DOCSLIB.ORG

Glial Cell Fate Specification by Hes5

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Glial Cell Fate Specification by Hes5 Development 127, 2515-2522 (2000) 2515 Printed in Great Britain © The Company of Biologists Limited 2000 DEV4317 Glial cell fate specification modulated by the bHLH gene Hes5 in mouse retina Masato Hojo1,2, Toshiyuki Ohtsuka1, Nobuo Hashimoto2, Gérald Gradwohl3, François Guillemot3 and Ryoichiro Kageyama1,* 1Institute for Virus Research, Kyoto University and 2Department of Neurosurgery, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8507, Japan 3Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur/Collège de France, 67404 Illkirch, CU de Strasbourg, France *Author for correspondence (e-mail: [email protected]) Accepted 29 March; published on WWW 23 May 2000 SUMMARY Neurons and glial cells differentiate from common retrovirus significantly increased the population of glial precursors. Whereas the gene glial cells missing (gcm) cells at the expense of neurons. Conversely, Hes5-deficient determines the glial fate in Drosophila, current data about retina showed 30-40% decrease of Müller glial cell number the expression patterns suggest that, in mammals, gcm without affecting cell survival. These results indicate that homologues are unlikely to regulate gliogenesis. Here, we Hes5 modulates glial cell fate specification in mouse retina. found that, in mouse retina, the bHLH gene Hes5 was specifically expressed by differentiating Müller glial cells Key words: bHLH, Glial specification, Hes5, Müller glia, Retina, and that misexpression of Hes5 with recombinant Mouse, Cell fate INTRODUCTION homologues have been characterized (Gcm1/Gcma and Gcm2/Gcmb) (Akiyama et al., 1996; Kim et al., 1998; Retina provides a powerful model system to investigate the Kanemura et al., 1999; Reifegerste et al., 1999) and it was mechanisms of cell fate decision in mammalian central nervous shown that one of them, Gcm1, can substitute functionally for system. From common retinal precursors, six types of neurons Drosophila gcm by transforming neurons into glia in and one type of glial cells (Müller glia) differentiate in the Drosophila embryos (Kim et al., 1998; Reifegerste et al., 1999), overlapping but precise time course (Cepko et al., 1996). These suggesting that mammalian gcm homologues may have a seven types of cells constitute three nuclear layers in the retina: conserved gliogenic function, at least, in Drosophila embryos. the outer nuclear layer (ONL), which contains rod and cone However, neither of the mammalian gcm homologues show the photoreceptors, the inner nuclear layer (INL), which contains expression pattern that may account for generation of glial cells bipolar, horizontal and amacrine interneurons as well as Müller in mammalian nervous system and therefore these genes are glia, and the ganglion cell layer, which contains ganglion cells unlikely to regulate glial fate decision in mammals (Kim et al., (projection neurons). Although the kinetic pattern of generation 1998). of these cell types has been well characterized, the molecular Here, we found that the bHLH gene Hes5 (Akazawa et al., mechanism for glial cell fate determination is not well 1992), one of Notch effectors (Kageyama and Nakanishi, 1997; understood. It was previously shown that activation of EGF Ohtsuka et al., 1999), is specifically expressed by differentiat- receptor increases the population of Müller glial cells (Lillien, ing glial cells in mouse retina and that misexpression of Hes5 1995), but the intracellular mechanism for gliogenesis still directs neural precursor cells toward the glial fate at the expense remains to be determined. Recent data demonstrated that of the neuronal fate. Furthermore, Müller glial cell number was transcription factors of the bHLH and homeobox classes reduced in Hes5-deficient retina. These results demonstrate positively or negatively regulate differentiation of many retinal that, in mouse retina, Hes5 modulates