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Pi Z, Huang J, Wang S, Xie H, Qu Y, Zhou Z, Wang S, Liu Y, Wang C, Meng F, Cai J. Intrapuparial stage aging and PMI estimation based on the developmental transcriptomes of forensically important Aldrichina grahami (Diptera: Calliphoridae) gene expression. Heliyon 2024; 10:e33319. [PMID: 39027590 PMCID: PMC11255450 DOI: 10.1016/j.heliyon.2024.e33319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/14/2024] [Accepted: 06/19/2024] [Indexed: 07/20/2024] Open
Abstract
Background The expression profiles of differentially expressed genes (DEGs) during pupal development have been demonstrated to be vital in age estimation of forensic entomological study. Here, using forensically important Aldrichina grahami (Diptera: Calliphoridae), we aimed to explore the potential of intrapuparial stage aging and postmortem interval (PMI) estimation based on characterization of successive developmental transcriptomes and gene expression patterns. Methods We collected A. grahami pupae at 11 successive intrapuparial stages at 20 °C and used the RNA-seq technique to build the transcriptome profiles of their intrapuparial stages. The DEGs were identified during the different intrapuparial stages using comparative transcriptome analysis. The selected marker DEGs were classified and clustered for intrapuparial stage aging and PMI estimation and then further verified for transcriptome data validation. Ultimately, we categorized the overall gene expression levels as the dependent variable and the age of intrapuparial A. grahami as the independent variable to conduct nonlinear regression analysis. Results We redefined the intrapuparial stages of A. grahami into five key successive substages (I, II, III, IV, and V), based on the overall gene expression patterns during pupal development. We screened 99 specific time-dependent expressed genes (stage-specific DEGs) to determine the different intrapuparial stages based on comparison of the gene expression levels during the 11 developmental intrapuparial stages of A. grahami. We observed that 55 DEGs showed persistent upregulation during the development of intrapuparial A. grahami. We then selected four DEGs (act79b, act88f, up and ninac) which presented consistent upregulation using RT-qPCR (quantitative real-time PCR) analysis, along with consideration of the maximum fold changes during the pupal development. We conducted nonlinear regression analysis to simulate the calculations of the relationships between the expression levels of the four selected DEGs and the developmental time of intrapuparial A. grahami and constructed fitting curves. The curves demonstrated that act79b and ninac showed continuous relatively increasing levels. Conclusions This study redefined the intrapuparial stages of A. grahami based on expression profiles of developmental transcriptomes for the first time. The stage-specific DEGs and those with consistent tendencies of expression were found to have potential in age estimation of intrapuparial A. grahami and could be supplementary to a more accurate prediction of PMI.
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Affiliation(s)
- Zhiyun Pi
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Jingjing Huang
- Department of Forensic Medicine, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Shiwen Wang
- Department of Forensic Medicine, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Hui Xie
- Department of Forensic Medicine, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Yihong Qu
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Ziqi Zhou
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Shujuan Wang
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Yishu Liu
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Chudong Wang
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Fanming Meng
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Jifeng Cai
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
- Department of Forensic Medicine, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, China
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George LF, Follmer ML, Fontenoy E, Moran HR, Brown JR, Ozekin YH, Bates EA. Endoplasmic Reticulum Calcium Mediates Drosophila Wing Development. Bioelectricity 2023; 5:290-306. [PMID: 38143873 PMCID: PMC10733776 DOI: 10.1089/bioe.2022.0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023] Open
Abstract
Background The temporal dynamics of morphogen presentation impacts transcriptional responses and tissue patterning. However, the mechanisms controlling morphogen release are far from clear. We found that inwardly rectifying potassium (Irk) channels regulate endogenous transient increases in intracellular calcium and bone morphogenetic protein (BMP/Dpp) release for Drosophila wing development. Inhibition of Irk channels reduces BMP/Dpp signaling, and ultimately disrupts wing morphology. Ion channels impact development of several tissues and organisms in which BMP signaling is essential. In neurons and pancreatic beta cells, Irk channels modulate membrane potential to affect intracellular Ca++ to control secretion of neurotransmitters and insulin. Based on Irk activity in neurons, we hypothesized that electrical activity controls endoplasmic reticulum (ER) Ca++ release into the cytoplasm to regulate the release of BMP. Materials and Methods To test this hypothesis, we reduced expression of four proteins that control ER calcium, Stromal interaction molecule 1 (Stim), Calcium release-activated calcium channel protein 1 (Orai), SarcoEndoplasmic Reticulum Calcium ATPase (SERCA), small conductance calcium-activated potassium channel (SK), and Bestrophin 2 (Best2) using RNAi and documented wing phenotypes. We use live imaging to study calcium and Dpp release within pupal wings and larval wing discs. Additionally, we employed immunohistochemistry to characterize Small Mothers Against Decapentaplegic (SMAD) phosphorylation downstream of the BMP/Dpp pathway following RNAi knockdown. Results We found that reduced Stim and SERCA function decreases amplitude and frequency of endogenous calcium transients in the wing disc and reduced BMP/Dpp release. Conclusion Our results suggest control of ER calcium homeostasis is required for BMP/Dpp release, and Drosophila wing development.
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Affiliation(s)
- Laura Faith George
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Mikaela Lynn Follmer
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emily Fontenoy
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Hannah Rose Moran
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jeremy Ryan Brown
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Yunus H. Ozekin
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emily Anne Bates
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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Baldenius M, Kautzmann S, Nanda S, Klämbt C. Signaling Pathways Controlling Axonal Wrapping in Drosophila. Cells 2023; 12:2553. [PMID: 37947631 PMCID: PMC10647682 DOI: 10.3390/cells12212553] [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: 10/02/2023] [Revised: 10/24/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023] Open
Abstract
The rapid transmission of action potentials is an important ability that enables efficient communication within the nervous system. Glial cells influence conduction velocity along axons by regulating the radial axonal diameter, providing electrical insulation as well as affecting the distribution of voltage-gated ion channels. Differentiation of these wrapping glial cells requires a complex set of neuron-glia interactions involving three basic mechanistic features. The glia must recognize the axon, grow around it, and eventually arrest its growth to form single or multiple axon wraps. This likely depends on the integration of numerous evolutionary conserved signaling and adhesion systems. Here, we summarize the mechanisms and underlying signaling pathways that control glial wrapping in Drosophila and compare those to the mechanisms that control glial differentiation in mammals. This analysis shows that Drosophila is a beneficial model to study the development of even complex structures like myelin.
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Affiliation(s)
| | | | | | - Christian Klämbt
- Institute for Neuro- and Behavioral Biology, Faculty of Biology, University of Münster, Röntgenstraße 16, D-48149 Münster, Germany; (M.B.)
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4
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Pogoda HM, Riedl-Quinkertz I, Hammerschmidt M. Direct BMP signaling to chordoblasts is required for the initiation of segmented notochord sheath mineralization in zebrafish vertebral column development. Front Endocrinol (Lausanne) 2023; 14:1107339. [PMID: 37223044 PMCID: PMC10200950 DOI: 10.3389/fendo.2023.1107339] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/15/2023] [Indexed: 05/25/2023] Open
Abstract
The vertebral column, with the centra as its iteratively arranged building blocks, represents the anatomical key feature of the vertebrate phylum. In contrast to amniotes, where vertebrae are formed from chondrocytes and osteoblasts deriving from the segmentally organized neural crest or paraxial sclerotome, teleost vertebral column development is initiated by chordoblasts of the primarily unsegmented axial notochord, while sclerotomal cells only contribute to later steps of vertebrae formation. Yet, for both mammalian and teleostean model systems, unrestricted signaling by Bone Morphogenetic Proteins (BMPs) or retinoic acid (RA) has been reported to cause fusions of vertebral elements, while the interplay of the two signaling processes and their exact cellular targets remain largely unknown. Here, we address this interplay in zebrafish, identifying BMPs as potent and indispensable factors that, as formerly shown for RA, directly signal to notochord epithelial cells/chordoblasts to promote entpd5a expression and thereby metameric notochord sheath mineralization. In contrast to RA, however, which promotes sheath mineralization at the expense of further collagen secretion and sheath formation, BMP defines an earlier transitory stage of chordoblasts, characterized by sustained matrix production/col2a1 expression and concomitant matrix mineralization/entpd5a expression. BMP-RA epistasis analyses further indicate that RA can only affect chordoblasts and their further progression to merely mineralizing cells after they have received BMP signals to enter the transitory col2a1/entpd5a double-positive stage. This way, both signals ensure consecutively for proper mineralization of the notochord sheath within segmented sections along its anteroposterior axis. Our work sheds further light onto the molecular mechanisms that orchestrate early steps of vertebral column segmentation in teleosts. Similarities and differences to BMP's working mechanisms during mammalian vertebral column formation and the pathomechanisms underlying human bone diseases such as Fibrodysplasia Ossificans Progressiva (FOP) caused by constitutively active BMP signaling are discussed.
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Affiliation(s)
- Hans-Martin Pogoda
- Institute of Zoology – Developmental Biology, University of Cologne, Cologne, Germany
| | - Iris Riedl-Quinkertz
- Institute of Zoology – Developmental Biology, University of Cologne, Cologne, Germany
| | - Matthias Hammerschmidt
- Institute of Zoology – Developmental Biology, University of Cologne, Cologne, Germany
- Cluster of Excellence, Cellular Stress Responses in Aging-Associated Diseases (CECAD) Cluster of Excellence, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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5
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Sharma V, Sarkar B, Mutsuddi M, Mukherjee A. Deltex modulates Dpp morphogen gradient formation and affects the Dpp signaling in Drosophila. J Cell Sci 2022; 135:276290. [PMID: 35950520 DOI: 10.1242/jcs.259658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 07/29/2022] [Indexed: 11/20/2022] Open
Abstract
Deltex (Dx) is a context-dependent regulator of Notch signaling and regulates Notch signaling in a non-canonical fashion by facilitating the endocytosis of its receptor. In an RNAi- based modifier screen of kinases and phosphatases Thickveins (Tkv), the receptor of Decapentaplegic (Dpp), was identified as one of the interactors of Dx. Dpp, a Drosophila TGF-β/Bone Morphogenetic Protein homolog acts as a morphogen to specify cell fate along the anterior-posterior axis of the wing. Tight regulation of Dpp signaling is thus indispensable for its proper functioning. Here we present Dx as a novel modulator of Dpp signaling. We show evidence for the very first time that dx genetically interacts with dpp and its pathway components. Immunocytochemical analysis shows that Dx co-localizes with Dpp and its receptor Tkv in the Drosophila third instar larval tissues. Further, Dx is also seen to modulate the expression of dpp and its target genes. Here, we attribute this modulation to the endocytosis and trafficking of Dpp through Dx. This study thus presents a whole new avenue of Dpp signaling regulation via the cytoplasmic protein Dx.
