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Bonneaud N, Layalle S, Colomb S, Jourdan C, Ghysen A, Severac D, Dantec C, Nègre N, Maschat F. Control of nerve cord formation by Engrailed and Gooseberry-Neuro: A multi-step, coordinated process. Dev Biol 2017; 432:273-285. [PMID: 29097190 DOI: 10.1016/j.ydbio.2017.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 10/06/2017] [Accepted: 10/24/2017] [Indexed: 01/05/2023]
Abstract
One way to better understand the molecular mechanisms involved in the construction of a nervous system is to identify the downstream effectors of major regulatory proteins. We previously showed that Engrailed (EN) and Gooseberry-Neuro (GsbN) transcription factors act in partnership to drive the formation of posterior commissures in the central nervous system of Drosophila. In this report, we identified genes regulated by both EN and GsbN through chromatin immunoprecipitation ("ChIP on chip") and transcriptome experiments, combined to a genetic screen relied to the gene dose titration method. The genomic-scale approaches allowed us to define 175 potential targets of EN-GsbN regulation. We chose a subset of these genes to examine ventral nerve cord (VNC) defects and found that half of the mutated targets show clear VNC phenotypes when doubly heterozygous with en or gsbn mutations, or when homozygous. This strategy revealed new groups of genes never described for their implication in the construction of the nerve cord. Their identification suggests that, to construct the nerve cord, EN-GsbN may act at three levels, in: (i) sequential control of the attractive-repulsive signaling that ensures contralateral projection of the commissural axons, (ii) temporal control of the translation of some mRNAs, (iii) regulation of the capability of glial cells to act as commissural guideposts for developing axons. These results illustrate how an early, coordinated transcriptional control may orchestrate the various mechanisms involved in the formation of stereotyped neuronal networks. They also validate the overall strategy to identify genes that play crucial role in axonal pathfinding.
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Affiliation(s)
- Nathalie Bonneaud
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France; CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France
| | - Sophie Layalle
- CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France; CNRS - INSERM - Université de Montpellier, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France
| | - Sophie Colomb
- CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France
| | - Christophe Jourdan
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France
| | - Alain Ghysen
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France
| | - Dany Severac
- MGX - Montpellier GenomiX, Institut de Génomique Fonctionnelle, Montpellier F-34094, France
| | - Christelle Dantec
- MGX - Montpellier GenomiX, Institut de Génomique Fonctionnelle, Montpellier F-34094, France
| | - Nicolas Nègre
- DGIMI, INRA, Université de Montpellier, 34095 Montpellier, France; Institut Universitaire de France (IUF), Paris, France
| | - Florence Maschat
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France; CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France.
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Fulkerson E, Estes PA. Common motifs shared by conserved enhancers of Drosophila midline glial genes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2010; 316:61-75. [PMID: 21154525 DOI: 10.1002/jez.b.21382] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/07/2010] [Accepted: 09/28/2010] [Indexed: 12/12/2022]
Abstract
Coding sequences are usually the most highly conserved sectors of DNA, but genomic regions controlling the expression pattern of certain genes can also be conserved across diverse species. In this study, we identify five enhancers capable of activating transcription in the midline glia of Drosophila melanogaster and each contains sequences conserved across at least 11 Drosophila species. In addition, the conserved sequences contain reiterated motifs for binding sites of the known midline transcriptional activators, Single-minded, Tango, Dichaete, and Pointed. To understand the molecular basis for the highly conserved genomic subregions within enhancers of the midline genes, we tested the ability of various motifs to affect midline expression, both individually and in combination, within synthetic reporter constructs. Multiple copies of the binding site for the midline regulators Single-minded and Tango can drive expression in midline cells; however, small changes to the sequences flanking this transcription factor binding site can inactivate expression in midline cells and activate expression in tracheal cells instead. For the midline genes described in this study, the highly conserved sequences appear to juxtapose positive and negative regulatory factors in a configuration that activates genes specifically in the midline glia, while maintaining them inactive in other tissues, including midline neurons and tracheal cells.
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Affiliation(s)
- Eric Fulkerson
- Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695, USA
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Abstract
The glia that reside at the midline of the Drosophila CNS are an important embryonic signaling center and also wrap the axons that cross the CNS. The development of the midline glia (MG) is characterized by migration, ensheathment, subdivision of axon commissures, apoptosis, and the extension of glial processes. All of these events are characterized by cell-cell contact between MG and adjacent neurons. Cell adhesion and signaling proteins that mediate different aspects of MG development and MG-neuron interactions have been identified. This provides a foundation for ultimately obtaining an integrated picture of how the MG assemble into a characteristic axonal support structure in the CNS.