the glial cell fate cells, but so far no genes that determine the glial fate are known specification. in the retina (Tomita et al., 1996a,b; Burmeister et al., 1996; Chen et al., 1997; Freund et al., 1997; Furukawa et al., 1997a,b; Kanekar et al., 1997; Mathers et al., 1997; Brown et al., 1998; MATERIALS AND METHODS Jean et al., 1998; Morrow et al., 1999). In situ hybridization In Drosophila, the gene glial cells missing (gcm) is known to In situ hybridization analysis of Hes5 was performed as previously determine the glial fate: in loss-of-function gcm mutants, nearly described (Ishibashi et al., 1995; Ishii et al., 1997). Digoxigenin- all glial cells fail to differentiate while ectopic gcm expression labeled antisense RNA probe was synthesized in vitro, as previously converts presumptive neurons into glia (Hosoya et al., 1995; described (Akazawa et al., 1992). The probe was hybridized to 12 µm Jones et al., 1995; Vincent et al., 1996). Two mammalian gcm cryostat sections of mouse retinae. 2516 M. Hojo and others Dissociation of retinal cells Amersham), mouse anti-HPC1 (1:200; Sigma), mouse anti-calbindin To count the cell numbers, retinae were dissociated, as previously (1:200; Sigma) and rabbit rhodopsin antibodies (1:2000; LSL). described (Morrow et al., 1998). Briefly, neural retinae were incubated Affinity-purified rabbit anti-Hes5 antibody was raised against the with 0.1% trypsin in HBSS lacking Ca2+/Mg2+ for 10 minutes at room peptide, AGPKSLHQDYSEGYSW, which is common to mouse and temperature and then soybean trypsin inhibitor was added (a final rat Hes5. To detect these antibodies, FITC-conjugated goat anti-mouse concentration of 2 mg/ml). The cells were pelleted, resuspended in IgG (1:200; Vector), FITC-conjugated goat anti-rabbit IgG (1:200; HBSS containing 100 µg/ml DNaseI, triturated and plated on poly-D- Vector), biotinylated anti-rabbit IgG (1:200; Vector), biotinylated anti- lysine-coated eight-well glass slides (Nalge Nunc). After incubation mouse IgG (1:200; Vector), FITC-avidin (1:2000; Vector) and Texas for 90 minutes at 37°C in 5% CO2, the cells were fixed with 4% red avidin (1:2000; Vector) were used. For BrdU staining, BrdU was paraformaldehyde for 10 minutes at room temperature and subjected to applied (2 µM) to the retinal explants 2 days after viral infection and immunostaining (see below). Cells were counted manually with the explants were cultured in the continued presence of BrdU. Sections masking the genotypes. were then made and stained with anti-BrdU antibody (1:5; Becton Dickinson). TUNEL assay was performed with a detection kit Retinal explant culture (Boehringer-Mannheim). Pictures were taken by confocal microscopy Retinal explant culture was performed, as previously described (Caffé (Carl Zeiss). et al., 1989; Sparrow et al., 1990; Stoppini et al., 1991; Tomita et al., 1996a). Eyes were isolated from mouse embryos and neonates and transferred to PBS solution. The neural retina without pigment RESULTS epithelium was placed onto a Millicell chamber filter (Millipore: diameter 30 mm, pore size 0.4 µm) with the ganglion cell layer upward. The chamber was placed in a 6-well culture plate, which Hes5 is specifically expressed by differentiating contained 0.8 ml of 50% MEM with Hepes, 25% Hank’s solution, 25% Müller glial cells heat-inactivated horse serum, 200 µM L-glutamine, and 6.75 mg/ml In situ hybridization analysis showed that, at postnatal day 1 glucose (Stoppini et al., 1991). Explants were incubated at 34°C in 5% (P1), Hes5 was expressed in the ventricular zone of the CO2. developing mouse retina, which contains common precursors Construction and infection of retrovirus for neurons and glial cells (Fig. 1A). During the postnatal period Hes5 expression was gradually restricted to the inner CLIG was constructed as follows. The SphI-SacI fragment of pIRES- EGFP (Clontech) was isolated, and the SphI and SacI sites were nuclear layer (INL) and, by P6, Hes5 was expressed only in the converted to EcoRI and the