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Ramon-Cañellas P, Peterson HP, Morante J. From Early to Late Neurogenesis: Neural Progenitors and the Glial Niche from a Fly's Point of View. Neuroscience 2018; 399:39-52. [PMID: 30578972 DOI: 10.1016/j.neuroscience.2018.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 12/06/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
Abstract
Drosophila melanogaster is an important model organism used to study the brain development of organisms ranging from insects to mammals. The central nervous system in fruit flies is formed primarily in two waves of neurogenesis, one of which occurs in the embryo and one of which occurs during larval stages. In order to understand neurogenesis, it is important to research the behavior of progenitor cells that give rise to the neural networks which make up the adult nervous system. This behavior has been shown to be influenced by different factors including interactions with other cells within the progenitor niche, or local tissue microenvironment. Glial cells form a crucial part of this niche and play an active role in the development of the brain. Although in the early years of neuroscience it was believed that glia were simply scaffolding for neurons and passive components of the nervous system, their importance is nowadays recognized. Recent discoveries in progenitors and niche cells have led to new understandings of how the developing brain shapes its diverse regions. In this review, we attempt to summarize the distinct neural progenitors and glia in the Drosophila melanogaster central nervous system, from embryo to late larval stages, and make note of homologous features in mammals. We also outline the recent advances in this field in order to define the impact that glial cells have on progenitor cell niches, and we finally emphasize the importance of communication between glia and progenitor cells for proper brain formation.
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Affiliation(s)
- Pol Ramon-Cañellas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain
| | - Hannah Payette Peterson
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain
| | - Javier Morante
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain.
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2
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Viktorin G, Riebli N, Popkova A, Giangrande A, Reichert H. Multipotent neural stem cells generate glial cells of the central complex through transit amplifying intermediate progenitors in Drosophila brain development. Dev Biol 2011; 356:553-65. [PMID: 21708145 DOI: 10.1016/j.ydbio.2011.06.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 05/27/2011] [Accepted: 06/11/2011] [Indexed: 10/18/2022]
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3
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Abstract
Neurons and glial cells show mutual interdependence in many developmental and functional aspects of their biology. To establish their intricate relationships with neurons, glial cells must migrate over what are often long distances. In the CNS glial cells generally migrate as single cells, whereas PNS glial cells tend to migrate as cohorts of cells. How are their journeys initiated and directed, and what stops the migratory phase once glial cells are aligned with their neuronal counterparts? A deeper understanding of glial migration and the underlying neuron-glia interactions may contribute to the development of therapeutics for demyelinating diseases or glial tumours.
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4
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Schubert SW, Abendroth A, Kilian K, Vogler T, Mayr B, Knerr I, Hashemolhosseini S. bZIP-Type transcription factors CREB and OASIS bind and stimulate the promoter of the mammalian transcription factor GCMa/Gcm1 in trophoblast cells. Nucleic Acids Res 2008; 36:3834-46. [PMID: 18495750 PMCID: PMC2441803 DOI: 10.1093/nar/gkn306] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
One of the master regulators of placental cell fusion in mammals leading to multi-nucleated syncytiotrophoblasts is the transcription factor GCMa. Recently, we proved that the cAMP-driven protein kinase A signaling pathway is fundamental for up-regulation of GCMa transcript levels and protein stability. Here, we show that Transducer of Regulated CREB activity (TORC1), the human co-activator of cAMP response element-binding protein (CREB), but not a dominant-negative CREB mutant, significantly up-regulates the GCMa promoter. We identified potential cAMP response element (CRE)-binding sites within the GCMa promoter upstream of the transcriptional start site. Only the CRE site at -1337 interacted strongly with CREB in promoter mapping experiments. The characterization of GCMa promoter mutants and additional bZIP-type family members demonstrated that also old astrocyte specifically-induced substance (OASIS) is able to stimulate GCMa transcription. Knockdown of endogenous CREB or OASIS in BeWo cells decreased endogenous GCMa mRNA level and activity. Overexpression of TORC1 or OASIS in choriocarcinoma cells led to placental cell fusion, accompanied by placental expression of gap junction forming protein connexin-43. Further, we show that CREB expression is replaced by OASIS expression around E12.5 suggesting that a sequential order of bZIP-type family members ensures a high rate of GCMa transcription throughout placentation.
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Affiliation(s)
- Steffen Wolfgang Schubert
- Institut für Biochemie, Emil-Fischer-Zentrum, Kinder- und Jugendklinik and Nikolaus-Fiebiger-Zentrum, Universität Erlangen-Nürnberg, Fahrstrasse 17, D-91054 Erlangen, Germany
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5
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Soustelle L, Aigouy B, Asensio ML, Giangrande A. UV laser mediated cell selective destruction by confocal microscopy. Neural Dev 2008; 3:11. [PMID: 18442390 PMCID: PMC2387153 DOI: 10.1186/1749-8104-3-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 04/28/2008] [Indexed: 11/29/2022] Open
Abstract
Analysis of cell-cell interactions, cell function and cell lineages greatly benefits selective destruction techniques, which, at present, rely on dedicated, high energy, pulsed lasers and are limited to cells that are detectable by conventional microscopy. We present here a high resolution/sensitivity technique based on confocal microscopy and relying on commonly used UV lasers. Coupling this technique with time-lapse enables the destruction and following of any cell(s) in any pattern(s) in living animals as well as in cell culture systems.
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Affiliation(s)
- Laurent Soustelle
- Institut de Génétique et Biologie Moléculaire et Cellulaire, IGBMC/CNRS/ULP/INSERM - BP 10142 67404 ILLKIRCH, c.u. de Strasbourg, France.