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Affiliation(s)
- Vartika Sharma
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| | - Bappi Sarkar
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
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6
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Follmer M, Shrawder B, Eckert K, Heinly B, Vivekanand P. The effectiveness of EGFR knockdown by RNAi lines varies depending on the tissue. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000612. [PMID: 35903780 PMCID: PMC9315407 DOI: 10.17912/micropub.biology.000612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/18/2022]
Abstract
In Drosophila , the Epidermal growth factor receptor (EGFR) signaling pathway is known to be critically involved in multiple stages of development. We induced a loss of function phenotype in the eyes, wings, and somatic follicle cells using four EGFR RNAi lines: HMS05003 and JF02283, which produce short hairpin RNAs, as well as JF01368 and KK100051, which produce long hairpin RNAs. Using these four lines, we completed a systematic comparison of the ability of short hairpin vs long hairpin RNAi lines to produce loss-of-function phenotypes in the above-mentioned tissues. Tissue specific knockdown was achieved by using Gal4 drivers specific to the three tissues being studied. In the eyes and wings, the KK100051 line induced the most severe phenotype, while the JF01368 line was the least severe, but in the somatic follicle cells, the KK100051 line was the least effective, while the JF01368 and JF02283 lines were comparable with respect to phenotypic severity. We conclude that there is significant tissue specific variability exhibited by the different RNAi lines.
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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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8
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Yang S, Wu X, Daoutidou EI, Zhang Y, Shimell M, Chuang KH, Peterson AJ, O'Connor MB, Zheng X. The NDNF-like factor Nord is a Hedgehog-induced extracellular BMP modulator that regulates Drosophila wing patterning and growth. eLife 2022; 11:e73357. [PMID: 35037619 PMCID: PMC8856659 DOI: 10.7554/elife.73357] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 01/15/2022] [Indexed: 11/23/2022] Open
Abstract
Hedgehog (Hh) and Bone Morphogenetic Proteins (BMPs) pattern the developing Drosophila wing by functioning as short- and long-range morphogens, respectively. Here, we show that a previously unknown Hh-dependent mechanism fine-tunes the activity of BMPs. Through genome-wide expression profiling of the Drosophila wing imaginal discs, we identify nord as a novel target gene of the Hh signaling pathway. Nord is related to the vertebrate Neuron-Derived Neurotrophic Factor (NDNF) involved in congenital hypogonadotropic hypogonadism and several types of cancer. Loss- and gain-of-function analyses implicate Nord in the regulation of wing growth and proper crossvein patterning. At the molecular level, we present biochemical evidence that Nord is a secreted BMP-binding protein and localizes to the extracellular matrix. Nord binds to Decapentaplegic (Dpp) or the heterodimer Dpp-Glass-bottom boat (Gbb) to modulate their release and activity. Furthermore, we demonstrate that Nord is a dosage-dependent BMP modulator, where low levels of Nord promote and high levels inhibit BMP signaling. Taken together, we propose that Hh-induced Nord expression fine-tunes both the range and strength of BMP signaling in the developing Drosophila wing.
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Affiliation(s)
- Shu Yang
- Department of Anatomy and Cell Biology and the GW Cancer Center, George Washington University School of Medicine and Health SciencesWashingtonUnited States
| | - Xuefeng Wu
- Department of Anatomy and Cell Biology and the GW Cancer Center, George Washington University School of Medicine and Health SciencesWashingtonUnited States
| | - Euphrosyne I Daoutidou
- Department of Genetics, Cell Biology & Development and the Developmental Biology Center, University of MinnesotaMinneapolisUnited States
| | - Ya Zhang
- Department of Anatomy and Cell Biology and the GW Cancer Center, George Washington University School of Medicine and Health SciencesWashingtonUnited States
| | - MaryJane Shimell
- Department of Genetics, Cell Biology & Development and the Developmental Biology Center, University of MinnesotaMinneapolisUnited States
| | - Kun-Han Chuang
- Department of Anatomy and Cell Biology and the GW Cancer Center, George Washington University School of Medicine and Health SciencesWashingtonUnited States
| | - Aidan J Peterson
- Department of Genetics, Cell Biology & Development and the Developmental Biology Center, University of MinnesotaMinneapolisUnited States
| | - Michael B O'Connor
- Department of Genetics, Cell Biology & Development and the Developmental Biology Center, University of MinnesotaMinneapolisUnited States
| | - Xiaoyan Zheng
- Department of Anatomy and Cell Biology and the GW Cancer Center, George Washington University School of Medicine and Health SciencesWashingtonUnited States
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9
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Soler Beatty J, Molnar C, Luque CM, de Celis JF, Martín-Bermudo MD. EGFRAP encodes a new negative regulator of the EGFR acting in both normal and oncogenic EGFR/Ras-driven tissue morphogenesis. PLoS Genet 2021; 17:e1009738. [PMID: 34411095 PMCID: PMC8407591 DOI: 10.1371/journal.pgen.1009738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 08/31/2021] [Accepted: 07/23/2021] [Indexed: 12/27/2022] Open
Abstract
Activation of Ras signaling occurs in ~30% of human cancers. However, activated Ras alone is insufficient to produce malignancy. Thus, it is imperative to identify those genes cooperating with activated Ras in driving tumoral growth. In this work, we have identified a novel EGFR inhibitor, which we have named EGFRAP, for EGFR adaptor protein. Elimination of EGFRAP potentiates activated Ras-induced overgrowth in the Drosophila wing imaginal disc. We show that EGFRAP interacts physically with the phosphorylated form of EGFR via its SH2 domain. EGFRAP is expressed at high levels in regions of maximal EGFR/Ras pathway activity, such as at the presumptive wing margin. In addition, EGFRAP expression is up-regulated in conditions of oncogenic EGFR/Ras activation. Normal and oncogenic EGFR/Ras-mediated upregulation of EGRAP levels depend on the Notch pathway. We also find that elimination of EGFRAP does not affect overall organogenesis or viability. However, simultaneous downregulation of EGFRAP and its ortholog PVRAP results in defects associated with increased EGFR function. Based on these results, we propose that EGFRAP is a new negative regulator of the EGFR/Ras pathway, which, while being required redundantly for normal morphogenesis, behaves as an important modulator of EGFR/Ras-driven tissue hyperplasia. We suggest that the ability of EGFRAP to functionally inhibit the EGFR pathway in oncogenic cells results from the activation of a feedback loop leading to increase EGFRAP expression. This could act as a surveillance mechanism to prevent excessive EGFR activity and uncontrolled cell growth. Activation of Ras signalling occurs in ~30% of human cancers. However, activated Ras alone is insufficient to produce malignancy. Thus, the discovery of genes cooperating with Ras in cancer is imperative to understand tumoral growth driven by Ras activating mutations. A key output of over-activated EGFR/Ras signalling is the induction of a complex and dynamic set of transcriptional networks leading to changes in gene expression. As a result of these changes, the normal function of some genes can become adjusted in a tumorigenic context. In this work, using the Drosophila wing imaginal disc as model system, we have identified a new EGFR inhibitor, EGFRAP, which function is redundant for proper morphogenesis, yet becomes an important limiter of the overgrowth driven by oncogenic EGFR/Ras activity. We show that the specificity of EGFRAP in cells with high levels of EGFR activity arises from activation of a negative feedback loop resulting in increased EGFRAP levels. This could act to prevent excessive EGFR activity and uncontrolled cell growth. We believe the identification of other factors behaving like EGFRAP, will help in our fight against cancer, as it might lead to the identification of new therapeutic drugs affecting cancer but not normal cells, a top priority in cancer research.
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Affiliation(s)
- Jennifer Soler Beatty
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC/JA, Sevilla, Spain
| | - Cristina Molnar
- Centro de Biología Molecular Severo Ochoa (UAM/CSIC), Univ. Autónoma de Madrid, Madrid, Spain
| | - Carlos M. Luque
- Centro de Biología Molecular Severo Ochoa (UAM/CSIC), Univ. Autónoma de Madrid, Madrid, Spain
| | - Jose F. de Celis
- Centro de Biología Molecular Severo Ochoa (UAM/CSIC), Univ. Autónoma de Madrid, Madrid, Spain
| | - María D. Martín-Bermudo
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC/JA, Sevilla, Spain
- * E-mail:
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Maier D. Membrane-Anchored Hairless Protein Restrains Notch Signaling Activity. Genes (Basel) 2020; 11:genes11111315. [PMID: 33171957 PMCID: PMC7694644 DOI: 10.3390/genes11111315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 11/16/2022] Open
Abstract
The Notch signaling pathway governs cell-to-cell communication in higher eukaryotes. In Drosophila, after cleavage of the transmembrane receptor Notch, the intracellular domain of Notch (ICN) binds to the transducer Suppressor of Hairless (Su(H)) and shuttles into the nucleus to activate Notch target genes. Similarly, the Notch antagonist Hairless transfers Su(H) into the nucleus to repress Notch target genes. With the aim to prevent Su(H) nuclear translocation, Hairless was fused to a transmembrane domain to anchor the protein at membranes. Indeed, endogenous Su(H) co-localized with membrane-anchored Hairless, demonstrating their binding in the cytoplasm. Moreover, adult phenotypes uncovered a loss of Notch activity, in support of membrane-anchored Hairless sequestering Su(H) in the cytosol. A combined overexpression of membrane-anchored Hairless with Su(H) lead to tissue proliferation, which is in contrast to the observed apoptosis after ectopic co-overexpression of the wild-type genes, indicating a shift to a gain of Notch activity. A mixed response, general de-repression of Notch signaling output, plus inhibition at places of highest Notch activity, perhaps reflects Su(H)’s role as activator and repressor, supported by results obtained with the Hairless-binding deficient Su(H)LLL mutant, inducing activation only. Overall, the results strengthen the idea of Su(H) and Hairless complex formation within the cytosolic compartment.
