1
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Merle T, Theis S, Kamgoué A, Martin E, Sarron F, Gay G, Farge E, Suzanne M. DISSECT is a tool to segment and explore cell and tissue mechanics in highly deformed 3D epithelia. Dev Cell 2023; 58:2181-2193.e4. [PMID: 37586367 DOI: 10.1016/j.devcel.2023.07.017] [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] [Received: 07/07/2022] [Revised: 03/17/2023] [Accepted: 07/24/2023] [Indexed: 08/18/2023]
Abstract
Understanding morphogenesis strongly relies on the characterization of tissue topology and mechanical properties deduced from imaging data. The development of new imaging techniques offers the possibility to go beyond the analysis of mostly flat surfaces and image and analyze complex tissue organization in depth. An important bottleneck in this field is the need to analyze imaging datasets and extract quantifications not only of cell and tissue morphology but also of the cytoskeletal network's organization in an automatized way. Here, we describe a method, called DISSECT, for DisPerSE (Discrete Persistent Structure Extractor)-based Segmentation and Exploration of Cells and Tissues, that offers the opportunity to extract automatically, in strongly deformed epithelia, a precise characterization of the spatial organization of a given cytoskeletal network combined with morphological quantifications in highly remodeled three-dimensional (3D) epithelial tissues. We believe that this method, applied here to Drosophila tissues, will be of general interest in the expanding field of morphogenesis and tissue biomechanics.
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Affiliation(s)
- Tatiana Merle
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
| | - Sophie Theis
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Alain Kamgoué
- Image Processing Facility, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Emmanuel Martin
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Florian Sarron
- IRAP, Institut de Recherche en Astrophysique et Planétologie, CNRS, 14 avenue E. Belin, 31400, Toulouse, France; Université de Toulouse, CNES, UPS-OMP, 14 avenue E. Belin, 31400 Toulouse, France
| | - Guillaume Gay
- Aix Marseille Université, Mutli-Engineering Platform, CENTURI, Marseille, France
| | - Emmanuel Farge
- Mechanics and Genetics of Embryonic Development group, Institut Curie, PSL Research University, CNRS, UMR168, Inserm, Marie Curie UnivParis 06, Institut Curie, 11 rue Pierre et Marie Curie, 75005 Paris, France
| | - Magali Suzanne
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
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2
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Ben Meriem Z, Mateo T, Faccini J, Denais C, Dusfour-Castan R, Guynet C, Merle T, Suzanne M, Di-Luoffo M, Guillermet-Guibert J, Alric B, Landiech S, Malaquin L, Mesnilgrente F, Laborde A, Mazenq L, Courson R, Delarue M. A microfluidic mechano-chemostat for tissues and organisms reveals that confined growth is accompanied with increased macromolecular crowding. Lab Chip 2023; 23:4445-4455. [PMID: 37740366 DOI: 10.1039/d3lc00313b] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Conventional culture conditions are oftentimes insufficient to study tissues, organisms, or 3D multicellular assemblies. They lack both dynamic chemical and mechanical control over the microenvironment. While specific microfluidic devices have been developed to address chemical control, they often do not allow the control of compressive forces emerging when cells proliferate in a confined environment. Here, we present a generic microfluidic device to control both chemical and mechanical compressive forces. This device relies on the use of sliding elements consisting of microfabricated rods that can be inserted inside a microfluidic device. Sliding elements enable the creation of reconfigurable closed culture chambers for the study of whole organisms or model micro-tissues. By confining the micro-tissues, we studied the biophysical impact of growth-induced pressure and showed that this mechanical stress is associated with an increase in macromolecular crowding, shedding light on this understudied type of mechanical stress. Our mechano-chemostat allows the long-term culture of biological samples and can be used to study both the impact of specific conditions as well as the consequences of mechanical compression.
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Affiliation(s)
| | - Tiphaine Mateo
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | - Julien Faccini
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | - Céline Denais
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | - Romane Dusfour-Castan
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, F-31000, Toulouse, France
| | - Catherine Guynet
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, F-31000, Toulouse, France
| | - Tatiana Merle
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Magali Suzanne
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Mickaël Di-Luoffo
- INSERM U1037, CRCT, Université de Toulouse, F-31037 Toulouse, France
| | - Julie Guillermet-Guibert
- INSERM U1037, CRCT, Université de Toulouse, F-31037 Toulouse, France
- Laboratoire d'Excellence TouCAN, F-31037 Toulouse, France
| | - Baptiste Alric
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | | | | | | | - Adrian Laborde
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | - Laurent Mazenq
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | | | - Morgan Delarue
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
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3
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Barbaste A, Schott S, Benassayag C, Suzanne M. Dissecting morphogenetic apoptosis through a genetic screen in Drosophila. Life Sci Alliance 2023; 6:e202301967. [PMID: 37495395 PMCID: PMC10372408 DOI: 10.26508/lsa.202301967] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/28/2023] Open
Abstract
Apoptosis is an essential cellular process both in normal development and pathological contexts. Screens performed to date have focused on the cell autonomous aspect of the process, deciphering the apoptotic cascade leading to cell destruction through the activation of caspases. However, the nonautonomous aspect of the apoptotic pathway, including signals regulating the apoptotic pattern or those sent by the apoptotic cell to its surroundings, is still poorly understood. Here, we describe an unbiased RNAi-based genetic screen whose goal is to identify elements of the "morphogenetic apoptosis pathway" in an integrated model system, the Drosophila leg. We screened about 1,400 candidates, using adult joint morphology, morphogenetic fold formation, and apoptotic pattern as readouts for the identification of potential apoptosis-related genes. We identified 41 genes potentially involved in specific aspects of morphogenetic apoptosis: (1) regulation of the apoptotic process; (2) formation, extrusion, and elimination of apoptotic bodies; and (3) contribution to morphogenesis downstream of apoptosis.
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Affiliation(s)
- Audrey Barbaste
- Laboratoire de Biologie Cellulaire et Moléculaire des Mécanismes du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Sonia Schott
- Laboratoire de Biologie Cellulaire et Moléculaire des Mécanismes du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Corinne Benassayag
- Laboratoire de Biologie Cellulaire et Moléculaire des Mécanismes du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Magali Suzanne
- Laboratoire de Biologie Cellulaire et Moléculaire des Mécanismes du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
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4
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Martin E, Suzanne M. mBeRFP: a versatile fluorescent tool to enhance multichannel live imaging and its applications. Development 2022; 149:276390. [DOI: 10.1242/dev.200495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 07/12/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Cell and developmental biology increasingly require live imaging of protein dynamics in cells, tissues or living organisms. Thanks to the discovery and development of a panel of fluorescent proteins over the last decades, live imaging has become a powerful and commonly used approach. However, multicolor live imaging remains challenging. The generation of long Stokes shift red fluorescent proteins offers interesting new perspectives to bypass this limitation. Here, we provide a detailed characterization of mBeRFP for in vivo live imaging and its applications in Drosophila. Briefly, we show that a single illumination source is sufficient to stimulate mBeRFP and GFP simultaneously. We demonstrate that mBeRFP can be easily combined with classical green and red fluorescent proteins without any crosstalk. We also show that the low photobleaching of mBeRFP is suitable for live imaging, and that this protein can be used for quantitative applications, such as FRAP or laser ablation. Finally, we believe that this fluorescent protein, with the set of new possibilities it offers, constitutes an important tool for cell, developmental and mechano-biologists in their current research.
