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Velázquez-Lizárraga AE, Sukonthamarn P, Junprung W, Nanakorn Z, Itsathitphaisarn O, Jaroenlak P, Tassanakajon A. Molecular characterization of turtle-like protein in whiteleg shrimp (Litopenaeus vannamei) and its role in Enterocytozoon hepatopenaei infection. FISH & SHELLFISH IMMUNOLOGY 2023; 140:108976. [PMID: 37506856 DOI: 10.1016/j.fsi.2023.108976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/22/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
Enterocytozoon hepatopenaei (EHP) is a microsporidian parasite that infects shrimp hepatopancreas, causing growth retardation and disease susceptibility. Knowledge of the host-pathogen molecular mechanisms is essential to understanding the microsporidian pathogenesis. Turtle-like protein (TLP) is part of the immunoglobulin superfamily of proteins, which is widely distributed in the animal kingdom. TLP has multiple functions, such as cell surface receptors and cell adhesion molecules. The spore wall proteins (SWPs) of microsporidia are involved in the infection mechanisms. Some SWPs are responsible for spore adherence, which is part of the activation and host cell invasion processes. Previous studies showed that TLP from silkworms (Bombyx mori) interacted with SWP26, contributing to the infectivity of Nosema bombycis to its host. In this study, we identified and characterized for the first time, the Litopenaeus vannamei TLP gene (LvTLP), which encodes an 827-aa protein (92.4 kDa) composed of five immunoglobulin domains, two fibronectin type III domains, and a transmembrane region. The LvTLP transcript was expressed in all tested tissues and upregulated in the hepatopancreas at 1 and 7 days post-cohabitation (dpc) and at 9 dpc in hemocytes. To identify the LvTLP binding counterpart, recombinant (r)LvTLP and recombinant (r)EhSWP1 were produced in Escherichia coli. Coimmunoprecipitation and enzyme-linked immunosorbent assays demonstrated that rLvTLP interacted with rEhSWP with high affinity (KD = 1.20 × 10-7 M). In EHP-infected hepatopancreases, LvTLP was clustered and co-localized with some of the developing EHP plasmodia. Furthermore, LvTLP gene silencing reduced the EHP copy numbers compared with those of the control group, suggesting the critical role of LvTLP in EHP infection. These results provide insight into the molecular mechanisms of the host-pathogen interactions during EHP infection.
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Affiliation(s)
- Adrián E Velázquez-Lizárraga
- Center of Excellence for Molecular Biology and Genomic of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd, Wang Mai, Pathum Wan, Bangkok, 10330, Thailand
| | - Pongsakorn Sukonthamarn
- Center of Excellence for Molecular Biology and Genomic of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd, Wang Mai, Pathum Wan, Bangkok, 10330, Thailand
| | - Wisarut Junprung
- Center of Excellence for Molecular Biology and Genomic of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd, Wang Mai, Pathum Wan, Bangkok, 10330, Thailand
| | - Zittipong Nanakorn
- Center of Excellence for Molecular Biology and Genomic of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd, Wang Mai, Pathum Wan, Bangkok, 10330, Thailand
| | - Ornchuma Itsathitphaisarn
- Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, 272 Rama VI, Road, Thung Phaya Thai, Ratchathewi, Bangkok, 10400, Thailand
| | - Pattana Jaroenlak
- Center of Excellence for Molecular Biology and Genomic of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd, Wang Mai, Pathum Wan, Bangkok, 10330, Thailand
| | - Anchalee Tassanakajon
- Center of Excellence for Molecular Biology and Genomic of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd, Wang Mai, Pathum Wan, Bangkok, 10330, Thailand.
