1
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Chen M, Gao E, Lin G, Shen J, Wang D. The transcription factor optomotor-blind restricts apterous expression through TrxG and PcG genes. Dev Biol 2023; 497:59-67. [PMID: 36907311 DOI: 10.1016/j.ydbio.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/20/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023]
Abstract
The establishment of body pattern is a fundamental process in developmental biology. In Drosophila, the wing disc is subdivided into dorsal (D) and ventral (V) compartments by the D/V boundary. The dorsal fate is adopted by expressing the selector gene apterous (ap). ap expression is regulated by three combinational cis-regulatory modules which are activated by EGFR pathway, Ap-Vg auto-regulatory and epigenetic mechanisms. Here, we found that the Tbx family transcription factor Optomotor-blind (Omb) restricted ap expression in the ventral compartment. Loss of omb induced autonomous initiation of ap expression in the middle third instar larvae in the ventral compartment. Oppositely, over-activation of omb inhibited ap in the medial pouch. All three enhancers apE, apDV and apP were upregulated in omb null mutants, indicating a combinational regulation of ap modulators. However, Omb affected ap expression neither by directly regulating EGFR signaling, nor via Vg regulation. Therefore, a genetic screen of epigenetic regulators, including the Trithorax group (TrxG) and Polycomb group (PcG) genes was performed. We found that knocking down the TrxG gene kohtalo (kto), domino (dom) or expressing the PcG gene grainy head (grh), the ectopic ap in omb mutants was repressed. The inhibition of apDV by kto knockdown and grh activation could contribute to ap repression. Moreover, Omb and the EGFR pathway are genetically parallel in ap regulation in the ventral compartment. Collectively, Omb is a repressive signal for ap expression in the ventral compartment, which requires TrxG and PcG genes.
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Affiliation(s)
- Min Chen
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, 100193, China; Yantai Academy of Agricultural Sciences, Yantai, 265500, China
| | - Erqing Gao
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Guangze Lin
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Jie Shen
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Dan Wang
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
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2
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Wang J, Michel M, Bialas L, Pierini G, Dahmann C. Preferential recruitment and stabilization of Myosin II at compartment boundaries in Drosophila. J Cell Sci 2023; 136:286802. [PMID: 36718636 PMCID: PMC10022687 DOI: 10.1242/jcs.260447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 01/23/2023] [Indexed: 02/01/2023] Open
Abstract
The regulation of mechanical tension exerted at cell junctions guides cell behavior during tissue formation and homeostasis. Cell junctions along compartment boundaries, which are lineage restrictions separating cells with different fates and functions within tissues, are characterized by increased mechanical tension compared to that of cell junctions in the bulk of the tissue. Mechanical tension depends on the actomyosin cytoskeleton; however, the mechanisms by which mechanical tension is locally increased at cell junctions along compartment boundaries remain elusive. Here, we show that non-muscle Myosin II and F-actin transiently accumulate and mechanical tension is increased at cell junctions along the forming anteroposterior compartment boundary in the Drosophila melanogaster pupal abdominal epidermis. Fluorescence recovery after photobleaching experiments showed that Myosin II accumulation correlated with its increased stabilization at these junctions. Moreover, photoconversion experiments indicated that Myosin II is preferentially recruited within cells to junctions along the compartment boundary. Our results indicate that the preferential recruitment and stabilization of Myosin II contribute to the initial build-up of mechanical tension at compartment boundaries.
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Affiliation(s)
- Jing Wang
- School of Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Marcus Michel
- School of Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Lisa Bialas
- School of Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Giulia Pierini
- School of Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Christian Dahmann
- School of Science, Technische Universität Dresden, 01062 Dresden, Germany.,Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062 Dresden, Germany
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3
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Abstract
The Drosophila wing imaginal disc is a tissue of undifferentiated cells that are precursors of the wing and most of the notum of the adult fly. The wing disc first forms during embryogenesis from a cluster of ∼30 cells located in the second thoracic segment, which invaginate to form a sac-like structure. They undergo extensive proliferation during larval stages to form a mature larval wing disc of ∼35,000 cells. During this time, distinct cell fates are assigned to different regions, and the wing disc develops a complex morphology. Finally, during pupal stages the wing disc undergoes morphogenetic processes and then differentiates to form the adult wing and notum. While the bulk of the wing disc comprises epithelial cells, it also includes neurons and glia, and is associated with tracheal cells and muscle precursor cells. The relative simplicity and accessibility of the wing disc, combined with the wealth of genetic tools available in Drosophila, have combined to make it a premier system for identifying genes and deciphering systems that play crucial roles in animal development. Studies in wing imaginal discs have made key contributions to many areas of biology, including tissue patterning, signal transduction, growth control, regeneration, planar cell polarity, morphogenesis, and tissue mechanics.
