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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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Fan Z, Zhang J, Wang D, Shen J. T-box transcription factors Dorsocross and optomotor-blind control Drosophila leg patterning in a functionally redundant manner. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 129:103516. [PMID: 33412239 DOI: 10.1016/j.ibmb.2020.103516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
The T-box genes are essential transcription factors during limb development. In Drosophila, Dorsocross (Doc) and optomotor-blind (omb), members of the Tbx2 and Tbx6 families, are best studied in the Drosophila wing development. Despite prominently expressed in leg discs, the specific function of these genes in leg growth is still not revealed. Here we demonstrated that Doc and omb regulated the morphogenesis of leg intermediate regions in a functionally redundant manner. Loss of Doc or omb individually did not result in any developmental defects of the legs, but loss of both genes induced significant defects in femur and proximal tibia of the adult legs. These genes located in the dorsal domain, where the Doc region expanded and cross-overlapped with the omb region corresponding to the presumptive leg intermediate region. We detected that the normal epithelial folds in the leg discs were disrupted along with dorsal repression of cell proliferation and activation of cell apoptosis when Doc and omb were both reduced. Furthermore, the dorsal expression of dachshund (dac), a canonical leg developmental gene specifying the leg intermediate region, was maintained by Doc and omb. Meanwhile, the Notch pathway was compromised in the dorsal domain when these genes were reduced, which might contribute to the joint defect of the adult leg intermediate regions. Our study provides cytological and genetic evidence for understanding the redundant function of Doc and omb in leg morphogenesis.
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Affiliation(s)
- Zongyang Fan
- Department of Entomology and MOA Lab for Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - JunZheng Zhang
- Department of Entomology and MOA Lab for Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Dan Wang
- Department of Entomology and MOA Lab for Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
| | - Jie Shen
- Department of Entomology and MOA Lab for Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
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3
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Sharrock TE, Sanson B. Cell sorting and morphogenesis in early Drosophila embryos. Semin Cell Dev Biol 2020; 107:147-160. [PMID: 32807642 DOI: 10.1016/j.semcdb.2020.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 12/25/2022]
Abstract
The regionalisation of growing tissues into compartments that do not mix is thought to be a common motif of animal development. Compartments and compartmental boundaries were discovered by lineage studies in the model organism Drosophila. Since then, many compartment boundaries have been identified in developing tissues, from insects to vertebrates. These are important for animal development, because boundaries localize signalling centres that control tissue morphogenesis. Compartment boundaries are boundaries of lineage restriction, where specific mechanisms keep boundaries straight and cells segregated. Here, we review the mechanisms of cell sorting at boundaries found in early Drosophila embryos. The parasegmental boundaries, separating anterior from posterior compartments in the embryo, keep cells segregated by increasing actomyosin contractility at boundary cell-cell interfaces. Differential actomyosin contractility in turn promotes fold formation and orients cell division. Earlier in development, actomyosin differentials are also important for cell sorting during axis extension. Specific cell surface asymmetries and signalling pathways are required to initiate and maintain these actomyosin differentials.
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Affiliation(s)
- Thomas E Sharrock
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Bénédicte Sanson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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4
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Zhang XB, Dong W, Li KX, Wang JJ, Shen J, Moussian B, Zhang JZ. Flexible manipulation of Omb levels in the endogenous expression region of Drosophila wing by combinational overexpression and suppression strategy. INSECT SCIENCE 2020; 27:14-21. [PMID: 31246335 DOI: 10.1111/1744-7917.12705] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 06/09/2023]
Abstract
Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of experiments. The Gal4/UAS system has been widely used to direct gene expression for studying complex genetic and biological problems in Drosophila melanogaster and other model organisms. Driven by a given tissue-specific Gal4, expressing UAS-transgene or UAS-RNAi (RNA interference) could be used to up- or down-regulate target gene expression, respectively. However, the efficiency of the Gal4/UAS system is roughly predefined by properties of transposon vector constructs and the insertion site in the transgenic stock. Here, we describe a simple way to modulate optomotor blind (omb) expression levels in its endogenous expression region of the wing disc. We co-expressed UAS-omb and UAS-omb-RNAi together under the control of dpp-Gal4 driver which is expressed in the omb expression region of the wing pouch. The repression effect is more sensitive to temperature than that of overexpression. At low temperature, overexpression plays a dominant role but the efficiency is attenuated by UAS-omb-RNAi. In contrast, at high temperature RNAi predominates in gene expression regulation. By this strategy, we could manipulate omb expression levels at a moderate level. It allows us to manipulate omb expression levels in the same tissue between overexpression and repression at different stages by temperature control.