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How axon and dendrite branching are guided by time, energy, and spatial constraints. Sci Rep 2022; 12:20810. [PMID: 36460669 PMCID: PMC9718790 DOI: 10.1038/s41598-022-24813-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022] Open
Abstract
Neurons are connected by complex branching processes-axons and dendrites-that process information for organisms to respond to their environment. Classifying neurons according to differences in structure or function is a fundamental part of neuroscience. Here, by constructing biophysical theory and testing against empirical measures of branching structure, we develop a general model that establishes a correspondence between neuron structure and function as mediated by principles such as time or power minimization for information processing as well as spatial constraints for forming connections. We test our predictions for radius scale factors against those extracted from neuronal images, measured for species that range from insects to whales, including data from light and electron microscopy studies. Notably, our findings reveal that the branching of axons and peripheral nervous system neurons is mainly determined by time minimization, while dendritic branching is determined by power minimization. Our model also predicts a quarter-power scaling relationship between conduction time delay and body size.
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3
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Hendi A, Niu LG, Snow AW, Ikegami R, Wang ZW, Mizumoto K. Channel-independent function of UNC-9/Innexin in spatial arrangement of GABAergic synapses in C. elegans. eLife 2022; 11:80555. [PMID: 36378164 PMCID: PMC9665852 DOI: 10.7554/elife.80555] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 11/03/2022] [Indexed: 11/16/2022] Open
Abstract
Precise synaptic connection of neurons with their targets is essential for the proper functioning of the nervous system. A plethora of signaling pathways act in concert to mediate the precise spatial arrangement of synaptic connections. Here we show a novel role for a gap junction protein in controlling tiled synaptic arrangement in the GABAergic motor neurons in Caenorhabditis elegans, in which their axons and synapses overlap minimally with their neighboring neurons within the same class. We found that while EGL-20/Wnt controls axonal tiling, their presynaptic tiling is mediated by a gap junction protein UNC-9/Innexin, that is localized at the presynaptic tiling border between neighboring dorsal D-type GABAergic motor neurons. Strikingly, the gap junction channel activity of UNC-9 is dispensable for its function in controlling tiled presynaptic patterning. While gap junctions are crucial for the proper functioning of the nervous system as channels, our finding uncovered the novel channel-independent role of UNC-9 in synapse patterning.
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Affiliation(s)
- Ardalan Hendi
- Department of Zoology, University of British Columbia
- Life Sciences Institute, University of British Columbia
| | - Long-Gang Niu
- Department of Neuroscience, University of Connecticut Health Center
| | - Andrew William Snow
- Graduate Program in Cell and Developmental Biology, University of British Columbia
| | | | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut Health Center
| | - Kota Mizumoto
- Department of Zoology, University of British Columbia
- Life Sciences Institute, University of British Columbia
- Graduate Program in Cell and Developmental Biology, University of British Columbia
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia
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4
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Barber HM, Ali MF, Kucenas S. Glial Patchwork: Oligodendrocyte Progenitor Cells and Astrocytes Blanket the Central Nervous System. Front Cell Neurosci 2022; 15:803057. [PMID: 35069117 PMCID: PMC8766310 DOI: 10.3389/fncel.2021.803057] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/06/2021] [Indexed: 12/20/2022] Open
Abstract
Tiling is a developmental process where cell populations become evenly distributed throughout a tissue. In this review, we discuss the developmental cellular tiling behaviors of the two major glial populations in the central nervous system (CNS)—oligodendrocyte progenitor cells (OPCs) and astrocytes. First, we discuss OPC tiling in the spinal cord, which is comprised of the three cellular behaviors of migration, proliferation, and contact-mediated repulsion (CMR). These cellular behaviors occur simultaneously during OPC development and converge to produce the emergent behavior of tiling which results in OPCs being evenly dispersed and occupying non-overlapping domains throughout the CNS. We next discuss astrocyte tiling in the cortex and hippocampus, where astrocytes migrate, proliferate, then ultimately determine their exclusive domains by gradual removal of overlap rather than sustained CMR. This results in domains that slightly overlap, allowing for both exclusive control of “synaptic islands” and astrocyte-astrocyte communication. We finally discuss the similarities and differences in the tiling behaviors of these glial populations and what remains unknown regarding glial tiling and how perturbations to this process may impact injury and disease.