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6
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Abstract
The function of a complex nervous system depends on an intricate interplay between neuronal and glial cell types. One of the many functions of glial cells is to provide an efficient insulation of the nervous system and thereby allowing a fine tuned homeostasis of ions and other small molecules. Here, we present a detailed cellular analysis of the glial cell complement constituting the blood-brain barrier in Drosophila. Using electron microscopic analysis and single cell-labeling experiments, we characterize different glial cell layers at the surface of the nervous system, the perineurial glial layer, the subperineurial glial layer, the wrapping glial cell layer, and a thick layer of extracellular matrix, the neural lamella. To test the functional roles of these sheaths we performed a series of dye penetration experiments in the nervous systems of wild-type and mutant embryos. Comparing the kinetics of uptake of different sized fluorescently labeled dyes in different mutants allowed to conclude that most of the barrier function is mediated by the septate junctions formed by the subperineurial cells, whereas the perineurial glial cell layer and the neural lamella contribute to barrier selectivity against much larger particles (i.e., the size of proteins). We further compare the requirements of different septate junction components for the integrity of the blood-brain barrier and provide evidence that two of the six Claudin-like proteins found in Drosophila are needed for normal blood-brain barrier function.
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7
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Soustelle L, Giangrande A. Novel gcm-dependent lineages in the postembryonic nervous system of Drosophila melanogaster. Dev Dyn 2007; 236:2101-8. [PMID: 17654713 DOI: 10.1002/dvdy.21232] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
glial cells missing genes (gcm and gcm2) act as the glial fate determinants in the Drosophila embryo. However, their requirement in the adult central nervous system (CNS) is at present not known, except for their role in lamina glia. This is particularly important with respect to two recent sets of data. Adult glial subpopulations differentiate through embryonic glia proliferation. Also, gcm-gcm2 are required for the differentiation of specific adult neurons. We here show that gcm is expressed in precursors and postmitotic, migrating, cells of the medulla neuropile glia (mng) lineage. It is also expressed in a thoracic glial lineage and in neurons of the ventral nerve cord (VNC). Finally, while gcm is required for gliogenesis in medulla and VNC, it does not seem to be required for the generation of VNC neurons.
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Affiliation(s)
- Laurent Soustelle
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Strasbourg, France
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8
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Colonques J, Ceron J, Tejedor FJ. Segregation of postembryonic neuronal and glial lineages inferred from a mosaic analysis of the Drosophila larval brain. Mech Dev 2007; 124:327-40. [PMID: 17344035 DOI: 10.1016/j.mod.2007.01.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 01/12/2007] [Accepted: 01/16/2007] [Indexed: 01/06/2023]
Abstract
Due to its intermediate complexity and its sophisticated genetic tools, the larval brain of Drosophila is a useful experimental system to study the mechanisms that control the generation of cell diversity in the CNS. In order to gain insight into the neuronal and glial lineage specificity of neural progenitor cells during postembryonic brain development, we have carried an extensive mosaic analysis throughout larval brain development. In contrast to embryonic CNS development, we have found that most postembryonic neurons and glial cells of the optic lobe and central brain originate from segregated progenitors. Our analysis also provides relevant information about the origin and proliferation patterns of several postembryonic lineages such as the superficial glia and the medial-anterior Medulla neuropile glia. Additionally, we have studied the spatio-temporal relationship between gcm expression and gliogenesis. We found that gcm expression is restricted to the post-mitotic cells of a few neuronal and glial lineages and it is mostly absent from postembryonic progenitors. Thus, in contrast to its major gliogenic role in the embryo, the function of gcm during postembryonic brain development seems to have evolved to the specification and differentiation of certain neuronal and glial lineages.
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Affiliation(s)
- J Colonques
- Instituto de Neurociencias, CSIC--Universidad Miguel Hernandez, Campus de San Juan, 03550 San Juan (Alicante), Spain
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9
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Kim SH, Kim HJ, Kim SY, Jeon SH, Kim SH. CNS midline cells influence the division and survival of lateral glia in the Drosophila nervous system. Genesis 2007; 45:266-74. [PMID: 17457927 DOI: 10.1002/dvg.20283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Central nervous system (CNS) midline cells are essential for identity determination and differentiation of neurons in the Drosophila nervous system. It is not clear, however, whether CNS midline cells are also involved in the development of lateral glial cells. The roles of CNS midline cells in lateral glia development were elucidated using general markers for lateral glia, such as glial cell missing and reverse polarity, and specific enhancer trap lines labeling the longitudinal, A, B, medial cell body, peripheral, and exit glia. We found that CNS midline cells were necessary for the proper expression of glial cell missing, reverse polarity, and other lateral glia markers only during the later stages of development, suggesting that they are not required for initial identity determination. Instead, CNS midline cells appear to be necessary for proper division and survival of lateral glia. CNS midline cells were also required for proper positioning of three exit glia at the junction of segmental and intersegmental nerves, as well as some peripheral glia along motor and sensory axon pathways. This study demonstrated that CNS midline cells are extrinsically required for the proper division, migration, and survival of various classes of lateral glia from the ventral neuroectoderm.
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Affiliation(s)
- So Hee Kim
- Department of Chemistry, Konkuk University, Seoul, Korea
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10
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Edenfeld G, Volohonsky G, Krukkert K, Naffin E, Lammel U, Grimm A, Engelen D, Reuveny A, Volk T, Klämbt C. The splicing factor crooked neck associates with the RNA-binding protein HOW to control glial cell maturation in Drosophila. Neuron 2007; 52:969-80. [PMID: 17178401 DOI: 10.1016/j.neuron.2006.10.029] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 09/08/2006] [Accepted: 10/26/2006] [Indexed: 11/21/2022]
Abstract
In both vertebrates and invertebrates, glial cells wrap axonal processes to ensure electrical conductance. Here we report that Crooked neck (Crn), the Drosophila homolog of the yeast Clf1p splicing factor, is directing peripheral glial cell maturation. We show that crooked neck is expressed and required in glial cells to control migration and axonal wrapping. Within the cytoplasm, Crn interacts with the RNA-binding protein HOW and then translocates to the nucleus where the Crn/HOW complex controls glial differentiation by facilitating splicing of specific target genes. By using a GFP-exon trap approach, we identified some of the in vivo target genes that encode proteins localized in autocellular septate junctions. In conclusion, here we show that glial cell differentiation is controlled by a cytoplasmic assembly of splicing components, which upon translocation to the nucleus promote the splicing of genes involved in the assembly of cellular junctions.
