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Leroy O, van Leen E, Girard P, Villedieu A, Hubert C, Bosveld F, Bellaïche Y, Renaud O. Multi-view confocal microscopy enables multiple organ and whole organism live-imaging. Development 2022; 149:274464. [DOI: 10.1242/dev.199760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 01/13/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Understanding how development is coordinated in multiple tissues and gives rise to fully functional organs or whole organisms necessitates microscopy tools. Over the last decade numerous advances have been made in live-imaging, enabling high resolution imaging of whole organisms at cellular resolution. Yet, these advances mainly rely on mounting the specimen in agarose or aqueous solutions, precluding imaging of organisms whose oxygen uptake depends on ventilation. Here, we implemented a multi-view multi-scale microscopy strategy based on confocal spinning disk microscopy, called Multi-View confocal microScopy (MuViScopy). MuViScopy enables live-imaging of multiple organs with cellular resolution using sample rotation and confocal imaging without the need of sample embedding. We illustrate the capacity of MuViScopy by live-imaging Drosophila melanogaster pupal development throughout metamorphosis, highlighting how internal organs are formed and multiple organ development is coordinated. We foresee that MuViScopy will open the path to better understand developmental processes at the whole organism scale in living systems that require gas exchange by ventilation.
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Affiliation(s)
- Olivier Leroy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Eric van Leen
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Philippe Girard
- Université de Paris, CNRS UMR7592, Institut Jacques Monod and Faculty of Basic and Biomedical Sciences, 75006, Paris, France
| | - Aurélien Villedieu
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Floris Bosveld
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Yohanns Bellaïche
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Olivier Renaud
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
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2
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Rich A, Fehon RG, Glotzer M. Rho1 activation recapitulates early gastrulation events in the ventral, but not dorsal, epithelium of Drosophila embryos. eLife 2020; 9:56893. [PMID: 33200987 PMCID: PMC7717907 DOI: 10.7554/elife.56893] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 11/16/2020] [Indexed: 12/27/2022] Open
Abstract
Ventral furrow formation, the first step in Drosophila gastrulation, is a well-studied example of tissue morphogenesis. Rho1 is highly active in a subset of ventral cells and is required for this morphogenetic event. However, it is unclear whether spatially patterned Rho1 activity alone is sufficient to recapitulate all aspects of this morphogenetic event, including anisotropic apical constriction and coordinated cell movements. Here, using an optogenetic probe that rapidly and robustly activates Rho1 in Drosophila tissues, we show that Rho1 activity induces ectopic deformations in the dorsal and ventral epithelia of Drosophila embryos. These perturbations reveal substantial differences in how ventral and dorsal cells, both within and outside the zone of Rho1 activation, respond to spatially and temporally identical patterns of Rho1 activation. Our results demonstrate that an asymmetric zone of Rho1 activity is not sufficient to recapitulate ventral furrow formation and reveal that additional, ventral-specific factors contribute to the cell- and tissue-level behaviors that emerge during ventral furrow formation.
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Affiliation(s)
- Ashley Rich
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
| | - Richard G Fehon
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
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3
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Murakawa T, Kiger AA, Sakamaki Y, Fukuda M, Fujita N. An autophagy-dependent tubular lysosomal network synchronizes degradative activity required for muscle remodeling. J Cell Sci 2020; 133:jcs248336. [PMID: 33077556 PMCID: PMC7673362 DOI: 10.1242/jcs.248336] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 10/01/2020] [Indexed: 11/20/2022] Open
Abstract
Lysosomes are compartments for the degradation of both endocytic and autophagic cargoes. The shape of lysosomes changes with cellular degradative demands; however, there is limited knowledge about the mechanisms or significance that underlies distinct lysosomal morphologies. Here, we found an extensive tubular autolysosomal network in Drosophila abdominal muscle remodeling during metamorphosis. The tubular network transiently appeared and exhibited the capacity to degrade autophagic cargoes. The tubular autolysosomal network was uniquely marked by the autophagic SNARE protein Syntaxin17 and its formation depended on both autophagic flux and degradative function, with the exception of the Atg12 and Atg8 ubiquitin-like conjugation systems. Among ATG-deficient mutants, the efficiency of lysosomal tubulation correlated with the phenotypic severity in muscle remodeling. The lumen of the tubular network was continuous and homogeneous across a broad region of the remodeling muscle. Altogether, we revealed that the dynamic expansion of a tubular autolysosomal network synchronizes the abundant degradative activity required for developmentally regulated muscle remodeling.