blunt end, respectively. This fragment was INL (Fig. 1B). After P7, Hes5 expression in the INL decreased ligated to EcoRI- and HpaI-digested pCLNCX v.2 (kindly provided by and became undetectable by P14 (Fig. 1C-E). At P6-8, Müller I. Verma) to replace the neo and the CMV promoter with the IRES- glial cells (vimentin+) were differentiating in the INL, where EGFP. The resultant vector was pCLIG. Hes5 cDNA was cloned into Hes5 expression was observed (Fig. 1G-I). Expression of the EcoRI site of pCLIG. The retroviral DNAs were transfected into the ecotropic packaging cells ψ2mp34 (Yoshimatsu et al., 1998), and 3 days later the medium was recovered and concentrated, as previously described (Tsuda et al., 1998). Virus solution was applied to the retinal explants, and after 2 weeks of culture, the explants were fixed with 4% paraformaldehyde, dehydrated in 25% sucrose, embedded in OCT compound (Miles) and sectioned. Immunostaining and TUNEL Sections and dissociated cells on slides were preincubated in PBS containing 5% goat serum and 0.1% Triton X-100 for 30 minutes and incubated in 1% goat serum and 0.1% Triton X-100 with the following primary antibodies (dilution rate): mouse anti-myc (1:500; Invitrogen), mouse anti- Fig. 1. Hes5 expression and Müller glial differentiation in the developing retina. (A-E) In situ hybridization vimentin (1:1; Histofine), of Hes5. Hes5 was initially expressed in the ventricular zone at P1 and later the expression was restricted to mouse anti-glutamine the INL. By P14, the expression disappears. (F-J) Expression of the Müller glial marker vimentin (Vim). synthetase (1:200; Chemicon), Müller glial cells differentiated in the INL, where Hes5 expression is observed. (K-O) Expression of the anti-GFP (1:500; Clontech), Müller glial marker glutamine synthetase (GS). By the time when GS was well expressed (P14), Hes5 mouse anti-PKC (1: 200; expression became undetectable. VZ, the ventricular zone. Scale bar, 50 µm. Glial cell fate specification by Hes5 2517 2D). In contrast, none of Hes5+ cells (green in Fig. 2F,H) expressed the retinal neuronal markers such as protein kinase C (PKC) (red in Fig.
Load more

Recommended publications
  • Early Neuronal and Glial Fate Restriction of Embryonic Neural Stem Cells
    The Journal of Neuroscience, March 5, 2008 • 28(10):2551–2562 • 2551 Development/Plasticity/Repair Early Neuronal and Glial Fate Restriction of Embryonic Neural Stem Cells Delphine Delaunay,1,2 Katharina Heydon,1,2 Ana Cumano,3 Markus H. Schwab,4 Jean-Le´on Thomas,1,2 Ueli Suter,5 Klaus-Armin Nave,4 Bernard Zalc,1,2 and Nathalie Spassky1,2 1Inserm, Unite´ 711, 75013 Paris, France, 2Institut Fe´de´ratif de Recherche 70, Faculte´deMe´decine, Universite´ Pierre et Marie Curie, 75013 Paris, France, 3Inserm, Unite´ 668, Institut Pasteur, 75724 Paris Cedex 15, France, 4Max-Planck-Institute of Experimental Medicine, D-37075 Goettingen, Germany, and 5Institute of Cell Biology, Swiss Federal Institute of Technology (ETH), ETH Ho¨nggerberg, CH-8093 Zu¨rich, Switzerland The question of how neurons and glial cells are generated during the development of the CNS has over time led to two alternative models: either neuroepithelial cells are capable of giving rise to neurons first and to glial cells at a later stage (switching model), or they are intrinsically committed to generate one or the other (segregating model). Using the developing diencephalon as a model and by selecting a subpopulation of ventricular cells, we analyzed both in vitro, using clonal analysis, and in vivo, using inducible Cre/loxP fate mapping, the fate of neuroepithelial and radial glial cells generated at different time points during embryonic development. We found that, during neurogenic periods [embryonic day 9.5 (E9.5) to 12.5], proteolipid protein ( plp)-expressing cells were lineage-restricted neuronal precursors, but later in embryogenesis, during gliogenic periods (E13.5 to early postnatal), plp-expressing cells were lineage-restricted glial precursors.