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Affiliation(s)
- Dieter Maier
- Deptartment of General Genetics 190g, University of Hohenheim, Garbenstr. 30, 70599 Stuttgart, Germany
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11
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Nagel AC, Maier D, Scharpf J, Ketelhut M, Preiss A. Limited Availability of General Co-Repressors Uncovered in an Overexpression Context during Wing Venation in Drosophila melanogaster. Genes (Basel) 2020; 11:genes11101141. [PMID: 32998295 PMCID: PMC7601384 DOI: 10.3390/genes11101141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/17/2020] [Accepted: 09/25/2020] [Indexed: 12/31/2022] Open
Abstract
Cell fate is determined by the coordinated activity of different pathways, including the conserved Notch pathway. Activation of Notch results in the transcription of Notch targets that are otherwise silenced by repressor complexes. In Drosophila, the repressor complex comprises the transcription factor Suppressor of Hairless (Su(H)) bound to the Notch antagonist Hairless (H) and the general co-repressors Groucho (Gro) and C-terminal binding protein (CtBP). The latter two are shared by different repressors from numerous pathways, raising the possibility that they are rate-limiting. We noted that the overexpression during wing development of H mutants HdNT and HLD compromised in Su(H)-binding induced ectopic veins. On the basis of the role of H as Notch antagonist, overexpression of Su(H)-binding defective H isoforms should be without consequence, implying different mechanisms but repression of Notch signaling activity. Perhaps excess H protein curbs general co-repressor availability. Supporting this model, nearly normal wings developed upon overexpression of H mutant isoforms that bound neither Su(H) nor co-repressor Gro and CtBP. Excessive H protein appeared to sequester general co-repressors, resulting in specific vein defects, indicating their limited availability during wing vein development. In conclusion, interpretation of overexpression phenotypes requires careful consideration of possible dominant negative effects from interception of limiting factors.
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Grandon B, Rincheval-Arnold A, Jah N, Corsi JM, Araujo LM, Glatigny S, Prevost E, Roche D, Chiocchia G, Guénal I, Gaumer S, Breban M. HLA-B27 alters BMP/TGFβ signalling in Drosophila, revealing putative pathogenic mechanism for spondyloarthritis. Ann Rheum Dis 2019; 78:1653-1662. [PMID: 31563893 DOI: 10.1136/annrheumdis-2019-215832] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/08/2019] [Accepted: 09/09/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVES The human leucocyte antigen (HLA)-B27 confers an increased risk of spondyloarthritis (SpA) by unknown mechanism. The objective of this work was to uncover HLA-B27 non-canonical properties that could explain its pathogenicity, using a new Drosophila model. METHODS We produced transgenic Drosophila expressing the SpA-associated HLA-B*27:04 or HLA-B*27:05 subtypes, or the non-associated HLA-B*07:02 allele, alone or in combination with human β2-microglobulin (hβ2m), under tissue-specific drivers. Consequences of transgenes expression in Drosophila were examined and affected pathways were investigated by the genetic interaction experiments. Predictions of the model were further tested in immune cells from patients with SpA. RESULTS Loss of crossveins in the wings and a reduced eye phenotype were observed after expression of HLA-B*27:04 or HLA-B*27:05 in Drosophila but not in fruit flies expressing the non-associated HLA-B*07:02 allele. These HLA-B27-induced phenotypes required the presence of hβ2m that allowed expression of well-folded HLA-B conformers at the cell surface. Loss of crossveins resulted from a dominant negative effect of HLA-B27 on the type I bone morphogenetic protein (BMP) receptor saxophone (Sax) with which it interacted, resulting in elevated mothers against decapentaplegic (Mad, a Drosophila receptor-mediated Smad) phosphorylation. Likewise, in immune cells from patients with SpA, HLA-B27 specifically interacted with activin receptor-like kinase-2 (ALK2), the mammalian Sax ortholog, at the cell surface and elevated Smad phosphorylation was observed in response to activin A and transforming growth factor β (TGFβ). CONCLUSIONS Antagonistic interaction of HLA-B27 with ALK2, which exerts inhibitory functions on the TGFβ/BMP signalling pathway at the cross-road between inflammation and ossification, could adequately explain SpA development.
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Affiliation(s)
- Benjamin Grandon
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France.,Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France
| | - Aurore Rincheval-Arnold
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France
| | - Nadège Jah
- Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France
| | - Jean-Marc Corsi
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France
| | - Luiza M Araujo
- Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France
| | - Simon Glatigny
- Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France
| | - Erwann Prevost
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France.,Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France
| | - Delphine Roche
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France
| | - Gilles Chiocchia
- Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France
| | - Isabelle Guénal
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France
| | - Sébastien Gaumer
- LGBC, EA4589, UVSQ/Université Paris-Saclay, EPHE/PSL Research University, Montigny-le-Bretonneux, France
| | - Maxime Breban
- Infection & Inflammation, UMR 1173, Inserm, UVSQ/ Université Paris Saclay, Montigny-le-Bretonneux, France .,Rheumatology, Ambroise Paré Hospital, Boulogne Billancourt, France
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13
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Ma Y, McKay DJ, Buttitta L. Changes in chromatin accessibility ensure robust cell cycle exit in terminally differentiated cells. PLoS Biol 2019; 17:e3000378. [PMID: 31479438 PMCID: PMC6743789 DOI: 10.1371/journal.pbio.3000378] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 09/13/2019] [Accepted: 08/13/2019] [Indexed: 12/12/2022] Open
Abstract
During terminal differentiation, most cells exit the cell cycle and enter into a prolonged or permanent G0 in which they are refractory to mitogenic signals. Entry into G0 is usually initiated through the repression of cell cycle gene expression by formation of a transcriptional repressor complex called dimerization partner (DP), retinoblastoma (RB)-like, E2F and MuvB (DREAM). However, when DREAM repressive function is compromised during terminal differentiation, additional unknown mechanisms act to stably repress cycling and ensure robust cell cycle exit. Here, we provide evidence that developmentally programmed, temporal changes in chromatin accessibility at a small subset of critical cell cycle genes act to enforce cell cycle exit during terminal differentiation in the Drosophila melanogaster wing. We show that during terminal differentiation, chromatin closes at a set of pupal wing enhancers for the key rate-limiting cell cycle regulators Cyclin E (cycE), E2F transcription factor 1 (e2f1), and string (stg). This closing coincides with wing cells entering a robust postmitotic state that is strongly refractory to cell cycle reactivation, and the regions that close contain known binding sites for effectors of mitogenic signaling pathways such as Yorkie and Notch. When cell cycle exit is genetically disrupted, chromatin accessibility at cell cycle genes remains unaffected, and the closing of distal enhancers at cycE, e2f1, and stg proceeds independent of the cell cycling status. Instead, disruption of cell cycle exit leads to changes in accessibility and expression of a subset of hormone-induced transcription factors involved in the progression of terminal differentiation. Our results uncover a mechanism that acts as a cell cycle–independent timer to limit the response to mitogenic signaling and aberrant cycling in terminally differentiating tissues. In addition, we provide a new molecular description of the cross talk between cell cycle exit and terminal differentiation during metamorphosis. The longer a cell remains in G0, the more refractory it becomes to re-entering the cell cycle. This study shows that in terminally differentiated cells in vivo, regulatory elements at genes encoding just three key cell cycle regulators (cycE, e2f1 and stg) become inaccessible, limiting their aberrant activation and maintaining a prolonged, robust G0.
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Affiliation(s)
- Yiqin Ma
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Daniel J McKay
- Department of Biology, Department of Genetics, Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Laura Buttitta
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
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14
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Negreiros E, Herszterg S, Kang KH, Câmara A, Dias WB, Carneiro K, Bier E, Todeschini AR, Araujo H. N-linked glycosylation restricts the function of Short gastrulation to bind and shuttle BMPs. Development 2018; 145:dev.167338. [PMID: 30355725 DOI: 10.1242/dev.167338] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/14/2018] [Indexed: 12/11/2022]
Abstract
Disorders of N-linked glycosylation are increasingly reported in the literature. However, the targets that are responsible for the associated developmental and physiological defects are largely unknown. Bone morphogenetic proteins (BMPs) act as highly dynamic complexes to regulate several functions during development. The range and strength of BMP activity depend on interactions with glycosylated protein complexes in the extracellular milieu. Here, we investigate the role of glycosylation for the function of the conserved extracellular BMP antagonist Short gastrulation (Sog). We identify conserved N-glycosylated sites and describe the effect of mutating these residues on BMP pathway activity in Drosophila Functional analysis reveals that loss of individual Sog glycosylation sites enhances BMP antagonism and/or increases the spatial range of Sog effects in the tissue. Mechanistically, we provide evidence that N-terminal and stem glycosylation controls extracellular Sog levels and distribution. The identification of similar residues in vertebrate Chordin proteins suggests that N-glycosylation may be an evolutionarily conserved process that adds complexity to the regulation of BMP activity.
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Affiliation(s)
- Erika Negreiros
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Sophie Herszterg
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Kyung-Hwa Kang
- Division of Biological Sciences, University of California at San Diego, CA 92093-0349, USA
| | - Amanda Câmara
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Wagner B Dias
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Katia Carneiro
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Ethan Bier
- Division of Biological Sciences, University of California at San Diego, CA 92093-0349, USA
| | - Adriane Regina Todeschini
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Helena Araujo
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902 .,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Brasil (INCT-ENEM)
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15
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Huang Y, Hatakeyama M, Shimmi O. Wing vein development in the sawfly Athalia rosae is regulated by spatial transcription of Dpp/BMP signaling components. ARTHROPOD STRUCTURE & DEVELOPMENT 2018; 47:408-415. [PMID: 29596913 DOI: 10.1016/j.asd.2018.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 06/08/2023]
Abstract
Wing venation among insects serves as an excellent model to address how diversified patterns are produced. Previous studies suggest that evolutionarily conserved Decapentaplegic (Dpp)/Bone Morphogenetic Protein (BMP) signal plays a critical role in wing vein development in the dipteran Drosophila melanogaster and the hymenopteran sawfly Athalia rosae. In sawfly, dpp is ubiquitously expressed in the wing during prepupal stages, but Dpp/BMP signal is localized in the future vein cells. Since localized BMP signaling involves BMP binding protein Crossveinless (Cv), redistribution of BMP ligands appears to be crucial for sawfly wing vein formation. However, how ubiquitously expressed ligands lead to a localized signal remains to be addressed. Here, we found that BMP binding protein short gastrulation (Sog) is highly expressed in the intervein cells. Our data also reveal that BMP type I receptors thickveins (Tkv) and saxophone (Sax) are highly expressed in intervein cells and at lower levels in the vein progenitor cells. RNAi knockdown of Ar-tkv or Ar-sax indicates that both receptors are required for localized BMP signaling in the wing vein progenitor cells. Taken together, our data suggest that spatial transcription of core- and co-factors of the BMP pathway sustain localized BMP signaling during sawfly wing vein development.