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Affiliation(s)
- Stephen T Crews
- Department of Biochemistry and Biophysics, Program in Molecular Biology and Biotechnology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Wang J, Jin S, Lin N, Wang B. Fluorescent indolylboronic acids that are useful reporters for the synthesis of boronolectins. Chem Biol Drug Des 2006; 67:137-44. [PMID: 16492161 DOI: 10.1111/j.1747-0285.2005.00338.x] [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] [Indexed: 11/27/2022]
Abstract
Lectins are known to regulate a wide variety of biological processes. Therefore, small molecule mimics of lectins have the potential to be used as novel diagnostic and therapeutic agents. In our combinatorial search for lectin mimics, we are in need a large number of boronic acids that change fluorescent properties upon carbohydrate binding. Along this line, a series of indolylboronic acids have been found to show significant fluorescent property changes upon binding with carbohydrates in 0.1 M phosphate buffer at physiological pH. These boronic acids will be very useful for the synthesis of lectin mimics for biological applications.
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Affiliation(s)
- Junfeng Wang
- Department of Chemistry, Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30302-4098, USA
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Gibson NJ, Tolbert LP. Activation of epidermal growth factor receptor mediates receptor axon sorting and extension in the developing olfactory system of the moth Manduca sexta. J Comp Neurol 2006; 495:554-72. [PMID: 16498681 PMCID: PMC2709604 DOI: 10.1002/cne.20890] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During development of the adult olfactory system of the moth Manduca sexta, olfactory receptor neurons extend axons from the olfactory epithelium in the antenna into the brain. As they arrive at the brain, interactions with centrally derived glial cells cause axons to sort and fasciculate with other axons destined to innervate the same glomeruli. Here we report studies indicating that activation of the epidermal growth factor receptor (EGFR) is involved in axon ingrowth and targeting. Blocking the EGFR kinase domain pharmacologically leads to stalling of many axons in the sorting zone and nerve layer as well as abnormal axonal fasciculation in the sorting zone. We also find that neuroglian, an IgCAM known to activate the EGFR through homophilic interactions in other systems, is transiently present on olfactory receptor neuron axons and on glia during the critical stages of the sorting process. The neuroglian is resistant to extraction with Triton X-100 in the sorting zone and nerve layer, possibly indicating its stabilization by homophilic binding in these regions. Our results suggest a mechanism whereby neuroglian molecules on axons and possibly sorting zone glia bind homophilically, leading to activation of EGFRs, with subsequent effects on axon sorting, pathfinding, and extension, and glomerulus development.
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Affiliation(s)
- Nicholas J Gibson
- Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson, Arizona 85721, USA.
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Vasenkova I, Luginbuhl D, Chiba A. Gliopodia extend the range of direct glia-neuron communication during the CNS development in Drosophila. Mol Cell Neurosci 2005; 31:123-30. [PMID: 16298140 DOI: 10.1016/j.mcn.2005.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 09/16/2005] [Accepted: 10/04/2005] [Indexed: 11/20/2022] Open
Abstract
Midline glia are a source of cues for neuronal navigation and differentiation in the Drosophila CNS. Despite their importance, how glia and neurons communicate during the development is not fully understood. Here, we examined dynamic morphology of midline glia and assessed their direct cellular interactions with neurons within the embryonic CNS. Midline glia extend filopodia-like "gliopodia" from the onset of axogenesis through the near completion of embryonic neural development. The most abundant and stable within the commissures, gliopodia frequently contact neurites extending from the neuropil on either side of the midline. Misexpression of Rac1N17 in midline glia not only reduces the number of gliopodia but also shifts the position of neuropils towards the midline. Midline-secreted signaling protein Slit accumulates along the surface of gliopodia. Mutant analysis supports the idea that gliopodia contribute to its presentation on neuronal surfaces at both the commissures and neuropils. We propose that gliopodia extend the range of direct glia-neuron communication during CNS development.