    [Show full text]
  • Notch-Signaling in Retinal Regeneration and Müller Glial Plasticity
    Notch-Signaling in Retinal Regeneration and Müller glial Plasticity DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Kanika Ghai, MS Neuroscience Graduate Studies Program The Ohio State University 2009 Dissertation Committee: Dr. Andy J Fischer, Advisor Dr. Heithem El-Hodiri Dr. Susan Cole Dr. Paul Henion Copyright by Kanika Ghai 2009 ABSTRACT Eye diseases such as blindness, age-related macular degeneration (AMD), diabetic retinopathy and glaucoma are highly prevalent in the developed world, especially in a rapidly aging population. These sight-threatening diseases all involve the progressive loss of cells from the retina, the light-sensing neural tissue that lines the back of the eye. Thus, developing strategies to replace dying retinal cells or prolonging neuronal survival is essential to preserving sight. In this regard, cell-based therapies hold great potential as a treatment for retinal diseases. One strategy is to stimulate cells within the retina to produce new neurons. This dissertation elucidates the properties of the primary support cell in the chicken retina, known as the Müller glia, which have recently been shown to possess stem-cell like properties, with the potential to form new neurons in damaged retinas. However, the mechanisms that govern this stem-cell like ability are less well understood. In order to better understand these properties, we analyze the role of one of the key developmental processes, i.e., the Notch-Signaling Pathway in regulating proliferative, neuroprotective and regenerative properties of Müller glia and bestow them with this plasticity.
    [Show full text]
  • Differential Timing and Coordination of Neurogenesis and Astrogenesis
    brain sciences Article Differential Timing and Coordination of Neurogenesis and Astrogenesis in Developing Mouse Hippocampal Subregions Allison M. Bond 1, Daniel A. Berg 1, Stephanie Lee 1, Alan S. Garcia-Epelboim 1, Vijay S. Adusumilli 1, Guo-li Ming 1,2,3,4 and Hongjun Song 1,2,3,5,* 1 Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; [email protected] (A.M.B.); [email protected] (D.A.B.); [email protected] (S.L.); [email protected] (A.S.G.-E.); [email protected] (V.S.A.); [email protected] (G.-l.M.) 2 Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA 3 Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA 4 Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA 5 The Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA * Correspondence: [email protected] Received: 19 October 2020; Accepted: 24 November 2020; Published: 26 November 2020 Abstract: Neocortical development has been extensively studied and therefore is the basis of our understanding of mammalian brain development. One fundamental principle of neocortical development is that neurogenesis and gliogenesis are temporally segregated processes. However, it is unclear how neurogenesis and gliogenesis are coordinated in non-neocortical regions of the cerebral cortex, such as the hippocampus, also known as the archicortex. Here, we show that the timing of neurogenesis and astrogenesis in the Cornu Ammonis (CA) 1 and CA3 regions of mouse hippocampus mirrors that of the neocortex; neurogenesis occurs embryonically, followed by astrogenesis during early postnatal development.