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Affiliation(s)
- Bipin Kumar Tripathi
- Department of Molecular Biology and Biochemistry, Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Kenneth D Irvine
- Department of Molecular Biology and Biochemistry, Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
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4
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Paci G, Mao Y. Forced into shape: Mechanical forces in Drosophila development and homeostasis. Semin Cell Dev Biol 2021; 120:160-170. [PMID: 34092509 PMCID: PMC8681862 DOI: 10.1016/j.semcdb.2021.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 12/03/2022]
Abstract
Mechanical forces play a central role in shaping tissues during development and maintaining epithelial integrity in homeostasis. In this review, we discuss the roles of mechanical forces in Drosophila development and homeostasis, starting from the interplay of mechanics with cell growth and division. We then discuss several examples of morphogenetic processes where complex 3D structures are shaped by mechanical forces, followed by a closer look at patterning processes. We also review the role of forces in homeostatic processes, including cell elimination and wound healing. Finally, we look at the interplay of mechanics and developmental robustness and discuss open questions in the field, as well as novel approaches that will help tackle them in the future.
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Affiliation(s)
- Giulia Paci
- MRC Laboratory for 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
| | - Yanlan Mao
- MRC Laboratory for 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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5
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Yu JC, Balaghi N, Erdemci-Tandogan G, Castle V, Fernandez-Gonzalez R. Myosin cables control the timing of tissue internalization in the Drosophila embryo. Cells Dev 2021; 168:203721. [PMID: 34271226 DOI: 10.1016/j.cdev.2021.203721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 11/25/2022]
Abstract
Compartment boundaries prevent cell mixing during animal development. In the early Drosophila embryo, the mesectoderm is a group of glial precursors that separate ectoderm and mesoderm, forming the ventral midline. Mesectoderm cells undergo one round of oriented divisions during axis elongation and are eventually internalized 6 h later. Using spinning disk confocal microscopy and image analysis, we found that after dividing, mesectoderm cells reversed their planar polarity. The polarity factor Bazooka was redistributed to mesectoderm-mesectoderm cell interfaces, and the molecular motor non-muscle Myosin II and its upstream activator Rho-kinase (Rok) accumulated at mesectoderm-ectoderm (ME) interfaces, forming supracellular cables flanking the mesectoderm on either side of the tissue. Laser ablation revealed the presence of increased tension at ME cables, where Myosin was stabilized, as shown by fluorescence recovery after photobleaching. We used laser nanosurgery to reduce tension at the ME boundary, and we found that Myosin fluorescence decreased rapidly, suggesting a role for tension in ME boundary maintenance. Mathematical modelling predicted that increased tension at the ME boundary was necessary to prevent the premature establishment of contacts between the two ectodermal sheets on opposite sides of the mesectoderm, thus controlling the timing of mesectoderm internalization. We validated the model in vivo: Myosin inhibition disrupted the linearity of the ME boundary and resulted in early internalization of the mesectoderm. Our results suggest that the redistribution of Rok polarizes Myosin and Bazooka within the mesectoderm to establish tissue boundaries, and that ME boundaries control the timely internalization of the mesectoderm as embryos develop.
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Affiliation(s)
- Jessica C Yu
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Negar Balaghi
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Gonca Erdemci-Tandogan
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Veronica Castle
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada; Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.