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Affiliation(s)
- Heather M. Barber
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
- Cell & Developmental Biology Graduate Program, University of Virginia, Charlottesville, VA, United States
| | - Maria F. Ali
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
- Department of Biology, University of Virginia, Charlottesville, VA, United States
| | - Sarah Kucenas
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
- Cell & Developmental Biology Graduate Program, University of Virginia, Charlottesville, VA, United States
- Department of Biology, University of Virginia, Charlottesville, VA, United States
- *Correspondence: Sarah Kucenas
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Ali MF, Latimer AJ, Wang Y, Hogenmiller L, Fontenas L, Isabella AJ, Moens CB, Yu G, Kucenas S. Met is required for oligodendrocyte progenitor cell migration in Danio rerio. G3 (BETHESDA, MD.) 2021; 11:jkab265. [PMID: 34568921 PMCID: PMC8473979 DOI: 10.1093/g3journal/jkab265] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022]
Abstract
During vertebrate central nervous system development, most oligodendrocyte progenitor cells (OPCs) are specified in the ventral spinal cord and must migrate throughout the neural tube until they become evenly distributed, occupying non-overlapping domains. While this process of developmental OPC migration is well characterized, the nature of the molecular mediators that govern it remain largely unknown. Here, using zebrafish as a model, we demonstrate that Met signaling is required for initial developmental migration of OPCs, and, using cell-specific knock-down of Met signaling, show that Met acts cell-autonomously in OPCs. Taken together, these findings demonstrate in vivo, the role of Met signaling in OPC migration and provide new insight into how OPC migration is regulated during development.
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Affiliation(s)
- Maria F Ali
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Andrew J Latimer
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Yinxue Wang
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Leah Hogenmiller
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Laura Fontenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Adam J Isabella
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Cecilia B Moens
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Guoqiang Yu
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
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Network Architecture of Gap Junctional Coupling among Parallel Processing Channels in the Mammalian Retina. J Neurosci 2020; 40:4483-4511. [PMID: 32332119 DOI: 10.1523/jneurosci.1810-19.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 03/27/2020] [Accepted: 04/12/2020] [Indexed: 01/04/2023] Open
Abstract
Gap junctions are ubiquitous throughout the nervous system, mediating critical signal transmission and integration, as well as emergent network properties. In mammalian retina, gap junctions within the Aii amacrine cell-ON cone bipolar cell (CBC) network are essential for night vision, modulation of day vision, and contribute to visual impairment in retinal degenerations, yet neither the extended network topology nor its conservation is well established. Here, we map the network contribution of gap junctions using a high-resolution connectomics dataset of an adult female rabbit retina. Gap junctions are prominent synaptic components of ON CBC classes, constituting 5%-25% of all axonal synaptic contacts. Many of these mediate canonical transfer of rod signals from Aii cells to ON CBCs for night vision, and we find that the uneven distribution of Aii signals to ON CBCs is conserved in rabbit, including one class entirely lacking direct Aii coupling. However, the majority of gap junctions formed by ON CBCs unexpectedly occur between ON CBCs, rather than with Aii cells. Such coupling is extensive, creating an interconnected network with numerous lateral paths both within, and particularly across, these parallel processing streams. Coupling patterns are precise with ON CBCs accepting and rejecting unique combinations of partnerships according to robust rulesets. Coupling specificity extends to both size and spatial topologies, thereby rivaling the synaptic specificity of chemical synapses. These ON CBC coupling motifs dramatically extend the coupled Aii-ON CBC network, with implications for signal flow in both scotopic and photopic retinal networks during visual processing and disease.SIGNIFICANCE STATEMENT Electrical synapses mediated by gap junctions are fundamental components of neural networks. In retina, coupling within the Aii-ON CBC network shapes visual processing in both the scotopic and photopic networks. In retinal degenerations, these same gap junctions mediate oscillatory activity that contributes to visual impairment. Here, we use high-resolution connectomics strategies to identify gap junctions and cellular partnerships. We describe novel, pervasive motifs both within and across classes of ON CBCs that dramatically extend the Aii-ON CBC network. These motifs are highly specific with implications for both signal processing within the retina and therapeutic interventions for blinding conditions. These findings highlight the underappreciated contribution of coupling motifs in retinal circuitry and the necessity of their detection in connectomics studies.
