The distribution of non-synaptic intercellular junctions during neurone differentiation in the developing spinal cord of the clawed toad

Brian P. Hayes; Alan Roberts

doi:10.1242/dev.33.2.403

The distribution of non-synaptic intercellular junctions during neurone differentiation in the developing spinal cord of the clawed toad

Development ◽

10.1242/dev.33.2.403 ◽

1975 ◽

Vol 33 (2) ◽

pp. 403-417

Author(s):

Brian P. Hayes ◽

Alan Roberts

Keyword(s):

Spinal Cord ◽

Gap Junctions ◽

Neural Differentiation ◽

Electrical Coupling ◽

Intercellular Junctions ◽

Ependymal Cells ◽

Freedom Of Movement ◽

Ventricular Cells ◽

Vertebrate Embryos ◽

Developing Spinal Cord

The distribution of intercellular junctions, other than synapses and their precursors, has beendescribed in the developing spinal cord of Xenopus laevis between the neurula andfree swimming tadpole stages. At the neurocoel, ventricular cells are joined in the apical contactzone by a sequence of junctions which usually has one or more intermediate junctions but often also includes close appositions, gap junctions and desmosomes. This apical complex is more diverse than that reported in other vertebrate embryos and between ependymal cells in the adult central nervous system. Gap junctions are also found between ventricular cells and their processes near the external cord surface. However, no other special junctions occur in this location under the basementlamella which surrounds the cord. Punctate intermediate junctions are generally distributed between undifferentiated and differentiating cells and their processes but were not found in neuropil after stage 28. These results are discussed in relation to cell movements during neural differentiation, possible effects on the freedom of movement of ions and molecules through extracellular pathways in the embryo, and possible intercytoplasmic pathways via gap junctions which may be responsible for the physiologically observed electrical coupling between neural tube cells.

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Sustained experimental activation of FGF8/ERK in the developing chicken spinal cord reproducibly models early events in ERK-mediated tumorigenesis

10.1101/2021.06.10.447891 ◽

2021 ◽

Author(s):

Axelle Wilmerding ◽

Lauranne Bouteille ◽

Nathalie Caruso ◽

Ghislain Bidaut ◽

Heather Corbett Etchevers ◽

...

Keyword(s):

Spinal Cord ◽

Chicken Embryo ◽

Active Form ◽

In Vivo Model ◽

Signal Attenuation ◽

Transcriptional Signature ◽

Undifferentiated State ◽

Vertebrate Embryos ◽

Developing Spinal Cord

Most human cancers demonstrate activated MAPK/ERK pathway signaling as a key tumor initiation step, but the immediate steps of further oncogenic progression are poorly understood due to a lack of appropriate models. Spinal cord differentiation follows caudal elongation in vertebrate embryos; both processes are regulated by a FGF8 gradient highest in neuromesodermal progenitors (NMP), where kinase effectors ERK1/2 maintain an undifferentiated state. FGF8/ERK signal attenuation is necessary for NMPs to progress to differentiation. We show that sustained ERK1/2 activity, using a constitutively active form of the kinase MEK1 (MEK1ca) in the chicken embryo, reproducibly provokes neopasia in the developing spinal cord. Transcriptomic data show that neoplasia not only relies on the maintenance of NMP gene expression, and the inhibition of genes expressed in the differentiating spinal cord, but also on a profound change in the transcriptional signature of the spinal cord cells leading to a complete loss of cell-type identity. MEK1ca expression in the developing spinal cord of the chicken embryo is therefore a tractable in vivo model to identify the critical factors fostering malignancy in ERK-induced tumorigenesis.

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The pattern of alkaline phosphatase activity in the developing mouse spinal cord

Development ◽

10.1242/dev.82.1.241 ◽

1984 ◽

Vol 82 (1) ◽

pp. 241-251

Author(s):

W. H. Kwong ◽

P. P. L. Tam

Keyword(s):

Spinal Cord ◽

Alkaline Phosphatase ◽

Enzymatic Activity ◽

Phosphatase Activity ◽

Alkaline Phosphatase Activity ◽

Similar Distribution ◽

Lumbosacral Region ◽

Ventricular Cells ◽

Neuronal Processes ◽

Developing Spinal Cord

The localization of alkaline phosphatase activity in the lumbosacral region of the developing spinal cord was studied in 9·5- to 17·5-day mouse embryos. The activity was uniformly distributed in the pseudostratified neuroepithelium of the 9·5-day cord. In the 11·5-day cord in which the lateral motor columns were being formed, the enzymatic activity was localized in the ventrolateral sector of the cord. The enzyme-positive ventricular cells tended to be located medially whereas radially oriented enzyme-positive processes extended into the marginal layer. The 13·5-day cord displayed a similar distribution pattern, but there were many more radial processes and the enzyme-positive cells had spread laterally. Close apposition betweenthe processes and the ventricular cells was observed. By 15·5 and 17·5 days, when the intermediate layer was fully developed and the ventricular layer had regressed to a thin ependyma, the activity had become diffusely located in the ventral half of the cord. The enzyme-positive cells and processes became less conspicuous. The silver-stained processes in the cord were found to be organized in an entirely different pattern from that of the enzyme-positive processes, suggesting that the enzyme-positive processes were not neuronal processes. The enzymatic activity found in the developing spinal cord may be associated with the migration of neuroblasts along the radially aligned processes.