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Affiliation(s)
- Yunxian Huang
- Institute of Biotechnology, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014, Helsinki, Finland
| | - Masatsugu Hatakeyama
- Division of Applied Genetics, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, 305-8634, Japan.
| | - Osamu Shimmi
- Institute of Biotechnology, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014, Helsinki, Finland.
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16
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Thuma L, Carter D, Weavers H, Martin P. Drosophila immune cells extravasate from vessels to wounds using Tre1 GPCR and Rho signaling. J Cell Biol 2018; 217:3045-3056. [PMID: 29941473 PMCID: PMC6122984 DOI: 10.1083/jcb.201801013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 05/04/2018] [Accepted: 05/29/2018] [Indexed: 12/17/2022] Open
Abstract
In contrast to vertebrates, adult Drosophila melanogaster have an open cardiovascular system. However, Thuma et al. find that in late pupation, hemolymph flows through Drosophila wing veins, providing a unique genetic and live-imaging opportunity to investigate the mechanisms driving immune cell extravasation from vessels to wounds and reveal new roles for Tre1 and Rho signaling in this process. Inflammation is pivotal to fight infection, clear debris, and orchestrate repair of injured tissues. Although Drosophila melanogaster have proven invaluable for studying extravascular recruitment of innate immune cells (hemocytes) to wounds, they have been somewhat neglected as viable models to investigate a key rate-limiting component of inflammation—that of immune cell extravasation across vessel walls—due to their open circulation. We have now identified a period during pupal development when wing hearts pulse hemolymph, including circulating hemocytes, through developing wing veins. Wounding near these vessels triggers local immune cell extravasation, enabling live imaging and correlative light-electron microscopy of these events in vivo. We show that RNAi knockdown of immune cell integrin blocks diapedesis, just as in vertebrates, and we uncover a novel role for Rho-like signaling through the GPCR Tre1, a gene previously implicated in the trans-epithelial migration of germ cells. We believe this new Drosophila model complements current murine models and provides new mechanistic insight into immune cell extravasation.
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Affiliation(s)
- Leila Thuma
- Department of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Deborah Carter
- Department of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Helen Weavers
- School of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, Bristol, UK .,School of Biochemistry, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Paul Martin
- Department of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK .,School of Biochemistry, Biomedical Sciences, University of Bristol, Bristol, UK.,School of Medicine, Cardiff University, Cardiff, UK
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17
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Wang XC, Liu Z, Jin LH. Anchor negatively regulates BMP signalling to control Drosophila wing development. Eur J Cell Biol 2018; 97:308-317. [PMID: 29735293 DOI: 10.1016/j.ejcb.2018.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/17/2018] [Accepted: 04/24/2018] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors play particularly important roles in many organisms. The novel Drosophila gene anchor is an orthologue of vertebrate GPR155. However, the roles of anchor in molecular functions and biological processes, especially in wing development, remain unknown. Knockdown of anchor resulted in an increased wing size and additional and thickened veins. These abnormal wing phenotypes were similar to those observed in BMP signalling gain-of-function experiments. We observed that the BMP signalling indicator p-Mad was significantly increased in wing discs in which anchor RNAi was induced in larvae and accumulated abnormally in intervein regions in pupae. Furthermore, the expression of target genes of the BMP signalling pathway was examined using a lacZ reporter, and the results indicated that omb and sal were substantially increased in anchor-knockdown wing discs. An investigation of genetic interactions between Anchor and the BMP signalling pathway revealed that the thickened and ectopic vein tissues were rescued by knocking down BMP levels. These results suggested that Anchor functions to negatively regulate BMP signalling during wing development and vein formation.
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Affiliation(s)
- Xiao Chun Wang
- College of Life Sciences, Northeast Forestry University, Harbin 150040, China
| | - Ziguang Liu
- Heilongjiang Academy of Agricultural Sciences, Harbin 150040, China
| | - Li Hua Jin
- College of Life Sciences, Northeast Forestry University, Harbin 150040, China.
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18
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19
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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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20
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Transcriptome Characterization of Dendrolimus punctatus and Expression Profiles at Different Developmental Stages. PLoS One 2016; 11:e0161667. [PMID: 27560151 PMCID: PMC4999207 DOI: 10.1371/journal.pone.0161667] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/09/2016] [Indexed: 11/19/2022] Open
Abstract
The pine moth Dendrolimus punctatus (Walker) is a common insect pest that confers serious damage to conifer forests in south of China. Extensive physiology and ecology studies on D. punctatus have been carried out, but the lack of genetic information has limited our understanding of the molecular mechanisms behind its development and resistance. Using RNA-seq approach, we characterized the transcriptome of this pine moth and investigated its developmental expression profiles during egg, larval, pupal, and adult stages. A total of 107.6 million raw reads were generated that were assembled into 70,664 unigenes. More than 30% unigenes were annotated by searching for homology in protein databases. To better understand the process of metamorphosis, we pairwise compared four developmental phases and obtained 17,624 differential expression genes. Functional enrichment analysis of differentially expressed genes showed positive correlation with specific physiological activities of each stage, and these results were confirmed by qRT-PCR experiments. This study provides a valuable genomic resource of D. punctatus covering all its developmental stages, and will promote future studies on biological processes at the molecular level.
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21
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Functional studies of TcRjl, a novel GTPase of Trypanosoma cruzi, reveals phenotypes related with MAPK activation during parasite differentiation and after heterologous expression in Drosophila model system. Biochem Biophys Res Commun 2015; 467:115-20. [PMID: 26408905 DOI: 10.1016/j.bbrc.2015.09.110] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/21/2015] [Indexed: 12/20/2022]
Abstract
The life cycle of the protozoan parasite Trypanosoma cruzi comprises rounds of proliferative cycles and differentiation in distinct host environments. Ras GTPases are molecular switches that play pivotal regulatory functions in cell fate. Rjl is a novel GTPase with unknown function. Herein we show that TcRjl blocks in vivo cell differentiation. The forced expression of TcRjl leads to changes in the overall tyrosine protein phosphorylation profile of parasites. TcRjl expressing parasites sustained DNA synthesis regardless the external stimuli for differentiation. Heterologous expression in the Drosophila melanogaster genetic system strongly suggests a role from TcRjl protein in RTK-dependent pathways and MAPK activation.
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22
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Molnar C, de Celis JF. Tay bridge is a negative regulator of EGFR signalling and interacts with Erk and Mkp3 in the Drosophila melanogaster wing. PLoS Genet 2013; 9:e1003982. [PMID: 24348264 PMCID: PMC3861119 DOI: 10.1371/journal.pgen.1003982] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 10/14/2013] [Indexed: 11/18/2022] Open
Abstract
The regulation of Extracellular regulated kinase (Erk) activity is a key aspect of signalling by pathways activated by extracellular ligands acting through tyrosine kinase transmembrane receptors. In this process, participate proteins with kinase activity that phosphorylate and activate Erk, as well as different phosphatases that inactivate Erk by de-phosphorylation. The state of Erk phosphorylation affects not only its activity, but also its subcellular localization, defining the repertoire of Erk target proteins, and consequently, the cellular response to Erk. In this work, we characterise Tay bridge as a novel component of the EGFR/Erk signalling pathway. Tay bridge is a large nuclear protein with a domain of homology with human AUTS2, and was previously identified due to the neuronal phenotypes displayed by loss-of-function mutations. We show that Tay bridge antagonizes EGFR signalling in the Drosophila melanogaster wing disc and other tissues, and that the protein interacts with both Erk and Mkp3. We suggest that Tay bridge constitutes a novel element involved in the regulation of Erk activity, acting as a nuclear docking for Erk that retains this protein in an inactive form in the nucleus. Extracellular regulated kinases (Erk) mediate signalling by pathways activated by tyrosine kinase transmembrane receptors. The level of activated Erk depends on a highly regulated balance between cytoplasmic kinases and nuclear/cytoplasmic phosphatases, which determine the state of Erk phosphorylation. This affects Erk activity and its subcellular localization, defining the repertoire of Erk targets, and consequently, the cellular response to Erk. In this work, we use a genetic approach to characterise the gene tay bridge as a novel component of the EGFR/Erk signalling pathway. Tay bridge has a domain of homology with human AUTS2, and was previously identified due to the neuronal phenotypes displayed by loss-of-function mutations. We show that Tay bridge antagonizes EGFR signalling in the Drosophila melanogaster wing disc and other tissues, and that the protein interacts with both Erk and Mkp3. We suggest that Tay bridge constitutes a novel element involved in the regulation of Erk activity, acting as a nuclear docking for Erk that retains this protein in an inactive form in the nucleus. These results could provide important insights into the clinical consequences of AUTS2 mutations in humans, which are related to behavioural perturbations including autism, mental retardation, Attention Deficit Hyperactivity Disorder and alcohol drinking behaviour.