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Affiliation(s)
- Emmanuel Martin
- Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS Molecular Cellular and Developmental Biology (MCD) , , 31000 Toulouse , France
| | - Magali Suzanne
- Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS Molecular Cellular and Developmental Biology (MCD) , , 31000 Toulouse , France
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5
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Suzanne M, Torres Sánchez M. Editorial overview: New insights into epithelial dynamics: From tissue homeostasis to morphogenesis. Curr Opin Genet Dev 2022; 75:101926. [PMID: 35714432 DOI: 10.1016/j.gde.2022.101926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Magali Suzanne
- Molecular, Cellular and Developmental Biology Unit (MCD), Center of Integrative Biology of Toulouse (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France.
| | - Miguel Torres Sánchez
- Cardiovascular Regeneration Program, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain.
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6
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Martin E, Suzanne M. Functions of Arp2/3 Complex in the Dynamics of Epithelial Tissues. Front Cell Dev Biol 2022; 10:886288. [PMID: 35557951 PMCID: PMC9089454 DOI: 10.3389/fcell.2022.886288] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
Epithelia are sheets of cells that communicate and coordinate their behavior in order to ensure their barrier function. Among the plethora of proteins involved in epithelial dynamics, actin nucleators play an essential role. The branched actin nucleation complex Arp2/3 has numerous functions, such as the regulation of cell-cell adhesion, intracellular trafficking, the formation of protrusions, that have been well described at the level of individual cells. Here, we chose to focus on its role in epithelial tissue, which is rising attention in recent works. We discuss how the cellular activities of the Arp2/3 complex drive epithelial dynamics and/or tissue morphogenesis. In the first part, we examined how this complex influences cell-cell cooperation at local scale in processes such as cell-cell fusion or cell corpses engulfment. In the second part, we summarized recent papers dealing with the impact of the Arp2/3 complex at larger scale, focusing on different morphogenetic events, including cell intercalation, epithelial tissue closure and epithelial folding. Altogether, this review highlights the central role of Arp2/3 in a diversity of epithelial tissue reorganization.
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Affiliation(s)
- Emmanuel Martin
- Molecular, Cellular and Developmental Biology (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Toulouse, France.,FR3743 Centre de Biologie Intégrative (CBI), Toulouse, France
| | - Magali Suzanne
- Molecular, Cellular and Developmental Biology (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Toulouse, France.,FR3743 Centre de Biologie Intégrative (CBI), Toulouse, France
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7
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Roellig D, Theis S, Proag A, Allio G, Bénazéraf B, Gros J, Suzanne M. Force-generating apoptotic cells orchestrate avian neural tube bending. Dev Cell 2022; 57:707-718.e6. [PMID: 35303434 PMCID: PMC8967407 DOI: 10.1016/j.devcel.2022.02.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 11/15/2021] [Accepted: 02/22/2022] [Indexed: 12/16/2022]
Abstract
Apoptosis plays an important role in morphogenesis, and the notion that apoptotic cells can impact their surroundings came to light recently. However, how this applies to vertebrate morphogenesis remains unknown. Here, we use the formation of the neural tube to determine how apoptosis contributes to morphogenesis in vertebrates. Neural tube closure defects have been reported when apoptosis is impaired in vertebrates, although the cellular mechanisms involved are unknown. Using avian embryos, we found that apoptotic cells generate an apico-basal force before being extruded from the neuro-epithelium. This force, which relies on a contractile actomyosin cable that extends along the apico-basal axis of the cell, drives nuclear fragmentation and influences the neighboring tissue. Together with the morphological defects observed when apoptosis is prevented, these data strongly suggest that the neuroepithelium keeps track of the mechanical impact of apoptotic cells and that the apoptotic forces, cumulatively, contribute actively to neural tube bending. Apoptotic cells are force-generating cells in the avian neural tube Apoptotic force drives the upward movement of the nucleus and nuclear fragmentation Apoptotic cells cumulatively impact the neighboring tissue Apoptotic force mechanical impact participates in progressive bending of the neural tube
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Affiliation(s)
- Daniela Roellig
- Centre de Biologie Intégrative, CNRS/UMR 5088, Université Toulouse III, Toulouse, France
| | - Sophie Theis
- Centre de Biologie Intégrative, CNRS/UMR 5088, Université Toulouse III, Toulouse, France; Morphogénie Logiciels, 32110 St Martin d'Armagnac, France
| | - Amsha Proag
- Centre de Biologie Intégrative, CNRS/UMR 5088, Université Toulouse III, Toulouse, France
| | - Guillaume Allio
- Centre de Biologie Intégrative, CNRS/UMR 5088, Université Toulouse III, Toulouse, France
| | - Bertrand Bénazéraf
- Centre de Biologie Intégrative, CNRS/UMR 5088, Université Toulouse III, Toulouse, France
| | - Jérôme Gros
- Institut Pasteur, CNRS/UMR 3738, Paris, France
| | - Magali Suzanne
- Centre de Biologie Intégrative, CNRS/UMR 5088, Université Toulouse III, Toulouse, France.
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8
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Font-Noguera M, Montemurro M, Benassayag C, Monier B, Suzanne M. Getting started for migration: A focus on EMT cellular dynamics and mechanics in developmental models. Cells Dev 2021; 168:203717. [PMID: 34245942 DOI: 10.1016/j.cdev.2021.203717] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/11/2021] [Accepted: 06/28/2021] [Indexed: 12/27/2022]
Abstract
The conversion of epithelial cells into mesenchymal ones, through a process known as epithelial-mesenchymal transition (or EMT) is a reversible process involved in critical steps of animal development as early as gastrulation and throughout organogenesis. In pathological conditions such as aggressive cancers, EMT is often associated with increased drug resistance, motility and invasiveness. The characterisation of the upstream signals and main decision takers, such as the EMT-transcription factors, has led to the identification of a core molecular machinery controlling the specification towards EMT. However, the cellular execution steps of this fundamental shift are poorly described, especially in cancerous cells. Here we review our current knowledge regarding the stepwise nature of EMT in model organisms as diverse as sea urchin, Drosophila, zebrafish, mouse or chicken. We focus on the cellular dynamics and mechanics of the transitional stages by which epithelial cells progressively become mesenchymal and leave the epithelium. We gather the currently available pieces of the puzzle, including the overlooked property of EMT cells to produce mechanical forces along their apico-basal axis before detaching from their neighbours. We discuss the interplay between EMT and the surrounding tissue. Finally, we propose a conceptual framework of EMT cell dynamics from the very first hint of epithelial cell reorganisation to the successful exit from the epithelial sheet.
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Affiliation(s)
- Meritxell Font-Noguera
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Marianne Montemurro
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Corinne Benassayag
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Bruno Monier
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Magali Suzanne
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France.