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Affiliation(s)
- Gundula Edenfeld
- Institut für Neurobiologie, Universität Münster, Badestrasse 9, D-48149 Münster, Germany
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11
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Soustelle L, Trousse F, Jacques C, Ceron J, Cochard P, Soula C, Giangrande A. Neurogenic role of Gcm transcription factors is conserved in chicken spinal cord. Development 2007; 134:625-34. [PMID: 17215311 DOI: 10.1242/dev.02750] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Although glial cells missing (gcm) genes are known as glial determinants in the fly embryo, the role of vertebrate orthologs in the central nervous system is still under debate. Here we show for the first time that the chicken ortholog of fly gcm (herein referred to as c-Gcm1), is expressed in early neuronal lineages of the developing spinal cord and is required for neural progenitors to differentiate as neurons. Moreover, c-Gcm1 overexpression is sufficient to trigger cell cycle exit and neuronal differentiation in neural progenitors. Thus, c-Gcm1 expression constitutes a crucial step in the developmental cascade that prompts progenitors to generate neurons: c-Gcm1 acts downstream of proneural (neurogenin) and progenitor (Sox1-3) factors and upstream of NeuroM neuronal differentiation factor. Strikingly, this neurogenic role is not specific to the vertebrate gene, as fly gcmand gcm2 are also sufficient to induce the expression of neuronal markers. Interestingly, the neurogenic role is restricted to post-embryonic stages and we identify two novel brain neuronal lineages expressing and requiring gcm genes. Finally, we show that fly gcm and the chick and mouse orthologs induce expression of neural markers in HeLa cells. These data, which demonstrate a conserved neurogenic role for Gcm transcription factors, call for a re-evaluation of the mode of action of these genes during evolution.
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Affiliation(s)
- Laurent Soustelle
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cedex, CU de Strasbourg, France
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12
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Guenin L, Grosjean Y, Fraichard S, Acebes A, Baba-Aissa F, Ferveur JF. Spatio-temporal expression of Prospero is finely tuned to allow the correct development and function of the nervous system in Drosophila melanogaster. Dev Biol 2006; 304:62-74. [PMID: 17223099 DOI: 10.1016/j.ydbio.2006.12.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 12/05/2006] [Accepted: 12/08/2006] [Indexed: 11/19/2022]
Abstract
Adaptive animal behaviors depend upon the precise development of the nervous system that underlies them. In Drosophila melanogaster, the pan-neural prospero gene (pros), is involved in various aspects of neurogenesis including cell cycle control, axonal outgrowth, neuronal and glial cell differentiation. As these results have been generally obtained with null pros mutants inducing embryonic lethality, the role of pros during later development remains poorly known. Using several pros-Voila (prosV) alleles, that induce multiple developmental and behavioral anomalies in the larva and in adult, we explored the relationship between these phenotypes and the variation of pros expression in 5 different neural regions during pre-imaginal development. We found that the quantity of pros mRNA spliced variants and of Pros protein varied between these alleles in a tissue-specific and developmental way. Moreover, in prosV1 and prosV13 alleles, the respective decrease or increase of pros expression, affected (i) neuronal and glial cell composition, (ii) cell proliferation and death and (iii) axonal-dendritic outgrowth in a stage and cellular context dependant way. The various phenotypic consequences induced during development, related to more or less subtle differences in gene expression, indicate that Pros level needs a precise and specific adjustment in each neural organ to allow its proper function.
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Affiliation(s)
- Laure Guenin
- Unité Mixte de Recherche 5548 Associée au Centre National de la Recherche Scientifique, Université de Bourgogne, 6, Bd Gabriel, 21 000 Dijon, France
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13
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Allodi S, Bressan CM, Carvalho SL, Cavalcante LA. Regionally specific distribution of the binding of anti-glutamine synthetase and anti-S100 antibodies and of Datura stramonium lectin in glial domains of the optic lobe of the giant prawn. Glia 2006; 53:612-20. [PMID: 16435368 DOI: 10.1002/glia.20317] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We previously characterized some crustacean glial cells by markers such as 2',3'-cyclic nucleotide 3'-phosphodiesterase and glial fibrillary acidic protein. Here we use antibodies against glutamine synthetase full-length molecule (anti-GS/FL), a GS C-terminal peptide (anti-GS/20aa-C), and brain S100 (anti-S100), as well as the binding of the insect glia and rat astrocytic marker Datura stramonium lectin (DSL), in the optic lobe of the prawn Macrobrachium rosenbergii. All markers label the lamina ganglionaris cartridge region (lighter: anti-GS/FL; heavier: DSL). In addition, anti-GS/FL labels superficial somata of external and internal medullas and internal chiasm cells. Both anti-GS/20aa-C and anti-S100 label heavily the glial sheaths of the lamina ganglionaris. In addition, anti-S100 binds to the perineurial glia of medullary parenchymal vessels. Western blot analyses show that both anti-GS/FL and anti-GS/20aa-C bind mostly to a band of 50-55 kDa, compatible with a long isoform of vertebrate GS, and accessorily to a possible dimer and, in the case of anti-GS/20aa-C, to an ill-defined band of intermediate mass. Binding of anti-S100 is selective for a single band of about 68 kDa but shows no protein in the weight range of the canonical S100 protein superfamily. DSL reveals two bands of about 75 and about 120 kDa, thus within the range of maximal recognition for rat astrocytes. Our results suggest that phenotype protein markers of the optic lobe glia share antigenic determinants with S100 and (a long form of) GS and that, similarly to vertebrate and insect glia, crustacean glia protein and N-glycan residue markers display regional heterogeneity.