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Affiliation(s)
- Xu-Bo Zhang
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
| | - Wei Dong
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
- Applied Zoology, Technical University Dresden, Zellescher Weg 20b, Dresden, Germany
- iBV, University of Nice Sophia-Antipolis, Parc Valrose, Nice, France
| | - Kai-Xia Li
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
| | - Juan-Juan Wang
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
| | - Jie Shen
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
- Department of Entomology, China Agricultural University, Beijing, China
| | - Bernard Moussian
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
- Applied Zoology, Technical University Dresden, Zellescher Weg 20b, Dresden, Germany
- iBV, University of Nice Sophia-Antipolis, Parc Valrose, Nice, France
| | - Jian-Zhen Zhang
- Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, China
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5
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Tozluoǧlu M, Duda M, Kirkland NJ, Barrientos R, Burden JJ, Muñoz JJ, Mao Y. Planar Differential Growth Rates Initiate Precise Fold Positions in Complex Epithelia. Dev Cell 2019; 51:299-312.e4. [PMID: 31607650 PMCID: PMC6838681 DOI: 10.1016/j.devcel.2019.09.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 07/10/2019] [Accepted: 09/11/2019] [Indexed: 02/08/2023]
Abstract
Tissue folding is a fundamental process that shapes epithelia into complex 3D organs. The initial positioning of folds is the foundation for the emergence of correct tissue morphology. Mechanisms forming individual folds have been studied, but the precise positioning of folds in complex, multi-folded epithelia is less well-understood. We present a computational model of morphogenesis, encompassing local differential growth and tissue mechanics, to investigate tissue fold positioning. We use the Drosophila wing disc as our model system and show that there is spatial-temporal heterogeneity in its planar growth rates. This differential growth, especially at the early stages of development, is the main driver for fold positioning. Increased apical layer stiffness and confinement by the basement membrane drive fold formation but influence positioning to a lesser degree. The model successfully predicts the in vivo morphology of overgrowth clones and wingless mutants via perturbations solely on planar differential growth in silico. Drosophila wing discs grow with spatial and temporal heterogeneity This differential growth determines the positions of epithelial folds Constriction from the basement membrane is necessary for correct fold initiation Our computational model correctly predicts the shape of growth mutants
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Affiliation(s)
- Melda Tozluoǧlu
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Maria Duda
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Natalie J Kirkland
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Ricardo Barrientos
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Jemima J Burden
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - José J Muñoz
- Mathematical and Computational Modeling (LaCàN), Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK; College of Information and Control, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
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6
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Quarta C, Fisette A, Xu Y, Colldén G, Legutko B, Tseng YT, Reim A, Wierer M, De Rosa MC, Klaus V, Rausch R, Thaker VV, Graf E, Strom TM, Poher AL, Gruber T, Le Thuc O, Cebrian-Serrano A, Kabra D, Bellocchio L, Woods SC, Pflugfelder GO, Nogueiras R, Zeltser L, Grunwald Kadow IC, Moon A, García-Cáceres C, Mann M, Treier M, Doege CA, Tschöp MH. Functional identity of hypothalamic melanocortin neurons depends on Tbx3. Nat Metab 2019; 1:222-235. [PMID: 32694784 PMCID: PMC8291379 DOI: 10.1038/s42255-018-0028-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 12/13/2018] [Indexed: 02/07/2023]
Abstract
Heterogeneous populations of hypothalamic neurons orchestrate energy balance via the release of specific signatures of neuropeptides. However, how specific intracellular machinery controls peptidergic identities and function of individual hypothalamic neurons remains largely unknown. The transcription factor T-box 3 (Tbx3) is expressed in hypothalamic neurons sensing and governing energy status, whereas human TBX3 haploinsufficiency has been linked with obesity. Here, we demonstrate that loss of Tbx3 function in hypothalamic neurons causes weight gain and other metabolic disturbances by disrupting both the peptidergic identity and plasticity of Pomc/Cart and Agrp/Npy neurons. These alterations are observed after loss of Tbx3 in both immature hypothalamic neurons and terminally differentiated mouse neurons. We further establish the importance of Tbx3 for body weight regulation in Drosophila melanogaster and show that TBX3 is implicated in the differentiation of human embryonic stem cells into hypothalamic Pomc neurons. Our data indicate that Tbx3 directs the terminal specification of neurons as functional components of the melanocortin system and is required for maintaining their peptidergic identity. In summary, we report the discovery of a key mechanistic process underlying the functional heterogeneity of hypothalamic neurons governing body weight and systemic metabolism.
