In contrast to mitosis, the molecular details underpinning the meiosis I arrest experienced by mouse oocytes exposed to spindle depolymerisation remain incompletely characterised. Notably, the role of Mad2 and the fate of the anaphase-marker, securin, are unexplored. As shown previously, we find that spindle depolymerisation by nocodazole inhibits first polar body extrusion (PBE) and stabilises cyclin B and cyclin-dependent kinase 1 activity in mouse oocytes. Here we show that stabilisation of cyclin B in nocodazole can be sustained for several hours and is associated with stabilisation of securin. These effects are SAC-mediated as, in oocytes depleted of the majority of Mad2 by morpholino antisense, securin and cyclin B are destabilised and 15% of oocytes undergo PBE. This reflects premature APC/C activation as a mutant form of cyclin B lacking its APC/C degradation signal is stable in Mad2-depleted oocytes. Moreover, homologues do not disjoin during the prolonged meiosis I arrest (> 18 h) induced by nocodaozole indicating that a non-cleavage mechanism is insufficient on its own for resolution of arm cohesion in mammalian oocytes. In conclusion, when all kinetochores lack attachment and tension, mouse oocytes mount a robust Mad2-dependent meiosis I arrest which inhibits the destruction of securin and cyclin B.
Collapse
Affiliation(s)
- Hayden A Homer
- Newcastle Fertility Centre at Life, International Centre for Life, Times Square, Newcastle upon Tyne, NE1 4EP, UK.
| | | | | | | | | |
Collapse
|
37
|
Abstract
Cell cycle calcium signals are generated by the inositol trisphosphate (InsP3)–mediated release of calcium from internal stores (Ciapa, B., D. Pesando, M. Wilding, and M. Whitaker. 1994. Nature. 368:875–878; Groigno, L., and M. Whitaker. 1998. Cell. 92:193–204). The major internal calcium store is the endoplasmic reticulum (ER); thus, the spatial organization of the ER during mitosis may be important in shaping and defining calcium signals. In early Drosophila melanogaster embryos, ER surrounds the nucleus and mitotic spindle during mitosis, offering an opportunity to determine whether perinuclear localization of ER conditions calcium signaling during mitosis. We establish that the nuclear divisions in syncytial Drosophila embryos are accompanied by both cortical and nuclear localized calcium transients. Constructs that chelate InsP3 also prevent nuclear division. An analysis of nuclear calcium concentrations demonstrates that they are differentially regulated. These observations demonstrate that mitotic calcium signals in Drosophila embryos are confined to mitotic microdomains and offer an explanation for the apparent absence of detectable global calcium signals during mitosis in some cell types.
Collapse
Affiliation(s)
- Huw Parry
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne Medical School, Newcastle upon Tyne NE2 4HH, England, UK
| | | | | |
Collapse
|
38
|
McDougall A, Elliott DJ, Hunter N. Pairing, connecting, exchanging, pausing and pulling chromosomes. EMBO Rep 2005; 6:120-5. [PMID: 15654318 PMCID: PMC1299241 DOI: 10.1038/sj.embor.7400331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Accepted: 12/02/2004] [Indexed: 11/09/2022] Open
Affiliation(s)
- Alex McDougall
- Biologie du Développement, UMR 7009 CNRS/Universite Pierre et Marie Curie (Paris VI), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France
- Tel: +00 33 493 76 3777; Fax: +00 33 493 76 3792;
| | - David J. Elliott
- Institute of Human Genetics, The International Centre for Life, Central Parkway, University of Newcastle Upon Tyne, Newcastle Upon Tyne NE1 3BZ, England
| | - Neil Hunter
- Center for Genetics and Development, Section of Microbiology, Division of Biological Sciences, UC Davis, One Shields Avenue, Davis, California 95616, USA
- Tel: +001 530 754 4401; Fax: +001 530 754 8973;
| |
Collapse
|
39
|
Homer HA, McDougall A, Levasseur M, Murdoch AP, Herbert M. RNA interference in meiosis I human oocytes: towards an understanding of human aneuploidy. ACTA ACUST UNITED AC 2005; 11:397-404. [PMID: 15908454 DOI: 10.1093/molehr/gah184] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although female meiosis I errors account for the majority of human aneuploidy, their molecular basis is largely unknown. By elucidating gene function, gene knockdown using RNA interference (RNAi) could shed light on this enigmatic process. In practice, however, the extreme paucity of immature human oocytes makes the evaluation of gene-targeting tools difficult. Here, we undertake RNAi in human oocytes and describe an approach employing mouse oocytes which could overcome the problem of limited biological material. We designed a short interfering RNA (siRNA) designated si539 to target the human mitotic arrest deficient 2 (hMad2) spindle checkpoint component. In human oocytes microinjected with si539, the hMad2 signal detected by Western blotting was 85-92% less intense than in oocytes injected with control siRNA indicating efficient silencing. Further examination of si539's targeting efficiency was undertaken using a green fluorescent protein (GFP)-tagged hMad2 mRNA construct in mouse oocytes. Consistent with Western blot analysis, si539 reduced hMad2-GFP expression in mouse oocytes by approximately 94% and relieved the meiosis I arrest otherwise induced by hMad2-GFP in mouse oocytes. By facilitating the investigation of candidate genes involved in regulating human female meiosis I, this approach can bring us closer to understanding the origins of aneuploidies such as Down's syndrome.