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9
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Mangeat T, Labouesse S, Allain M, Negash A, Martin E, Guénolé A, Poincloux R, Estibal C, Bouissou A, Cantaloube S, Vega E, Li T, Rouvière C, Allart S, Keller D, Debarnot V, Wang XB, Michaux G, Pinot M, Le Borgne R, Tournier S, Suzanne M, Idier J, Sentenac A. Super-resolved live-cell imaging using random illumination microscopy. Cell Rep Methods 2021; 1:100009. [PMID: 35474693 PMCID: PMC9017237 DOI: 10.1016/j.crmeth.2021.100009] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/12/2021] [Accepted: 04/08/2021] [Indexed: 12/11/2022]
Abstract
Current super-resolution microscopy (SRM) methods suffer from an intrinsic complexity that might curtail their routine use in cell biology. We describe here random illumination microscopy (RIM) for live-cell imaging at super-resolutions matching that of 3D structured illumination microscopy, in a robust fashion. Based on speckled illumination and statistical image reconstruction, easy to implement and user-friendly, RIM is unaffected by optical aberrations on the excitation side, linear to brightness, and compatible with multicolor live-cell imaging over extended periods of time. We illustrate the potential of RIM on diverse biological applications, from the mobility of proliferating cell nuclear antigen (PCNA) in U2OS cells and kinetochore dynamics in mitotic S. pombe cells to the 3D motion of myosin minifilaments deep inside Drosophila tissues. RIM's inherent simplicity and extended biological applicability, particularly for imaging at increased depths, could help make SRM accessible to biology laboratories.
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Affiliation(s)
- Thomas Mangeat
- LITC Core Facility, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Simon Labouesse
- Institut Fresnel, Aix Marseille Université, CNRS, Centrale Marseille, Marseille, France
| | - Marc Allain
- Institut Fresnel, Aix Marseille Université, CNRS, Centrale Marseille, Marseille, France
| | - Awoke Negash
- Institut Fresnel, Aix Marseille Université, CNRS, Centrale Marseille, Marseille, France
| | - Emmanuel Martin
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Aude Guénolé
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Renaud Poincloux
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Claire Estibal
- LITC Core Facility, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Anaïs Bouissou
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Sylvain Cantaloube
- LITC Core Facility, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Elodie Vega
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Tong Li
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Christian Rouvière
- LITC Core Facility, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Sophie Allart
- INSERM Université de Toulouse, UPS, CNRS, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Debora Keller
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Valentin Debarnot
- LITC Core Facility, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Xia Bo Wang
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Grégoire Michaux
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) - UMR 6290, 35000 Rennes, France
| | - Mathieu Pinot
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) - UMR 6290, 35000 Rennes, France
| | - Roland Le Borgne
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) - UMR 6290, 35000 Rennes, France
| | - Sylvie Tournier
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Magali Suzanne
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Jérome Idier
- LS2N, CNRS UMR 6004, 1 rue de la Noë, F44321 Nantes Cedex 3, France
| | - Anne Sentenac
- Institut Fresnel, Aix Marseille Université, CNRS, Centrale Marseille, Marseille, France
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10
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Martin E, Theis S, Gay G, Monier B, Rouvière C, Suzanne M. Arp2/3-dependent mechanical control of morphogenetic robustness in an inherently challenging environment. Dev Cell 2021; 56:687-701.e7. [PMID: 33535069 PMCID: PMC7955168 DOI: 10.1016/j.devcel.2021.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 10/23/2020] [Accepted: 01/08/2021] [Indexed: 12/21/2022]
Abstract
Epithelial sheets undergo highly reproducible remodeling to shape organs. This stereotyped morphogenesis depends on a well-defined sequence of events leading to the regionalized expression of developmental patterning genes that finally triggers downstream mechanical forces to drive tissue remodeling at a pre-defined position. However, how tissue mechanics controls morphogenetic robustness when challenged by intrinsic perturbations in close proximity has never been addressed. Using Drosophila developing leg, we show that a bias in force propagation ensures stereotyped morphogenesis despite the presence of mechanical noise in the environment. We found that knockdown of the Arp2/3 complex member Arpc5 specifically affects fold directionality while altering neither the developmental nor the force generation patterns. By combining in silico modeling, biophysical tools, and ad hoc genetic tools, our data reveal that junctional myosin II planar polarity favors long-range force channeling and ensures folding robustness, avoiding force scattering and thus isolating the fold domain from surrounding mechanical perturbations. Drosophila developing leg folding is extremely robust Fold orientation becomes variable in Arp2/3 knockdown condition Arp2/3 controls junctional myosin II planar polarity Myosin II planar polarity ensures fold robustness through force channeling
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Affiliation(s)
- Emmanuel Martin
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Sophie Theis
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France; Morphogénie Logiciels, 32110 St Martin d'Armagnac, France
| | - Guillaume Gay
- Morphogénie Logiciels, 32110 St Martin d'Armagnac, France; Turing Center For Living Systems, Aix-MarseilleUniversity, 13009, Marseille, France.
| | - Bruno Monier
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Christian Rouvière
- Image Processing Facility, Center of Integrative Biology (CBI), Université de Toulouse, CNRS, UPS, France
| | - Magali Suzanne
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France.
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11
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Abstract
How the high degree of shape reproducibility is conferred between individuals remains unclear. In this issue of Developmental Cell, Eritano et al. show that tissue-scale mechanical coupling corrects the intrinsic noise of gene expression pattern and tissue mechanics to ensure the high degree of precision of Drosophila cephalic furrow formation.
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Affiliation(s)
- Emmanuel Martin
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
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12
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Fouchard J, Wyatt TPJ, Proag A, Lisica A, Khalilgharibi N, Recho P, Suzanne M, Kabla A, Charras G. Curling of epithelial monolayers reveals coupling between active bending and tissue tension. Proc Natl Acad Sci U S A 2020; 117:9377-9383. [PMID: 32284424 PMCID: PMC7196817 DOI: 10.1073/pnas.1917838117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [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] [Indexed: 01/09/2023] Open
Abstract
Epithelial monolayers are two-dimensional cell sheets which compartmentalize the body and organs of multicellular organisms. Their morphogenesis during development or pathology results from patterned endogenous and exogenous forces and their interplay with tissue mechanical properties. In particular, bending of epithelia is thought to result from active torques generated by the polarization of myosin motors along their apicobasal axis. However, the contribution of these out-of-plane forces to morphogenesis remains challenging to evaluate because of the lack of direct mechanical measurement. Here we use epithelial curling to characterize the out-of-plane mechanics of epithelial monolayers. We find that curls of high curvature form spontaneously at the free edge of epithelial monolayers devoid of substrate in vivo and in vitro. Curling originates from an enrichment of myosin in the basal domain that generates an active spontaneous curvature. By measuring the force necessary to flatten curls, we can then estimate the active torques and the bending modulus of the tissue. Finally, we show that the extent of curling is controlled by the interplay between in-plane and out-of-plane stresses in the monolayer. Such mechanical coupling emphasizes a possible role for in-plane stresses in shaping epithelia during morphogenesis.