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Affiliation(s)
- Carmelo Quarta
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, Bordeaux, France
| | - Alexandre Fisette
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Yanjun Xu
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - Gustav Colldén
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Beata Legutko
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Yu-Ting Tseng
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Alexander Reim
- Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany
| | - Michael Wierer
- Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany
| | - Maria Caterina De Rosa
- Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Department of Pediatrics, Columbia University, New York, NY, USA
| | - Valentina Klaus
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - Rick Rausch
- Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Department of Pediatrics, Columbia University, New York, NY, USA
| | - Vidhu V Thaker
- Naomi Berrie Diabetes Center, Division of Molecular Genetics, Department of Pediatrics, Columbia University, New York, NY, USA
| | - Elisabeth Graf
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Tim M Strom
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Anne-Laure Poher
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Tim Gruber
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Ophélia Le Thuc
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Alberto Cebrian-Serrano
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Dhiraj Kabra
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Luigi Bellocchio
- INSERM U1215, NeuroCentre Magendie, Bordeaux, France
- Université de Bordeaux, NeuroCentre Magendie, Bordeaux, France
| | - Stephen C Woods
- University of Cincinnati College of Medicine, Department of Psychiatry and Behavioral Neuroscience, Metabolic Diseases Institute, Cincinnati, OH, USA
| | - Gert O Pflugfelder
- Institute of Developmental and Neurobiology. Johannes Gutenberg-University, Mainz, Germany
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Madrid, Spain
| | - Lori Zeltser
- Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Ilona C Grunwald Kadow
- Technical University of Munich, School of Life Sciences, ZIEL - Institute for Food and Health, Freising, Germany
| | - Anne Moon
- Department of Molecular and Functional Genomics, Geisinger Clinic, Danville PA, USA
- Departments of Pediatrics and Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Cristina García-Cáceres
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany
| | - Mathias Treier
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Claudia A Doege
- Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
- Division of Metabolic Diseases, Technische Universität München, Munich, Germany.
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7
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Kane NS, Vora M, Padgett RW, Li Y. bantam microRNA is a negative regulator of the Drosophila decapentaplegic pathway. Fly (Austin) 2018; 12:105-117. [PMID: 30015555 PMCID: PMC6150632 DOI: 10.1080/19336934.2018.1499370] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Decapentaplegic (Dpp), the Drosophila homolog of the vertebrate bone morphogenetic protein (BMP2/4), is crucial for patterning and growth in many developmental contexts. The Dpp pathway is regulated at many different levels to exquisitely control its activity. We show that bantam (ban), a microRNA, modulates Dpp signaling activity. Over expression of ban decreases phosphorylated Mothers against decapentaplegic (Mad) levels and negatively affects Dpp pathway transcriptional target genes, while null mutant clones of ban upregulate the pathway. We provide evidence that dpp upregulates ban in the wing imaginal disc, and attenuation of Dpp signaling results in a reduction of ban expression, showing that they function in a feedback loop. Furthermore, we show that this feedback loop is important for maintaining anterior-posterior compartment boundary stability in the wing disc through regulation of optomotor blind (omb), a known target of the pathway. Our results support a model that ban functions with dpp in a negative feedback loop.