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Affiliation(s)
- Silvana Allodi
- Departamento de Histologia e Embriologia, Instituto de Ciências Biomédicas, ICB, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Chuang HC, Chang CW, Chang GD, Yao TP, Chen H. Histone deacetylase 3 binds to and regulates the GCMa transcription factor. Nucleic Acids Res 2006; 34:1459-69. [PMID: 16528103 PMCID: PMC1401512 DOI: 10.1093/nar/gkl048] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Human GCMa transcription factor regulates expression of syncytin, a placental fusogenic protein mediating trophoblastic fusion. Recently, we have demonstrated that CBP-mediated GCMa acetylation underlies the activated cAMP/PKA signaling pathway that stimulates trophoblastic fusion. Because protein acetylation is a reversible modification governed by histone acetyltransferases (HATs) and histone deacetylase (HDACs), in this study we investigated the key HDACs responsible for deacetylation of GCMa and thus the reduction in GCMa activity to avoid unwanted fusion events that may have adverse effects on placental morphogenesis. We herein demonstrate that the HDAC inhibitor, trichostatin A (TSA), increases the level of acetylated GCMa and that HDAC1, 3, 4 and 5 interact with and deacetylate GCMa. Glutathione S-transferase (GST) pull-down assays further verified direct interaction between GCMa and HDAC3 or CBP and HDAC3. HDAC3 counteracts the transcriptional coactivator activity of CBP and the enhancement effect of CBP on GCMa-mediated transcriptional activation. Correlatively, we found in placental cells that HDAC3 associates with the proximal GCMa-binding site (pGBS) in the syncytin promoter and dissociates from pGBS in the presence of forskolin, which stimulates the association of CBP and GCMa with pGBS. Our studies support that trophoblastic fusion in placental morphogenesis depends on the regulation of GCMa activity by HAT and HDAC.
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Affiliation(s)
- Hsiao-Ching Chuang
- Graduate Institute of Biochemical Sciences, National Taiwan UniversityTaipei 106, Taiwan
| | - Ching-Wen Chang
- Institute of Biological Chemistry, Academia SinicaNankang, Taipei 115, Taiwan
| | - Geen-Dong Chang
- Graduate Institute of Biochemical Sciences, National Taiwan UniversityTaipei 106, Taiwan
| | - Tso-Pang Yao
- Department of Pharmacology and Cancer Biology, Duke UniversityDurham, NC 277103, USA
| | - Hungwen Chen
- Graduate Institute of Biochemical Sciences, National Taiwan UniversityTaipei 106, Taiwan
- Institute of Biological Chemistry, Academia SinicaNankang, Taipei 115, Taiwan
- To whom correspondence should be addressed. Tel: +011 886 2 27855696, ext. 6090; Fax: +011 886 2 27889759;
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De Iaco R, Soustelle L, Kammerer M, Sorrentino S, Jacques C, Giangrande A. Huckebein-mediated autoregulation of Glide/Gcm triggers glia specification. EMBO J 2005; 25:244-54. [PMID: 16362045 PMCID: PMC1356350 DOI: 10.1038/sj.emboj.7600907] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 11/16/2005] [Indexed: 11/09/2022] Open
Abstract
Cell specification in the nervous system requires patterning genes dictating spatio-temporal coordinates as well as fate determinants. In the case of neurons, which are controlled by the family of proneural transcription factors, binding specificity and patterned expression trigger both differentiation and specification. In contrast, a single gene, glide cell deficient/glial cell missing (glide/gcm), is sufficient for all fly lateral glial differentiation. How can different types of cells develop in the presence of a single fate determinant, that is, how do differentiation and specification pathways integrate and produce distinct glial populations is not known. By following an identified lineage, we here show that glia specification is triggered by high glide/gcm expression levels, mediated by cell-specific protein-protein interactions. Huckebein (Hkb), a lineage-specific factor, provides a molecular link between glide/gcm and positional cues. Importantly, Hkb does not activate transcription; rather, it physically interacts with Glide/Gcm thereby triggering its autoregulation. These data emphasize the importance of fate determinant cell-specific quantitative regulation in the establishment of cell diversity.
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Affiliation(s)
- Rossana De Iaco
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
| | - Laurent Soustelle
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
| | - Martial Kammerer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
| | - Sandro Sorrentino
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
| | - Cécile Jacques
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
| | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP 10142, 67404 Illkirch Cedex, CU de Strasbourg, France. Tel.: +33 3 88 65 33 81; Fax: +33 3 88 65 32 01; E-mail:
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16
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Chang CW, Chuang HC, Yu C, Yao TP, Chen H. Stimulation of GCMa transcriptional activity by cyclic AMP/protein kinase A signaling is attributed to CBP-mediated acetylation of GCMa. Mol Cell Biol 2005; 25:8401-14. [PMID: 16166624 PMCID: PMC1265739 DOI: 10.1128/mcb.25.19.8401-8414.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human GCMa is a zinc-containing transcription factor primarily expressed in placenta. GCMa regulates expression of syncytin gene, which encodes for a placenta-specific membrane protein that mediates trophoblastic fusion and the formation of syncytiotrophoblast layer required for efficient fetal-maternal exchange of nutrients and oxygen. The adenylate cyclase activator, forskolin, stimulates syncytin gene expression and cell fusion in cultured placental cells. Here we present evidence that cyclic AMP (cAMP) signaling pathway activates the syncytin gene expression by regulating GCMa activity. We found that forskolin and protein kinase A (PKA) enhances GCMa-mediated transcriptional activation. Furthermore, PKA treatment stimulates the association of GCMa with CBP and increases GCMa acetylation. CBP primarily acetylates GCMa at lysine367, lysine406, and lysine409 in the transactivation domain (TAD). We found that acetylation of these residues is required to protect GCMa from ubiquitination and increases the TAD stability with a concomitant increase in transcriptional activity, supporting the importance of acetylation in PKA-dependent GCMa activation. Our results reveal a novel regulation of GCMa activity by cAMP-dependent protein acetylation and provide a molecular mechanism by which cAMP signaling regulates trophoblastic fusion.