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Affiliation(s)
- Jonathan Fouchard
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Tom P J Wyatt
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Amsha Proag
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, CNRS, Université Toulouse III Paul Sabatier, Université de Toulouse, 31062 Toulouse, France
| | - Ana Lisica
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Nargess Khalilgharibi
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Pierre Recho
- Department of Engineering, Cambridge University, Cambridge CB2 1PZ, United Kingdom
- Laboratoire Interdisciplinaire de Physique, CNRS, Université Grenoble Alpes, F-38000 Grenoble, France
| | - Magali Suzanne
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, CNRS, Université Toulouse III Paul Sabatier, Université de Toulouse, 31062 Toulouse, France
| | - Alexandre Kabla
- Department of Engineering, Cambridge University, Cambridge CB2 1PZ, United Kingdom;
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom;
- Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
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13
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Gracia M, Theis S, Proag A, Gay G, Benassayag C, Suzanne M. Mechanical impact of epithelial-mesenchymal transition on epithelial morphogenesis in Drosophila. Nat Commun 2019; 10:2951. [PMID: 31273212 PMCID: PMC6609679 DOI: 10.1038/s41467-019-10720-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [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: 11/07/2018] [Accepted: 05/28/2019] [Indexed: 12/20/2022] Open
Abstract
Epithelial-mesenchymal transition (EMT) is an essential process both in physiological and pathological contexts. Intriguingly, EMT is often associated with tissue invagination during development; however, the impact of EMT on tissue remodeling remain unexplored. Here, we show that at the initiation of the EMT process, cells produce an apico-basal force, orthogonal to the surface of the epithelium, that constitutes an important driving force for tissue invagination in Drosophila. When EMT is ectopically induced, cells starting their delamination generate an orthogonal force and induce ectopic folding. Similarly, during mesoderm invagination, cells undergoing EMT generate an apico-basal force through the formation of apico-basal structures of myosin II. Using both laser microdissection and in silico physical modelling, we show that mesoderm invagination does not proceed if apico-basal forces are impaired, indicating that they constitute driving forces in the folding process. Altogether, these data reveal the mechanical impact of EMT on morphogenesis.
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Affiliation(s)
- Mélanie Gracia
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Sophie Theis
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.,Morphogénie Logiciels, 32110, St Martin d'Armagnac, France
| | - Amsha Proag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Guillaume Gay
- Morphogénie Logiciels, 32110, St Martin d'Armagnac, France.
| | - Corinne Benassayag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.
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14
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Ambrosini A, Rayer M, Monier B, Suzanne M. Mechanical Function of the Nucleus in Force Generation during Epithelial Morphogenesis. Dev Cell 2019; 50:197-211.e5. [PMID: 31204174 PMCID: PMC6658619 DOI: 10.1016/j.devcel.2019.05.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/11/2019] [Accepted: 05/10/2019] [Indexed: 12/21/2022]
Abstract
Mechanical forces are critical regulators of cell shape changes and developmental morphogenetic processes. Forces generated along the epithelium apico-basal cell axis have recently emerged as essential for tissue remodeling in three dimensions. Yet the cellular machinery underlying those orthogonal forces remains poorly described. We found that during Drosophila leg folding cells eventually committed to die produce apico-basal forces through the formation of a dynamic actomyosin contractile tether connecting the apical surface to a basally relocalized nucleus. We show that the nucleus is anchored to basal adhesions by a basal F-actin network and constitutes an essential component of the force-producing machinery. Finally, we demonstrate force transmission to the apical surface and the basal nucleus by laser ablation. Thus, this work reveals that the nucleus, in addition to its role in genome protection, actively participates in mechanical force production and connects the contractile actomyosin cytoskeleton to basal adhesions.
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Affiliation(s)
- Arnaud Ambrosini
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Mégane Rayer
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Bruno Monier
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, 31062 Toulouse, France.
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, 31062 Toulouse, France.
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15
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Proag A, Monier B, Suzanne M. Physical and functional cell-matrix uncoupling in a developing tissue under tension. Development 2019; 146:dev.172577. [PMID: 31064785 PMCID: PMC6589077 DOI: 10.1242/dev.172577] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 04/26/2019] [Indexed: 01/02/2023]
Abstract
Tissue mechanics play a crucial role in organ development. They rely on the properties of cells and the extracellular matrix (ECM), but the relative physical contribution of cells and ECM to morphogenesis is poorly understood. Here, we have analyzed the behavior of the peripodial epithelium (PE) of the Drosophila leg disc in the light of the dynamics of its cellular and ECM components. The PE undergoes successive changes during leg development, including elongation, opening and removal to free the leg. During elongation, we found that the ECM and cell layer are progressively uncoupled. Concomitantly, the tension, mainly borne by the ECM at first, builds up in the cell monolayer. Then, each layer of the peripodial epithelium is removed by an independent mechanism: while the ECM layer withdraws following local proteolysis, cellular monolayer withdrawal is independent of ECM degradation and is driven by myosin II-dependent contraction. These results reveal a surprising physical and functional cell-matrix uncoupling in a monolayer epithelium under tension during development. This article has an associated ‘The people behind the papers’ interview. Highlighted Article: The independent behavior of extracellular matrix and cell monolayer of an epithelium under tension during Drosophila leg development highlights the interplay between tissue mechanics and cell-matrix coupling.
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Affiliation(s)
- Amsha Proag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Bruno Monier
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
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16
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Schott S, Ambrosini A, Barbaste A, Benassayag C, Gracia M, Proag A, Rayer M, Monier B, Suzanne M. A fluorescent toolkit for spatiotemporal tracking of apoptotic cells in living Drosophila tissues. Development 2017; 144:3840-3846. [PMID: 28870988 DOI: 10.1242/dev.149807] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [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: 01/31/2017] [Accepted: 08/29/2017] [Indexed: 02/01/2023]
Abstract
Far from being passive, apoptotic cells influence their environment. For example, they promote tissue folding, myoblast fusion and modulate tumor growth. Understanding the role of apoptotic cells necessitates their efficient tracking within living tissues, a task that is currently challenging. In order to easily spot apoptotic cells in developing Drosophila tissues, we generated a series of fly lines expressing different fluorescent sensors of caspase activity. We show that three of these reporters (GFP-, Cerulean- and Venus-derived molecules) are detected specifically in apoptotic cells and throughout the whole process of programmed cell death. These reporters allow the specific visualization of apoptotic cells directly within living tissues, without any post-acquisition processing. They overcome the limitations of other apoptosis detection methods developed so far and, notably, they can be combined with any kind of fluorophore.
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Affiliation(s)
- Sonia Schott
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Arnaud Ambrosini
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Audrey Barbaste
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Corinne Benassayag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Mélanie Gracia
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Amsha Proag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Mégane Rayer
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Bruno Monier
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS/UPS, 118 route de Narbonne, 31062 Toulouse, France
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17
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Suzanne M, Monier B, Gettings M, Ambrosini A, Gracia M, Mangeat T, Schott S, Gay G. Apoptotic forces in tissue morphogenesis. Mech Dev 2017. [DOI: 10.1016/j.mod.2017.04.230] [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: 10/19/2022]
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18
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Suzanne M. Molecular and cellular mechanisms involved in leg joint morphogenesis. Semin Cell Dev Biol 2016; 55:131-8. [DOI: 10.1016/j.semcdb.2016.01.032] [Citation(s) in RCA: 9] [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] [Received: 12/15/2015] [Accepted: 01/22/2016] [Indexed: 01/09/2023]
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19
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Anais Tiberghien M, Lebreton G, Cribbs D, Benassayag C, Suzanne M. The Hox gene Dfd controls organogenesis by shaping territorial border through regulation of basal DE-Cadherin distribution. Dev Biol 2015. [PMID: 26206615 DOI: 10.1016/j.ydbio.2015.07.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [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: 01/07/2023]
Abstract
Hox genes are highly conserved selector genes controlling tissue identity and organogenesis. Recent work indicates that Hox genes also controls cell segregation and segmental boundary in various species, however the underlying cellular mechanisms involved in this function are poorly understood. In Drosophila melanogaster, the Hox gene Deformed (Dfd) is required for specification and organogenesis of the adult Maxillary (Mx) palp. Here, we demonstrate that differential Dfd expression control Mx morphogenesis through the formation of a physical boundary separating the Mx field and the Peripodial Epithelium (PE). We show that this boundary relies on DE-cadherin (DE-cad) basal accumulation in Mx cells controlled by differential Dfd expression. Indeed, Dfd controls boundary formation through cell autonomous basal redistribution of DE-cad which leads to subsequent fold at the Dfd expression border. Finally, the loss of Mx DE-cad basal accumulation and hence of Mx-PE folding is sufficient to prevent Mx organogenesis thus revealing the crucial role of boundaries in organ differentiation. Altogether, these results reveal that Hox coordination of tissue morphogenesis relies on boundary fold formation through the modulation of DE-cad positioning.