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Affiliation(s)
- Tadayoshi Murakawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Amy A Kiger
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yuriko Sakamaki
- Microscopy Research Support Unit Research Core, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Naonobu Fujita
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- Precursory Research for Embryonic Science & Technology (PRESTO), Japan Science & Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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4
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Lam MSY, Lisica A, Ramkumar N, Hunter G, Mao Y, Charras G, Baum B. Isotropic myosin-generated tissue tension is required for the dynamic orientation of the mitotic spindle. Mol Biol Cell 2020; 31:1370-1379. [PMID: 32320325 PMCID: PMC7353144 DOI: 10.1091/mbc.e19-09-0545] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/19/2020] [Accepted: 04/14/2020] [Indexed: 12/01/2022] Open
Abstract
The ability of cells to divide along their longest axis has been proposed to play an important role in maintaining epithelial tissue homeostasis in many systems. Because the division plane is largely set by the position of the anaphase spindle, it is important to understand how spindles become oriented. While several molecules have been identified that play key roles in spindle orientation across systems, most notably Mud/NuMA and cortical dynein, the precise mechanism by which spindles detect and align with the long cell axis remain poorly understood. Here, in exploring the dynamics of spindle orientation in mechanically distinct regions of the fly notum, we find that the ability of cells to properly reorient their divisions depends on local tissue tension. Thus, spindles reorient to align with the long cell axis in regions where isotropic tension is elevated, but fail to do so in elongated cells within the crowded midline, where tension is low, or in regions that have been mechanically isolated from the rest of the tissue via laser ablation. Importantly, these differences in spindle behavior outside and inside the midline can be recapitulated by corresponding changes in tension induced by perturbations that alter nonmuscle myosin II activity. These data lead us to propose that isotropic tension within an epithelium provides cells with a mechanically stable substrate upon which localized cortical motor complexes can act on astral microtubules to orient the spindle.
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Affiliation(s)
| | - Ana Lisica
- London Centre for Nanotechnology
- Institute for the Physics of Living Systems, and
| | | | | | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology
- Institute for the Physics of Living Systems, and
| | - Guillaume Charras
- London Centre for Nanotechnology
- Institute for the Physics of Living Systems, and
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology
- Institute for the Physics of Living Systems, and
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5
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Curran S, Strandkvist C, Bathmann J, de Gennes M, Kabla A, Salbreux G, Baum B. Myosin II Controls Junction Fluctuations to Guide Epithelial Tissue Ordering. Dev Cell 2017; 43:480-492.e6. [PMID: 29107560 PMCID: PMC5703647 DOI: 10.1016/j.devcel.2017.09.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 07/24/2017] [Accepted: 09/22/2017] [Indexed: 11/24/2022]
Abstract
Under conditions of homeostasis, dynamic changes in the length of individual adherens junctions (AJs) provide epithelia with the fluidity required to maintain tissue integrity in the face of intrinsic and extrinsic forces. While the contribution of AJ remodeling to developmental morphogenesis has been intensively studied, less is known about AJ dynamics in other circumstances. Here, we study AJ dynamics in an epithelium that undergoes a gradual increase in packing order, without concomitant large-scale changes in tissue size or shape. We find that neighbor exchange events are driven by stochastic fluctuations in junction length, regulated in part by junctional actomyosin. In this context, the developmental increase of isotropic junctional actomyosin reduces the rate of neighbor exchange, contributing to tissue order. We propose a model in which the local variance in tension between junctions determines whether actomyosin-based forces will inhibit or drive the topological transitions that either refine or deform a tissue.