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6
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Wang J, Dahmann C. Establishing compartment boundaries in Drosophila wing imaginal discs: An interplay between selector genes, signaling pathways and cell mechanics. Semin Cell Dev Biol 2020; 107:161-169. [PMID: 32732129 DOI: 10.1016/j.semcdb.2020.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 01/02/2023]
Abstract
The partitioning of cells into groups or 'compartments' separated by straight and sharp boundaries is important for tissue formation in animal development. Cells from neighboring compartments are characterized by distinct fates and functions and their continuous separation at compartment boundaries maintains proper tissue organization. Signaling across compartment boundaries can induce the local expression of morphogens that in turn direct growth and patterning of the surrounding cells. Compartment boundaries play therefore an important role in tissue development. Compartment boundaries were first identified in the early 1970s in the Drosophila wing. Here, we review the role of compartment boundaries in growth and patterning of the developing wing and then discuss the genetic and physical mechanisms underlying cell separation at compartment boundaries in this tissue.
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Affiliation(s)
- Jing Wang
- Institute of Genetics, Technische Universität Dresden, 01062 Dresden, Germany
| | - Christian Dahmann
- Institute of Genetics, Technische Universität Dresden, 01062 Dresden, Germany; Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062 Dresden, Germany.
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7
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Gou J, Stotsky JA, Othmer HG. Growth control in the Drosophila wing disk. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1478. [PMID: 31917525 DOI: 10.1002/wsbm.1478] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/02/2019] [Accepted: 12/17/2019] [Indexed: 12/16/2022]
Abstract
The regulation of size and shape is a fundamental requirement of biological development and has been a subject of scientific study for centuries, but we still lack an understanding of how organisms know when to stop growing. Imaginal wing disks of the fruit fly Drosophila melanogaster, which are precursors of the adult wings, are an archetypal tissue for studying growth control. The growth of the disks is dependent on many inter- and intra-organ factors such as morphogens, mechanical forces, nutrient levels, and hormones that influence gene expression and cell growth. Extracellular signals are transduced into gene-control signals via complex signal transduction networks, and since cells typically receive many different signals, a mechanism for integrating the signals is needed. Our understanding of the effect of morphogens on tissue-level growth regulation via individual pathways has increased significantly in the last half century, but our understanding of how multiple biochemical and mechanical signals are integrated to determine whether or not a cell decides to divide is still rudimentary. Numerous fundamental questions are involved in understanding the decision-making process, and here we review the major biochemical and mechanical pathways involved in disk development with a view toward providing a basis for beginning to understand how multiple signals can be integrated at the cell level, and how this translates into growth control at the level of the imaginal disk. This article is categorized under: Analytical and Computational Methods > Computational Methods Biological Mechanisms > Cell Signaling Models of Systems Properties and Processes > Cellular Models.
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Affiliation(s)
- Jia Gou
- School of Mathematics, University of Minnesota, Minneapolis, Minnesota
| | - Jay A Stotsky
- School of Mathematics, University of Minnesota, Minneapolis, Minnesota
| | - Hans G Othmer
- School of Mathematics, University of Minnesota, Minneapolis, Minnesota
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8
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Klipa O, Hamaratoglu F. Cell elimination strategies upon identity switch via modulation of apterous in Drosophila wing disc. PLoS Genet 2019; 15:e1008573. [PMID: 31877129 PMCID: PMC6952109 DOI: 10.1371/journal.pgen.1008573] [Citation(s) in RCA: 4] [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: 10/18/2019] [Revised: 01/09/2020] [Accepted: 12/17/2019] [Indexed: 12/04/2022] Open
Abstract
The ability to establish spatial organization is an essential feature of any developing tissue and is achieved through well-defined rules of cell-cell communication. Maintenance of this organization requires elimination of cells with inappropriate positional identity, a poorly understood phenomenon. Here we studied mechanisms regulating cell elimination in the context of a growing tissue, the Drosophila wing disc and its dorsal determinant Apterous. Systematic analysis of apterous mutant clones along with their twin spots shows that they are eliminated from the dorsal compartment via three different mechanisms: relocation to the ventral compartment, basal extrusion, and death, depending on the position of the clone in the wing disc. We find that basal extrusion is the main elimination mechanism in the hinge, whereas apoptosis dominates in the pouch and in the notum. In the absence of apoptosis, extrusion takes over to ensure clearance in all regions. Notably, clones in the hinge grow larger than those in the pouch, emphasizing spatial differences. Mechanistically, we find that limiting cell division within the clones does not prevent their extrusion. Indeed, even clones of one or two cells can be extruded basally, demonstrating that the clone size is not the main determinant of the elimination mechanism to be used. Overall, we revealed three elimination mechanisms and their spatial biases for preserving pattern in a growing organ. As development proceeds, cells become more specialized and the compartmentalization ensures spatial separation of the specialized cells. This process of pattern formation is rather well understood. How the pattern is maintained afterwards though is largely unknown. Using the Drosophila wing disc as a model organ, we examined what happens to dorsal cells if they lose their dorsal identity. Formerly, it was shown that these cells are eliminated from the dorsal compartment via apoptosis or through relocation to the ventral compartment. Here we show that a third mode of elimination, basal extrusion, also contributes to their clearing. We quantified, for the first time, contributions of each mechanism and discovered a regional bias in their operation. Importantly, if apoptosis is blocked, basal extrusion takes over to ensure clearance from all regions. Recent modeling approaches suggested that there is a lower limit to the clone size for extrusion. Therefore, we tested the hypothesis that the choice of elimination mechanism may be dictated by the clone size. We prevented cell divisions within the clones to be eliminated and found that even 1–2 cell clones readily underwent basal extrusion, demonstrating that there is no lower limit to the clone size for extrusion.