    [Show full text]
  • Postnatal Neurogenesis and Gliogenesis in the Olfactory Bulb from NG2-Expressing Progenitors of the Subventricular Zone
    10530 • The Journal of Neuroscience, November 17, 2004 • 24(46):10530–10541 Development/Plasticity/Repair Postnatal Neurogenesis and Gliogenesis in the Olfactory Bulb from NG2-Expressing Progenitors of the Subventricular Zone Adan Aguirre and Vittorio Gallo Center for Neuroscience Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC 20010 We used a 2Ј,3Ј-cyclic nucleotide 3Ј-phosphodiesterase (CNP)–enhanced green fluorescent protein (EGFP) transgenic mouse to study postnatal subventricular zone (SVZ) progenitor fate, with a focus on the olfactory bulb (OB). The postnatal OB of the CNP–EGFP mouse contained EGFP ϩ interneurons and oligodendrocytes. In the anterior SVZ, the majority of EGFP ϩ progenitors were NG2 ϩ. These NG2 ϩ/EGFP ϩ progenitors expressed the OB interneuron marker Er81, the neuroblast markers doublecortin (DC) and Distalless-related homeobox (DLX), or the oligodendrocyte progenitor marker Nkx2.2. In the rostral migratory stream (RMS), EGFP ϩ cells displayed a migrating phenotype. A fraction of these cells were either NG2 Ϫ/Er81 ϩ/DC ϩ/DLX ϩ or NG2 ϩ/Nkx2.2 ϩ. DiI (1,1Ј-dioctadecyl-3,3,3Ј,3Ј- tetramethylindocarbocyanine perchlorate) injection into the lateral ventricle (LV) of early postnatal mice demonstrated that NG2ϩ/ EGFP ϩ progenitors migrate from the SVZ through the RMS into the OB. Moreover, fluorescence-activated cell-sorting-purified NG2ϩ/ CNP–EGFP ϩ or NG2 ϩ/␤-actin–enhanced yellow fluorescent protein-positive (EYFP ϩ) progenitors transplanted into the early postnatal LV displayed extensive rostral and caudal migration. EYFP ϩ or EGFP ϩ graft-derived cells within the RMS were DLX ϩ/Er81 ϩ or Nkx2.2 ϩ, migrated to the OB, and differentiated to interneurons and oligodendrocytes.
    [Show full text]
  • Microglia Enhance Neurogenesis and Oligodendrogenesis in the Early Postnatal Subventricular Zone
    The Journal of Neuroscience, February 5, 2014 • 34(6):2231–2243 • 2231 Development/Plasticity/Repair Microglia Enhance Neurogenesis and Oligodendrogenesis in the Early Postnatal Subventricular Zone Yukari Shigemoto-Mogami,1 Kazue Hoshikawa,1 James E. Goldman,2 Yuko Sekino,1 and Kaoru Sato1 1Laboratory of Neuropharmacology, Division of Pharmacology, National Institute of Health Sciences, Tokyo 158-8501, Japan, and 2Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York 10032 Although microglia have long been considered as brain resident immune cells, increasing evidence suggests that they also have physio- logical roles in the development of the normal CNS. In this study, we found large numbers of activated microglia in the forebrain subventricular zone (SVZ) of the rat from P1 to P10. Pharmacological suppression of the activation, which produces a decrease in levels of a number of proinflammatory cytokines (i.e., IL-1␤, IL-6, TNF-␣, and IFN-␥) significantly inhibited neurogenesis and oligodendro- genesis in the SVZ. In vitro neurosphere assays reproduced the enhancement of neurogenesis and oligodendrogenesis by activated microglia and showed that the cytokines revealed the effects complementarily. These results suggest that activated microglia accumulate in the early postnatal SVZ and that they enhance neurogenesis and oligodendrogenesis via released cytokines. Key words: cytokine; microglia; neurogenesis; neurosphere; oligodendrogenesis; subventricular zone Introduction SVZ
    [Show full text]
  • Transcription Factor Lhx2 Is Necessary and Sufficient to Suppress
    Transcription factor Lhx2 is necessary and sufficient PNAS PLUS to suppress astrogliogenesis and promote neurogenesis in the developing hippocampus Lakshmi Subramaniana,1, Anindita Sarkara,1, Ashwin S. Shettya, Bhavana Muralidharana, Hari Padmanabhana, Michael Piperb, Edwin S. Monukic, Ingolf Bachd, Richard M. Gronostajskie,f, Linda J. Richardsb, and Shubha Tolea,2 aDepartment of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India; bQueensland Brain Institute and School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; cDepartment of Pathology and Laboratory Medicine, School of Medicine, University of California, Irvine, CA 92697; dPrograms in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605; eDepartment of Biochemistry, State University of New York, Buffalo, NY 14203; and fDevelopmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY 14203 AUTHOR SUMMARY During the development of the verte- memory. We used two approaches to brate CNS, progenitor cells generate disrupt Lhx2 function in progenitors at neurons, the primary players in circuits, the peak of hippocampal neurogenesis, and glia, the support cells. A character- embryonic gestation day (E) 15. Condi- istic feature of this process, common to tional KO mice were used, in which the all vertebrate species, is that the pro- gene encoding Lhx2 protein was dis- duction of neurons precedes that of glial rupted by the introduction of an enzyme cells (1). The transition from neuro- called “Cre recombinase,” which can cut genesis to gliogenesis determines the and paste DNA (2). The second ap- number of neurons vs. support cells that proach used a “dominant-negative” con- NEUROSCIENCE are produced in a given structure.