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Affiliation(s)
- Ching-Wen Chang
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
| | - Hsiao-Ching Chuang
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
| | - Chenchou Yu
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
| | - Tso-Pang Yao
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
| | - Hungwen Chen
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
- Corresponding author. Mailing address: Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan. Phone: 886-2-27855696, ext. 6090. Fax: 886-2-27889759. E-mail:
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17
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Yoshida S, Soustelle L, Giangrande A, Umetsu D, Murakami S, Yasugi T, Awasaki T, Ito K, Sato M, Tabata T. DPP signaling controls development of the lamina glia required for retinal axon targeting in the visual system of Drosophila. Development 2005; 132:4587-98. [PMID: 16176948 DOI: 10.1242/dev.02040] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The Drosophila visual system consists of the compound eyes and the optic ganglia in the brain. Among the eight photoreceptor (R) neurons, axons from the R1-R6 neurons stop between two layers of glial cells in the lamina, the most superficial ganglion in the optic lobe. Although it has been suggested that the lamina glia serve as intermediate targets of R axons, little is known about the mechanisms by which these cells develop. We show that DPP signaling plays a key role in this process. dpp is expressed at the margin of the lamina target region, where glial precursors reside. The generation of clones mutant for Medea, the DPP signal transducer, or inhibition of DPP signaling in this region resulted in defects in R neuron projection patterns and in the lamina morphology, which was caused by defects in the differentiation of the lamina glial cells. glial cells missing/glial cells deficient (gcm; also known as glide) is expressed shortly after glia precursors start to differentiate and migrate. Its expression depends on DPP; gcm is reduced or absent in dpp mutants or Medea clones, and ectopic activation of DPP signaling induces ectopic expression of gcm and REPO. In addition, R axon projections and lamina glia development were impaired by the expression of a dominant-negative form of gcm, suggesting that gcm indeed controls the differentiation of lamina glial cells. These results suggest that DPP signaling mediates the maturation of the lamina glia required for the correct R axon projection pattern by controlling the expression of gcm.
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Affiliation(s)
- Shoko Yoshida
- Laboratory of Pattern Formation, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-0032, Japan
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18
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Bataillé L, Augé B, Ferjoux G, Haenlin M, Waltzer L. Resolving embryonic blood cell fate choice in Drosophila: interplay of GCM and RUNX factors. Development 2005; 132:4635-44. [PMID: 16176949 DOI: 10.1242/dev.02034] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The differentiation of Drosophila embryonic blood cell progenitors (prohemocytes) into plasmatocytes or crystal cells is controlled by lineage-specific transcription factors. The related proteins Glial cells missing (GCM) and GCM2 control plasmatocyte development, whereas the RUNX factor Lozenge (LZ) is required for crystal cell differentiation. We have investigated the segregation process that leads to the formation of these two cell types, and the interplay between LZ and GCM/GCM2. We show that, surprisingly, gcm is initially expressed in all prohemocytes but is rapidly downregulated in the anterior-most row of prohemocytes, which then initiates lz expression. However, the lz+ progenitors constitute a mixed-lineage population whose fate depends on the relative levels of LZ and GCM/GCM2. Notably, we demonstrate that GCM/GCM2 play a key role in controlling the size of the crystal cell population by inhibiting lz activation and maintenance. Furthermore, we show that prohemocytes are bipotent progenitors, and that downregulation of gcm/gcm2 is required for lz-induced crystal cell formation. These results provide new insight into the mechanisms controlling Drosophila hematopoiesis and establish the basis for an original model for the resolution of the choice of blood cell fate.
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Affiliation(s)
- Laetitia Bataillé
- Centre de Biologie du Développement, CNRS UMR 5547, 118 route de Narbonne, 31062 Toulouse, France
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19
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Pereanu W, Shy D, Hartenstein V. Morphogenesis and proliferation of the larval brain glia in Drosophila. Dev Biol 2005; 283:191-203. [PMID: 15907832 DOI: 10.1016/j.ydbio.2005.04.024] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 03/31/2005] [Accepted: 04/04/2005] [Indexed: 11/26/2022]
Abstract
Glial cells subserve a number of essential functions during development and function of the Drosophila brain, including the control of neuroblast proliferation, neuronal positioning and axonal pathfinding. Three major classes of glial cells have been identified. Surface glia surround the brain externally. Neuropile glia ensheath the neuropile and form septa within the neuropile that define distinct neuropile compartments. Cortex glia form a scaffold around neuronal cell bodies in the cortex. In this paper we have used global glial markers and GFP-labeled clones to describe the morphology, development and proliferation pattern of the three types of glial cells in the larval brain. We show that both surface glia and cortex glia contribute to the glial layer surrounding the brain. Cortex glia also form a significant part of the glial layer surrounding the neuropile. Glial cell numbers increase slowly during the first half of larval development but show a rapid incline in the third larval instar. This increase results from mitosis of differentiated glia, but, more significantly, from the proliferation of neuroblasts.
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Affiliation(s)
- Wayne Pereanu
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, CA 90095, USA
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20
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Abstract
In all complex organisms, glial cells are pivotal for neuronal development and function. Insects are characterized by having only a small number of these cells, which nevertheless display a remarkable molecular diversity. An intricate relationship between neurons and glia is initially required for glial migration and during axonal patterning. Recent data suggest that in organisms such as Drosophila, a prime role of glial cells lies in setting boundaries to guide and constrain axonal growth.