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Affiliation(s)
- Scott Curran
- Medical Research Council - Laboratory of Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Charlotte Strandkvist
- Medical Research Council - Laboratory of Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Jasper Bathmann
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Marc de Gennes
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Alexandre Kabla
- Department of Engineering, University of Cambridge, Cambridge CB2 OQH, UK
| | - Guillaume Salbreux
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK.
| | - Buzz Baum
- Medical Research Council - Laboratory of Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK.
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6
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Fujita N, Huang W, Lin TH, Groulx JF, Jean S, Nguyen J, Kuchitsu Y, Koyama-Honda I, Mizushima N, Fukuda M, Kiger AA. Genetic screen in Drosophila muscle identifies autophagy-mediated T-tubule remodeling and a Rab2 role in autophagy. eLife 2017; 6. [PMID: 28063257 PMCID: PMC5249261 DOI: 10.7554/elife.23367] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/17/2016] [Indexed: 01/04/2023] Open
Abstract
Transverse (T)-tubules make-up a specialized network of tubulated muscle cell membranes involved in excitation-contraction coupling for power of contraction. Little is known about how T-tubules maintain highly organized structures and contacts throughout the contractile system despite the ongoing muscle remodeling that occurs with muscle atrophy, damage and aging. We uncovered an essential role for autophagy in T-tubule remodeling with genetic screens of a developmentally regulated remodeling program in Drosophila abdominal muscles. Here, we show that autophagy is both upregulated with and required for progression through T-tubule disassembly stages. Along with known mediators of autophagosome-lysosome fusion, our screens uncovered an unexpected shared role for Rab2 with a broadly conserved function in autophagic clearance. Rab2 localizes to autophagosomes and binds to HOPS complex members, suggesting a direct role in autophagosome tethering/fusion. Together, the high membrane flux with muscle remodeling permits unprecedented analysis both of T-tubule dynamics and fundamental trafficking mechanisms. DOI:http://dx.doi.org/10.7554/eLife.23367.001
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Affiliation(s)
- Naonobu Fujita
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States.,Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Wilson Huang
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Tzu-Han Lin
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Jean-Francois Groulx
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Steve Jean
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Jen Nguyen
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Yoshihiko Kuchitsu
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Ikuko Koyama-Honda
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Amy A Kiger
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
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Hadjivasiliou Z, Hunter GL, Baum B. A new mechanism for spatial pattern formation via lateral and protrusion-mediated lateral signalling. J R Soc Interface 2016; 13:20160484. [PMID: 27807273 PMCID: PMC5134009 DOI: 10.1098/rsif.2016.0484] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023] Open
Abstract
Tissue organization and patterning are critical during development when genetically identical cells take on different fates. Lateral signalling plays an important role in this process by helping to generate self-organized spatial patterns in an otherwise uniform collection of cells. Recent data suggest that lateral signalling can be mediated both by junctional contacts between neighbouring cells and via cellular protrusions that allow non-neighbouring cells to interact with one another at a distance. However, it remains unclear precisely how signalling mediated by these distinct types of cell-cell contact can physically contribute to the generation of complex patterns without the assistance of diffusible morphogens or pre-patterns. To explore this question, in this work we develop a model of lateral signalling based on a single receptor/ligand pair as exemplified by Notch and Delta. We show that allowing the signalling kinetics to differ at junctional versus protrusion-mediated contacts, an assumption inspired by recent data which show that the cleavage of Notch in several systems requires both Delta binding and the application of mechanical force, permits individual cells to act to promote both lateral activation and lateral inhibition. Strikingly, under this model, in which Delta can sequester Notch, a variety of patterns resembling those typical of reaction-diffusion systems is observed, together with more unusual patterns that arise when we consider changes in signalling kinetics, and in the length and distribution of protrusions. Importantly, these patterns are self-organizing-so that local interactions drive tissue-scale patterning. Together, these data show that protrusions can, in principle, generate different types of patterns in addition to contributing to long-range signalling and to pattern refinement.