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Affiliation(s)
- Nanci S Kane
- a Waksman Institute, Department of Molecular Biology and Biochemistry , Cancer Institute of New Jersey, Rutgers University , Piscataway , NJ , USA
| | - Mehul Vora
- a Waksman Institute, Department of Molecular Biology and Biochemistry , Cancer Institute of New Jersey, Rutgers University , Piscataway , NJ , USA
| | - Richard W Padgett
- a Waksman Institute, Department of Molecular Biology and Biochemistry , Cancer Institute of New Jersey, Rutgers University , Piscataway , NJ , USA
| | - Ying Li
- b Life Science Institute , Chongqing Medical University , Chongqing , China
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8
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Apitz H, Salecker I. Spatio-temporal relays control layer identity of direction-selective neuron subtypes in Drosophila. Nat Commun 2018; 9:2295. [PMID: 29895891 PMCID: PMC5997761 DOI: 10.1038/s41467-018-04592-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/04/2018] [Indexed: 11/09/2022] Open
Abstract
Visual motion detection in sighted animals is essential to guide behavioral actions ensuring their survival. In Drosophila, motion direction is first detected by T4/T5 neurons. Their axons innervate one of the four lobula plate layers. How T4/T5 neurons with layer-specific representation of motion-direction preferences are specified during development is unknown. We show that diffusible Wingless (Wg) between adjacent neuroepithelia induces its own expression to form secondary signaling centers. These activate Decapentaplegic (Dpp) signaling in adjacent lateral tertiary neuroepithelial domains dedicated to producing layer 3/4-specific T4/T5 neurons. T4/T5 neurons derived from the core domain devoid of Dpp signaling adopt the default layer 1/2 fate. Dpp signaling induces the expression of the T-box transcription factor Optomotor-blind (Omb), serving as a relay to postmitotic neurons. Omb-mediated repression of Dachshund transforms layer 1/2- into layer 3/4-specific neurons. Hence, spatio-temporal relay mechanisms, bridging the distances between neuroepithelial domains and their postmitotic progeny, implement T4/T5 neuron-subtype identity.
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Affiliation(s)
- Holger Apitz
- The Francis Crick Institute, Visual Circuit Assembly Laboratory, 1 Midland Road, London, NW1 1AT, UK
| | - Iris Salecker
- The Francis Crick Institute, Visual Circuit Assembly Laboratory, 1 Midland Road, London, NW1 1AT, UK.
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9
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Urbano JM, Naylor HW, Scarpa E, Muresan L, Sanson B. Suppression of epithelial folding at actomyosin-enriched compartment boundaries downstream of Wingless signalling in Drosophila. Development 2018; 145:dev155325. [PMID: 29691225 PMCID: PMC5964650 DOI: 10.1242/dev.155325] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 03/09/2018] [Indexed: 01/01/2023]
Abstract
Epithelial folding shapes embryos and tissues during development. Here, we investigate the coupling between epithelial folding and actomyosin-enriched compartmental boundaries. The mechanistic relationship between the two is unclear, because actomyosin-enriched boundaries are not necessarily associated with folds. Also, some cases of epithelial folding occur independently of actomyosin contractility. We investigated the shallow folds called parasegment grooves that form at boundaries between anterior and posterior compartments in the early Drosophila embryo. We demonstrate that formation of these folds requires the presence of an actomyosin enrichment along the boundary cell-cell contacts. These enrichments, which require Wingless signalling, increase interfacial tension not only at the level of the adherens junctions but also along the lateral surfaces. We find that epithelial folding is normally under inhibitory control because different genetic manipulations, including depletion of the Myosin II phosphatase Flapwing, increase the depth of folds at boundaries. Fold depth correlates with the levels of Bazooka (Baz), the Par-3 homologue, along the boundary cell-cell contacts. Moreover, Wingless and Hedgehog signalling have opposite effects on fold depth at the boundary that correlate with changes in Baz planar polarity.
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Affiliation(s)
- Jose M Urbano
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Huw W Naylor
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Elena Scarpa
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Leila Muresan
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
- Cambridge Advanced Imaging Centre, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Bénédicte Sanson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
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10
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Pflugfelder G, Eichinger F, Shen J. T-Box Genes in Drosophila Limb Development. Curr Top Dev Biol 2017; 122:313-354. [DOI: 10.1016/bs.ctdb.2016.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Liu S, Sun J, Wang D, Pflugfelder GO, Shen J. Fold formation at the compartment boundary of Drosophila wing requires Yki signaling to suppress JNK dependent apoptosis. Sci Rep 2016; 6:38003. [PMID: 27897227 PMCID: PMC5126554 DOI: 10.1038/srep38003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/02/2016] [Indexed: 12/18/2022] Open
Abstract
Compartment boundaries prevent cell populations of different lineage from intermingling. In many cases, compartment boundaries are associated with morphological folds. However, in the Drosophila wing imaginal disc, fold formation at the anterior/posterior (A/P) compartment boundary is suppressed, probably as a prerequisite for the formation of a flat wing surface. Fold suppression depends on optomotor-blind (omb). Omb mutant animals develop a deep apical fold at the A/P boundary of the larval wing disc and an A/P cleft in the adult wing. A/P fold formation is controlled by different signaling pathways. Jun N-terminal kinase (JNK) and Yorkie (Yki) signaling are activated in cells along the fold and are necessary for the A/P fold to develop. While JNK promotes cell shape changes and cell death, Yki target genes are required to antagonize apoptosis, explaining why both pathways need to be active for the formation of a stable fold.