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Affiliation(s)
- Gundula Edenfeld
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
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21
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Yang CS, Yu C, Chuang HC, Chang CW, Chang GD, Yao TP, Chen H. FBW2 targets GCMa to the ubiquitin-proteasome degradation system. J Biol Chem 2005; 280:10083-90. [PMID: 15640526 DOI: 10.1074/jbc.m413986200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The GCM proteins GCMa/1 and GCMb/2 are novel zinc-containing transcription factors critical for glial cell differentiation in fly and for placental as well as parathyroid gland development in mouse. Previous pulse-chase experiments have demonstrated differential protein stabilities of GCM proteins with half-lives from approximately 30 min to 2 h (Tuerk, E. E., Schreiber, J., and Wegner, M. (2000) J. Biol. Chem. 275, 4774-4782). However, little is known about the machinery that controls GCM protein degradation. Here, we report the identification of an SCF complex as the GCM ubiquitin-protein isopeptide ligase (E3) that regulates human GCMa (hGCMa) degradation. We found that SKP1 and CUL1, two key components of the SCF complex, associate with hGCMa in vivo. We further identify the human F-box protein FBW2 (hFBW2) as the substrate recognition subunit in the SCF E3 complex for hGCMa. We show that hFBW2 interacts with hGCMa in a phosphorylation-dependent manner and promotes hGCMa ubiquitination. Supporting a critical role for hFBW2 in hGCMa degradation, knockdown of hFBW2 expression by RNA interference leads to a reduction in hGCMa ubiquitination and a concomitant increase in hGCMa protein stability. Our study identifies the SCF(hFBW2) E3 complex as the key machinery that targets hGCMa to the ubiquitin-proteasome degradation system.
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Affiliation(s)
- Chih-Sheng Yang
- Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
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22
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Aigouy B, Van de Bor V, Boeglin M, Giangrande A. Time-lapse and cell ablation reveal the role of cell interactions in fly glia migration and proliferation. Development 2004; 131:5127-38. [PMID: 15459105 DOI: 10.1242/dev.01398] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Migration and proliferation have been mostly explored in culture systems or fixed preparations. We present a simple genetic model, the chains of glia moving along fly wing nerves, to follow such dynamic processes by time-lapse in the whole animal. We show that glia undergo extensive cytoskeleton and mitotic apparatus rearrangements during division and migration. Single cell labelling identifies different glia: pioneers with high filopodial,exploratory, activity and, less active followers. In combination with time-lapse, altering this cellular environment by genetic means or cell ablation has allowed to us define the role of specific cell-cell interactions. First, neurone-glia interactions are not necessary for glia motility but do affect the direction of migration. Second, repulsive interactions between glia control the extent of movement. Finally, autonomous cues control proliferation.
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Affiliation(s)
- Benoît Aigouy
- Institut de Génétique et Biologie Moléculaire et Cellulaire, IGBMC/CNRS/ULP/INSERM - BP 10142, ILLKIRCH, C. U. de Strasbourg 67404, France
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23
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Soustelle L, Jacques C, Altenhein B, Technau GM, Volk T, Giangrande A. Terminal tendon cell differentiation requires the glide/gcm complex. Development 2004; 131:4521-32. [PMID: 15342477 DOI: 10.1242/dev.01290] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Locomotion relies on stable attachment of muscle fibres to their target sites, a process that allows for muscle contraction to generate movement. Here, we show that glide/gcm and glide2/gcm2, the fly glial cell determinants, are expressed in a subpopulation of embryonic tendon cells and required for their terminal differentiation. By using loss-of-function approaches, we show that in the absence of both genes, muscle attachment to tendon cells is altered, even though the molecular cascade induced by stripe, the tendon cell determinant, is normal. Moreover, we show that glide/gcm activates a new tendon cell gene independently of stripe. Finally, we show that segment polarity genes control the epidermal expression of glide/gcm and determine, within the segment,whether it induces glial or tendon cell-specific markers. Thus, under the control of positional cues, glide/gcm triggers a new molecular pathway involved in terminal tendon cell differentiation, which allows the establishment of functional muscle attachment sites and locomotion.
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Affiliation(s)
- Laurent Soustelle
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP 10142, 67404 Illkirch Cedex, C.U. de Strasbourg, France
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24
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Hashemolhosseini S, Wegner M. Impacts of a new transcription factor family: mammalian GCM proteins in health and disease. ACTA ACUST UNITED AC 2004; 166:765-8. [PMID: 15353544 PMCID: PMC2172107 DOI: 10.1083/jcb.200406097] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
GCM proteins constitute a small transcription factor family with a DNA-binding domain exhibiting a novel fold composed of two subdomains rigidly held together by coordination of one of two structural zinc cations. In all known cases, GCM proteins exert the role of master regulators: the prototypical family member determines gliogenesis in Drosophila melanogaster, whereas mammalian GCM proteins orchestrate divergent aspects of development and physiology in placenta, kidney, thymus, and parathyroid gland. Recent data point to an involvement of GCM proteins in different pathological contexts, such as preeclampsia, hyper- or hypoparathyroidism, and parathyroid gland tumors.
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25
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Hashemolhosseini S, Schmidt K, Kilian K, Rodriguez E, Wegner M. Conservation and variation of structure and function in a newly identified GCM homolog from chicken. J Mol Biol 2004; 336:441-51. [PMID: 14757056 DOI: 10.1016/j.jmb.2003.12.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glial cell missing (GCM) proteins constitute a small family of transcription factors with two members each described in Drosophila and several mammalian species. Here, we report the identification of a GCM homolog from chicken. Although the exon-intron structure is well conserved between chicken GCM and other family members, sequence similarity is largely restricted to the DNA-binding GCM-domain (residues 24-176). In accord with the high degree of sequence conservation within the GCM-domain, the chicken GCM protein has a DNA-binding specificity similar to that of other GCM proteins. Like other GCM proteins, it is located to the nucleus and can act as a transcriptional activator despite the strong divergence in sequences outside the GCM-domain. The chicken GCM protein contains two transactivation domains with cell-specific function, one immediately following the DNA-binding domain, the other at its extreme carboxy terminus. Intriguingly, chicken GCM is expressed only transiently during embryogenesis and is restricted exclusively to extraembryonic tissues where it was detected in close vicinity to embryonic blood vessels. Taking the extraembryonic expression of chicken GCM and mammalian GCMa into account, it is tempting to speculate that a conserved extraembryonic function exists for GCM proteins in birds and mammals.