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Affiliation(s)
- Cristina Molnar
- Centro de Biología Molecular “Severo Ochoa,” CSIC and Universidad Autónoma de Madrid, Madrid, Spain
| | - Jose F. de Celis
- Centro de Biología Molecular “Severo Ochoa,” CSIC and Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
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23
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Shen W, Chen X, Cormier O, Cheng DCP, Reed B, Harden N. Modulation of morphogenesis by Egfr during dorsal closure in Drosophila. PLoS One 2013; 8:e60180. [PMID: 23579691 PMCID: PMC3620322 DOI: 10.1371/journal.pone.0060180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 02/23/2013] [Indexed: 01/12/2023] Open
Abstract
During Drosophila embryogenesis the process of dorsal closure (DC) results in continuity of the embryonic epidermis, and DC is well recognized as a model system for the analysis of epithelial morphogenesis as well as wound healing. During DC the flanking lateral epidermal sheets stretch, align, and fuse along the dorsal midline, thereby sealing a hole in the epidermis occupied by an extra-embryonic tissue known as the amnioserosa (AS). Successful DC requires the regulation of cell shape change via actomyosin contractility in both the epidermis and the AS, and this involves bidirectional communication between these two tissues. We previously demonstrated that transcriptional regulation of myosin from the zipper (zip) locus in both the epidermis and the AS involves the expression of Ack family tyrosine kinases in the AS in conjunction with Dpp secreted from the epidermis. A major function of Ack in other species, however, involves the negative regulation of Egfr. We have, therefore, asked what role Egfr might play in the regulation of DC. Our studies demonstrate that Egfr is required to negatively regulate epidermal expression of dpp during DC. Interestingly, we also find that Egfr signaling in the AS is required to repress zip expression in both the AS and the epidermis, and this may be generally restrictive to the progression of morphogenesis in these tissues. Consistent with this theme of restricting morphogenesis, it has previously been shown that programmed cell death of the AS is essential for proper DC, and we show that Egfr signaling also functions to inhibit or delay AS programmed cell death. Finally, we present evidence that Ack regulates zip expression by promoting the endocytosis of Egfr in the AS. We propose that the general role of Egfr signaling during DC is that of a braking mechanism on the overall progression of DC.
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Affiliation(s)
- Weiping Shen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Xi Chen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Olga Cormier
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - David Chung-Pei Cheng
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Bruce Reed
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Nicholas Harden
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
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24
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Curtis BJ, Zraly CB, Dingwall AK. Drosophila LSD1-CoREST demethylase complex regulates DPP/TGFβ signaling during wing development. Genesis 2012; 51:16-31. [PMID: 22965777 DOI: 10.1002/dvg.22346] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 08/27/2012] [Accepted: 08/30/2012] [Indexed: 12/30/2022]
Abstract
The choice and timing of specific developmental pathways in organogenesis are determined by tissue-specific temporal and spatial cues that are acted upon to impart unique cellular and compartmental identities. A consequence of cellular signaling is the rapid transcriptional reprogramming of a wide variety of target genes. To overcome intrinsic epigenetic chromatin barriers to transcription modulation, histone modifying and remodeling complexes are employed. The deposition or erasure of specific covalent histone modifications, including acetylation, methylation, and ubiquitination are essential features of gene activation and repression. We have found that the activity of a specific class of histone demethylation enzymes is required for the specification of vein cell fates during Drosophila wing development. Genetic tests revealed that the Drosophila LSD1-CoREST complex is required for proper cell specification through regulation of the DPP/TGFβ pathway. An important finding from this analysis is that LSD1-CoREST functions through control of rhomboid expression in an EGFR-independent pathway.
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Affiliation(s)
- Brenda J Curtis
- Program in Molecular and Cellular Biochemistry, Stritch School of Medicine, Loyola University of Chicago, Maywood, Illinois, USA
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25
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O'Keefe DD, Gonzalez-Niño E, Edgar BA, Curtiss J. Discontinuities in Rap1 activity determine epithelial cell morphology within the developing wing of Drosophila. Dev Biol 2012; 369:223-34. [PMID: 22776378 DOI: 10.1016/j.ydbio.2012.06.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 05/31/2012] [Accepted: 06/28/2012] [Indexed: 11/28/2022]
Abstract
Mechanisms that govern cell-fate specification within developing epithelia have been intensely investigated, with many of the critical intercellular signaling pathways identified, and well characterized. Much less is known, however, about downstream events that drive the morphological differentiation of these cells, once their fate has been determined. In the Drosophila wing-blade epithelium, two cell types predominate: vein and intervein. After cell proliferation is complete and adhesive cell-cell contacts have been refined, the vast majority of intervein cells adopt a hexagonal morphology. Within vein territories, however, cell-shape refinement results in trapezoids. Signaling events that differentiate between vein and intervein cell fates are well understood, but the genetic pathways underlying vein/intervein cyto-architectural differences remain largely undescribed. We show here that the Rap1 GTPase plays a critical role in determining cell-type-specific morphologies within the developing wing epithelium. Rap1, together with its effector Canoe, promotes symmetric distribution of the adhesion molecule DE-cadherin about the apicolateral circumference of epithelial cells. We provide evidence that in presumptive vein tissue Rap1/Canoe activity is down-regulated, resulting in adhesive asymmetries and non-hexagonal cell morphologies. In particular Canoe levels are reduced in vein cells as they morphologically differentiate. We also demonstrate that over-expression of Rap1 disrupts vein formation both in the developing epithelium and the adult wing blade. Therefore, vein/intervein morphological differences result, at least in part, from the patterned regulation of Rap1 activity.
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Affiliation(s)
- David D O'Keefe
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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26
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Matsuda S, Shimmi O. Directional transport and active retention of Dpp/BMP create wing vein patterns in Drosophila. Dev Biol 2012; 366:153-62. [PMID: 22542596 DOI: 10.1016/j.ydbio.2012.04.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 03/30/2012] [Accepted: 04/02/2012] [Indexed: 11/19/2022]
Abstract
The bone morphogenetic protein (BMP) family ligand decapentaplegic (Dpp) plays critical roles in wing vein development during pupal stages in Drosophila. However, how the diffusible Dpp specifies elaborate wing vein patterns remains unknown. Here, we visualized Dpp distribution in the pupal wing and found that it tightly reflects the wing vein patterns. We show that Dpp is directionally transported from the longitudinal veins (LVs) into the posterior crossvein (PCV) primordial region by the extracellular BMP-binding proteins, short gastrulation (Sog) and crossveinless (Cv). Another BMP-type ligand, glass bottom boat (Gbb), also moves into the PCV region and is required for Dpp distribution, presumably as a Dpp-Gbb heterodimer. In contrast, we found that most of the Dpp is actively retained in the LVs by the BMP type I receptor thickveins (Tkv) and a positive feedback mechanism. We provide evidence that the directionality of Dpp transport is manifested by sog transcription that prepatterns the PCV position in a Dpp signal-independent manner. Taken together, our data suggest that spatial distribution of Dpp is tightly regulated at the extracellular level by combination of long-range facilitated transport toward the PCV and short-range signaling by active retention in the LVs, thereby allowing diffusible ligands to form elaborate wing vein patterns.
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Affiliation(s)
- Shinya Matsuda
- Institute of Biotechnology, University of Helsinki, PO Box 65 (Viikinkaari 1), 00014 Helsinki, Finland
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Carreira VP, Soto IM, Mensch J, Fanara JJ. Genetic basis of wing morphogenesis in Drosophila: sexual dimorphism and non-allometric effects of shape variation. BMC DEVELOPMENTAL BIOLOGY 2011; 11:32. [PMID: 21635778 PMCID: PMC3129315 DOI: 10.1186/1471-213x-11-32] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 06/02/2011] [Indexed: 12/17/2022]
Abstract
BACKGROUND The Drosophila wing represents a particularly appropriate model to investigate the developmental control of phenotypic variation. Previous studies which aimed to identify candidate genes for wing morphology demonstrated that the genetic basis of wing shape variation in D. melanogaster is composed of numerous genetic factors causing small, additive effects. In this study, we analyzed wing shape in males and females from 191 lines of D. melanogaster, homozygous for a single P-element insertion, using geometric morphometrics techniques. The analysis allowed us to identify known and novel candidate genes that may contribute to the expression of wing shape in each sex separately and to compare them to candidate genes affecting wing size which have been identified previously using the same lines. RESULTS Our results indicate that more than 63% of induced mutations affected wing shape in one or both sexes, although only 33% showed significant differences in both males and females. The joint analysis of wing size and shape revealed that only 19% of the P-element insertions caused coincident effects on both components of wing form in one or both sexes. Further morphometrical analyses revealed that the intersection between veins showed the smallest displacements in the proximal region of the wing. Finally, we observed that mutations causing general deformations were more common than expected in both sexes whereas the opposite occurred with those generating local changes. For most of the 94 candidate genes identified, this seems to be the first record relating them with wing shape variation. CONCLUSIONS Our results support the idea that the genetic architecture of wing shape is complex with many different genes contributing to the trait in a sexually dimorphic manner. This polygenic basis, which is relatively independent from that of wing size, is composed of genes generally involved in development and/or metabolic functions, especially related to the regulation of different cellular processes such as motility, adhesion, communication and signal transduction. This study suggests that understanding the genetic basis of wing shape requires merging the regulation of vein patterning by signalling pathways with processes that occur during wing development at the cellular level.
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Affiliation(s)
- Valeria P Carreira
- Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Ciudad Universitaria, Pabellón II (C1428 EHA) Buenos Aires. Argentina
| | - Ignacio M Soto
- Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Ciudad Universitaria, Pabellón II (C1428 EHA) Buenos Aires. Argentina
| | - Julián Mensch
- Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Ciudad Universitaria, Pabellón II (C1428 EHA) Buenos Aires. Argentina
| | - Juan J Fanara
- Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Ciudad Universitaria, Pabellón II (C1428 EHA) Buenos Aires. Argentina
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Musashi1 and hairy and enhancer of split 1 high expression cells derived from embryonic stem cells enhance the repair of small-intestinal injury in the mouse. Dig Dis Sci 2011; 56:1354-68. [PMID: 21221806 DOI: 10.1007/s10620-010-1441-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 09/19/2010] [Indexed: 12/13/2022]
Abstract
BACKGROUND Embryonic stem cells have great plasticity. In this study, we repaired impaired small intestine by transplanting putative intestinal epithelial stem cells (Musashi1 and hairy and enhancer of split 1 high expression cells) derived from embryonic stem cells. METHODS The differentiation of definitive endoderm in embryoid bodies, derived from male ES-E14TG2a cells by the hanging-drop method, was monitored to define a time point for maximal induction of putative intestinal epithelial stem cells by epidermal growth factor. Furthermore, to evaluate the regenerative potential of intestinal epithelium, these putative stem cells were engrafted into NOD/SCID mice and female mice with enteritis. Donor cells were located by SRY DNA in situ hybridization. RESULTS The results revealed that definitive endodermal markers were highly expressed in 5-day embryoid bodies. These embryoid body cells were induced into putative intestinal epithelial stem cells on the 5th day of epidermal growth factor administration. Grafts from these cells consisted of adenoid structures and nonspecific structural cells with strong expression of small-intestinal epithelial cell markers. In situ hybridization revealed that the donor cells could specifically locate in damaged intestinal epithelium, contribute to epithelial structures, and enhance regeneration. CONCLUSIONS In conclusion, the Musashi1 and hairy and enhancer of split 1 high expression cells, derived from mouse embryonic stem cells, locate predominantly in impaired small-intestinal epithelium after transplantation and contribute to epithelial regeneration.