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Affiliation(s)
- Marie Anais Tiberghien
- LBCMCP, Université Paul Sabatier, CNRS UMR 5088 Bâtiment 4R3-B1, 118 Route de Narbonne, 31062 Toulouse cedex, France
| | - Gaelle Lebreton
- IBV-Institut de Biologie Valrose, Bâtiment de biochimie, Université Nice Sophia Antipolis, Parc Valrose, 06108 Nice cedex, France
| | - David Cribbs
- CBD, Université Paul Sabatier, UMR5547 Batiment 4R3-B3, 118 Route de Narbonne, 31062 Toulouse cedex, France
| | - Corinne Benassayag
- LBCMCP, Université Paul Sabatier, CNRS UMR 5088 Bâtiment 4R3-B1, 118 Route de Narbonne, 31062 Toulouse cedex, France.
| | - Magali Suzanne
- LBCMCP, Université Paul Sabatier, CNRS UMR 5088 Bâtiment 4R3-B1, 118 Route de Narbonne, 31062 Toulouse cedex, France
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20
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Monier B, Gettings M, Gay G, Mangeat T, Schott S, Guarner A, Suzanne M. [The last surge of dying cells, a key stage during the tissular morphogenesis]. Med Sci (Paris) 2015; 31:475-7. [PMID: 26059294 DOI: 10.1051/medsci/20153105005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Bruno Monier
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Melanie Gettings
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Guillaume Gay
- DamCB, Data Analysis and Modelling for Cell Biology, 13005 Marseille, France
| | - Thomas Mangeat
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Sonia Schott
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Ana Guarner
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera 1, Cantoblanco, 28049 Madrid, Espagne
| | - Magali Suzanne
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
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21
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Monier B, Gettings M, Gay G, Mangeat T, Schott S, Guarner A, Suzanne M. Apico-basal forces exerted by apoptotic cells drive epithelium folding. Nature 2015; 518:245-8. [PMID: 25607361 DOI: 10.1038/nature14152] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/09/2014] [Indexed: 12/29/2022]
Abstract
Epithelium folding is a basic morphogenetic event that is essential in transforming simple two-dimensional epithelial sheets into three-dimensional structures in both vertebrates and invertebrates. Folding has been shown to rely on apical constriction. The resulting cell-shape changes depend either on adherens junction basal shift or on a redistribution of myosin II, which could be driven by mechanical signals. Yet the initial cellular mechanisms that trigger and coordinate cell remodelling remain largely unknown. Here we unravel the active role of apoptotic cells in initiating morphogenesis, thus revealing a novel mechanism of epithelium folding. We show that, in a live developing tissue, apoptotic cells exert a transient pulling force upon the apical surface of the epithelium through a highly dynamic apico-basal myosin II cable. The apoptotic cells then induce a non-autonomous increase in tissue tension together with cortical myosin II apical stabilization in the surrounding tissue, eventually resulting in epithelium folding. Together our results, supported by a theoretical biophysical three-dimensional model, identify an apoptotic myosin-II-dependent signal as the initial signal leading to cell reorganization and tissue folding. This work further reveals that, far from being passively eliminated as generally assumed (for example, during digit individualization), apoptotic cells actively influence their surroundings and trigger tissue remodelling through regulation of tissue tension.
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Affiliation(s)
- Bruno Monier
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Melanie Gettings
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Guillaume Gay
- DamCB, Data Analysis and Modelling for Cell Biology, 13005 Marseille, France
| | - Thomas Mangeat
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Sonia Schott
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Ana Guarner
- Centro de Biología Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, Nicolás Cabrera 1, Cantoblanco, 28049 Madrid, Spain
| | - Magali Suzanne
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
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22
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Petzoldt AG, Coutelis JB, Géminard C, Spéder P, Suzanne M, Cerezo D, Noselli S. DE-Cadherin regulates unconventional Myosin ID and Myosin IC in Drosophila left-right asymmetry establishment. Development 2012; 139:1874-84. [DOI: 10.1242/dev.047589] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [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
In bilateria, positioning and looping of visceral organs requires proper left-right (L/R) asymmetry establishment. Recent work in Drosophila has identified a novel situs inversus gene encoding the unconventional type ID myosin (MyoID). In myoID mutant flies, the L/R axis is inverted, causing reversed looping of organs, such as the gut, spermiduct and genitalia. We have previously shown that MyoID interacts physically with β-Catenin, suggesting a role of the adherens junction in Drosophila L/R asymmetry. Here, we show that DE-Cadherin co-immunoprecipitates with MyoID and is required for MyoID L/R activity. We further demonstrate that MyoIC, a closely related unconventional type I myosin, can antagonize MyoID L/R activity by preventing its binding to adherens junction components, both in vitro and in vivo. Interestingly, DE-Cadherin inhibits MyoIC, providing a protective mechanism to MyoID function. Conditional genetic experiments indicate that DE-Cadherin, MyoIC and MyoID show temporal synchronicity for their function in L/R asymmetry. These data suggest that following MyoID recruitment by β-Catenin at the adherens junction, DE-Cadherin has a twofold effect on Drosophila L/R asymmetry by promoting MyoID activity and repressing that of MyoIC. Interestingly, the product of the vertebrate situs inversus gene inversin also physically interacts with β-Catenin, suggesting that the adherens junction might serve as a conserved platform for determinants to establish L/R asymmetry both in vertebrates and invertebrates.