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Canzio D, Maniatis T. The generation of a protocadherin cell-surface recognition code for neural circuit assembly. Curr Opin Neurobiol 2019; 59:213-220. [PMID: 31710891 DOI: 10.1016/j.conb.2019.10.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/18/2019] [Indexed: 10/25/2022]
Abstract
The assembly of functional neural circuits in vertebrate organisms requires complex mechanisms of self-recognition and self-avoidance. Neurites (axons and dendrites) from the same neuron recognize and avoid self, but engage in synaptic interactions with other neurons. Vertebrate neural self-avoidance requires the expression of distinct repertoires of clustered Protocadherin (Pcdh) cell-surface protein isoforms, which act as cell-surface molecular barcodes that mediate highly specific homophilic self-recognition, followed by repulsion. The generation of sufficiently diverse cell-surface barcodes is achieved by the stochastic and combinatorial activation of a subset of clustered Pcdh promoters in individual neurons. This remarkable mechanism leads to the generation of enormous molecular diversity at the cell surface. Here we review recent studies showing that stochastic expression of individual Pcdhα isoforms is accomplished through an extraordinary mechanism involving the activation of 'antisense strand' promoter within Pcdhα 'variable' exons, antisense transcription of a long non-coding RNA through the upstream 'sense strand' promoter, demethylation of this promoter, binding of the CTCF/cohesin complex and DNA looping to a distant enhancer through a mechanism of chromatin 'extrusion'.
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Affiliation(s)
- Daniele Canzio
- UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, 94143, United States; Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, United States; Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94143, United States; Department of Psychiatry, University of California San Francisco, San Francisco, CA, 94143, United States.
| | - Tom Maniatis
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, United States; Mortimer B. Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY, 10027, United States; New York Genome Center, New York, NY 10013, United States.
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8
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Inberg S, Meledin A, Kravtsov V, Iosilevskii Y, Oren-Suissa M, Podbilewicz B. Lessons from Worm Dendritic Patterning. Annu Rev Neurosci 2019; 42:365-383. [PMID: 30939099 DOI: 10.1146/annurev-neuro-072116-031437] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The structural and functional properties of neurons have intrigued scientists since the pioneering work of Santiago Ramón y Cajal. Since then, emerging cutting-edge technologies, including light and electron microscopy, electrophysiology, biochemistry, optogenetics, and molecular biology, have dramatically increased our understanding of dendritic properties. This advancement was also facilitated by the establishment of different animal model organisms, from flies to mammals. Here we describe the emerging model system of a Caenorhabditis elegans polymodal neuron named PVD, whose dendritic tree follows a stereotypical structure characterized by repeating candelabra-like structural units. In the past decade, progress has been made in understanding PVD's functions, morphogenesis, regeneration, and aging, yet many questions still remain.