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Szuperák M, Salah S, Meyer EJ, Nagarajan U, Ikmi A, Gibson MC. Feedback regulation of Drosophila BMP signaling by the novel extracellular protein larval translucida. Development 2011; 138:715-24. [PMID: 21266407 DOI: 10.1242/dev.059477] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cellular response to the Drosophila BMP 2/4-like ligand Decapentaplegic (DPP) serves as one of the best-studied models for understanding the long-range control of tissue growth and pattern formation during animal development. Nevertheless, fundamental questions remain unanswered regarding extracellular regulation of the ligand itself, as well as the nature of the downstream transcriptional response to BMP pathway activation. Here, we report the identification of larval translucida (ltl), a novel target of BMP activity in Drosophila. Both gain- and loss-of-function analyses implicate LTL, a leucine-rich repeat protein, in the regulation of wing growth and vein patterning. At the molecular level, we demonstrate that LTL is a secreted protein that antagonizes BMP-dependent MAD phosphorylation, indicating that it regulates DPP/BMP signaling at or above the level of ligand-receptor interactions. Furthermore, based on genetic interactions with the DPP-binding protein Crossveinless 2 and biochemical interactions with the glypican Dally-like, we propose that LTL acts in the extracellular space where it completes a novel auto-regulatory loop that modulates BMP activity.
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Affiliation(s)
- Milán Szuperák
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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30
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Terriente-Félix A, Molnar C, Gómez-Skarmeta JL, de Celis JF. A conserved function of the chromatin ATPase Kismet in the regulation of hedgehog expression. Dev Biol 2010; 350:382-92. [PMID: 21146514 DOI: 10.1016/j.ydbio.2010.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 11/24/2010] [Accepted: 12/01/2010] [Indexed: 12/31/2022]
Abstract
The development of the Drosophila melanogaster wing depends on its subdivision into anterior and posterior compartments, which constitute two independent cell lineages since their origin in the embryonic ectoderm. The anterior-posterior compartment boundary is the place where signaling by the Hedgehog pathway takes place, and this requires pathway activation in anterior cells by ligand expressed exclusively in posterior cells. Several mechanisms ensure the confinement of hedgehog expression to posterior cells, including repression by Cubitus interruptus, the co-repressor Groucho and Master of thick veins. In this work we identified Kismet, a chromodomain-containing protein of the SNF2-like family of ATPases, as a novel component of the hedgehog transcriptional repression mechanism in anterior compartment cells. In kismet mutants, hedgehog is ectopically expressed in a domain of anterior cells close to the anterior-posterior compartment boundary, causing inappropriate activation of the pathway and changes in the development of the central region of the wing. The contribution of Kismet to the silencing of hedgehog expression is limited to anterior cells with low levels of the repressor form of Cubitus interruptus. We also show that knockdown of CHD8, the kismet homolog in Xenopus tropicalis, is also associated with ectopic sonic hedgehog expression and up-regulation of one of its target genes in the eye, Pax2, indicating the evolutionary conservation of Kismet/CHD8 function in negatively controlling hedgehog expression.
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Affiliation(s)
- Ana Terriente-Félix
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid Cantoblanco, Madrid, Spain
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31
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Bap170, a subunit of the Drosophila PBAP chromatin remodeling complex, negatively regulates the EGFR signaling. Genetics 2010; 186:167-81. [PMID: 20551433 DOI: 10.1534/genetics.110.118695] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BAP and PBAP constitute the two different forms of the Drosophila melanogaster Brahma chromatin remodelers. A common multisubunit core, containing the Brahma ATPase, can associate either with Osa to form the BAP complex or with Bap170, Bap180, and Sayp to constitute the PBAP complex. Although required for many biological processes, recent genetic analyses revealed that one role of the BAP complex during Drosophila wing development is the proper regulation of EGFR target genes. Here, we show that Bap170, a distinctive subunit of the PBAP complex, participates instead in the negative regulation of EGFR signaling. In adults, loss of Bap170 generates phenotypes similar to the defects induced by hyperactivation of the EGFR pathway, such as overrecruitment of cone and photoreceptor cells and formation extra veins. In genetic interactions, bap170 mutations suppress the loss of veins and photoreceptors caused by mutations affecting the activity of the EGFR pathway. Our results suggest a dual requirement of the PBAP complex: for transcriptional repression of rhomboid and for efficient expression of argos. Interestingly, genetic evidence also indicates that Bap170-mediated repression of rho is inhibited by EGFR signaling, suggesting a scenario of mutual antagonism between EGFR signaling and PBAP function.
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Sander V, Eivers E, Choi RH, De Robertis EM. Drosophila Smad2 opposes Mad signaling during wing vein development. PLoS One 2010; 5:e10383. [PMID: 20442782 PMCID: PMC2860994 DOI: 10.1371/journal.pone.0010383] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 04/06/2010] [Indexed: 12/28/2022] Open
Abstract
In the vertebrates, the BMP/Smad1 and TGF-β/Smad2 signaling pathways execute antagonistic functions in different contexts of development. The differentiation of specific structures results from the balance between these two pathways. For example, the gastrula organizer/node of the vertebrates requires a region of low Smad1 and high Smad2 signaling. In Drosophila, Mad regulates tissue determination and growth in the wing, but the function of dSmad2 in wing patterning is largely unknown. In this study, we used an RNAi loss-of-function approach to investigate dSmad2 signaling during wing development. RNAi-mediated knockdown of dSmad2 caused formation of extra vein tissue, with phenotypes similar to those seen in Dpp/Mad gain-of-function. Clonal analyses revealed that the normal function of dSmad2 is to inhibit the response of wing intervein cells to the extracellular Dpp morphogen gradient that specifies vein formation, as measured by expression of the activated phospho-Mad protein. The effect of dSmad2 depletion in promoting vein differentiation was dependent on Medea, the co-factor shared by Mad and dSmad2. Furthermore, double RNAi experiments showed that Mad is epistatic to dSmad2. In other words, depletion of Smad2 had no effect in Mad-deficient wings. Our results demonstrate a novel role for dSmad2 in opposing Mad-mediated vein formation in the wing. We propose that the main function of dActivin/dSmad2 in Drosophila wing development is to antagonize Dpp/Mad signaling. Possible molecular mechanisms for the opposition between dSmad2 and Mad signaling are discussed.
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Affiliation(s)
- Veronika Sander
- Howard Hughes Medical Institute, Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Edward Eivers
- Howard Hughes Medical Institute, Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Renee H. Choi
- Howard Hughes Medical Institute, Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Edward M. De Robertis
- Howard Hughes Medical Institute, Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Herr A, Mckenzie L, Suryadinata R, Sadowski M, Parsons LM, Sarcevic B, Richardson HE. Geminin and Brahma act antagonistically to regulate EGFR-Ras-MAPK signaling in Drosophila. Dev Biol 2010; 344:36-51. [PMID: 20416294 DOI: 10.1016/j.ydbio.2010.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/04/2010] [Accepted: 04/08/2010] [Indexed: 12/21/2022]
Abstract
Geminin was identified in Xenopus as a dual function protein involved in the regulation of DNA replication and neural differentiation. In Xenopus, Geminin acts to antagonize the Brahma (Brm) chromatin-remodeling protein, Brg1, during neural differentiation. Here, we investigate the interaction of Geminin with the Brm complex during Drosophila development. We demonstrate that Drosophila Geminin (Gem) interacts antagonistically with the Brm-BAP complex during wing development. Moreover, we show in vivo during wing development and biochemically that Brm acts to promote EGFR-Ras-MAPK signaling, as indicated by its effects on pERK levels, while Gem opposes this. Furthermore, gem and brm alleles modulate the wing phenotype of a Raf gain-of-function mutant and the eye phenotype of a EGFR gain-of-function mutant. Western analysis revealed that Gem over-expression in a background compromised for Brm function reduces Mek (MAPKK/Sor) protein levels, consistent with the decrease in ERK activation observed. Taken together, our results show that Gem and Brm act antagonistically to modulate the EGFR-Ras-MAPK signaling pathway, by affecting Mek levels during Drosophila development.
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Affiliation(s)
- Anabel Herr
- Peter MacCallum Cancer Center, Melbourne, Victoria, Australia
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34
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Identification of genes affecting wing patterning through a loss-of-function mutagenesis screen and characterization of med15 function during wing development. Genetics 2010; 185:671-84. [PMID: 20233856 DOI: 10.1534/genetics.109.113670] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The development of the Drosophila melanogaster wing depends on the correct regulation of cell survival, growth, proliferation, differentiation, and pattern formation. These processes, and the genes controlling then, are common to the development of epithelia in many different organisms. To identify additional genes contributing to wing development we have carried out a genetic screen in mosaic wings carrying clones of homozygous mutant cells. We obtained 12 complementation groups corresponding to genes with a proven role in wing formation such as smoothened, thick veins, mothers against dpp, expanded, and fat and 71 new complementation groups affecting the pattern of veins and the size of wing. We mapped one of these groups to the mediator15 gene (med15), a component of the Mediator complex. We show that Med15 and other members of the Mediator complex are required, among other processes, for the transcription of decapentaplegic target genes.
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35
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Bistability coordinates activation of the EGFR and DPP pathways in Drosophila vein differentiation. Mol Syst Biol 2009; 5:278. [PMID: 19536201 PMCID: PMC2710866 DOI: 10.1038/msb.2009.35] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 04/23/2009] [Indexed: 01/21/2023] Open
Abstract
Cell differentiation in developing tissues is controlled by a small set of signaling pathways, which must coordinate the timing and levels of activation to ensure robust and precise outcomes. Highly coordinated activation of signaling pathways can result from cross-regulatory interactions in multi-pathway networks. Here we explore the dynamics and function of pathway coordination between the EGFR and DPP pathways during Drosophila wing-vein differentiation. We show that simultaneous activation of both the EGFR and DPP pathways must be maintained for vein cell differentiation and that above-threshold ectopic activation of either pathway is sufficient to drive vein cell differentiation outside the proveins. The joint activation of the EGFR and DPP signaling systems is ensured by a positive feedback loop, in which the two pathways stimulate each other at the level of ligand production.