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Affiliation(s)
- Olga Klipa
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Fisun Hamaratoglu
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
- * E-mail:
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9
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Perochon J, Grandon B, Roche D, Wintz C, Demay Y, Mignotte B, Szuplewski S, Gaumer S. The endoplasmic reticulum unfolded protein response varies depending on the affected region of the tissue but independently from the source of stress. Cell Stress Chaperones 2019; 24:817-824. [PMID: 31144193 PMCID: PMC6629755 DOI: 10.1007/s12192-019-01009-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/30/2019] [Accepted: 05/15/2019] [Indexed: 10/26/2022] Open
Abstract
Accumulation of unfolded proteins and calcium dyshomeostasis induces endoplasmic reticulum (ER) stress, which can be resolved by the unfolded protein response (UPR). We have previously reported that activation of the PERK/ATF4 branch of the UPR, by overexpressing Presenilin in part of the vestigial domain of Drosophila wing imaginal discs, induces both a caspase-dependent apoptosis and a Slpr/JNK/Dilp8-dependent developmental delay that allows compensation of cell death in the tissue. Recently, dDad1 depletion in Drosophila in engrailed-expressing cells of wing imaginal discs was also reported to activate the PERK/ATF4 branch but induced Mekk1/JNK-dependent apoptosis. Here, we assessed whether the stressed cell location in the wing imaginal disc could explain these differences in response to chronic ER stress or whether the stress source could be responsible for the signaling discrepancy. To address this question, we overexpressed a Rhodopsin-1 mutant prone to aggregate either in vestigial- or engrailed-expressing cells. We observed similar responses to the Presenilin overexpression in the vestigial domain and to the dDad1 depletion in the engrailed domain. Therefore, the consequences of a PERK/ATF4 branch activation depend on the position of the cell in the Drosophila wing imaginal disc, suggesting interactions of PERK signaling with developmental pathways involved in the determination or maintenance of wing domains.
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Affiliation(s)
- Jessica Perochon
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
- Present Address: Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1QH UK
| | - Benjamin Grandon
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Delphine Roche
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Christine Wintz
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Yohan Demay
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Bernard Mignotte
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Sébastien Szuplewski
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Sébastien Gaumer
- Laboratoire de Génétique et Biologie Cellulaire, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
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10
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Salazar JL, Yamamoto S. Integration of Drosophila and Human Genetics to Understand Notch Signaling Related Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1066:141-185. [PMID: 30030826 PMCID: PMC6233323 DOI: 10.1007/978-3-319-89512-3_8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Notch signaling research dates back to more than one hundred years, beginning with the identification of the Notch mutant in the fruit fly Drosophila melanogaster. Since then, research on Notch and related genes in flies has laid the foundation of what we now know as the Notch signaling pathway. In the 1990s, basic biological and biochemical studies of Notch signaling components in mammalian systems, as well as identification of rare mutations in Notch signaling pathway genes in human patients with rare Mendelian diseases or cancer, increased the significance of this pathway in human biology and medicine. In the 21st century, Drosophila and other genetic model organisms continue to play a leading role in understanding basic Notch biology. Furthermore, these model organisms can be used in a translational manner to study underlying mechanisms of Notch-related human diseases and to investigate the function of novel disease associated genes and variants. In this chapter, we first briefly review the major contributions of Drosophila to Notch signaling research, discussing the similarities and differences between the fly and human pathways. Next, we introduce several biological contexts in Drosophila in which Notch signaling has been extensively characterized. Finally, we discuss a number of genetic diseases caused by mutations in genes in the Notch signaling pathway in humans and we expand on how Drosophila can be used to study rare genetic variants associated with these and novel disorders. By combining modern genomics and state-of-the art technologies, Drosophila research is continuing to reveal exciting biology that sheds light onto mechanisms of disease.