Collapse
Affiliation(s)
- Hayden A Homer
- Newcastle Fertility Centre at Life, International Centre for Life, Times Square, Newcastle upon Tyne NE1, UK.
| | | | | | | | | |
Collapse
|
40
|
Homer HA, McDougall A, Levasseur M, Yallop K, Murdoch AP, Herbert M. Mad2 prevents aneuploidy and premature proteolysis of cyclin B and securin during meiosis I in mouse oocytes. Genes Dev 2005; 19:202-7. [PMID: 15655110 PMCID: PMC545877 DOI: 10.1101/gad.328105] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In mitosis, the spindle checkpoint protein Mad2 averts aneuploidy by delaying anaphase onset until chromosomes align. Here we show that depletion of Mad2 in meiosis I mouse oocytes induced an increased incidence of aneuploidy. Proteolysis of cyclin B and securin commenced earlier in Mad2-depleted oocytes, resulting in a shortened duration of meiosis I. Furthermore, overexpression of Mad2 inhibited homolog disjunction. We conclude that Mad2 delays the onset of cyclin B and securin degradation and averts aneuploidy during meiosis I in mammalian oocytes. The data suggest a link between trisomies such as Down syndrome and defective oocyte spindle checkpoint function.
Collapse
Affiliation(s)
- Hayden A Homer
- Newcastle Fertility Centre at Life, Centre for Life, Newcastle upon Tyne NE1 4EP, United Kingdom.
| | | | | | | | | | | |
Collapse
|
41
|
Abstract
In mammalian somatic cells, the spindle assembly checkpoint (SAC) is indispensable for ensuring the fidelity of chromosome segregation by delaying cell-cycle progression in the face of even a single misaligned chromosome. In contrast, the role of the SAC in unperturbed mammalian oocytes is less well defined as progression through meiosis I is unaltered in mouse oocytes in the presence of one or a few misaligned chromosomes. Furthermore, attempts to disable the function of the SAC protein, Mad2, in mouse oocytes have produced conflicting results. To gain further insight into SAC function during female mammalian meiosis I, we recently utilised a morpholino-based antisense approach to deplete the majority of Mad2 in mouse oocytes. Our results define a clear role for Mad2 in ensuring the proper timing of meiosis I events and ultimately, in ensuring the fidelity of homologue disjunction. We discuss the implications of these results for the regulation of meiosis I in mammalian oocytes and for the genesis of human aneuploidy.
Collapse
Affiliation(s)
- Hayden A Homer
- Newcastle Fertility Centre at Life, Centre for Life, Times Square, Newcastle upon Tyne, UK.
| | | | | | | |
Collapse
|
42
|
Hyslop LA, Nixon VL, Levasseur M, Chapman F, Chiba K, McDougall A, Venables JP, Elliott DJ, Jones KT. Ca2+-promoted cyclin B1 degradation in mouse oocytes requires the establishment of a metaphase arrest. Dev Biol 2004; 269:206-19. [PMID: 15081368 DOI: 10.1016/j.ydbio.2004.01.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 01/22/2004] [Accepted: 01/27/2004] [Indexed: 02/05/2023]
Abstract
CDK1-cyclin B1 is a universal cell cycle kinase required for mitotic/meiotic cell cycle entry and its activity needs to decline for mitotic/meiotic exit. During their maturation, mouse oocytes proceed through meiosis I and arrest at second meiotic metaphase with high CDK1-cyclin B1 activity. Meiotic arrest is achieved by the action of a cytostatic factor (CSF), which reduces cyclin B1 degradation. Meiotic arrest is broken by a Ca2+ signal from the sperm that accelerates it. Here we visualised degradation of cyclin B1::GFP in oocytes and found that its degradation rate was the same for both meiotic divisions. Ca2+ was the necessary and sufficient trigger for cyclin B1 destruction during meiosis II; but it played no role during meiosis I and furthermore could not accelerate cyclin B1 destruction during this time. The ability of Ca2+ to trigger cyclin B1 destruction developed in oocytes following a restabilisation of cyclin B1 levels at about 12 h of culture. This was independent of actual first polar body extrusion. Thus, in metaphase I arrested oocytes, Ca2+ would induce cyclin B1 destruction and the first polar body would be extruded. In contrast to some reports in lower species, we found no evidence that oocyte activation was associated with an increase in 26S proteasome activity. We therefore conclude that Ca2+ mediates cyclin B1 degradation by increasing the activity of an E3 ubiquitin ligase. However, this stimulation occurs only in the presence of the ubiquitin ligase inhibitor CSF. We propose a model in which Ca2+ directly stimulates destruction of CSF during mammalian fertilisation.