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36
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Cai Y, Laughon A. The Drosophila Smad cofactor Schnurri engages in redundant and synergistic interactions with multiple corepressors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:232-45. [PMID: 19437622 DOI: 10.1016/j.bbagrm.2009.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In Drosophila a large zinc finger protein, Schnurri, functions as a Smad cofactor required for repression of brinker and other negative targets in response to signaling by the transforming growth factor beta ligand, Decapentaplegic. Schnurri binds to the silencer-bound Smads through a cluster of zinc fingers located near its carboxy-terminus and silences via a separate repression domain adjacent to this zinc-finger cluster. Here we show that this repression domain functions through interaction with two corepressors, dCtBP and dSin3A, and that either interaction is sufficient for repression. We also report that Schnurri contains additional repression domains that function through interaction with dCtBP, Groucho, dSin3A and SMRTER. By testing for the ability to rescue a shn RNAi phenotype we provide evidence that these diverse repression domains are both cooperative and partially redundant. In addition we find that Shn harbors a region capable of transcriptional activation, consistent with evidence that Schnurri can function as an activator as well as a repressor.
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Affiliation(s)
- Yi Cai
- Laboratory of Genetics, University of Wisconsin, 425G Henry Mall, Madison, WI 53706, USA
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37
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Terriente-Félix A, de Celis JF. Osa, a subunit of the BAP chromatin-remodelling complex, participates in the regulation of gene expression in response to EGFR signalling in the Drosophila wing. Dev Biol 2009; 329:350-61. [PMID: 19306864 DOI: 10.1016/j.ydbio.2009.03.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 03/05/2009] [Accepted: 03/12/2009] [Indexed: 01/27/2023]
Abstract
Gene expression is regulated in part by protein complexes containing ATP-dependent chromatin-remodelling factors of the SWI/SNF family. In Drosophila there is only one SWI/SNF protein, named Brahma, which forms the catalytic subunit of two complexes composed of different proteins. The protein Osa defines the BAP complex, and the proteins Polybromo and Bap170 are only present in the complex named PBAP. In this work we have analysed the functional requirements of Osa during Drosophila wing development, and found that osa is needed for cell growth and survival in the wing imaginal disc, and for the correct patterning of sensory organs, veins and the wing margin. Other members of the BAP complex, such as Snr1, Bap55, Mor and Brm, also share these functions of Osa. We focused on the requirement of Osa during the formation of the wing veins. Genetic interactions between osa alleles and mutations affecting the activity of the EGFR pathway suggest that one aspect of Osa is intimately related to the response to EGFR activity. Thus, loss of osa and EGFR signalling results in similar wing vein phenotypes, and osa alleles enhance the loss of veins caused by reduced EGFR activity. In addition, Osa is required for the expression of several targets of EGFR signalling, such as Delta, rhomboid and argos. We suggest that one role of Osa and Brm in the wing is to establish a chromatin environment in the regulatory regions of EGFR target genes, making them available for both activators and repressors and facilitating transcription in response to EGFR signalling.
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Affiliation(s)
- Ana Terriente-Félix
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain
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Abstract
The nuclear lamina represents a protein network required for nuclear structure and function. One family of lamina proteins is defined by an approximately 40-aa LAP2, Emerin, and MAN1 (LEM) domain (LEM-D) that binds the nonspecific DNA-binding protein, barrier-to-autointegration factor (BAF). Through interactions with BAF, LEM-D proteins serve as a bridge between chromosomes and the nuclear envelope. Mutations in genes encoding LEM-D proteins cause human laminopathies that are associated with tissue-restricted pathologies. Drosophila has five genes that encode proteins with LEM homology. Using yeast two-hybrid analyses, we demonstrate that four encode proteins that bind Drosophila (d)BAF. In addition to dBAF, dMAN1 associates with lamins, the LEM-D protein Bocksbeutel, and the receptor-regulated Smads, demonstrating parallel protein interactions with vertebrate homologs. P-element mobilization was used to generate null dMAN1 alleles. These mutants showed decreased viability, with surviving adults displaying male sterility, decreased female fertility, wing patterning and positioning defects, flightlessness, and locomotion difficulties that became more severe with age. Increased phospho-Smad staining in dMAN1 mutant wing discs is consistent with a role in transforming growth factor (TGF)-beta/bone morphogenic protein (BMP) signaling. The tissue-specific, age-enhanced dMAN1 mutant phenotypes are reminiscent of human laminopathies, suggesting that studies in Drosophila will provide insights into lamina dysfunction associated with disease.
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Abstract
The positioning and elaboration of ectodermal veins in the wing of Drosophila melanogaster rely on widely utilized developmental signals, including those mediated by EGF, BMP, Hedgehog, Notch, and Wnt. Analysis of vein patterning mutants, using the molecular and genetic mosaic techniques available in Drosophila, has provided important insights into how a combination of short-range and long-range signaling can pattern a simple epidermal tissue. Moreover, venation has become a powerful system for isolating and analyzing novel components in these signaling pathways. I here review the basic events of vein patterning and give examples of how changes in venation have been used to identify important features of cell signaling pathways.
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Affiliation(s)
- Seth S Blair
- Department of Zoology, University of Wisconsin, Madison, WI 53706, USA.
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40
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Christoforou CP, Greer CE, Challoner BR, Charizanos D, Ray RP. The detached locus encodes Drosophila Dystrophin, which acts with other components of the Dystrophin Associated Protein Complex to influence intercellular signalling in developing wing veins. Dev Biol 2007; 313:519-32. [PMID: 18093579 DOI: 10.1016/j.ydbio.2007.09.044] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Revised: 09/24/2007] [Accepted: 09/24/2007] [Indexed: 11/29/2022]
Abstract
Dystrophin and Dystroglycan are the two central components of the multimeric Dystrophin Associated Protein Complex, or DAPC, that is thought to provide a mechanical link between the extracellular matrix and the actin cytoskeleton, disruption of which leads to muscular dystrophy in humans. We present the characterization of the Drosophila 'crossveinless' mutation detached (det), and show that the gene encodes the fly ortholog of Dystrophin. Our genetic analysis shows that, in flies, Dystrophin is a non-essential gene, and the sole overt morphological defect associated with null mutations in the locus is the variable loss of the posterior crossvein that has been described for alleles of det. Null mutations in Drosophila Dystroglycan (Dg) are similarly viable and exhibit this crossvein defect, indicating that both of the central DAPC components have been co-opted for this atypical function of the complex. In the developing wing, the Drosophila DAPC affects the intercellular signalling pathways involved in vein specification. In det and Dg mutant wings, the early BMP signalling that initiates crossvein specification is not maintained, particularly in the pro-vein territories adjacent to the longitudinal veins, and this results in the production of a crossvein fragment in the intervein between the two longitudinal veins. Genetic interaction studies suggest that the DAPC may exert this effect indirectly by down-regulating Notch signalling in pro-vein territories, leading to enhanced BMP signalling in the intervein by diffusion of BMP ligands from the longitudinal veins.
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Affiliation(s)
- Christina P Christoforou
- Department of Biology and Environmental Science, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
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O’Keefe DD, Prober DA, Moyle PS, Rickoll WL, Edgar BA. Egfr/Ras signaling regulates DE-cadherin/Shotgun localization to control vein morphogenesis in the Drosophila wing. Dev Biol 2007; 311:25-39. [PMID: 17888420 PMCID: PMC2128780 DOI: 10.1016/j.ydbio.2007.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 08/01/2007] [Accepted: 08/02/2007] [Indexed: 12/31/2022]
Abstract
Egfr/Ras signaling promotes vein cell fate specification in the developing Drosophila wing. While the importance of Ras signaling in vein determination has been extensively documented, the mechanisms linking Ras activity to vein differentiation remain unclear. We found that Ras signaling regulates both the levels and subcellular localization of the cell adhesion molecule DE-cadherin/Shotgun (Shg) in the differentiating wing epithelium. High Ras activity in presumptive vein cells directs the apical localization of Shg containing adherens junctions, whereas low Ras activity in intervein cells allows Shg to relocalize basally. These alterations in Shg-mediated adhesion control cell shape changes that are essential for vein morphogenesis. While Decapentaplegic (Dpp) acts downstream of Ras to maintain vein cell identity in the pupal wing, our results indicate that Ras controls Shg localization via a Dpp-independent mechanism. Ras, therefore, regulates both the transcriptional responses necessary for vein cell identity, and the cell adhesive changes that determine vein and intervein cell morphology.
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Affiliation(s)
- David D. O’Keefe
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - David A. Prober
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195
| | | | | | - Bruce A. Edgar
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Corresponding author: , phone: (206) 667-4185, FAX: (206) 667-3308
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Vrailas-Mortimer AD, Majumdar N, Middleton G, Cooke EM, Marenda DR. Delta and Egfr expression are regulated by Importin-7/Moleskin in Drosophila wing development. Dev Biol 2007; 308:534-46. [PMID: 17628519 PMCID: PMC1994573 DOI: 10.1016/j.ydbio.2007.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 06/08/2007] [Accepted: 06/15/2007] [Indexed: 01/27/2023]
Abstract
Drosophila DIM-7 (encoded by the moleskin gene, msk) is the orthologue of vertebrate Importin-7. Both Importin-7 and Msk/DIM-7 function as nuclear import cofactors, and have been implicated in the control of multiple signal transduction pathways, including the direct nuclear import of the activated (phosphorylated) form of MAP kinase. We performed two genetic deficiency screens to identify deficiencies that similarly modified Msk overexpression phenotypes in both eyes and wings. We identified 11 total deficiencies, one of which removes the Delta locus. In this report, we show that Delta loss-of-function alleles dominantly suppress Msk gain-of-function phenotypes in the developing wing. We find that Msk overexpression increases both Delta protein expression and Delta transcription, though Msk expression alone is not sufficient to activate Delta protein function. We also find that Msk overexpression increases Egfr protein levels, and that msk gene function is required for proper Egfr expression in both developing wings and eyes. These results indicate a novel function for Msk in Egfr expression. We discuss the implications of these data with respect to the integration of Egfr and Delta/Notch signaling, specifically through the control of MAP kinase subcellular localization.