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Affiliation(s)
- Zena Hadjivasiliou
- Centre for Mathematics, Physics, and Engineering in the Life Sciences and Experimental Biology, University College London, London WC1E 6BT, UK
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Ginger L Hunter
- MRC-Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- Institute of Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Buzz Baum
- MRC-Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- Institute of Physics of Living Systems, University College London, London WC1E 6BT, UK
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8
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Aghajanian P, Takashima S, Paul M, Younossi-Hartenstein A, Hartenstein V. Metamorphosis of the Drosophila visceral musculature and its role in intestinal morphogenesis and stem cell formation. Dev Biol 2016; 420:43-59. [PMID: 27765651 DOI: 10.1016/j.ydbio.2016.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 10/10/2016] [Accepted: 10/15/2016] [Indexed: 10/20/2022]
Abstract
The visceral musculature of the Drosophila intestine plays important roles in digestion as well as development. Detailed studies investigating the embryonic development of the visceral muscle exist; comparatively little is known about postembryonic development and metamorphosis of this tissue. In this study we have combined the use of specific markers with electron microscopy to follow the formation of the adult visceral musculature and its involvement in gut development during metamorphosis. Unlike the adult somatic musculature, which is derived from a pool of undifferentiated myoblasts, the visceral musculature of the adult is a direct descendant of the larval fibers, as shown by activating a lineage tracing construct in the larval muscle and obtaining labeled visceral fibers in the adult. However, visceral muscles undergo a phase of remodeling that coincides with the metamorphosis of the intestinal epithelium. During the first day following puparium formation, both circular and longitudinal syncytial fibers dedifferentiate, losing their myofibrils and extracellular matrix, and dissociating into mononuclear cells ("secondary myoblasts"). Towards the end of the second day, this process is reversed, and between 48 and 72h after puparium formation, a structurally fully differentiated adult muscle layer has formed. We could not obtain evidence that cells apart from the dedifferentiated larval visceral muscle contributed to the adult muscle, nor does it appear that the number of adult fibers (or nuclei per fiber) is increased over that of the larva by proliferation. In contrast to the musculature, the intestinal epithelium is completely renewed during metamorphosis. The adult midgut epithelium rapidly expands over the larval layer during the first few hours after puparium formation; in case of the hindgut, replacement takes longer, and proceeds by the gradual caudad extension of a proliferating growth zone, the hindgut proliferation zone (HPZ). The subsequent elongation of the hindgut and midgut, as well as the establishment of a population of intestinal stem cells active in the adult midgut and hindgut, requires the presence of the visceral muscle layer, based on the finding that ablation of this layer causes a severe disruption of both processes.
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Affiliation(s)
- Patrick Aghajanian
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Shigeo Takashima
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Manash Paul
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Amelia Younossi-Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA.