    [Show full text]
  • Concerted Control of Gliogenesis by Inr/TOR and FGF Signalling in the Drosophila Post-Embryonic Brain Amélie Avet-Rochex1, Aamna K
    RESEARCH ARTICLE 2763 Development 139, 2763-2772 (2012) doi:10.1242/dev.074179 © 2012. Published by The Company of Biologists Ltd Concerted control of gliogenesis by InR/TOR and FGF signalling in the Drosophila post-embryonic brain Amélie Avet-Rochex1, Aamna K. Kaul1, Ariana P. Gatt1, Helen McNeill2 and Joseph M. Bateman1,* SUMMARY Glial cells are essential for the development and function of the nervous system. In the mammalian brain, vast numbers of glia of several different functional types are generated during late embryonic and early foetal development. However, the molecular cues that instruct gliogenesis and determine glial cell type are poorly understood. During post-embryonic development, the number of glia in the Drosophila larval brain increases dramatically, potentially providing a powerful model for understanding gliogenesis. Using glial-specific clonal analysis we find that perineural glia and cortex glia proliferate extensively through symmetric cell division in the post-embryonic brain. Using pan-glial inhibition and loss-of-function clonal analysis we find that Insulin-like receptor (InR)/Target of rapamycin (TOR) signalling is required for the proliferation of perineural glia. Fibroblast growth factor (FGF) signalling is also required for perineural glia proliferation and acts synergistically with the InR/TOR pathway. Cortex glia require InR in part, but not downstream components of the TOR pathway, for proliferation. Moreover, cortex glia absolutely require FGF signalling, such that inhibition of the FGF pathway almost completely blocks the generation of cortex glia. Neuronal expression of the FGF receptor ligand Pyramus is also required for the generation of cortex glia, suggesting a mechanism whereby neuronal FGF expression coordinates neurogenesis and cortex gliogenesis.
    [Show full text]
  • Notch Signaling, Brain Development, and Human Disease
    0031-3998/05/5705-0104R PEDIATRIC RESEARCH Vol. 57, No. 5, Pt 2, 2005 Copyright © 2005 International Pediatric Research Foundation, Inc. Printed in U.S.A. Notch Signaling, Brain Development, and Human Disease JOSEPH L. LASKY AND HONG WU University of California, Los Angeles School of Medicine, Department of Molecular and Medical Pharmacology, Los Angeles, California, 90025 ABSTRACT The Notch signaling pathway is central to a wide array of summarizes what is currently known about the role of the Notch developmental processes in a number of organ systems, includ- pathway in neural stem cells, gliogenesis, learning and memory, ing hematopoiesis, somitogenesis, vasculogenesis, and neuro- and neurologic disease. (Pediatr Res 57: 104R–109R, 2005) genesis. These processes involve maintenance of stem cell self- renewal, proliferation, specification of cell fate or differentiation, Abbreviations and apoptosis. Recent studies have led to the recognition of the FCD, focal cortical dysplasia role of the Notch pathway in early neurodevelopment, learning, ICD, intracellular domain and memory, as well as late-life neurodegeneration. This review PS1, presenilin1 The formation of the mammalian nervous system takes place interacts with Notch ligands, such as Delta or Serrate (in via a number of developmental steps. All phases of brain Drosophila), on an adjacent cell (Fig. 1). This interaction development involve the recurrent themes of induction, cell triggers two proteolytic events culminating in the release of the proliferation, cell fate determination (differentiation), cell Notch ICD. The free intracellular fragment then translocates to movement (migration), cell process formation, and targeting the nucleus where it binds to the transcriptional regulator CSL (synapse formation) (1).