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Affiliation(s)
- Irina Vasenkova
- Department of Cell and Developmental Biology, University of Illinois, 601 South Goodwin Avenue, Urbana, IL 61801, USA
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Araújo SJ, Aslam H, Tear G, Casanova J. mummy/cystic encodes an enzyme required for chitin and glycan synthesis, involved in trachea, embryonic cuticle and CNS development--analysis of its role in Drosophila tracheal morphogenesis. Dev Biol 2005; 288:179-93. [PMID: 16277981 DOI: 10.1016/j.ydbio.2005.09.031] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 09/09/2005] [Accepted: 09/11/2005] [Indexed: 11/24/2022]
Abstract
Tracheal and nervous system development are two model systems for the study of organogenesis in Drosophila. In two independent screens, we identified three alleles of a gene involved in tracheal, cuticle and CNS development. Here, we show that these alleles, and the previously identified cystic and mummy, all belong to the same complementation group. These are mutants of a gene encoding the UDP-N-acetylglucosamine diphosphorylase, an enzyme responsible for the production of UDP-N-acetylglucosamine, an important intermediate in chitin and glycan biosynthesis. cyst was originally singled out as a gene required for the regulation of tracheal tube diameter. We characterized the cyst/mmy tracheal phenotype and upon histological examination concluded that mmy mutant embryos lack chitin-containing structures, such as the procuticle at the epidermis and the taenidial folds in the tracheal lumen. While most of their tracheal morphogenesis defects can be attributed to the lack of chitin, when compared to krotzkopf verkehrt (kkv) chitin-synthase mutants, mmy mutants showed a stronger phenotype, suggesting that some of the mmy phenotypes, like the axon guidance defects, are chitin-independent. We discuss the implications of these new data in the mechanism of size control in the Drosophila trachea.
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Affiliation(s)
- Sofia J Araújo
- Institut de Biologia Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Carrer Josep Samitier 1-5, 08028 Barcelona, Spain
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Brumby A, Secombe J, Horsfield J, Coombe M, Amin N, Coates D, Saint R, Richardson H. A genetic screen for dominant modifiers of a cyclin E hypomorphic mutation identifies novel regulators of S-phase entry in Drosophila. Genetics 2005; 168:227-51. [PMID: 15454540 PMCID: PMC1448096 DOI: 10.1534/genetics.104.026617] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cyclin E together with its kinase partner Cdk2 is a critical regulator of entry into S phase. To identify novel genes that regulate the G1- to S-phase transition within a whole animal we made use of a hypomorphic cyclin E mutation, DmcycEJP, which results in a rough eye phenotype. We screened the X and third chromosome deficiencies, tested candidate genes, and carried out a genetic screen of 55,000 EMS or X-ray-mutagenized flies for second or third chromosome mutations that dominantly modified the DmcycEJP rough eye phenotype. We have focused on the DmcycEJP suppressors, S(DmcycEJP), to identify novel negative regulators of S-phase entry. There are 18 suppressor gene groups with more than one allele and several genes that are represented by only a single allele. All S(DmcycEJP) tested suppress the DmcycEJP rough eye phenotype by increasing the number of S phases in the postmorphogenetic furrow S-phase band. By testing candidates we have identified several modifier genes from the mutagenic screen as well as from the deficiency screen. DmcycEJP suppressor genes fall into the classes of: (1) chromatin remodeling or transcription factors; (2) signaling pathways; and (3) cytoskeletal, (4) cell adhesion, and (5) cytoarchitectural tumor suppressors. The cytoarchitectural tumor suppressors include scribble, lethal-2-giant-larvae (lgl), and discs-large (dlg), loss of function of which leads to neoplastic tumors and disruption of apical-basal cell polarity. We further explored the genetic interactions of scribble with S(DmcycEJP) genes and show that hypomorphic scribble mutants exhibit genetic interactions with lgl, scab (alphaPS3-integrin--cell adhesion), phyllopod (signaling), dEB1 (microtubule-binding protein--cytoskeletal), and moira (chromatin remodeling). These interactions of the cytoarchitectural suppressor gene, scribble, with cell adhesion, signaling, cytoskeletal, and chromatin remodeling genes, suggest that these genes may act in a common pathway to negatively regulate cyclin E or S-phase entry.