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Affiliation(s)
- Sharon Inberg
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Anna Meledin
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Veronika Kravtsov
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Yael Iosilevskii
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
| | - Meital Oren-Suissa
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion Israel Institute of Technology, Haifa 3200003, Israel;
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9
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DSCAM differentially modulates pre- and postsynaptic structural and functional central connectivity during visual system wiring. Neural Dev 2018; 13:22. [PMID: 30219101 PMCID: PMC6138929 DOI: 10.1186/s13064-018-0118-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/26/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Proper patterning of dendritic and axonal arbors is a critical step in the formation of functional neuronal circuits. Developing circuits rely on an array of molecular cues to shape arbor morphology, but the underlying mechanisms guiding the structural formation and interconnectivity of pre- and postsynaptic arbors in real time remain unclear. Here we explore how Down syndrome cell adhesion molecule (DSCAM) differentially shapes the dendritic morphology of central neurons and their presynaptic retinal ganglion cell (RGC) axons in the developing vertebrate visual system. METHODS The cell-autonomous role of DSCAM, in tectal neurons and in RGCs, was examined using targeted single-cell knockdown and overexpression approaches in developing Xenopus laevis tadpoles. Axonal arbors of RGCs and dendritic arbors of tectal neurons were visualized using real-time in vivo confocal microscopy imaging over the course of 3 days. RESULTS In the Xenopus visual system, DSCAM immunoreactivity is present in RGCs, cells in the optic tectum and the tectal neuropil at the time retinotectal synaptic connections are made. Downregulating DSCAM in tectal neurons significantly increased dendritic growth and branching rates while inducing dendrites to take on tortuous paths. Overexpression of DSCAM, in contrast, reduced dendritic branching and growth rate. Functional deficits mediated by tectal DSCAM knockdown were examined using visually guided behavioral assays in swimming tadpoles, revealing irregular behavioral responses to visual stimulus. Functional deficits in visual behavior also corresponded with changes in VGLUT/VGAT expression, markers of excitatory and inhibitory transmission, in the tectum. Conversely, single-cell DSCAM knockdown in the retina revealed that RGC axon arborization at the target is influenced by DSCAM, where axons grew at a slower rate and remained relatively simple. In the retina, dendritic arbors of RGCs were not affected by the reduction of DSCAM expression. CONCLUSIONS Together, our observations implicate DSCAM in the control of both pre- and postsynaptic structural and functional connectivity in the developing retinotectal circuit, where it primarily acts as a neuronal brake to limit and guide postsynaptic dendrite growth of tectal neurons while it also facilitates arborization of presynaptic RGC axons cell autonomously.
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Mazzochette EA, Nekimken AL, Loizeau F, Whitworth J, Huynh B, Goodman MB, Pruitt BL. The tactile receptive fields of freely moving Caenorhabditis elegans nematodes. Integr Biol (Camb) 2018; 10:450-463. [PMID: 30027970 PMCID: PMC6168290 DOI: 10.1039/c8ib00045j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sensory neurons embedded in skin are responsible for the sense of touch. In humans and other mammals, touch sensation depends on thousands of diverse somatosensory neurons. By contrast, Caenorhabditis elegans nematodes have six gentle touch receptor neurons linked to simple behaviors. The classical touch assay uses an eyebrow hair to stimulate freely moving C. elegans, evoking evasive behavioral responses. This assay has led to the discovery of genes required for touch sensation, but does not provide control over stimulus strength or position. Here, we present an integrated system for performing automated, quantitative touch assays that circumvents these limitations and incorporates automated measurements of behavioral responses. The Highly Automated Worm Kicker (HAWK) unites a microfabricated silicon force sensor holding a glass bead forming the contact surface and video analysis with real-time force and position control. Using this system, we stimulated animals along the anterior-posterior axis and compared responses in wild-type and spc-1(dn) transgenic animals, which have a touch defect due to expression of a dominant-negative α-spectrin protein fragment. As expected from prior studies, delivering large stimuli anterior and posterior to the mid-point of the body evoked a reversal and a speed-up, respectively. The probability of evoking a response of either kind depended on stimulus strength and location; once initiated, the magnitude and quality of both reversal and speed-up behavioral responses were uncorrelated with stimulus location, strength, or the absence or presence of the spc-1(dn) transgene. Wild-type animals failed to respond when the stimulus was applied near the mid-point. These results show that stimulus strength and location govern the activation of a characteristic motor program and that the C. elegans body surface consists of two receptive fields separated by a gap.