    [Show full text]
  • Clonal Analysis of Gliogenesis in the Cerebral Cortex Reveals Stochastic Expansion of Glia and Cell Autonomous Responses to Egfr Dosage
    cells Article Clonal Analysis of Gliogenesis in the Cerebral Cortex Reveals Stochastic Expansion of Glia and Cell Autonomous Responses to Egfr Dosage 1, 2, 1, 3 Xuying Zhang y, Christine V. Mennicke y, Guanxi Xiao y, Robert Beattie , Mansoor A. Haider 2 , Simon Hippenmeyer 3 and H. Troy Ghashghaei 1,* 1 Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA; [email protected] (X.Z.); [email protected] (G.X.) 2 Department of Mathematics, North Carolina State University, Raleigh, NC 27695, USA; [email protected] (C.V.M.); [email protected] (M.A.H.) 3 Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria; [email protected] (R.B.); [email protected] (S.H.) * Correspondence: [email protected] These authors contributed equally to this work. y Received: 16 November 2020; Accepted: 7 December 2020; Published: 11 December 2020 Abstract: Development of the nervous system undergoes important transitions, including one from neurogenesis to gliogenesis which occurs late during embryonic gestation. Here we report on clonal analysis of gliogenesis in mice using Mosaic Analysis with Double Markers (MADM) with quantitative and computational methods. Results reveal that developmental gliogenesis in the cerebral cortex occurs in a fraction of earlier neurogenic clones, accelerating around E16.5, and giving rise to both astrocytes and oligodendrocytes. Moreover, MADM-based genetic deletion of the epidermal growth factor receptor (Egfr) in gliogenic clones revealed that Egfr is cell autonomously required for gliogenesis in the mouse dorsolateral cortices. A broad range in the proliferation capacity, symmetry of clones, and competitive advantage of MADM cells was evident in clones that contained one cellular lineage with double dosage of Egfr relative to their environment, while their sibling Egfr-null cells failed to generate glia.
    [Show full text]
  • All in the Family: Proneural Bhlh Genes and Neuronal Diversity Nicholas E
    © 2018. Published by The Company of Biologists Ltd | Development (2018) 145, dev159426. doi:10.1242/dev.159426 REVIEW All in the family: proneural bHLH genes and neuronal diversity Nicholas E. Baker1,* and Nadean L. Brown2,* ABSTRACT lethal of scute [lsc,orl(1)sc] and asense (ase) – that are responsible Proneural basic Helix-Loop-Helix (bHLH) proteins are required for for development of much of the Drosophila CNS and PNS (Cubas neuronal determination and the differentiation of most neural et al., 1991; Garcia-Bellido and de Celis, 2009). Expression of these precursor cells. These transcription factors are expressed in vastly proneural genes defines regions of ectoderm with neurogenic divergent organisms, ranging from sponges to primates. Here, we competence, such that their default fate will be that of neural review proneural bHLH gene evolution and function in the Drosophila precursors unless diverted to another fate, for example by Notch and vertebrate nervous systems, arguing that the Drosophila gene signaling (Knust and Campos-Ortega, 1989; Simpson, 1990). ac, sc atonal provides a useful platform for understanding proneural gene and lsc are proneural genes, conferring proneural competence that structure and regulation. We also discuss how functional equivalency may or may not lead to neuronal determination in every cell, experiments using distinct proneural genes can reveal how proneural whereas ase is a neural precursor gene, expressed after the neural gene duplication and divergence are interwoven with neuronal fate decision has been made. It has been suggested that the complexity. vertebrate homologs of these genes are expressed in ectoderm with previously acquired neural character, and therefore are not true KEY WORDS: bHLH gene, Neural development, Neurogenesis, proneural genes (Bertrand et al., 2002).