Collapse
Affiliation(s)
- Louise A Hyslop
- Cell and Developmental Physiology Research Group, School of Cell and Molecular Biosciences, The Medical School, University of Newcastle, Newcastle NE2 4HH, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Herbert M, Levasseur M, Homer H, Yallop K, Murdoch A, McDougall A. Homologue disjunction in mouse oocytes requires proteolysis of securin and cyclin B1. Nat Cell Biol 2004; 5:1023-5. [PMID: 14593421 DOI: 10.1038/ncb1062] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Accepted: 09/12/2003] [Indexed: 01/09/2023]
Abstract
Disjunction of pairs of homologous chromosomes during the first meiotic division (MI) requires anaphase-promoting complex (APC)-mediated activation of separase in budding yeast and Caenorhabditis elegans, but not Xenopus laevis. It is not clear which model best fits the mammalian system. Here we show that homologue disjunction in mouse oocytes is dependent on proteolysis of the separase inhibitor securin and the Cdk1 regulatory sub-unit cyclin B1. Proteolysis of both proteins was entirely dependent on their conserved destruction box (D-box) motifs, through which they are targeted to the APC. These data indicate that the mechanisms regulating homologue disjunction in mammalian oocytes are similar to those of budding yeast and C.elegans.
Collapse
Affiliation(s)
- Mary Herbert
- Cell and Developmental Physiology Research Group, School of Surgical and Reproductive Sciences, Bioscience Centre, International Centre for Life, Times Square, Newcastle upon Tyne, NE1 4EP, UK.
| | | | | | | | | | | |
Collapse
|
44
|
Carroll M, Levasseur M, Wood C, Whitaker M, Jones KT, McDougall A. Exploring the mechanism of action of the sperm-triggered calcium-wave pacemaker in ascidian zygotes. J Cell Sci 2003; 116:4997-5004. [PMID: 14625393 DOI: 10.1242/jcs.00846] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In ascidians, as in mammals, sperm trigger repetitive Ca2+-waves that originate from cortical pacemakers situated in the vegetal hemisphere of the zygotes. In ascidians, a vegetal protrusion termed the contraction pole (CP) acts as the Ca2+-wave pacemaker, but the mechanism that underlies the generation of a Ca2+-wave pacemaker is not known. Here, we tested four hypotheses to determine which factors at the CP are involved in setting the pace of the ascidian Ca2+-wave pacemaker: (1) localized Ca2+ influx; (2) accumulation of phosphatidylinositol (4,5)bisphosphate [PtdIns(4,5)P2]; (3) accumulation of cortical endoplasmic reticulum (cER); and (4) enrichment of the sperm activating factor. We developed a method of dynamically monitoring the location of the CP during fertilization using a plekstrin homology (PH) domain from phospholipase Cδ1 coupled to green fluorescent protein (GFP) that binds PtdIns(4,5)P2. We found that eggs in Ca2+-free sea water displayed Ca2+ waves that originated from the CP, showing that enhanced CP Ca2+ influx does not determine the origin of the pacemaker. Also, disruption of the PH::GFP-labelled CP once it had formed did not dislodge the Ca2+-wave pacemaker from that site. Next, when we prevented the accumulation of cER at the CP, all of the Ca2+ waves came from the site of sperm-egg fusion and the frequency of Ca2+ oscillations was unaltered. These data show that local Ca2+ influx, the accumulation of PtdIns(4,5)P2 and cER at the CP are not required for Ca2+-wave pacemaker function and instead suggest that a factor associated with the sperm determines the site of the Ca2+-wave pacemaker. Finally, when we injected ascidian sperm extract into the centre of unfertilized ascidian eggs that had been treated with microfilament- and microtubule-disrupting drugs, all the Ca2+ waves still originated from near the plasma membrane, showing that the sperm factor does not require an intact cortex if it is enriched near the plasma membrane (PM). We suggest that the Ca2+-releasing sperm factor might be tethered near or on the PM and that following the cortical contraction, it is translocated to the vegetal CP, thus making that site act as a Ca2+-wave pacemaker.