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Affiliation(s)
- Suning Liu
- Department of Entomology, China Agricultural University, 100193 Beijing, China
| | - Jie Sun
- Department of Entomology, China Agricultural University, 100193 Beijing, China
| | - Dan Wang
- Department of Entomology, China Agricultural University, 100193 Beijing, China
| | - Gert O Pflugfelder
- Institute of Genetics, Johannes Gutenberg-University, 55128 Mainz, Germany
| | - Jie Shen
- Department of Entomology, China Agricultural University, 100193 Beijing, China
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12
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Wang D, Li L, Lu J, Liu S, Shen J. Complementary expression of optomotor-blind and the Iroquois complex promotes fold formation to separate wing notum and hinge territories. Dev Biol 2016; 416:225-234. [DOI: 10.1016/j.ydbio.2016.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 04/13/2016] [Accepted: 05/16/2016] [Indexed: 01/05/2023]
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13
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Shen J, Lu J, Sui L, Wang D, Yin M, Hoffmann I, Legler A, Pflugfelder GO. The orthologous Tbx transcription factors Omb and TBX2 induce epithelial cell migration and extrusion in vivo without involvement of matrix metalloproteinases. Oncotarget 2015; 5:11998-2015. [PMID: 25344916 PMCID: PMC4322970 DOI: 10.18632/oncotarget.2426] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/02/2014] [Indexed: 01/06/2023] Open
Abstract
The transcription factors TBX2 and TBX3 are overexpressed in various human cancers. Here, we investigated the effect of overexpressing the orthologous Tbx genes Drosophila optomotor-blind (omb) and human TBX2 in the epithelium of the Drosophila wing imaginal disc and observed two types of cell motility. Omb/TBX2 overexpressing cells could move within the plane of the epithelium. Invasive cells migrated long-distance as single cells retaining or regaining normal cell shape and apico-basal polarity in spite of attenuated apical DE-cadherin concentration. Inappropriate levels of DE-cadherin were sufficient to drive cell migration in the wing disc epithelium. Omb/TBX2 overexpression and reduced DE-cadherin-dependent adhesion caused the formation of actin-rich lateral cell protrusions. Omb/TBX2 overexpressing cells could also delaminate basally, penetratingthe basal lamina, however, without degradation of extracellular matrix. Expression of Timp, an inhibitor of matrix metalloproteases, blocked neither intraepithelial motility nor basal extrusion. Our results reveal an MMP-independent mechanism of cell invasion and suggest a conserved role of Tbx2-related proteins in cell invasion and metastasis-related processes.
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Affiliation(s)
- Jie Shen
- Department of Entomology, China Agricultural University, Beijing, China
| | - Juan Lu
- Department of Entomology, China Agricultural University, Beijing, China
| | - Liyuan Sui
- Department of Entomology, China Agricultural University, Beijing, China
| | - Dan Wang
- Department of Entomology, China Agricultural University, Beijing, China
| | - Meizhen Yin
- Key Laboratory of Carbon Fiber and Functional Polymers, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing, China
| | - Inka Hoffmann
- Institute of Genetics, Johannes Gutenberg-University, Mainz, Germany
| | - Anne Legler
- Institute of Genetics, Johannes Gutenberg-University, Mainz, Germany
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14
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Tsai YC, Grimm S, Chao JL, Wang SC, Hofmeyer K, Shen J, Eichinger F, Michalopoulou T, Yao CK, Chang CH, Lin SH, Sun YH, Pflugfelder GO. Optomotor-blind negatively regulates Drosophila eye development by blocking Jak/STAT signaling. PLoS One 2015; 10:e0120236. [PMID: 25781970 PMCID: PMC4363906 DOI: 10.1371/journal.pone.0120236] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 01/27/2015] [Indexed: 12/23/2022] Open
Abstract
Organ formation requires a delicate balance of positive and negative regulators. In Drosophila eye development, wingless (wg) is expressed at the lateral margins of the eye disc and serves to block retinal development. The T-box gene optomotor-blind (omb) is expressed in a similar pattern and is regulated by Wg. Omb mediates part of Wg activity in blocking eye development. Omb exerts its function primarily by blocking cell proliferation. These effects occur predominantly in the ventral margin. Our results suggest that the primary effect of Omb is the blocking of Jak/STAT signaling by repressing transcription of upd which encodes the Jak receptor ligand Unpaired.