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Affiliation(s)
- E A Mazzochette
- Department of Electrical Engineering, Stanford University, 94305, USA
| | - A L Nekimken
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA
| | - F Loizeau
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - J Whitworth
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - B Huynh
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - M B Goodman
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA
| | - B L Pruitt
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA and Department of Bioengineering, Stanford University, 94305, USA and Department of Mechanical Engineering, University of California, Santa Barbara, 93106, USA.
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11
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Lomvardas S, Maniatis T. Histone and DNA Modifications as Regulators of Neuronal Development and Function. Cold Spring Harb Perspect Biol 2016; 8:8/7/a024208. [PMID: 27371659 DOI: 10.1101/cshperspect.a024208] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
DNA and histone modifications, together with constraints imposed by nuclear architecture, contribute to the transcriptional regulatory landscape of the nervous system. Here, we provide select examples showing how these regulatory layers, often referred to as epigenetic, contribute to neuronal differentiation and function. We describe the interplay between DNA methylation and Polycomb-mediated repression during neuronal differentiation, the role of DNA methylation and long-range enhancer-promoter interactions in Protocadherin promoter choice, and the contribution of heterochromatic silencing and nuclear organization in singular olfactory receptor expression. Finally, we explain how the activity-dependent expression of a histone variant determines the longevity of olfactory sensory neurons.
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Affiliation(s)
- Stavros Lomvardas
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032
| | - Tom Maniatis
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032
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12
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Yip ZC, Heiman MG. Duplication of a Single Neuron in C. elegans Reveals a Pathway for Dendrite Tiling by Mutual Repulsion. Cell Rep 2016; 15:2109-2117. [PMID: 27239028 DOI: 10.1016/j.celrep.2016.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 03/16/2016] [Accepted: 04/24/2016] [Indexed: 11/30/2022] Open
Abstract
Simple cell-cell interactions can give rise to complex cellular patterns. For example, neurons of the same type can interact to create a complex patchwork of non-overlapping dendrite arbors, a pattern known as dendrite tiling. Dendrite tiling often involves mutual repulsion between neighboring neurons. While dendrite tiling is found across nervous systems, the nematode Caenorhabditis elegans has a relatively simple nervous system with few opportunities for tiling. Here, we show that genetic duplication of a single neuron, PVD, is sufficient to create dendrite tiling among the resulting ectopic neurons. We use laser ablation to show that this tiling is mediated by mutual repulsion between neighbors. Furthermore, we find that tiling requires a repulsion signal (UNC-6/Netrin and its receptors UNC-40/DCC and UNC-5) that normally patterns the PVD dendrite arbor. These results demonstrate that an apparently complex cellular pattern can emerge in a simple nervous system merely by increasing neuron number.
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Affiliation(s)
- Zhiqi Candice Yip
- Division of Genetics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Maxwell G Heiman
- Division of Genetics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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13
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Levine J. The reactions and role of NG2 glia in spinal cord injury. Brain Res 2016; 1638:199-208. [PMID: 26232070 PMCID: PMC4732922 DOI: 10.1016/j.brainres.2015.07.026] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/02/2015] [Accepted: 07/18/2015] [Indexed: 01/06/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) react rapidly to brain and spinal cord injuries. This reaction is characterized by the retraction of cell processes, cell body swelling and increased expression of the NG2 chondroitin sulfate proteoglycan. Reactive OPCs rapidly divide and accumulate surrounding the injury site where they become major cellular components of the glial scar. The glial reaction to injury is an attempt to restore normal homeostasis and re-establish the glia limitans but the exact role of reactive OPCs in these processes is not well understood. Traumatic injury results in extensive oligodendrocyte cell death and the proliferating OPCs generate the large number of precursor cells necessary for remyelination. Reactive OPCs, however, also are a source of axon-growth inhibitory proteoglycans and may interact with invading inflammatory cells in complex ways. Here, I discuss these and other properties of OPCs after spinal cord injury. Understanding the regulation of these disparate properties may lead to new therapeutic approaches to devastating injuries of the spinal cord. This article is part of a Special Issue entitled SI:NG2-glia(Invited only).