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9
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Hunter GL, Hadjivasiliou Z, Bonin H, He L, Perrimon N, Charras G, Baum B. Coordinated control of Notch/Delta signalling and cell cycle progression drives lateral inhibition-mediated tissue patterning. Development 2016; 143:2305-10. [PMID: 27226324 PMCID: PMC4958321 DOI: 10.1242/dev.134213] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 05/10/2016] [Indexed: 01/07/2023]
Abstract
Coordinating cell differentiation with cell growth and division is crucial for the successful development, homeostasis and regeneration of multicellular tissues. Here, we use bristle patterning in the fly notum as a model system to explore the regulatory and functional coupling of cell cycle progression and cell fate decision-making. The pattern of bristles and intervening epithelial cells (ECs) becomes established through Notch-mediated lateral inhibition during G2 phase of the cell cycle, as neighbouring cells physically interact with each other via lateral contacts and/or basal protrusions. Since Notch signalling controls cell division timing downstream of Cdc25, ECs in lateral contact with a Delta-expressing cell experience higher levels of Notch signalling and divide first, followed by more distant neighbours, and lastly Delta-expressing cells. Conversely, mitotic entry and cell division makes ECs refractory to lateral inhibition signalling, fixing their fate. Using a combination of experiments and computational modelling, we show that this reciprocal relationship between Notch signalling and cell cycle progression acts like a developmental clock, providing a delimited window of time during which cells decide their fate, ensuring efficient and orderly bristle patterning. Summary: In the fly notum, a reciprocal relationship between Notch signalling and cell cycle progression acts like a clock, providing a delimited window of time during which cells decide their fate.
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Affiliation(s)
- Ginger L Hunter
- MRC-Laboratory for Molecular and Cell Biology, University College London, London WC1E 6BT, UK Institute of Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Zena Hadjivasiliou
- Centre for Mathematics, Physics, and Engineering in the Life Sciences and Experimental Biology, University College London, London WC1E 6BT, UK Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Hope Bonin
- MRC-Laboratory for Molecular and Cell Biology, University College London, London WC1E 6BT, UK
| | - Li He
- Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Norbert Perrimon
- Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Guillaume Charras
- Institute of Physics of Living Systems, University College London, London WC1E 6BT, UK London Centre for Nanotechnology, University College London, London WC1E 6BT, UK Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Buzz Baum
- MRC-Laboratory for Molecular and Cell Biology, University College London, London WC1E 6BT, UK Institute of Physics of Living Systems, University College London, London WC1E 6BT, UK
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10
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Abstract
Inherent processes of Drosophila pupal development can shift and distort the eye epithelium in ways that make individual cell behavior difficult to track during live cell imaging. These processes include: retinal rotation, cell growth and organismal movement. Additionally, irregularities in the topology of the epithelium, including subtle bumps and folds often introduced as the pupa is prepared for imaging, make it challenging to acquire in-focus images of more than a few ommatidia in a single focal plane. The workflow outlined here remedies these issues, allowing easy analysis of cellular processes during Drosophila pupal eye development. Appropriately-staged pupae are arranged in an imaging rig that can be easily assembled in most laboratories. Ubiquitin-DE-Cadherin:GFP and GMR-GAL4-driven UAS-α-catenin:GFP are used to visualize cell boundaries in the eye epithelium (1-3). After deconvolution is applied to fluorescent images captured at multiple focal planes, maximum projection images are generated for each time point and enhanced using image editing software. Alignment algorithms are used to quickly stabilize superfluous motion, making individual cell behavior easier to track.
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Upadhyay A, Kandachar V, Zitserman D, Tong X, Roegiers F. Sanpodo controls sensory organ precursor fate by directing Notch trafficking and binding γ-secretase. ACTA ACUST UNITED AC 2013; 201:439-48. [PMID: 23609534 PMCID: PMC3639393 DOI: 10.1083/jcb.201209023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In sensory organ precursor cells, Sanpodo can enhance or suppress Notch signaling by promoting interaction with Presenilin or driving receptor internalization, respectively. In Drosophila peripheral neurogenesis, Notch controls cell fates in sensory organ precursor (SOP) cells. SOPs undergo asymmetric cell division by segregating Numb, which inhibits Notch signaling, into the pIIb daughter cell after cytokinesis. In contrast, in the pIIa daughter cell, Notch is activated and requires Sanpodo, but its mechanism of action has not been elucidated. As Sanpodo is present in both pIIa and pIIb cells, a second role for Sanpodo in regulating Notch signaling in the low-Notch pIIb cell has been proposed. Here we demonstrate that Sanpodo regulates Notch signaling levels in both pIIa and pIIb cells via distinct mechanisms. The interaction of Sanpodo with Presenilin, a component of the γ-secretase complex, was required for Notch activation and pIIa cell fate. In contrast, Sanpodo suppresses Notch signaling in the pIIb cell by driving Notch receptor internalization. Together, these results demonstrate that a single protein can regulate Notch signaling through distinct mechanisms to either promote or suppress signaling depending on the local cellular context.