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Affiliation(s)
- Yu-Chen Tsai
- Institute of Genetics, National Yang-Ming University, Taipei; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
- Department of Life Science and Life Science Center, Tunghai University, Taichung, Taiwan, Republic of China
| | - Stefan Grimm
- Theodor-Boveri-Institut, Biozentrum, Lehrstuhl für Genetik und Neurobiologie, Universität Würzburg, Am Hubland, Würzburg, Germany
| | - Ju-Lan Chao
- Institute of Genetics, National Yang-Ming University, Taipei; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Shih-Chin Wang
- Department of Life Science and Life Science Center, Tunghai University, Taichung, Taiwan, Republic of China
| | - Kerstin Hofmeyer
- Theodor-Boveri-Institut, Biozentrum, Lehrstuhl für Genetik und Neurobiologie, Universität Würzburg, Am Hubland, Würzburg, Germany
| | - Jie Shen
- Institut für Genetik, Universität Mainz, Mainz, Germany
- Department of Entomology, China Agricultural University, Beijing, China
| | | | | | - Chi-Kuang Yao
- Institute of Genetics, National Yang-Ming University, Taipei; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Chih-Hsuan Chang
- Department of Life Science and Life Science Center, Tunghai University, Taichung, Taiwan, Republic of China
| | - Shih-Han Lin
- Department of Life Science and Life Science Center, Tunghai University, Taichung, Taiwan, Republic of China
| | - Y. Henry Sun
- Institute of Genetics, National Yang-Ming University, Taipei; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
- * E-mail: (YHS); (GOP)
| | - Gert O. Pflugfelder
- Theodor-Boveri-Institut, Biozentrum, Lehrstuhl für Genetik und Neurobiologie, Universität Würzburg, Am Hubland, Würzburg, Germany
- Institut für Genetik, Universität Mainz, Mainz, Germany
- * E-mail: (YHS); (GOP)
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15
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Sen A, Grimm S, Hofmeyer K, Pflugfelder GO. Optomotor-blindin the Development of theDrosophilaHS and VS Lobula Plate Tangential Cells. J Neurogenet 2014; 28:250-63. [DOI: 10.3109/01677063.2014.917645] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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16
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Zhang X, Luo D, Pflugfelder GO, Shen J. Dpp signaling inhibits proliferation in the Drosophila wing by Omb-dependent regional control of bantam. Development 2013; 140:2917-22. [PMID: 23821035 DOI: 10.1242/dev.094300] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The control of organ growth is a fundamental aspect of animal development but remains poorly understood. The morphogen Dpp has long been considered as a general promoter of cell proliferation during Drosophila wing development. It is an ongoing debate whether the Dpp gradient is required for the uniform cell proliferation observed in the wing imaginal disc. Here, we investigated how the Dpp signaling pathway regulates proliferation during wing development. By systematic manipulation of Dpp signaling we observed that it controls proliferation in a region-specific manner: Dpp, via omb, promoted proliferation in the lateral and repressed proliferation in the medial wing disc. Omb controlled the regional proliferation rate by oppositely regulating transcription of the microRNA gene bantam in medial versus lateral wing disc. However, neither the Dpp nor Omb gradient was essential for uniform proliferation along the anteroposterior axis.
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Affiliation(s)
- Xubo Zhang
- Department of Entomology, China Agricultural University, 100193 Beijing, China
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The embryonic transcription factor Zelda of Drosophila melanogaster is also expressed in larvae and may regulate developmentally important genes. Biochem Biophys Res Commun 2013; 438:329-33. [PMID: 23891688 DOI: 10.1016/j.bbrc.2013.07.071] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 07/17/2013] [Indexed: 11/20/2022]
Abstract
The transcription factor Zelda plays a pivotal role in promoting the maternal to zygotic transition during embryogenesis in Drosophila melanogaster. However, little is known about its role later in development. Here we are showing that Zelda is essential for proper wing development through gain and loss of function experiments. Zelda's transcript variants RB, RC and RD are present in imaginal wing discs of third instar larvae and the production of 2 protein isoforms of ∼180 and ∼70kD was detected in the same tissue. In ChIP experiments using larval wing discs, Zelda was found to bind to a region of the optomotor-blind gene, suggesting an interaction with a Dpp target that promotes wing growth and patterning.