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Affiliation(s)
- Jose L Salazar
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA.
- Program in Developmental Biology, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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11
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Ventrella R, Kaplan N, Getsios S. Asymmetry at cell-cell interfaces direct cell sorting, boundary formation, and tissue morphogenesis. Exp Cell Res 2017; 358:58-64. [PMID: 28322822 PMCID: PMC5544567 DOI: 10.1016/j.yexcr.2017.03.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 03/13/2017] [Indexed: 01/22/2023]
Abstract
During development, cells of seemingly homogenous character sort themselves out into distinct compartments in order to generate cell types with specialized features that support tissue morphogenesis and function. This process is often driven by receptors at the cell membrane that probe the extracellular microenvironment for specific ligands and alter downstream signaling pathways impacting transcription, cytoskeletal organization, and cell adhesion to regulate cell sorting and subsequent boundary formation. This review will focus on two of these receptor families, Eph and Notch, both of which are intrinsically non-adhesive and are activated by a unique set of ligands that are asymmetrically distributed from their receptor on neighboring cells. Understanding the requirement of asymmetric ligand-receptor signaling at the membrane under homeostatic conditions gives insight into how misregulation of these pathways contributes to boundary disruption in diseases like cancer.
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Affiliation(s)
- Rosa Ventrella
- Department of Dermatology, Northwestern University, 303 E. Chicago Ave, Chicago, IL 60611, USA
| | - Nihal Kaplan
- Department of Dermatology, Northwestern University, 303 E. Chicago Ave, Chicago, IL 60611, USA
| | - Spiro Getsios
- Department of Dermatology, Northwestern University, 303 E. Chicago Ave, Chicago, IL 60611, USA.
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12
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Ly D, Resch E, Ordiway G, DiNardo S. Asymmetrically deployed actomyosin-based contractility generates a boundary between developing leg segments in Drosophila. Dev Biol 2017; 429:165-176. [PMID: 28689737 DOI: 10.1016/j.ydbio.2017.06.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/22/2017] [Accepted: 06/27/2017] [Indexed: 02/02/2023]
Abstract
The formation of complex tissues from simple epithelial sheets requires the regional subdivision of the developing tissue. This is initially accomplished by a sequence of gene regulatory hierarchies that set up distinct fates within adjacent territories, and rely on cross-regulatory interactions to do so. However, once adjacent territories are established, cells that confront one another across territorial boundaries must actively participate in maintaining separation from each other. Classically, it was assumed that adhesive differences would be a primary means of sorting cells to their respective territories. Yet it is becoming clear that no single, simple mechanism is at play. In the few instances studied, an emergent theme along developmental boundaries is the generation of asymmetry in cell mechanical properties. The repertoire of ways in which cells might establish and then put mechanical asymmetry to work is not fully appreciated since only a few boundaries have been molecularly studied. Here, we characterize once such boundary in the develop leg epithelium of Drosophila. The region of the pretarsus / tarsus is a known gene expression boundary that also exhibits a lineage restriction (Sakurai et al., 2007). We now show that the interface comprising this boundary is strikingly aligned compared to other cell interfaces across the disk. The boundary also exhibits an asymmetry for both Myosin II accumulation as well as one of its activators, Rho Kinase. Furthermore, the enrichment correlates with increased mechanical tension across that interface, and that tension is Rho Kinase-dependent. Lastly, interfering with actomyosin contractility, either by depletion of myosin heavy chain or expression of a phosphomimetic variant of regulatory light chain causes defects in alignment of the interfaces. These data suggest strongly that mechanical asymmetries are key in establishing and maintaining this developmental boundary.
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Affiliation(s)
- Dan Ly
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Erin Resch
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - George Ordiway
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Stephen DiNardo
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
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