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Affiliation(s)
- Astrid G. Petzoldt
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
- Center for Biological Systems Analysis, University of Freiburg; Habsburger Str. 49, 78104 Freiburg, Germany
| | - Jean-Baptiste Coutelis
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
| | - Charles Géminard
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
| | - Pauline Spéder
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
- The Gurdon Institute; University of Cambridge; Tennis Court Road, Cambridge CB2 1QN, United Kingdom
| | - Magali Suzanne
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
- Laboratory of Cellular and Molecular Biology of Cell Proliferation (LBCMCP) UMR5088, University Paul Sabatier, 31062 Toulouse, France
| | - Delphine Cerezo
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
| | - Stéphane Noselli
- Institute of Biology Valrose, University of Nice Sophia-Antipolis, UMR7277-CNRS, UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
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24
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Petzoldt AG, Coutelis JB, Géminard C, Spéder P, Suzanne M, Cerezo D, Noselli S. DE-Cadherin regulates unconventional Myosin ID and Myosin IC in Drosophila left-right asymmetry establishment. J Cell Sci 2012. [DOI: 10.1242/jcs.112862] [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
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25
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Patricia C, Colin O, Suzanne M. 01 War and peace? strategies by emergency care practitioners to integrate into health care teams in the UK. Arch Emerg Med 2011. [DOI: 10.1136/emj.2010.108597.1] [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: 11/04/2022]
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26
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Patricia C, Colin O, Suzanne M. 01 War and peace? strategies by emergency care practitioners to integrate into health care teams in the UK. Arch Emerg Med 2011. [DOI: 10.1136/emj.2010.108605.1] [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: 11/04/2022]
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27
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Suzanne M, Petzoldt AG, Spéder P, Coutelis JB, Steller H, Noselli S. Coupling of apoptosis and L/R patterning controls stepwise organ looping. Curr Biol 2010; 20:1773-8. [PMID: 20832313 DOI: 10.1016/j.cub.2010.08.056] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 08/25/2010] [Accepted: 08/25/2010] [Indexed: 10/19/2022]
Abstract
Handed asymmetry in organ shape and positioning is a common feature among bilateria, yet little is known about the morphogenetic mechanisms underlying left-right (LR) organogenesis. We utilize the directional 360° clockwise rotation of genitalia in Drosophila to study LR-dependent organ looping. Using time-lapse imaging, we show that rotation of genitalia by 360° results from an additive process involving two ring-shaped domains, each undergoing 180° rotation. Our results show that the direction of rotation for each ring is autonomous and strictly depends on the LR determinant myosin ID (MyoID). Specific inactivation of MyoID in one domain causes rings to rotate in opposite directions and thereby cancels out the overall movement. We further reveal a specific pattern of apoptosis at the ring boundaries and show that local cell death is required for the movement of each domain, acting as a brake-releaser. These data indicate that organ looping can proceed through an incremental mechanism coupling LR determination and apoptosis. Furthermore, they suggest a model for the stepwise evolution of genitalia posture in Diptera, through the emergence and duplication of a 180° LR module.
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Affiliation(s)
- Magali Suzanne
- University of Nice Sophia-Antipolis, CNRS, Institute of Developmental Biology and Cancer, Parc Valrose, 06108 Nice Cedex 2, France
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Rousset R, Bono-Lauriol S, Gettings M, Suzanne M, Spéder P, Noselli S. The Drosophila serine protease homologue Scarface regulates JNK signalling in a negative-feedback loop during epithelial morphogenesis. Development 2010; 137:2177-86. [PMID: 20530545 DOI: 10.1242/dev.050781] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In Drosophila melanogaster, dorsal closure is a model of tissue morphogenesis leading to the dorsal migration and sealing of the embryonic ectoderm. The activation of the JNK signal transduction pathway, specifically in the leading edge cells, is essential to this process. In a genome-wide microarray screen, we identified new JNK target genes during dorsal closure. One of them is the gene scarface (scaf), which belongs to the large family of trypsin-like serine proteases. Some proteins of this family, like Scaf, bear an inactive catalytic site, representing a subgroup of serine protease homologues (SPH) whose functions are poorly understood. Here, we show that scaf is a general transcriptional target of the JNK pathway coding for a secreted SPH. scaf loss-of-function induces defects in JNK-controlled morphogenetic events such as embryonic dorsal closure and adult male terminalia rotation. Live imaging of the latter process reveals that, like for dorsal closure, JNK directs the dorsal fusion of two epithelial layers in the pupal genital disc. Genetic data show that scaf loss-of-function mimics JNK over-activity. Moreover, scaf ectopic expression aggravates the effect of the JNK negative regulator puc on male genitalia rotation. We finally demonstrate that scaf acts as an antagonist by negatively regulating JNK activity. Overall, our results identify the SPH-encoding gene scaf as a new transcriptional target of JNK signalling and reveal the first secreted regulator of the JNK pathway acting in a negative-feedback loop during epithelial morphogenesis.
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Affiliation(s)
- Raphaël Rousset
- University of Nice Sophia-Antipolis, UMR 6543 CNRS, Institute of Developmental Biology and Cancer, Parc Valrose, 06108 Nice CEDEX2, France
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Petzoldt AG, Coutelis JB, Spéder P, Suzanne M, Noselli S. GR-04 A novel regulatory network of left–right asymmetry establishment in Drosophila melanogaster: Interaction between the unconventional myosins ID and IC and the adherens junction component DE-cadherin. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.944] [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: 11/28/2022]
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30
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Abstract
Apoptosis appears to be a carefully orchestrated process for the ordered dismantling of cells. A recent paper in BMC Developmental Biology shows that the disassembly of adherens junctions during apoptosis in Drosophila is progressive and requires the amino-terminal cleavage of the β-catenin Armadillo by the apoptotic effector caspase DrICE.
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Affiliation(s)
- Magali Suzanne
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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31
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Coutelis JB, Petzoldt AG, Spéder P, Suzanne M, Noselli S. Left-right asymmetry in Drosophila. Semin Cell Dev Biol 2008; 19:252-62. [PMID: 18328746 DOI: 10.1016/j.semcdb.2008.01.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 12/11/2007] [Accepted: 01/23/2008] [Indexed: 01/22/2023]
Abstract
Seminal studies of left-right (L/R) patterning in vertebrate models have led to the discovery of roles for the nodal pathway, ion flows and cilia in this process. Although the molecular mechanisms underlying L/R asymmetries seen in protostomes are less well understood, recent work using Drosophila melanogaster as a novel genetic model system to study this process has identified a number of mutations affecting directional organ looping. The genetic analysis of this, the most evolutionary conserved feature of L/R patterning, revealed the existence of a L/R pathway that involves the actin cytoskeleton and an associated type I myosin. In this review, we describe this work in the context of Drosophila development, and discuss the implications of these results for our understanding of L/R patterning in general.
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Affiliation(s)
- J B Coutelis
- Institute of Developmental Biology & Cancer, University of Nice Sophia-Antipolis, CNRS UMR6543, Parc Valrose, 06108 NICE Cedex 2, France
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Spéder P, Petzoldt A, Suzanne M, Noselli S. Strategies to establish left/right asymmetry in vertebrates and invertebrates. Curr Opin Genet Dev 2007; 17:351-8. [PMID: 17643981 DOI: 10.1016/j.gde.2007.05.008] [Citation(s) in RCA: 78] [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] [Received: 04/30/2007] [Revised: 05/18/2007] [Accepted: 05/22/2007] [Indexed: 10/23/2022]
Abstract
Left/right (L/R) asymmetry is essential during embryonic development for organ positioning, looping and handed morphogenesis. A major goal in the field is to understand how embryos initially determine their left and right hand sides, a process known as symmetry breaking. A number of recent studies on several vertebrate and invertebrate model organisms have provided a more complex view on how L/R asymmetry is established, revealing an apparent partition between deuterostomes and protostomes. In deuterostomes, nodal cilia represent a conserved symmetry-breaking process; nevertheless, growing evidence shows the existence of pre-cilia L/R asymmetries involving active ion flows. In protostomes like snails and Drosophila, symmetry breaking relies on different mechanisms, involving, in particular, the actin cytoskeleton and associated molecular motors.
