Membrane proteins and glycoproteins specific to central nervous system axons and growth cones

1985 ◽  
Vol 19 (2) ◽  
pp. 237-244 ◽  
Author(s):  
Burkhard Schlosshauer
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Membrane Proteins ◽  
Growth Cones

Targeted ablation of glia disrupts axon tract formation in the Drosophila CNS

Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3703-3712 ◽  
Author(s):  
A. Hidalgo ◽  
J. Urban ◽  
A.H. Brand
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Growth Cone ◽  
Growth Cones ◽  
Complete Loss ◽  
Drosophila Embryo ◽  
Novel Technique ◽  
Cell Ablation ◽  
Longitudinal Axon ◽  
Growth Cone Guidance

Glial cells are thought to play a role in growth cone guidance, both in insects and in vertebrates. In the developing central nervous system of the Drosophila embryo, the interface glia form a scaffold prior to the extension of the first pioneer growth cones. Growing axons appear to contact the glial scaffold as the axon tracts are established. We have used a novel technique for targeted cell ablation to kill the interface glia and thus to test their role in establishment of the embryonic axon tracts. We show that ablation of the interface glia early in development leads to a complete loss of the longitudinal axon tracts. Ablation of the glia later in embryonic development results in defects comprising weakening and loss of axon fascicles within the connectives. We conclude that the interface glia are required first for growth cone guidance in the formation of the longitudinal axon tracts in the Drosophila embryo and then either to direct the follower growth cones, or to maintain the longitudinal axon tracts.

Axon repulsion from the midline of the Drosophila CNS requires slit function

Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2475-2481 ◽  
Author(s):  
R. Battye ◽  
A. Stevens ◽  
J.R. Jacobs
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Transgene Expression ◽  
Ectopic Expression ◽  
Growth Cones ◽  
Drosophila Embryogenesis ◽  
Putative Receptor ◽  
Midline Crossing ◽  
The Central Nervous System ◽  
Axon Repulsion

Guidance of axons towards or away from the midline of the central nervous system during Drosophila embryogenesis reflects a balance of attractive and repulsive cues originating from the midline. Here we demonstrate that Slit, a protein secreted by the midline glial cells provides a repulsive cue for the growth cones of axons and muscle cells. Embryos lacking slit function show a medial collapse of lateral axon tracts and ectopic midline crossing of ventral muscles. Transgene expression of slit in the midline restores axon patterning. Ectopic expression of slit inhibits formation of axon tracts at locations of high Slit production and misdirects axon tracts towards the midline. slit interacts genetically with roundabout, which encodes a putative receptor for growth cone repulsion.

scholarly journals The role of repulsive guidance molecules in the embryonic and adult vertebrate central nervous system

2006 ◽  
Vol 361 (1473) ◽  
pp. 1513-1529 ◽  
Author(s):  
Bernhard K Mueller ◽  
Toshihide Yamashita ◽  
Gregor Schaffar ◽  
Reinhold Mueller
Keyword(s):  
Neural Network ◽  
Central Nervous System ◽  
Nervous System ◽  
Synapse Formation ◽  
Neurite Growth ◽  
Local Environment ◽  
Growth Cones ◽  
Guidance Cues ◽  
Growth Guidance ◽  
Guidance Molecules

During the development of the nervous system, outgrowing axons often have to travel long distances to reach their target neurons. In this process, outgrowing neurites tipped with motile growth cones rely on guidance cues present in their local environment. These cues are detected by specific receptors expressed on growth cones and neurites and influence the trajectory of the growing fibres. Neurite growth, guidance, target innervation and synapse formation and maturation are the processes that occur predominantly but not exclusively during embryonic or early post-natal development in vertebrates. As a result, a functional neural network is established, which is usually remarkably stable. However, the stability of the neural network in higher vertebrates comes at an expensive price, i.e. the loss of any significant ability to regenerate injured or damaged neuronal connections in their central nervous system (CNS). Most importantly, neurite growth inhibitors prevent any regenerative growth of injured nerve fibres. Some of these inhibitors are associated with CNS myelin, others are found at the lesion site and in the scar tissue. Traumatic injuries in brain and spinal cord of mammals induce upregulation of embryonic inhibitory or repulsive guidance cues and their receptors on the neurites. An example for embryonic repulsive directional cues re-expressed at lesion sites in both the rat and human CNS is provided with repulsive guidance molecules, a new family of directional guidance cues.

scholarly journals Identification and Characterization of microRNAs during Retinoic Acid-Induced Regeneration of a Molluscan Central Nervous System