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Affiliation(s)
- Said Hashemolhosseini
- Institut für Biochemie, Universität Erlangen, Fahrstrasse 17, D-91054, Erlangen, Germany.
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26
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Abstract
In contrast to vertebrates, the fruit fly Drosophila melanogaster contains only a small number of regulator of G-protein signaling (RGS) domain genes. This article reviews current knowledge on these genes. Although the fruit fly is particularly amenable to genetic analysis and manipulation, not much is known about the functions and mechanisms of action. The best-studied RGS gene in Drosophila is loco, a member of the D/R12 subfamily. The four different protein isoforms all contain RGS, GoLoco, and RBD domains. This article describes the identification and functional analyses of loco in the Drosophila system and discusses some mechanistic models that may underlie loco function.
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Affiliation(s)
- Sebastian Granderath
- International Graduate School in Genetics and Functional Genomics, University of Cologne, Köln, Germany
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27
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Hashemolhosseini S, Kilian K, Kardash E, Lischka P, Stamminger T, Wegner M. Structural requirements for nuclear localization of GCMa/Gcm-1. FEBS Lett 2003; 553:315-20. [PMID: 14572643 DOI: 10.1016/s0014-5793(03)01037-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
GCM proteins constitute a small transcription factor family. Nuclear localization of Drosophila GCM is mediated by a typical bipartite nuclear localization sequence (NLS) close to the DNA-binding GCM domain. Here, we have analyzed nuclear localization of the mammalian GCM proteins. Whereas GCMb/Gcm-2 contained a classical bipartite NLS, nuclear localization of GCMa/Gcm-1 was mediated by two regions without resemblance to known NLS, one corresponding to the amino-terminal part of the GCM domain, the second defined as a tyrosine-and-proline-rich carboxy-terminal region. Nuclear import was counteracted by an amino-terminal nuclear export activity. This complex regulation of subcellular localization has important implications for GCMa/Gcm-1 function.
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Affiliation(s)
- Said Hashemolhosseini
- Institut für Biochemie, Universität Erlangen-Nürnberg, Fahrstrasse 17, D-91054 Erlangen, Germany.
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28
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Selkoe D, Kopan R. Notch and Presenilin: regulated intramembrane proteolysis links development and degeneration. Annu Rev Neurosci 2003; 26:565-97. [PMID: 12730322 DOI: 10.1146/annurev.neuro.26.041002.131334] [Citation(s) in RCA: 485] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intensive studies of three proteins--Presenilin, Notch, and the amyloid precursor protein (APP)--have led to the recognition of a direct intersection between early development and late-life neurodegeneration. Notch signaling mediates many different intercellular communication events that are essential for determining the fates of neural and nonneural cells during development and in the adult. The Notch receptor acts in a core pathway as a membrane-bound transcription factor that is released to the nucleus by a two-step cleavage mechanism called regulated intramembrane proteolysis (RIP). The second cleavage is effected by Presenilin, an unusual polytopic aspartyl protease that apparently cleaves Notch and numerous other single-transmembrane substrates within the lipid bilayer. Another Presenilin substrate, APP, releases the amyloid ss-protein that can accumulate over time in limbic and association cortices and help initiate Alzheimer's disease. Elucidating the detailed mechanism of Presenilin processing of membrane proteins is important for understanding diverse signal transduction pathways and potentially for treating and preventing Alzheimer's disease.
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Affiliation(s)
- Dennis Selkoe
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA.
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29
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Nicolaï M, Lasbleiz C, Dura JM. Gain-of-function screen identifies a role of theSrc64oncogene inDrosophilamushroom body development. ACTA ACUST UNITED AC 2003; 57:291-302. [PMID: 14608664 DOI: 10.1002/neu.10277] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Mushroom bodies (MB) are substructures in the Drosophila brain that are essential for memory. At present, MB anatomy is rather well described when compared to other brain areas, and elucidation of the genetic control of the development and projection patterns of MB neurons will be important to the understanding of their functions. We have performed a gain-of-function screen in order to identify genes that are involved in MB development. We drove expression of genes in MB neurons by crossing 2407 GAL4-driven UY element lines to lines containing an MB GAL4 source and UAS-GFP elements, and looked for defects in the MB structure. We have molecularly identified the genomic regions adjacent to the 26 positive UY insertions and found 18 potential genes that exhibit adult MB gain-of-function phenotypes. The proteins encoded by these candidate genes include, as well as genes with yet unknown function, transcription factors (e.g., tramtrack), nanos RNA-binding protein, microtubule-severing protein, vesicle trafficking proteins, axon guidance receptor, and the Src64 cytoplasmic protein tyrosine kinase. These genes are involved in key features of neuron cell biology. In three cases, tramtrack, nanos, and Src64, we show that the open reading frame located directly downstream of the UY P element is indeed the expressed target gene. Loss-of-function mutations of both ttk and Src64 lead to MB phenotypes proving that these genes are involved in the genetic control of MB development. Moreover, Src64 is shown here to act in a cell-autonomous fashion and is likely to interact with the previously-identified linotte/derailed receptor tyrosine kinase in MB development.
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Affiliation(s)
- Maryse Nicolaï
- Institut de Génétique Humaine, CNRS UPR1142, 141, rue de la cardonille, 34396 Montpellier Cedex, France
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30
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Cohen SX, Moulin M, Hashemolhosseini S, Kilian K, Wegner M, Müller CW. Structure of the GCM domain-DNA complex: a DNA-binding domain with a novel fold and mode of target site recognition. EMBO J 2003; 22:1835-45. [PMID: 12682016 PMCID: PMC154474 DOI: 10.1093/emboj/cdg182] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glia cell missing (GCM) transcription factors form a small family of transcriptional regulators in metazoans. The prototypical Drosophila GCM protein directs the differentiation of neuron precursor cells into glia cells, whereas mammalian GCM proteins are involved in placenta and parathyroid development. GCM proteins share a highly conserved 150 amino acid residue region responsible for DNA binding, known as the GCM domain. Here we present the crystal structure of the GCM domain from murine GCMa bound to its octameric DNA target site at 2.85 A resolution. The GCM domain exhibits a novel fold consisting of two domains tethered together by one of two structural Zn ions. We observe the novel use of a beta-sheet in DNA recognition, whereby a five- stranded beta-sheet protrudes into the major groove perpendicular to the DNA axis. The structure combined with mutational analysis of the target site and of DNA-contacting residues provides insight into DNA recognition by this new type of Zn-containing DNA-binding domain.