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Affiliation(s)
- Pauline Spéder
- ISBDC, University of Nice Sophia-Antipolis, CNRS, Parc Valrose, 06108 NICE Cedex 2, France
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Manjón C, Sánchez-Herrero E, Suzanne M. Sharp boundaries of Dpp signalling trigger local cell death required for Drosophila leg morphogenesis. Nat Cell Biol 2006; 9:57-63. [PMID: 17143268 DOI: 10.1038/ncb1518] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [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: 07/28/2006] [Accepted: 10/06/2006] [Indexed: 11/09/2022]
Abstract
Morphogens are secreted signalling molecules that govern many developmental processes. In the Drosophila wing disc, the transforming growth factor beta (TGFbeta) homologue Decapentaplegic (Dpp) forms a smooth gradient and specifies cell fate by conferring a defined value of morphogen activity. Thus, neighbouring cells have similar amounts of Dpp protein, and if a sharp discontinuity in Dpp activity is generated between these cells, Jun kinase (JNK)-dependent apoptosis is triggered to restore graded positional information. To date, it has been assumed that this apoptotic process is only activated when normal signalling is distorted. However, we now show that a similar process occurs during normal development: rupture in Dpp activity occurs during normal segmentation of the distal legs of Drosophila. This sharp boundary of Dpp signalling, independently of the absolute level of Dpp activity, induces a JNK-reaper-dependent apoptosis required for the morphogenesis of a particular structure of the leg, the joint. Our results show that Dpp could induce a developmental programme not only in a concentration dependent manner, but also by the creation of a sharp boundary of Dpp activity. Furthermore, the same process could be used either to restore a normal pattern in response to artificial disturbance or to direct a morphogenetic process.
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Affiliation(s)
- Cristina Manjón
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Cantoblanco 28 049 Madrid, Spain
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de Navas L, Foronda D, Suzanne M, Sánchez-Herrero E. A simple and efficient method to identify replacements of P-lacZ by P-Gal4 lines allows obtaining Gal4 insertions in the bithorax complex of Drosophila. Mech Dev 2006; 123:860-7. [PMID: 16971094 DOI: 10.1016/j.mod.2006.07.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 07/25/2006] [Accepted: 07/26/2006] [Indexed: 01/12/2023]
Abstract
The functional replacement of one gene product by another one is a powerful method to study specificity in development and evolution. In Drosophila, the Gal4/UAS method has been used to analyze in vivo such functional substitutions. To this aim, Gal4 lines that inactivate a gene and reproduce its expression pattern are required, and they can be frequently obtained by replacing pre-existing P-lacZ lines with such characteristics. We have devised a new method to quickly identify replacements of P-lacZ lines by P-Gal4 lines, and applied it successfully to obtain Gal4 insertions in the Ultrabithorax and Abdominal-B Hox genes. We have used these lines to study the functional replacement of a Hox gene by another one. Our experiments confirm that the abdominal-A gene can replace Ultrabithorax in haltere development but that it cannot substitute for Abdominal-B in the formation of the genitalia.
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Affiliation(s)
- Luis de Navas
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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35
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Negre B, Casillas S, Suzanne M, Sánchez-Herrero E, Akam M, Nefedov M, Barbadilla A, de Jong P, Ruiz A. Conservation of regulatory sequences and gene expression patterns in the disintegrating Drosophila Hox gene complex. Genome Res 2005; 15:692-700. [PMID: 15867430 PMCID: PMC1088297 DOI: 10.1101/gr.3468605] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Accepted: 01/26/2005] [Indexed: 11/25/2022]
Abstract
Homeotic (Hox) genes are usually clustered and arranged in the same order as they are expressed along the anteroposterior body axis of metazoans. The mechanistic explanation for this colinearity has been elusive, and it may well be that a single and universal cause does not exist. The Hox-gene complex (HOM-C) has been rearranged differently in several Drosophila species, producing a striking diversity of Hox gene organizations. We investigated the genomic and functional consequences of the two HOM-C splits present in Drosophila buzzatii. Firstly, we sequenced two regions of the D. buzzatii genome, one containing the genes labial and abdominal A, and another one including proboscipedia, and compared their organization with that of D. melanogaster and D. pseudoobscura in order to map precisely the two splits. Then, a plethora of conserved noncoding sequences, which are putative enhancers, were identified around the three Hox genes closer to the splits. The position and order of these enhancers are conserved, with minor exceptions, between the three Drosophila species. Finally, we analyzed the expression patterns of the same three genes in embryos and imaginal discs of four Drosophila species with different Hox-gene organizations. The results show that their expression patterns are conserved despite the HOM-C splits. We conclude that, in Drosophila, Hox-gene clustering is not an absolute requirement for proper function. Rather, the organization of Hox genes is modular, and their clustering seems the result of phylogenetic inertia more than functional necessity.
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Affiliation(s)
- Bárbara Negre
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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36
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Abstract
The "pipsqueak" family is composed of proteins that contain a pipsqueak motif, a previously characterised DNA binding domain, and thus represents a new family of potential transcription factors. Previous functional characterisation of several Drosophila genes encoding pipsqueak domain-containing proteins has shown their crucial role in development. Here, I report the embryonic, larval, and pupal expression pattern of two Drosophila genes, fernández/distal antenna and hernández/distal antenna related, which encode protein members of the pipsqueak family with similar pipsqueak motifs. Furthermore, I show that, consistently with their expression pattern, these two genes are required in the nervous system during the embryonic development.
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Affiliation(s)
- Magali Suzanne
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
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37
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Abstract
The formation of different structures in Drosophila depends on the combined activities of selector genes and signaling pathways. For instance, the antenna requires the selector gene homothorax, which distinguishes between the leg and the antenna and can specify distal antenna if expressed ectopically. Similarly, the eye is formed by a group of "eye-specifying" genes, among them eyeless, which can direct eye development ectopically. We report here the characterization of the hernandez and fernandez genes, expressed in the antennal and eye primordia of the eye-antenna imaginal disc. The predicted proteins encoded by these two genes have 27% common amino acids and include a Pipsqueak domain. Reduced expression of either hernandez or fernandez mildly affects antenna and eye development, while the inactivation of both genes partially transforms distal antenna into leg. Ectopic expression of either of the two genes results in two different phenotypes: it can form distal antenna, activating genes like homothorax, spineless, and spalt, and it can promote eye development and activates eyeless. Reciprocally, eyeless can induce hernandez and fernandez expression, and homothorax and spineless can activate both hernandez and fernandez when ectopically expressed. The formation of eye by these genes seems to require Notch signaling, since the induction of ectopic eyes and the activation of eyeless by the hernandez gene are suppressed when the Notch function is compromised. Our results show that the hernandez and fernandez genes are required for antennal and eye development and are also able to specify eye or antenna ectopically.