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Ramel MC, Emery CM, Emery CS, Foulger R, Goberdhan DCI, van den Heuvel M, Wilson C. Drosophila SnoN modulates growth and patterning by antagonizing TGF-beta signalling. Mech Dev 2006; 124:304-17. [PMID: 17289352 DOI: 10.1016/j.mod.2006.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 12/18/2006] [Accepted: 12/20/2006] [Indexed: 11/22/2022]
Abstract
Signalling by TGF-beta ligands through the Smad family of transcription factors is critical for developmental patterning and growth. Disruption of this pathway has been observed in various cancers. In vertebrates, members of the Ski/Sno protein family can act as negative regulators of TGF-beta signalling, interfering with the Smad machinery to inhibit the transcriptional output of this pathway. In some contexts ski/sno genes function as tumour suppressors, but they were originally identified as oncogenes, whose expression is up-regulated in many tumours. These growth regulatory effects and the normal physiological functions of Ski/Sno proteins have been proposed to result from changes in TGF-beta signalling. However, this model is controversial and may be over-simplified, because recent findings indicate that Ski/Sno proteins can affect other signalling pathways. To address this issue in an in vivo context, we have analyzed the function of the Drosophila Ski/Sno orthologue, SnoN. We found that SnoN inhibits growth when overexpressed, indicating a tumour suppressor role in flies. It can act in multiple tissues to selectively and cell autonomously antagonise signalling by TGF-beta ligands from both the BMP and Activin sub-families. By contrast, analysis of a snoN mutant indicates that the gene does not play a global role in TGF-beta-mediated functions, but specifically inhibits TGF-beta-induced wing vein formation. We propose that SnoN normally functions redundantly with other TGF-beta pathway antagonists to finely adjust signalling levels, but that it can behave as an extremely potent inhibitor of TGF-beta signalling when highly expressed, highlighting the significance of its deregulation in cancer cells.
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Affiliation(s)
- M-C Ramel
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford OX1 3QX, UK.
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Molnar C, López-Varea A, Hernández R, de Celis JF. A gain-of-function screen identifying genes required for vein formation in the Drosophila melanogaster wing. Genetics 2006; 174:1635-59. [PMID: 16980395 PMCID: PMC1667087 DOI: 10.1534/genetics.106.061283] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The formation of the Drosophila wing involves developmental processes such as cell proliferation, pattern formation, and cell differentiation that are common to all multicellular organisms. The genes controlling these cellular behaviors are conserved throughout the animal kingdom, and the genetic analysis of wing development has been instrumental in their identification and functional characterization. The wing is a postembryonic structure, and most loss-of-function mutations are lethal in homozygous flies before metamorphosis. In this manner, loss-of-function genetic screens aiming to identify genes affecting wing formation have not been systematically utilized. As an alternative, a number of genetic searches have utilized the phenotypic consequences of gene gain-of-expression, as a method more efficient to search for genes required during imaginal development. Here we present the results of a gain-of-function screen designed to identify genes involved in the formation of the wing veins. We generated 13,000 P-GS insertions of a P element containing UAS sequences (P-GS) and combined them with a Gal4 driver expressed mainly in the developing pupal veins. We selected 500 P-GSs that, in combination with the Gal4 driver, result in modifications of the veins, changes in the morphology of the wing, or defects in the differentiation of the trichomes. The P-element insertion sites were mapped to the genomic sequence, identifying 373 gene candidates to participate in wing morphogenesis and vein formation.
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Affiliation(s)
- Cristina Molnar
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Pallavi SK, Kannan R, Shashidhara LS. Negative regulation of Egfr/Ras pathway by Ultrabithorax during haltere development in Drosophila. Dev Biol 2006; 296:340-52. [PMID: 16815386 DOI: 10.1016/j.ydbio.2006.05.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Revised: 05/21/2006] [Accepted: 05/24/2006] [Indexed: 11/30/2022]
Abstract
In Drosophila, wings and halteres are the dorsal appendages of the second and third thoracic segments, respectively. In the third thoracic segment, homeotic selector gene Ultrabithorax (Ubx) suppresses wing development to mediate haltere development (E.B. Lewis, 1978. A gene complex controlling segmentation in Drosophila. Nature 276, 565-570). Halteres lack stout sensory bristles of the wing margin and veins that reticulate the wing blade. Furthermore, wing and haltere epithelia differ in the size, shape, spacing and number of cuticular hairs. The differential development of wing and haltere, thus, constitutes a good genetic system to study cell fate determination. Here, we report that down-regulation of Egfr/Ras pathway is critical for haltere fate specification: over-expression of positive components of this pathway causes significant haltere-to-wing transformations. RNA in situ, immunohistochemistry, and epistasis genetic experiments suggest that Ubx negatively regulates the expression of the ligand vein as well as the receptor Egf-r to down-regulate the signaling pathway. Electromobility shift assays further suggest that Egf-r is a potential direct target of Ubx. These results and other recent findings suggest that homeotic genes may regulate cell fate determination by directly regulating few steps at the top of the hierarchy of selected signal transduction pathways.
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Affiliation(s)
- S K Pallavi
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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Joshi M, Buchanan KT, Shroff S, Orenic TV. Delta and Hairy establish a periodic prepattern that positions sensory bristles in Drosophila legs. Dev Biol 2006; 293:64-76. [PMID: 16542648 DOI: 10.1016/j.ydbio.2006.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 12/05/2005] [Accepted: 01/04/2006] [Indexed: 10/24/2022]
Abstract
In vertebrates and invertebrates, spatially defined proneural gene expression is an early and essential event in neuronal patterning. In this study, we investigate the mechanisms involved in establishing proneural gene expression in the primordia of a group of small mechanosensory bristles (microchaetae), which on the legs of the Drosophila adult are arranged in a series of longitudinal rows along the leg circumference. In prepupal legs, the proneural gene achaete (ac) is expressed in longitudinal stripes, which comprise the leg microchaete primordia. We have previously shown that periodic ac expression is partially established by the prepattern gene, hairy, which represses ac expression in four of eight interstripe domains. Here, we identify Delta (Dl), which encodes a Notch (N) ligand, as a second leg prepattern gene. We show that Hairy and Dl function concertedly and nonredundantly to define periodic ac expression. We also explore the regulation of periodic hairy expression. In prior studies, we have found that expression of two hairy stripes along the D/V axis is induced in response to the Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless (Wg) morphogens. Here, we show that expression of two other hairy stripes along the orthogonal A/P axis is established through a distinct mechanism which involves uniform activation combined with repressive influences from Dpp and Wg. Our findings allow us to formulate a general model for generation of periodic pattern in the adult leg. This process involves broad and late activation of ac expression combined with refinement in response to a prepattern of repression, established by Hairy and Dl, which unfolds progressively during larval and early prepupal stages.
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Affiliation(s)
- Meghana Joshi
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
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Dworkin I, Gibson G. Epidermal growth factor receptor and transforming growth factor-beta signaling contributes to variation for wing shape in Drosophila melanogaster. Genetics 2006; 173:1417-31. [PMID: 16648592 PMCID: PMC1526698 DOI: 10.1534/genetics.105.053868] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wing development in Drosophila is a common model system for the dissection of genetic networks and their roles during development. In particular, the RTK and TGF-beta regulatory networks appear to be involved with numerous aspects of wing development, including patterning, cell determination, growth, proliferation, and survival in the developing imaginal wing disc. However, little is known as to how subtle changes in the function of these genes may contribute to quantitative variation for wing shape, per se. In this study 50 insertional mutations, representing 43 loci in the RTK, Hedgehog, TGF-beta pathways, and their genetically interacting factors were used to study the role of these networks on wing shape. To concurrently examine how genetic background modulates the effects of the mutation, each insertion was introgressed into two wild-type genetic backgrounds. Using geometric morphometric methods, it is shown that the majority of these mutations have profound effects on shape but not size of the wing when measured as heterozygotes. To examine the relationships between how each mutation affects wing shape hierarchical clustering was used. Unlike previous observations of environmental canalization, these mutations did not generally increase within-line variation relative to their wild-type counterparts. These results provide an entry point into the genetics of wing shape and are discussed within the framework of the dissection of complex phenotypes.
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Affiliation(s)
- Ian Dworkin
- Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695, USA.
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Abstract
The epidermal growth factor receptor (EGFR) signaling cascade represents one of the cardinal pathways that transmits information between cells during development in a broad range of multicellular organisms. Most of the elements that constitute the core EGFR signaling module, as well as a variety of negative and positive modulators, have been identified. Although this molecular pathway is utilized multiple times during development, the spatial and temporal features of its signaling can be modified to fit a particular developmental setting. Recent work has unraveled the various mechanisms by which the EGFR pathway can be modulated.
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Affiliation(s)
- Ben-Zion Shilo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
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Sotillos S, de Celis JF. Regulation of decapentaplegic expression during Drosophila wing veins pupal development. Mech Dev 2006; 123:241-51. [PMID: 16423512 DOI: 10.1016/j.mod.2005.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 12/07/2005] [Accepted: 12/08/2005] [Indexed: 10/25/2022]
Abstract
The differentiation of veins in the Drosophila wing relies on localised expression of decapentaplegic (dpp) in pro-vein territories during pupal development. The expression of dpp in the pupal veins requires the integrity of the shortvein region (shv), localised 5' to the coding region. It is likely that this DNA integrates positive and negative regulatory signals directing dpp transcription during pupal development. Here, we identify a minimal 0.9 kb fragment giving localised expression in the vein L5 and a 0.5 kb fragment giving expression in all longitudinal veins. Using a combination of in vivo expression of reporter genes regulated by shv sequences, in vitro binding assays and sequence comparisons between the shv region of different Drosophila species, we found binding sites for the vein-specific transciption factors Araucan, Knirps and Ventral veinless, as well as binding sites for the Dpp pathway effectors Mad and Med. We conclude that conserved vein-specific enhancers regulated by transcription factors expressed in individual veins collaborate with general vein and intervein regulators to establish and maintain the expression of dpp confined to the veins during pupal development.
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Affiliation(s)
- Sol Sotillos
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Crta. de Utrera Km1, 41013 Sevilla, Spain.
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