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Mayer LR, Diegelmann S, Abassi Y, Eichinger F, Pflugfelder GO. Enhancer trap infidelity in Drosophila optomotor-blind. Fly (Austin) 2013; 7:118-28. [PMID: 23519069 DOI: 10.4161/fly.23657] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Reporter gene activity in enhancer trap lines is often implicitly assumed to mirror quite faithfully the endogenous expression of the "trapped" gene, even though there are numerous examples of enhancer trap infidelity. optomotor-blind (omb) is a 160 kb gene in which 16 independent P-element enhancer trap insertions of three different types have been mapped in a range of more than 60 kb. We have determined the expression pattern of these elements in wing, eye-antennal and leg imaginal discs as well as in the pupal tergites. We noted that one pGawB insertion (omb (P4) ) selectively failed to report parts of the omb pattern even though the missing pattern elements were apparent in all other 15 lines. We ruled out that omb (P4) was defective in the Gal4 promoter region or had inactivated genomic enhancers in the integration process. We propose that the Gal4 reporter gene in pGawB may be sensitive to orientation or promoter proximity effects.
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Affiliation(s)
- Lisa R Mayer
- Institute of Genetics, Johannes Gutenberg-Universität, Mainz, Germany
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Sui L, Pflugfelder GO, Shen J. The Dorsocross T-box transcription factors promote tissue morphogenesis in the Drosophila wing imaginal disc. Development 2012; 139:2773-82. [PMID: 22782723 DOI: 10.1242/dev.079384] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The Drosophila wing imaginal disc is subdivided into notum, hinge and blade territories during the third larval instar by formation of several deep apical folds. The molecular mechanisms of these subdivisions and the subsequent initiation of morphogenic processes during metamorphosis are poorly understood. Here, we demonstrate that the Dorsocross (Doc) T-box genes promote the progression of epithelial folds that not only separate the hinge and blade regions of the wing disc but also contribute to metamorphic development by changing cell shapes and bending the wing disc. We found that Doc expression was restricted by two inhibitors, Vestigial and Homothorax, leading to two narrow Doc stripes where the folds separating hinge and blade are forming. Doc mutant clones prevented the lateral extension and deepening of these folds at the larval stage and delayed wing disc bending in the early pupal stage. Ectopic Doc expression was sufficient to generate deep apical folds by causing a basolateral redistribution of the apical microtubule web and a shortening of cells. Cells of both the endogenous blade/hinge folds and of folds elicited by ectopic Doc expression expressed Matrix metalloproteinase 2 (Mmp2). In these folds, integrins and extracellular matrix proteins were depleted. Overexpression of Doc along the blade/hinge folds caused precocious wing disc bending, which could be suppressed by co-expressing MMP2RNAi.
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Affiliation(s)
- Liyuan Sui
- Department of Entomology, China Agricultural University, Beijing, China
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20
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Monier B, Pélissier-Monier A, Sanson B. Establishment and maintenance of compartmental boundaries: role of contractile actomyosin barriers. Cell Mol Life Sci 2011; 68:1897-910. [PMID: 21437644 PMCID: PMC11114499 DOI: 10.1007/s00018-011-0668-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 02/12/2011] [Accepted: 03/08/2011] [Indexed: 12/29/2022]
Abstract
During animal development, tissues and organs are partitioned into compartments that do not intermix. This organizing principle is essential for correct tissue morphogenesis. Given that cell sorting defects during compartmentalization in humans are thought to cause malignant invasion and congenital defects such as cranio-fronto-nasal syndrome, identifying the molecular and cellular mechanisms that keep cells apart at boundaries between compartments is important. In both vertebrates and invertebrates, transcription factors and short-range signalling pathways, such as EPH/Ephrin, Hedgehog, or Notch signalling, govern compartmental cell sorting. However, the mechanisms that mediate cell sorting downstream of these factors have remained elusive for decades. Here, we review recent data gathered in Drosophila that suggest that the generation of cortical tensile forces at compartmental boundaries by the actomyosin cytoskeleton could be a general mechanism that inhibits cell mixing between compartments.