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Ependymal morphogenesis in a simple vertebrate spinal cord

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147958 ◽

1993 ◽

Vol 51 ◽

pp. 424-425

Author(s):

Jill K. Frey ◽

Aileen Chen ◽

R. David Heathcote

Keyword(s):

Spinal Cord ◽

Cerebrospinal Fluid ◽

Single Layer ◽

Central Canal ◽

Floor Plate ◽

Turn Of The Century ◽

Ependymal Cells ◽

Embryonic Spinal Cord ◽

Developing Spinal Cord ◽

Tyrosine Hydroxylase Immunocytochemistry

All cells of the spinal cord originate from the single layer of neuroepithelium that lines the central canal. Since the turn of the century, it has been known that a subclass of these ependymal cells can differentiate into neurons and extend cytoplasmic projections and cilia into the central canal. We have recently used tyrosine hydroxylase immunocytochemistry to identify a catecholaminergic subpopulation of cerebrospinal fluid (CSF) contacting ependymal neurons in the developing spinal cord of the frog Xenopus laevis (Fig. 1). The interneurons are located in the floor plate region of the spinal cord and have axons that extend rostrally toward the hindbrain. During the morphogenesis of the catecholaminergic population of cells, two longitudinal columns gradually appear and then rapidly “converge” at the ventral midline. Transverse sections of embryonic spinal cord (see Fig. 1) showed that the cell bodies decreased in size and underwent changes in shape, number and position within the spinal cord.

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Junctional complexes and variations in gap junctions between spinal cord ependymal cells of a teleost, Sternarchus albifrons (gymnotoidei)

Brain Research ◽

10.1016/0006-8993(78)90750-3 ◽

1978 ◽

Vol 143 (1) ◽

pp. 27-41 ◽

Cited By ~ 16

Author(s):

C. Sandri ◽

K. Akert ◽

M.V.L. Bennett

Keyword(s):

Spinal Cord ◽

Gap Junctions ◽

Ependymal Cells ◽

Junctional Complexes

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Mitochondrial Reshaping Accompanies Neural Differentiation in the Developing Spinal Cord

PLoS ONE ◽

10.1371/journal.pone.0128130 ◽

2015 ◽

Vol 10 (5) ◽

pp. e0128130 ◽

Cited By ~ 13

Author(s):

Valérie Mils ◽

Stéphanie Bosch ◽

Julie Roy ◽

Sophie Bel-Vialar ◽

Pascale Belenguer ◽

...

Keyword(s):

Spinal Cord ◽

Neural Differentiation ◽

Developing Spinal Cord

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Quantitative EM of gap junction distribution in mutant drosophila wing discs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077177 ◽

1983 ◽

Vol 41 ◽

pp. 720-721

Author(s):

J.S. Ryerse

Keyword(s):

Gap Junctions ◽

Growth Control ◽

Intercellular Junctions ◽

Wing Disc ◽

En Bloc ◽

Metabolic Cooperation ◽

Drosophila Wing ◽

Adult Wing ◽

Wing Discs ◽

Wing Pouch

Gap junctions are intercellular junctions found in both vertebrates and invertebrates through which ions and small molecules can pass. Their distribution in tissues could be of critical importance for ionic coupling or metabolic cooperation between cells or for regulating the intracellular movement of growth control and pattern formation factors. Studies of the distribution of gap junctions in mutants which develop abnormally may shed light upon their role in normal development. I report here the distribution of gap junctions in the wing pouch of 3 Drosophila wing disc mutants, vg (vestigial) a cell death mutant, 1(2)gd (lethal giant disc) a pattern abnormality mutant and 1(2)gl (lethal giant larva) a neoplastic mutant and compare these with wildtype wing discs.The wing pouch (the anlagen of the adult wing blade) of a wild-type wing disc is shown in Fig. 1 and consists of columnar cells (Fig. 5) joined by gap junctions (Fig. 6). 14000x EMs of conventionally processed, UA en bloc stained, longitudinally sectioned wing pouches were enlarged to 45000x with a projector and tracings were made on which the lateral plasma membrane (LPM) and gap junctions were marked.

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Structural modifications of intercellular junctions.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082510 ◽

1978 ◽

Vol 36 (2) ◽

pp. 330-331

Author(s):

J. Metz ◽

M. Merlo ◽

W. G. Forssmann

Keyword(s):

Gap Junctions ◽

Intercellular Junctions ◽

Cell Isolation ◽

Extrahepatic Cholestasis ◽

Structural Modifications ◽

Pancreatic Duct Ligation ◽

Pancreatic Cells ◽

Duct Ligation ◽

Thin Sectioning ◽

And Function

Structure and function of intercellular junctions were studied under the electronmicroscope using conventional thin sectioning and freeze-etch replicas. Alterations of tight and gap junctions were analyzed 1. of exocrine pancreatic cells under cell isolation conditions and pancreatic duct ligation and 2. of hepatocytes during extrahepatic cholestasis.During the different steps of cell isolation of exocrine pancreatic cells, gradual changes of tight and gap junctions were observed. Tight junctions, which formed belt-like structures around the apex of control acinar cells in situ, subsequently diminished, became interrupted and were concentrated into macular areas (Fig. 1). Aggregations of membrane associated particles, which looked similar to gap junctions, were intermixed within tight junctional areas (Fig. 1). These structures continously disappeared in the last stages of the isolation procedure. The intercellular junctions were finally separated without destroying the integrity of the cell membrane, which was confirmed with porcion yellow, lanthanum chloride and horse radish peroxidase.

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