2018 ◽  
Vol 19 (9) ◽  
pp. 2741 ◽  
Author(s):  
Sarah Walker ◽  
Gaynor Spencer ◽  
Aleksandar Necakov ◽  
Robert Carlone
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Retinoic Acid ◽  
Lymnaea Stagnalis ◽  
System Development ◽  
Growth Cones ◽  
Nervous System Development ◽  
Biologically Active ◽  
Sequencing Analysis

Retinoic acid (RA) is the biologically active metabolite of vitamin A and has become a well-established factor that induces neurite outgrowth and regeneration in both vertebrates and invertebrates. However, the underlying regulatory mechanisms that may mediate RA-induced neurite sprouting remain unclear. In the past decade, microRNAs have emerged as important regulators of nervous system development and regeneration, and have been shown to contribute to processes such as neurite sprouting. However, few studies have demonstrated the role of miRNAs in RA-induced neurite sprouting. By miRNA sequencing analysis, we identify 482 miRNAs in the regenerating central nervous system (CNS) of the mollusc Lymnaea stagnalis, 219 of which represent potentially novel miRNAs. Of the remaining conserved miRNAs, 38 show a statistically significant up- or downregulation in regenerating CNS as a result of RA treatment. We further characterized the expression of one neuronally-enriched miRNA upregulated by RA, miR-124. We demonstrate, for the first time, that miR-124 is expressed within the cell bodies and neurites of regenerating motorneurons. Moreover, we identify miR-124 expression within the growth cones of cultured ciliary motorneurons (pedal A), whereas expression in the growth cones of another class of respiratory motorneurons (right parietal A) was absent in vitro. These findings support our hypothesis that miRNAs are important regulators of retinoic acid-induced neuronal outgrowth and regeneration in regeneration-competent species.

Identification of a novel protein from adult chicken brain that inhibits neurite outgrowth

1994 ◽  
Vol 107 (12) ◽  
pp. 3393-3402 ◽  
Author(s):  
G.A. Clarke ◽  
D.J. Moss
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Dorsal Root Ganglion ◽  
Neurite Outgrowth ◽  
Dorsal Root ◽  
Growth Cones ◽  
Dorsal Root Ganglion Neurons ◽  
Adult Chicken ◽  
Chicken Brain ◽  
Ganglion Neurons

Glycoproteins that inhibit neurite outgrowth may guide growth cones during development by acting as a barrier and closing off inappropriate routes. Their continued expression in the adult central nervous system may be a key factor in preventing regeneration of central nervous system neurons. A glycoprotein of 55 kDa has been isolated from the detergent-insoluble membrane skeleton from adult chicken brain. Initial experiments showed that dorsal root ganglion neurons would not adhere to or extend neurites on a substratum coated with GP55. Furthermore, GP55 will act as a barrier to the advance of established growth cones in the presence of poly-L-lysine, laminin or G4. Central nervous system neurons from forebrain as well as dorsal root ganglion neurons from the peripheral nervous system are inhibited by GP55. GP55 is also effective in blocking the initial adhesion of neurons to a substratum of poly-L-lysine and, particularly, laminin. In contrast to the inhibition of neurite outgrowth, neuronal adhesion is concentration independent over the range tested. A preliminary investigation of the mechanism by which GP55 inhibits outgrowth suggests that a pertussis toxin-sensitive G protein is required. Preliminary evidence suggests that GP55 is anchored in the membrane by a glycosyl phosphatidylinositol moiety. GP55 is distinct from previously identified inhibitory proteins, based on the source and molecular mass, and is thus a new member of this rapidly expanding family.

Neurotropic enteroviruses co-opt “fair-weather-friend” commensal gut microbiota to drive host infection and central nervous system disturbances

2019 ◽  
Vol 42 ◽  
Author(s):  
Kevin B. Clark
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Gut Bacteria ◽  
Infection Cycle ◽  
Fair Weather ◽  
Host Health ◽  
Microbe Interactions ◽  
Animal Hosts ◽  
Host Infection ◽  
Neuropsychiatric Conditions

Abstract Some neurotropic enteroviruses hijack Trojan horse/raft commensal gut bacteria to render devastating biomimicking cryptic attacks on human/animal hosts. Such virus-microbe interactions manipulate hosts’ gut-brain axes with accompanying infection-cycle-optimizing central nervous system (CNS) disturbances, including severe neurodevelopmental, neuromotor, and neuropsychiatric conditions. Co-opted bacteria thus indirectly influence host health, development, behavior, and mind as possible “fair-weather-friend” symbionts, switching from commensal to context-dependent pathogen-like strategies benefiting gut-bacteria fitness.

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