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Affiliation(s)
- Joel Levine
- Department of Neurobiology and Behavior, Stonybrook University, Stony Brook, NY 11794, USA.
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14
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Petrovic M, Schmucker D. Axonal wiring in neural development: Target-independent mechanisms help to establish precision and complexity. Bioessays 2015; 37:996-1004. [DOI: 10.1002/bies.201400222] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Milan Petrovic
- Neuronal Wiring Laboratory; VIB; Leuven Belgium
- Department of Oncology, School of Medicine; University of Leuven; Leuven Belgium
| | - Dietmar Schmucker
- Neuronal Wiring Laboratory; VIB; Leuven Belgium
- Department of Oncology, School of Medicine; University of Leuven; Leuven Belgium
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15
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Visual circuit assembly requires fine tuning of the novel Ig transmembrane protein Borderless. J Neurosci 2013; 33:17413-21. [PMID: 24174674 DOI: 10.1523/jneurosci.1878-13.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Establishment of synaptic connections in the neuropils of the developing nervous system requires the coordination of specific neurite-neurite interactions (i.e., axon-axon, dendrite-dendrite and axon-dendrite interactions). The molecular mechanisms underlying coordination of neurite-neurite interactions for circuit assembly are incompletely understood. In this report, we identify a novel Ig superfamily transmembrane protein that we named Borderless (Bdl), as a novel regulator of neurite-neurite interactions in Drosophila. Bdl induces homotypic cell-cell adhesion in vitro and mediates neurite-neurite interactions in the developing visual system. Bdl interacts physically and genetically with the Ig transmembrane protein Turtle, a key regulator of axonal tiling. Our results also show that the receptor tyrosine phosphatase leukocyte common antigen-related protein (LAR) negatively regulates Bdl to control synaptic-layer selection. We propose that precise regulation of Bdl action coordinates neurite-neurite interactions for circuit formation in Drosophila.
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16
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Abstract
Productive cell proliferation involves efficient and accurate splitting of the dividing cell into two separate entities. This orderly process reflects coordination of diverse cytological events by regulatory systems that drive the cell from mitosis into G1. In the budding yeast Saccharomyces cerevisiae, separation of mother and daughter cells involves coordinated actomyosin ring contraction and septum synthesis, followed by septum destruction. These events occur in precise and rapid sequence once chromosomes are segregated and are linked with spindle organization and mitotic progress by intricate cell cycle control machinery. Additionally, critical paarts of the mother/daughter separation process are asymmetric, reflecting a form of fate specification that occurs in every cell division. This chapter describes central events of budding yeast cell separation, as well as the control pathways that integrate them and link them with the cell cycle.
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17
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Hansen M, Walmod PS. IGSF9 family proteins. Neurochem Res 2013; 38:1236-51. [PMID: 23417431 DOI: 10.1007/s11064-013-0999-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 02/06/2013] [Accepted: 02/08/2013] [Indexed: 12/22/2022]
Abstract
The Drosophila protein Turtle and the vertebrate proteins immunoglobulin superfamily (IgSF), member 9 (IGSF9/Dasm1) and IGSF9B are members of an evolutionarily ancient protein family. A bioinformatics analysis of the protein family revealed that invertebrates contain only a single IGSF9 family gene, whereas vertebrates contain two to four genes. In cnidarians, the gene appears to encode a secreted protein, but transmembrane isoforms of the protein have also evolved, and in many species, alternative splicing facilitates the expression of both transmembrane and secreted isoforms. In most species, the longest isoforms of the proteins have the same general organization as the neural cell adhesion molecule family of cell adhesion molecule proteins, and like this family of proteins, IGSF9 family members are expressed in the nervous system. A review of the literature revealed that Drosophila Turtle facilitates homophilic cell adhesion. Moreover, IGSF9 family proteins have been implicated in the outgrowth and branching of neurites, axon guidance, synapse maturation, self-avoidance, and tiling. However, despite the few published studies on IGSF9 family proteins, reports on the functions of both Turtle and mammalian IGSF9 proteins are contradictory.