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Affiliation(s)
- Serge X Cohen
- European Molecular Biology Laboratory, Grenoble Outstation, BP 181, 38042 Grenoble Cedex 9, France
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31
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Giesen K, Lammel U, Langehans D, Krukkert K, Bunse I, Klämbt C. Regulation of glial cell number and differentiation by ecdysone and Fos signaling. Mech Dev 2003; 120:401-13. [PMID: 12676319 DOI: 10.1016/s0925-4773(03)00009-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the midline glia of the embryonic ventral nerve cord of Drosophila, differentiation as well as the subsequent regulation of cell number is under the control of EGF-receptor signaling. During pupal stages apoptosis of all midline glial cells is initiated by ecdysone signaling. In a genetic screen we have identified mutations in disembodied, rippchen, spook, shade, shadow, shroud and tramtrack that all share a number of phenotypic traits, including defects in cuticle differentiation and nervous system development. Some of these genes were previously placed in the so-called 'Halloween-group' and were shown to affect ecdysone synthesis during embryogenesis. Here we demonstrate that the Halloween mutations not only affect glial differentiation but also lead to an increase in the number of midline glial cells, suggesting that during embryogenesis ecdysone signaling is required to adjust glial cell number similar to pupal stages. Finally we isolated a P-element-induced mutation of shroud, which controls the expression of ecdysone inducible genes. The P-element insertion occurs in one of the promoters of the Drosophila fos gene for which we present a yet undescribed complex genomic organization. The recently described kayak alleles affect only one of the six different Fos isoforms. This work for the first time links ecydsone signaling to Fos function and shows that during embryonic and pupal stages similar developmental mechanisms control midline glia survival.
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Affiliation(s)
- Kay Giesen
- Institut für Neurobiologie, Badestrasse 9, Universität Münster, 48149 Münster, Germany
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32
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Ragone G, Van De Bor V, Sorrentino S, Kammerer M, Galy A, Schenck A, Bernardoni R, Miller AA, Roy N, Giangrande A. Transcriptional regulation of glial cell specification. Dev Biol 2003; 255:138-50. [PMID: 12618139 DOI: 10.1016/s0012-1606(02)00081-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neuronal differentiation relies on proneural factors that also integrate positional information and contribute to the specification of the neuronal type. The molecular pathway triggering glial specification is not understood yet. In Drosophila, all lateral glial precursors and glial-promoting activity have been identified, which provides us with a unique opportunity to dissect the regulatory pathways controlling glial differentiation and specification. Although glial lineages are very heterogeneous with respect to position, time of differentiation, and lineage tree, they all express and require two homologous genes, glial cell deficient/glial cell missing (glide/gcm) and glide2, that act in concert, with glide/gcm constituting the major glial-promoting factor. Here, we show that glial specification resides in glide/gcm transcriptional regulation. The glide/gcm promoter contains lineage-specific elements as well as quantitative and turmoil elements scattered throughout several kilobases. Interestingly, there is no correlation between a specific regulatory element and the type of glial lineage. Thus, the glial-promoting factor acts as a naive switch-on button that triggers gliogenesis in response to multiple pathways converging onto its promoter. Both negative and positive regulation are required to control glide/gcm expression, indicating that gliogenesis is actively repressed in some neural lineages.
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Affiliation(s)
- Gianluca Ragone
- Institut de Génétique et Biologie Moléculaire et Cellulaire, IGBMC/CNRS/ULP/INSERM - BP 10142 67404 Illkirch, c.u., de Strasbourg, France
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33
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Fichelson P, Gho M. The glial cell undergoes apoptosis in the microchaete lineage of Drosophila. Development 2003; 130:123-33. [PMID: 12441297 DOI: 10.1242/dev.00198] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apoptosis plays a major role in vertebrate and invertebrate development. The adult Drosophila thoracic microchaete is a mechanosensory organ whose development has been extensively studied as a model of how cell division and cell determination intermingle. This sensory organ arises from a cell lineage that produces a glial cell and four other cells that form the organ. In this study, using an in vivo approach as well as fixed material, we show that the glial cell undergoes nucleus fragmentation shortly after birth. Fragmentation was blocked after overexpression of the caspase inhibitor p35 or removal of the pro-apoptotic genes reaper, hid and grim, showing that the glial cell undergoes apoptosis. Moreover, it seems that fragments are eliminated from the epithelium by mobile macrophages. Forcing survival of the glial cells induces precocious axonal outgrowth but does not affect final axonal patterning and connectivity. However, under these conditions, glial cells do not fragment but leave the epithelium by a mechanism that is reminiscent of cell competition. Finally, we present evidences showing that glial cells are committed to apoptosis independently of gcm and prospero expression. We suggest that apoptosis is triggered by a cell autonomous mechanism.
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Affiliation(s)
- Pierre Fichelson
- UMR 7622, CNRS-Université Paris VI, 9, Quai St Bernard, 75252 Paris Cedex 05, France
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34
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Abstract
Nervous system development requires the specification of numerous neural stem cells. Subsequently these stem cells divide in a spatially and temporally controlled manner to generate the diverse cell types found in the different layers of the nervous system. Lineage specification is brought about by transcriptional regulators, which often act as transcriptional repressors.
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Affiliation(s)
- Gundula Edenfeld
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
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