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Affiliation(s)
- Bruno Monier
- Department of Physiology, Development and Neuroscience, Anatomy Building, Downing Street, Cambridge, CB2 3DY UK
- Present Address: Institut de Biologie du Développement de Marseille-Luminy, UMR6216, Campus de Luminy, Case 907, 13288 Marseille cedex 9, France
| | - Anne Pélissier-Monier
- Department of Physiology, Development and Neuroscience, Anatomy Building, Downing Street, Cambridge, CB2 3DY UK
- Wellcome Trust, Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN UK
- Present Address: Institut de Biologie du Développement de Marseille-Luminy, UMR6216, Campus de Luminy, Case 907, 13288 Marseille cedex 9, France
| | - Bénédicte Sanson
- Department of Physiology, Development and Neuroscience, Anatomy Building, Downing Street, Cambridge, CB2 3DY UK
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Abstract
During morphogenesis, tissues are shaped by cell behaviors such as apical cell constriction and cell intercalation, which are the result of cell intrinsic forces, but are also shaped passively by forces acting on the cells. The latter extrinsic forces can be produced either within the deforming tissue by the tissue-scale integration of intrinsic forces, or outside the tissue by other tissue movements or by fluid flows. Here we review the intrinsic and extrinsic forces that sculpt the epithelium of early Drosophila embryos, focusing on three conserved morphogenetic processes: tissue internalization, axis extension, and segment boundary formation. Finally, we look at how the actomyosin cytoskeleton forms force-generating structures that power these three morphogenetic events at the cell and the tissue scales.
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Shen J, Dahmann C, Pflugfelder GO. Spatial discontinuity of optomotor-blind expression in the Drosophila wing imaginal disc disrupts epithelial architecture and promotes cell sorting. BMC DEVELOPMENTAL BIOLOGY 2010; 10:23. [PMID: 20178599 PMCID: PMC2838827 DOI: 10.1186/1471-213x-10-23] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 02/23/2010] [Indexed: 12/02/2022]
Abstract
Background Decapentaplegic (Dpp) is one of the best characterized morphogens, required for dorso-ventral patterning of the Drosophila embryo and for anterior-posterior (A/P) patterning of the wing imaginal disc. In the larval wing pouch, the Dpp target gene optomotor-blind (omb) is generally assumed to be expressed in a step function above a certain threshold of Dpp signaling activity. Results We show that the transcription factor Omb forms, in fact, a symmetrical gradient on both sides of the A/P compartment boundary. Disruptions of the Omb gradient lead to a re-organization of the epithelial cytoskeleton and to a retraction of cells toward the basal membrane suggesting that the Omb gradient is required for correct epithelial morphology. Moreover, by analysing the shape of omb gain- and loss-of-function clones, we find that Omb promotes cell sorting along the A/P axis in a concentration-dependent manner. Conclusions Our findings show that Omb distribution in the wing imaginal disc is described by a gradient rather than a step function. Graded Omb expression is necessary for normal cell morphogenesis and cell affinity and sharp spatial discontinuities must be avoided to allow normal wing development.
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Affiliation(s)
- Jie Shen
- Department of Entomology, China Agricultural University, Beijing, China
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Sen A, Gadomski C, Balles J, Abassi Y, Dorner C, Pflugfelder GO. Null mutations in Drosophila Optomotor-blind affect T-domain residues conserved in all Tbx proteins. Mol Genet Genomics 2009; 283:147-56. [PMID: 20033428 DOI: 10.1007/s00438-009-0505-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 12/05/2009] [Indexed: 12/11/2022]
Abstract
The T-box transcription factors TBX2 and TBX3 are overexpressed in many human cancers raising the need for a thorough understanding of the cellular function of these proteins. In Drosophila, there is one corresponding ortholog, Optomotor-blind (Omb). Currently, only two missense mutations are known for the two human proteins. Making use of the developmental defects caused by inactivation of omb, we have isolated and molecularly characterized four new omb mutations, three of them are missense mutations of amino acids fully conserved in all Tbx proteins. We interpret the functional defects in the framework of the known structure of the human TBX3 protein and provide evidence for loss of Omb DNA-binding activity in all three newly identified missense mutations.
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Affiliation(s)
- Aditya Sen
- Institute of Genetics, Johannes Gutenberg-Universität, Becherweg 32, 55128, Mainz, Germany
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24
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Abstract
Transforming growth factor beta (TGFbeta) pathways are implicated in metazoan development, adult homeostasis and disease. TGFbeta ligands signal via receptor serine/threonine kinases that phosphorylate, and activate, intracellular Smad effectors as well as other signaling proteins. Oligomeric Smad complexes associate with chromatin and regulate transcription, defining the biological response of a cell to TGFbeta family members. Signaling is modulated by negative-feedback regulation via inhibitory Smads. We review here the mechanisms of TGFbeta signal transduction in metazoans and emphasize events crucial for embryonic development.
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