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Affiliation(s)
- Maria Hansen
- Protein Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Panum Institute, University of Copenhagen, Building 24.2, Blegdamsvej 3, 2200 Copenhagen N, Denmark
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18
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Zhou Y, Cameron S, Chang WT, Rao Y. Control of directional change after mechanical stimulation in Drosophila. Mol Brain 2012; 5:39. [PMID: 23107101 PMCID: PMC3514245 DOI: 10.1186/1756-6606-5-39] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 10/23/2012] [Indexed: 11/11/2022] Open
Abstract
Background Proper adjustment of moving direction after external mechanical stimulation is essential for animals to avoid danger (e.g. predators), and thus is vital for survival. This process involves sensory inputs, central processing and motor outputs. Recent studies have made considerable progress in identifying mechanosensitive neurons and mechanosensation receptor proteins. Our understandings of molecular and cellular mechanisms that link mechanosensation with the changes in moving direction, however, remain limited. Results In this study, we investigate the control of movement adjustment in Drosophila. In response to gentle touch at the anterior segments, Drosophila larvae reorient and select a new direction for forward movement. The extent of change in moving direction is correlated with the intensity of tactile stimuli. Sensation of gentle touch requires chordotonal organs and class IV da neurons. Genetic analysis indicates an important role for the evolutionarily conserved immunoglobulin (Ig) superfamily protein Turtle (Tutl) to regulate touch-initiated directional change. Tutl is required specifically in post-mitotic neurons at larval stage after the completion of embryonic development. Circuit breaking analysis identified a small subset of Tutl-positive neurons that are involved in the adjustment of moving direction. Conclusion We identify Tutl and a small subset of CNS neurons in modulating directional change in response to gentle touch. This study presents an excellent starting point for further dissection of molecular and cellular mechanisms controlling directional adjustment after mechanical stimulation.
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Affiliation(s)
- Yating Zhou
- McGill Centre for Research in Neuroscience, McGill University Health Centre, Montreal, Quebec, Canada
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Matthews BJ, Grueber WB. Dscam1-mediated self-avoidance counters netrin-dependent targeting of dendrites in Drosophila. Curr Biol 2011; 21:1480-7. [PMID: 21871804 DOI: 10.1016/j.cub.2011.07.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 10/17/2022]
Abstract
Dendrites and axons show precise targeting and spacing patterns for proper reception and transmission of information in the nervous system. Self-avoidance promotes complete territory coverage and nonoverlapping spacing between processes from the same cell [1, 2]. Neurons that lack Drosophila Down syndrome cell adhesion molecule 1 (Dscam1) show aberrant overlap, fasciculation, and accumulation of dendrites and axons, demonstrating a role in self-recognition and repulsion leading to self-avoidance [3-11]. Fasciculation and accumulation of processes suggested that Dscam1 might promote process spacing by counterbalancing developmental signals that otherwise promote self-association [9, 12]. Here we show that Dscam1 functions to counter Drosophila sensory neuron dendritic targeting signals provided by secreted Netrin-B and Frazzled, a netrin receptor. Loss of Dscam1 function resulted in aberrant dendrite accumulation at a Netrin-B-expressing target, whereas concomitant loss of Frazzled prevented accumulation and caused severe deficits in dendritic territory coverage. Netrin misexpression was sufficient to induce ectopic dendritic targeting in a Frazzled-dependent manner, whereas Dscam1 was required to prevent ectopic accumulation, consistent with separable roles for these receptors. Our results suggest that Dscam1-mediated self-avoidance counters extrinsic signals that are required for normal dendritic patterning, but whose action would otherwise favor neurite accumulation. Counterbalancing roles for Dscam1 may be deployed in diverse contexts during neural circuit formation.
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Affiliation(s)
- Benjamin J Matthews
- Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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