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Affiliation(s)
- Anthony Brumby
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, 3002, Australia
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Mucha J, Domlatil J, Lochnit G, Rendić D, Paschinger K, HINTERKöRNER G, Hofinger A, Kosma P, Wilson I. The Drosophila melanogaster homologue of the human histo-blood group Pk gene encodes a glycolipid-modifying alpha1,4-N-acetylgalactosaminyltransferase. Biochem J 2005; 382:67-74. [PMID: 15130086 PMCID: PMC1133916 DOI: 10.1042/bj20040535] [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: 03/31/2004] [Revised: 04/29/2004] [Accepted: 05/07/2004] [Indexed: 11/17/2022]
Abstract
Insects express arthro-series glycosphingolipids, which contain an alpha1,4-linked GalNAc residue. To determine the genetic basis for this linkage, we cloned a cDNA (CG17223) from Drosophila melanogaster encoding a protein with homology to mammalian alpha1,4-glycosyltransferases and expressed it in the yeast Pichia pastoris. Culture supernatants from the transformed yeast were found to display a novel UDP-GalNAc:GalNAcbeta1,4GlcNAcbeta1-R alpha-N-acetylgalactosaminyltransferase activity when using either a glycolipid, p-nitrophenylglycoside or an N-glycan carrying one or two terminal beta-N-acetylgalactosamine residues. NMR and MS in combination with glycosidase digestion and methylation analysis indicate that the cloned cDNA encodes an alpha1,4-N-acetylgalactosaminyltransferase. We hypothesize that this enzyme and its orthologues in other insects are required for the biosynthesis of the N5a and subsequent members of the arthro-series of glycolipids as well as of N-glycan receptors for Bacillus thuringiensis crystal toxin Cry1Ac.
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Affiliation(s)
- Ján Mucha
- *Chemický ústav, Slovenská akadémia vied, Dúbravská cesta 9, 845 38 Bratislava, Slovakia
| | - Jiří Domlatil
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Günter Lochnit
- ‡Institut für Biochemie, Justus-Liebig-Universität Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
| | - Dubravko Rendić
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Katharina Paschinger
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Georg HINTERKöRNER
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Andreas Hofinger
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Paul Kosma
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Iain B. H. Wilson
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
- To whom correspondence should be addressed (email )
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Gibson NJ, Hildebrand JG, Tolbert LP. Glycosylation patterns are sexually dimorphic throughout development of the olfactory system in Manduca sexta. J Comp Neurol 2004; 476:1-18. [PMID: 15236463 DOI: 10.1002/cne.20178] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the moth Manduca sexta, development of the adult olfactory system depends on complex interactions between olfactory receptor neurons in the antenna, antennal-lobe neurons in the brain, and several classes of glial cells. As one approach to characterizing molecules that may play roles in these interactions, we used lectins to screen antennae and antennal lobes at different stages of adult development. We find that each of the major neural cell types has a distinct pattern of labeling by lectins. Effects of enzymatic and other treatments on lectin labeling lead us to conclude that the predominant lectin ligands are: glycosphingolipids and an O-linked, fucose-containing glycoprotein on axons of olfactory receptor neurons, O-linked glycoproteins on antennal-lobe neurons, and N-linked glycoproteins on all classes of glial cells in the primary olfactory pathway. Wheat germ agglutinin labels all olfactory axons uniformly during much of development, but labeling becomes restricted to the pheromone-responsive olfactory receptor neurons in the adult male. Succinylated WGA reveals differences in these axon classes earlier, as glomerului develop from protoglomeruli. The adult female displays a less pronounced difference in labeling of axons targeting ordinary and sexually dimorphic glomeruli. Differences in labeling of receptor axons targeted to ordinary and sexually dimorphic glomeruli may be correlated with differences in function or connectivity in different regions of the antennal lobe.
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Affiliation(s)
- Nicholas J Gibson
- Arizona Research Laboratories, Division of Neurobiology, University of Arizona, Tucson, Arizona 85721-0077, USA.
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Oland LA, Tolbert LP. Key interactions between neurons and glial cells during neural development in insects. ANNUAL REVIEW OF ENTOMOLOGY 2002; 48:89-110. [PMID: 12194908 DOI: 10.1146/annurev.ento.48.091801.112654] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nervous system function is entirely dependent on the intricate and precise pattern of connections made by individual neurons. Much of the insightful research into mechanisms underlying the development of this pattern of connections has been done in insect nervous systems. Studies of developmental mechanisms have revealed critical interactions between neurons and glia, the non-neuronal cells of the nervous system. Glial cells provide trophic support for neurons, act as struts for migrating neurons and growing axons, form boundaries that restrict neuritic growth, and have reciprocal interactions with neurons that govern specification of cell fate and axonal pathfinding. The molecular mechanisms underlying these interactions are beginning to be understood. Because many of the cellular and molecular mechanisms underlying neural development appear to be common across disparate insect species, and even between insects and vertebrates, studies in developing insect nervous systems are elucidating mechanisms likely to be of broad significance.
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Affiliation(s)
- Lynne A Oland
- Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson, Arizona 85721, USA.
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