    [Show full text]
  • Proneural Genes and the Specification of Neural Cell Types
    REVIEWS PRONEURAL GENES AND THE SPECIFICATION OF NEURAL CELL TYPES Nicolas Bertrand*, Diogo S. Castro* and François Guillemot Certain morphological, physiological and molecular characteristics are shared by all neurons. However, despite these similarities, neurons constitute the most diverse cell population of any organism. Recently, considerable attention has been focused on identifying the molecular mechanisms that underlie this cellular diversity. Parallel studies in Drosophila and vertebrates have revealed that proneural genes are key regulators of neurogenesis, coordinating the acquisition of a generic neuronal fate and of specific subtype identities that are appropriate for the location and time of neuronal generation. These studies reveal that, in spite of differences between invertebrate and vertebrate neural lineages, Drosophila and vertebrate proneural genes have remarkably similar roles. BASIC HELIX–LOOP–HELIX Building a nervous system involves the production of a ‘proneural genes’,which encode transcription factors of A structural motif that is present vast array of neuronal and glial cell types that must be the BASIC HELIX–LOOP–HELIX (bHLH) class, are both neces- in many transcription factors, produced in the correct numbers and at appropriate sary and sufficient, in the context of the ectoderm, which is characterized by two positions. The uniform epithelial sheath that constitutes to initiate the development of neuronal lineages and to α-helices separated by a loop. The helices mediate the primordium of the nervous system in invertebrate promote the generation of progenitors that are com- dimerization, and the adjacent and vertebrate embryos consists of cells that have the mitted to differentiation. Importantly, proneural genes basic region is required for DNA potential to generate both neurons and glia.
    [Show full text]
  • Neural Stem Cells: What Happens When They Go Viral?
    viruses Review Neural Stem Cells: What Happens When They Go Viral? Yashika S. Kamte, Manisha N. Chandwani, Alexa C. Michaels and Lauren A. O’Donnell * Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA; [email protected] (Y.S.K.); [email protected] (M.N.C.); [email protected] (A.C.M.) * Correspondence: [email protected]; Tel.: +1-412-396-5133 Abstract: Viruses that infect the central nervous system (CNS) are associated with developmental abnormalities as well as neuropsychiatric and degenerative conditions. Many of these viruses such as Zika virus (ZIKV), cytomegalovirus (CMV), and herpes simplex virus (HSV) demonstrate tropism for neural stem cells (NSCs). NSCs are the multipotent progenitor cells of the brain that have the ability to form neurons, astrocytes, and oligodendrocytes. Viral infections often alter the function of NSCs, with profound impacts on the growth and repair of the brain. There are a wide spectrum of effects on NSCs, which differ by the type of virus, the model system, the cell types studied, and the age of the host. Thus, it is a challenge to predict and define the consequences of interactions between viruses and NSCs. The purpose of this review is to dissect the mechanisms by which viruses can affect survival, proliferation, and differentiation of NSCs. This review also sheds light on the contribution of key antiviral cytokines in the impairment of NSC activity during a viral infection, revealing a complex interplay between NSCs, viruses, and the immune system. Keywords: neural stem cells; viruses; proliferation; survival; neurogenesis; differentiation; gliogenesis; cell death; cytokines Citation: Kamte, Y.S.; Chandwani, M.N.; Michaels, A.C.; O’Donnell, L.A.
    [Show full text]