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Affiliation(s)
- Alok Upadhyay
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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12
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Zitserman D, Gupta S, Kruger WD, Karbowniczek M, Roegiers F. The TSC1/2 complex controls Drosophila pigmentation through TORC1-dependent regulation of catecholamine biosynthesis. PLoS One 2012; 7:e48720. [PMID: 23144943 PMCID: PMC3492411 DOI: 10.1371/journal.pone.0048720] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 09/27/2012] [Indexed: 02/05/2023] Open
Abstract
In Drosophila, the pattern of adult pigmentation is initiated during late pupal stages by the production of catecholamines DOPA and dopamine, which are converted to melanin. The pattern and degree of melanin deposition is controlled by the expression of genes such as ebony and yellow as well as by the enzymes involved in catecholamine biosynthesis. In this study, we show that the conserved TSC/TORC1 cell growth pathway controls catecholamine biosynthesis in Drosophila during pigmentation. We find that high levels of Rheb, an activator of the TORC1 complex, promote premature pigmentation in the mechanosensory bristles during pupal stages, and alter pigmentation in the cuticle of the adult fly. Disrupting either melanin synthesis by RNAi knockdown of melanogenic enzymes such as tyrosine hydroxylase (TH), or downregulating TORC1 activity by Raptor knockdown, suppresses the Rheb-dependent pigmentation phenotype in vivo. Increased Rheb activity drives pigmentation by increasing levels of TH in epidermal cells. Our findings indicate that control of pigmentation is linked to the cellular nutrient-sensing pathway by regulating levels of a critical enzyme in melanogenesis, providing further evidence that inappropriate activation of TORC1, a hallmark of the human tuberous sclerosis complex tumor syndrome disorder, can alter metabolic and differentiation pathways in unexpected ways.
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Affiliation(s)
- Diana Zitserman
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America
| | - Sapna Gupta
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America
| | - Warren D. Kruger
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America
| | | | - Fabrice Roegiers
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Giagtzoglou N, Yamamoto S, Zitserman D, Graves HK, Schulze KL, Wang H, Klein H, Roegiers F, Bellen HJ. dEHBP1 controls exocytosis and recycling of Delta during asymmetric divisions. ACTA ACUST UNITED AC 2012; 196:65-83. [PMID: 22213802 PMCID: PMC3255984 DOI: 10.1083/jcb.201106088] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Drosophila EHBP1 is a novel regulator of Notch signaling that may function as an adaptor protein during the exocytosis and recycling of the Notch ligand Delta. Notch signaling governs binary cell fate determination in asymmetrically dividing cells. Through a forward genetic screen we identified the fly homologue of Eps15 homology domain containing protein-binding protein 1 (dEHBP1) as a novel regulator of Notch signaling in asymmetrically dividing cells. dEHBP1 is enriched basally and at the actin-rich interface of pII cells of the external mechanosensory organs, where Notch signaling occurs. Loss of function of dEHBP1 leads to up-regulation of Sanpodo, a regulator of Notch signaling, and aberrant trafficking of the Notch ligand, Delta. Furthermore, Sec15 and Rab11, which have been previously shown to regulate the localization of Delta, physically interact with dEHBP1. We propose that dEHBP1 functions as an adaptor molecule for the exocytosis and recycling of Delta, thereby affecting cell fate decisions in asymmetrically dividing cells.
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Affiliation(s)
- Nikolaos Giagtzoglou
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
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