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Affiliation(s)
- Magali Suzanne
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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38
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Abstract
During Drosophila oogenesis, the formation of the egg respiratory appendages and the micropyle require the shaping of anterior and dorsal follicle cells. Prior to their morphogenesis, cells of the presumptive appendages are determined by integrating dorsal-ventral and anterior-posterior positional information provided by the epidermal growth factor receptor (EGFR) and Decapentaplegic (Dpp) pathways, respectively. We show here that another signaling pathway, the Drosophila Jun-N-terminal kinase (JNK) cascade, is essential for the correct morphogenesis of the dorsal appendages and the micropyle during oogenesis. Mutant follicle cell clones of members of the JNK pathway, including DJNKK/hemipterous (hep), DJNK/basket (bsk), and Djun, block dorsal appendage formation and affect the micropyle shape and size, suggesting a late requirement for the JNK pathway in anterior chorion morphogenesis. In support of this view, hep does not affect early follicle cell patterning as indicated by the normal expression of kekkon (kek) and Broad-Complex (BR-C), two of the targets of the EGFR pathway in dorsal follicle cells. Furthermore, the expression of the TGF-beta homolog dpp, which is under the control of hep in embryos, is not coupled to JNK activity during oogenesis. We show that hep controls the expression of puckered (puc) in the follicular epithelium in a cell-autonomous manner. Since puc overexpression in the egg follicular epithelium mimics JNK appendages and micropyle phenotypes, it indicates a negative role of puc in their morphogenesis. The role of the JNK pathway in the morphogenesis of follicle cells and other epithelia during development is discussed.
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Affiliation(s)
- M Suzanne
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Conter A, Gangneux C, Suzanne M, Gutierrez C. Survival of Escherichia coli during long-term starvation: effects of aeration, NaCl, and the rpoS and osmC gene products. Res Microbiol 2001; 152:17-26. [PMID: 11281321 DOI: 10.1016/s0923-2508(00)01164-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [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: 10/27/2022]
Abstract
The survival of Escherichia coli was investigated during long-term starvation in rich media. In aerated cultures, E. coli lost the ability to form colonies earlier in NaCl-free Luria broth than in LB medium containing NaCl. Improved survival at low aeration and the sensitivity to hydrogen peroxide in aging cultures indicated a major role for oxidative stress in cell mortality. Mutants in rpoS, lacking the sigmaS subunit of RNA polymerase, showed altered survival in salt-containing media. However, in the absence of NaCl, although these mutants exhibited a massive loss of viability during the first 2 days, this was followed by a stabilization of the number of survivors. The starved culture contained survivors until at least day 9, long after a wild-type strain had completely lost viability. This peculiar behavior suggests that, in rich media of low osmotic pressure, sigmaS helps in short-term survival but hampers long-term survival. Mutants in osmC, a member of the rpoS regulon, also exhibited reduced survival and increased sensitivity to oxidative stress. The biochemical function of the envelope protein OsmC remains unknown, but present data indicated that it participates, directly or indirectly, in the defense against oxidative compounds.
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Affiliation(s)
- A Conter
- Laboratoire de microbiologie et génétique moléculaire, UMR 5100 CNRS-université Toulouse III, France.
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Abstract
In Drosophila, the Jun-N-terminal Kinase-(JNK) signaling pathway is required for epithelial cell shape changes during dorsal closure of the embryo. In the absence of JNK pathway activity, as in the DJNKK/hemipterous (hep) mutant, the dorsolateral ectodermal cells fail both to elongate and move toward the dorsal midline, leading to dorsally open embryos. We show here that hep and the JNK pathway are required later in development, for correct morphogenesis of other epithelia, the imaginal discs. During metamorphosis, the imaginal discs undergo profound morphological changes, giving rise to the adult head and thoracic structures, including the cuticle and appendages. hep mutant pupae and pharate adults show severe defects in discs morphogenesis, especially in the fusion of the two lateral wing discs. We show that these defects are accompanied by a loss of expression of puckered (puc), a JNK phosphatase-encoding gene, in a subset of peripodial cells that ultimately delineates the margins of fusing discs. In further support of a role of puc in discs morphogenesis, pupal and adult hep phenotypes are suppressed by reducing puc function, indicative of a negative role of puc in disc morphogenesis. Furthermore, we show that the small GTPase Dcdc42, but not Drac1, is an activator of puc expression in a hep-dependent manner in imaginal discs. Altogether, these results demonstrate a new role for the JNK pathway in epithelial morphogenesis, and provide genetic evidence for a role of the peripodial membrane in disc morphogenesis. We discuss a general model whereby the JNK pathway regulates morphogenesis of epithelia with differentiated edges.
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Affiliation(s)
- F Agnès
- Centre de Biologie du Développement, UMR 5547, 31062 Toulouse cedex, France
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Suzanne M, Irie K, Glise B, Agnès F, Mori E, Matsumoto K, Noselli S. The Drosophila p38 MAPK pathway is required during oogenesis for egg asymmetric development. Genes Dev 1999; 13:1464-74. [PMID: 10364162 PMCID: PMC316763 DOI: 10.1101/gad.13.11.1464] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [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: 11/24/2022]
Abstract
In mammalian cells, the p38 mitogen-activated protein kinase (MAPK) pathway is activated in response to a variety of environmental stresses and inflammatory stimuli. However, the role of p38 MAPK signaling in unchallenged conditions remains largely unknown. We have isolated mutations in a Drosophila p38 MAPKK gene homolog, licorne (lic), and show that during oogenesis, lic is required in the germ line for correct asymmetric development of the egg. In lic mutant egg chambers, oskar mRNA posterior localization is not properly maintained, resulting in anteroposterior patterning defects in the embryo. Furthermore, lic loss-of-function in the germ line leads to reduced EGF receptor activity in dorsal follicle cells and ventralization of the egg shell. Both these defects are associated with a diminution of gurken protein levels in the oocyte. Our phenotypic data argue for a role of lic in a post-transcriptional regulation of the grk gene. Furthermore, they show that in addition to the well-characterized Ras/Raf/ERK MAPK pathway acting in the follicle cells, another related signaling cascade, the p38 MAPK pathway, is required in the germ line for correct axes determination. These results provide the first genetic demonstration of an essential function for a p38 pathway during development.
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Affiliation(s)
- M Suzanne
- Centre de Biologie du Développement, UMR5547 Centre National de la Recherche Scientifique (CNRS), 31062 Toulouse Cedex, France
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Holland PM, Suzanne M, Campbell JS, Noselli S, Cooper JA. MKK7 is a stress-activated mitogen-activated protein kinase kinase functionally related to hemipterous. J Biol Chem 1997; 272:24994-8. [PMID: 9312105 DOI: 10.1074/jbc.272.40.24994] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Exposure of mammalian cells to stressful stimuli results in activation of the c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinases (SAPKs), a family of protein kinases related to mitogen-activated protein (MAP) kinase. JNK/SAPKs are activated by specific MAP kinase kinases (MKKs), one of which, MKK4/SEK1, has been characterized extensively. In Drosophila, the JNK/SAPK Basket (Bsk) and the MKK Hemipterous (Hep), are important for embryonic development. Loss of function of either gene inhibits dorsal closure, a morphogenetic movement in which the edges of the embryonic ectoderm move together over the amnioserosa. There is evidence that the Rho GTPases Rac and Cdc42 are also required for dorsal closure, suggesting that Rac or Cdc42 may regulate Hep and Bsk. We have identified MKK7, a murine homolog of Hep. MKK7 functionally rescues hep mutant flies. In fibroblasts, MKK7 is activated by stress and by the GTPase Rac1. MKK7 directly phosphorylates and activates JNK/SAPK. Thus, MKK7 is a homolog of hep and functions in a conserved signaling pathway involving JNK/SAPK and the GTPase Rac1.
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Affiliation(s)
- P M Holland
- Fred Hutchinson Cancer Research Center, A2-025, Seattle, Washington 98109, USA
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