Collapse
Affiliation(s)
- Michael Carroll
- Cell and Developmental Physiology Group, School of Cell and Molecular Biosciences, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
| | | | | | | | | | | |
Collapse
|
45
|
Levasseur M, McDougall A. Inositol 1,4,5-trisphosphate (IP3) responsiveness is regulated in a meiotic cell cycle dependent manner: implications for fertilization induced calcium signaling. Cell Cycle 2003; 2:610-3. [PMID: 14504479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
Fertilisation of mammalian eggs is known to trigger a series of transient rises in cytosolic calcium, known as calcium oscillations, the initiation and duration of which are crucial for meiotic exit and subsequent entry into embryogenesis. It is not known how these calcium oscillations are terminated when the zygote exits meiosis; it is thought that responsiveness to inositol 1,4,5-trisphosphate (IP3) is involved, since the oscillations are known to be mediated by an IP3 dependent mechanism. Here we report that IP3 responsiveness is maintained throughout meiotic maturation and falls very rapidly after meiotic exit. We also show that inhibition of the major cell cycle kinase, CDK1, has no effect on responsiveness, but that prolonging CDK1 activity prevents the decline in responsiveness normally seen at meiotic exit. We conclude that CDK1 plays a role, but is not the only factor involved in controlling IP3 responsiveness during the meiotic cell cycle.
Collapse
Affiliation(s)
- Mark Levasseur
- School of Cell and Molecular Biosciences, University of Newcastle, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH UK.
| | | |
Collapse
|
46
|
Nixon VL, Levasseur M, McDougall A, Jones KT. Ca(2+) oscillations promote APC/C-dependent cyclin B1 degradation during metaphase arrest and completion of meiosis in fertilizing mouse eggs. Curr Biol 2002; 12:746-50. [PMID: 12007419 DOI: 10.1016/s0960-9822(02)00811-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cyclin B1, the regulatory component of M phase-promoting factor (MPF), is degraded during the metaphase-anaphase transition in an anaphase-promoting complex/cyclosome (APC/C)-dependent process. MPF activity is stable in eggs, and a sperm-triggered Ca(2+) signal is needed to promote cyclin degradation. In frogs, a single Ca(2+) spike promotes cell cycle resumption, but, in mammals, the Ca(2+) signal is more complex, consisting of a series of spikes that stop several hours after sperm fusion. Using dual imaging in mouse eggs, we have examined how the Ca(2+) signal generates cyclin B1 destruction using destructible and nondestructible GFP-tagged constructs. APC/C activity was present in unfertilized eggs, giving cyclin B1 a half-life of 1.15 +/- 0.28 hr. However, APC/C-dependent cyclin degradation was elevated 6-fold when sperm raised cytosolic Ca(2+) levels above 600 nM. This activation was transitory since cyclin B1 levels recovered between Ca(2+) spikes. For continued cyclin degradation at basal Ca(2+) levels, multiple spikes were needed. APC/C-mediated degradation was observed until eggs had completed meiosis with the formation of pronuclei, and, at this time, Ca(2+) spikes stopped. Therefore, the physiological need for a repetitive Ca(2+) signal in mammals is to ensure long-term cyclin destruction during a protracted exit from meiosis.
Collapse
Affiliation(s)
- Victoria L Nixon
- Department of Physiological Sciences, The Medical School, Framlington Place, University of Newcastle, Newcastle NE2 4HH, United Kingdom
| | | | | | | |
Collapse
|
47
|
Hyslop LA, Carroll M, Nixon VL, McDougall A, Jones KT. Simultaneous Measurement of Intracellular Nitric Oxide and Free Calcium Levels in Chordate Eggs Demonstrates That Nitric Oxide Has No Role at Fertilization. Dev Biol 2001; 234:216-30. [PMID: 11356031 DOI: 10.1006/dbio.2001.0252] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
At fertilization in sea urchin, the free radical nitric oxide (NO) has recently been suggested to cause the intracellular Ca(2+) rise responsible for egg activation. The authors suggested that NO could be a universal activator of eggs and the present study was set up to test this hypothesis. Intracellular NO and Ca(2+) levels were monitored simultaneously in eggs of the mouse or the urochordate ascidian Ascidiella aspersa. Eggs were either fertilized or sperm extracts microinjected. Sperm-induced Ca(2+) rises were not associated with any global, or local, change in intracellular NO, although we were able to detect NO produced by the addition of a NO donor. Furthermore, the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester had no effect on sperm-induced Ca(2+) release but did block completely ionomycin-induced NO synthase activation. Therefore, we suggest that the current data provide evidence that NO has no role in the fertilization of these two chordate eggs.
Collapse
Affiliation(s)
- L A Hyslop
- Department of Physiological Sciences, The Medical School, Framlington Place, The University of Newcastle, Newcastle, NE2 4HH, England, UK
| | | | | | | | | |
Collapse
|
48
|
McDougall A, Levasseur M, O'Sullivan AJ, Jones KT. Cell cycle-dependent repetitive Ca(2+)waves induced by a cytosolic sperm extract in mature ascidian eggs mimic those observed at fertilization. J Cell Sci 2000; 113 Pt 19:3453-62. [PMID: 10984436 DOI: 10.1242/jcs.113.19.3453] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sperm-triggered Ca(2+) oscillations occur throughout the animal kingdom. The mechanism sperm use to trigger Ca(2+) oscillations at fertilization has not been resolved in any egg. The temporal, spatial and regulatory characteristics of the Ca(2+) oscillations during fertilization in ascidians offer a unique advantage over other systems for determining the mechanism of fertilization. For example, sperm trigger two phases of Ca(2+) oscillations that are all waves in ascidians. The first of these Ca(2+) waves begins at the point of sperm-egg fusion while a second phase of Ca(2+) waves originates at a vegetal protrusion termed the contraction pole. In addition, cyclin B1-dependent kinase activity provides a form of positive feedback, maintaining the second phase of Ca(2+) waves during meiosis and thereby ensuring meiotic exit. We therefore prepared cytosolic ascidian sperm extracts or MonoQ-fractionated ascidian sperm extracts from this urochordate to investigate if a Ca(2+)-releasing sperm-borne factor was responsible for egg activation. Spatially, ascidian sperm extract induced repetitive Ca(2+) waves that mimicked the spatial pattern displayed during fertilization: all the second-phase Ca(2+) waves originated at a vegetal protrusion termed the contraction pole (thus mimicking fertilisation). We also demonstrated that ascidian sperm extract-induced Ca(2+) oscillations were maintained when CDK activity was elevated and MAP kinase activity was low, as found previously for sperm-triggered Ca(2+) oscillations. As would be predicted, large doses of ascidian sperm extract injected into prophase-stage oocytes, lacking CDK activity, failed to induce any Ca(2+) release even though they responded to microinjection of the Ca(2+)-releasing second messenger inositol 1,4,5-trisphosphate. Finally, since the Ca(2+)-releasing activity from Mono-Q fractionated ascidian sperm extract eluted predominantly as one fraction, this may imply that one factor is responsible for the Ca(2+)-releasing activity. These data support a model of egg activation whereby the sperm introduces a Ca(2+)-releasing cytosolic factor into the egg. We demonstrated that ascidian sperm contain a protein factor(s) that is regulated by the egg CDK activity and can trigger all the Ca(2+)waves observed at fertilization with a spatial pattern that mimics those initiated by sperm.
Collapse
Affiliation(s)
- A McDougall
- Department of Physiological Sciences, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
| | | | | | | |
Collapse
|
49
|
McDougall A. Replaying a suicidal phone call. Nurs N Z 2000; 6:14-6. [PMID: 12012519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
|
50
|
Abstract
At fertilisation of mammalian and ascidian eggs the sperm induces a series of Ca2+ oscillations. These Ca2+ oscillations are triggered by a sperm-borne Ca2+-releasing factor whose identity is still unresolved. In both mammals and ascidians Ca2+ oscillations in eggs are associated with the period leading up to exit from meiosis and entry into the first embryonic cell cycle. Thus, in mammals Ca2+ oscillations continue for several hours but are complete by within 30 min in the ascidian. In mammals and ascidians Ca2+ oscillations stop at around the time when pronuclei form in the 1-cell embryo. There is evidence to show that cell cycle factors are important in regulating the fertilisation Ca2+ signal. If the formation of pronuclei is blocked either in mammals (by spindle disruption) or in ascidians (by clamping maturation promoting factor levels high) then Ca2+ oscillations continue indefinitely. Here, we explore the nature of the sperm Ca2+-releasing factor and examine the relationship between cell cycle resumption and the control of Ca2+ oscillations at fertilisation.
Collapse
Affiliation(s)
- V L Nixon
- Department of Physiological Sciences, The Medical School, University of Newcastle-upon-Tyne, UK.
| | | | | |
Collapse
|