scholarly journals Segmental lineage restrictions in the chick embryo spinal cord depend on the adjacent somites

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 239-244 ◽  
Author(s):  
C.D. Stern ◽  
K.F. Jaques ◽  
T.M. Lim ◽  
S.E. Fraser ◽  
R.J. Keynes
Keyword(s):  
Spinal Cord ◽  
Chick Embryo ◽  
Single Cell ◽  
Neural Tube ◽  
Fluorescent Tracer ◽  
Anteroposterior Axis ◽  
Somite Formation ◽  
Developing Spinal Cord

We have investigated whether the developing spinal cord is intrinsically segmented in its rostrocaudal (anteroposterior) axis by mapping the spread of clones derived from single labelled cells within the neural tube of the chick embryo. A single cell in the ventrolateral neural tube of the trunk was marked in situ with the fluorescent tracer lysinated rhodamine dextran (LRD) and its descendants located after two days of further incubation. We find that clones derived from cells labelled before overt segmentation of the adjacent mesoderm do not respect any boundaries within the neural tube. Those derived from cells marked after mesodermal segmentation, however, never cross an invisible boundary aligned with the middle of each somite, and tend to be elongated along the mediolateral axis of the neural tube. When the somite pattern is surgically disturbed, neighbouring clones derived from neuroectodermal cells labelled after somite formation behave like clones derived from younger cells: they no longer respect any boundaries, and are not elongated mediolaterally. These results indicate that periodic lineage restrictions do exist in the developing spinal cord of the chick embryo, but their maintenance requires the presence of the adjacent somite mesoderm.

scholarly journals Single cell transcriptome profiling of the human developing spinal cord reveals a conserved genetic programme with human specific features

2021 ◽  
Author(s):  
Teresa Rayon ◽  
Rory J. Maizels ◽  
Christopher Barrington ◽  
James Briscoe
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Single Cell ◽  
Motor Neurons ◽  
Neural Tube ◽  
Transcriptome Profiling ◽  
Cell Types ◽  
Human Embryos ◽  
Neuronal Populations ◽  
Cell Transcriptome

AbstractThe spinal cord receives input from peripheral sensory neurons and controls motor output by regulating muscle innervating motor neurons. These functions are carried out by neural circuits comprising molecularly and physiologically distinct neuronal subtypes that are generated in a characteristic spatial-temporal arrangement from progenitors in the embryonic neural tube. The systematic mapping of gene expression in mouse embryos has provided insight into the diversity and complexity of cells in the neural tube. For human embryos, however, less information has been available. To address this, we used single cell mRNA sequencing to profile cervical and thoracic regions in four human embryos of Carnegie Stages (CS) CS12, CS14, CS17 and CS19 from Gestational Weeks (W) 4-7. In total we recovered the transcriptomes of 71,219 cells. Analysis of progenitor and neuronal populations from the neural tube, as well as cells of the peripheral nervous system, in dorsal root ganglia adjacent to the neural tube, identified dozens of distinct cell types and facilitated the reconstruction of the differentiation pathways of specific neuronal subtypes. Comparison with existing mouse datasets revealed the overall similarity of mouse and human neural tube development while highlighting specific features that differed between species. These data provide a catalogue of gene expression and cell type identity in the developing neural tube that will support future studies of sensory and motor control systems and can be explored at https://shiny.crick.ac.uk/scviewer/neuraltube/.

Protein Accumulation in Early Chick Embryos Grown under Different Conditions of Explantation

Development ◽  
1959 ◽  
Vol 7 (1) ◽  
pp. 66-72
Author(s):  
L. Gwen Britt ◽  
Heinz Herrmann
Keyword(s):  
Chick Embryo ◽  
Slow Rate ◽  
The Other ◽  
Protein Accumulation ◽  
Chick Embryos ◽  
Developmental Processes ◽  
Embryonic Tissues ◽  
Somite Formation ◽  
Explanted Chick Embryo

The recent development of techniques originally devised by Waddington (1932) for the maintenance of the explanted chick embryo (Spratt, 1947; New, 1955; Wolff & Simon, 1955) has opened the possibility of determining quantitatively some parameters of the developmental processes occurring in embryonic tissues under these conditions. As a result of such measurements, protein accumulation in explanted embryos was found to be much smaller than in embryos developing in the egg. On the other hand, the progress of somite formation was found to take place at similar rates in embryos developing as explants or in situ (Herrmann & Schultz, 1958). The slow rate of protein accumulation in the explanted embryos made it seem desirable to investigate whether under some other conditions of explantation protein accumulation would approach more closely the rate of protein formation observed in the naturally developing embryo.

The control of rostrocaudal pattern in the developing spinal cord: specification of motor neuron subtype identity is initiated by signals from paraxial mesoderm

Development ◽  
1998 ◽  
Vol 125 (6) ◽  
pp. 969-982 ◽  
Author(s):  
M. Ensini ◽  
T.N. Tsuchida ◽  
H.G. Belting ◽  
T.M. Jessell
Keyword(s):  
Spinal Cord ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Neural Tube ◽  
Motor Behavior ◽  
Neural Tube Closure ◽  
Paraxial Mesoderm ◽  
Homeodomain Protein ◽  
Mesodermal Cell ◽  
Developing Spinal Cord

The generation of distinct classes of motor neurons is an early step in the control of vertebrate motor behavior. To study the interactions that control the generation of motor neuron subclasses in the developing avian spinal cord we performed in vivo grafting studies in which either the neural tube or flanking mesoderm were displaced between thoracic and brachial levels. The positional identity of neural tube cells and motor neuron subtype identity was assessed by Hox and LIM homeodomain protein expression. Our results show that the rostrocaudal identity of neural cells is plastic at the time of neural tube closure and is sensitive to positionally restricted signals from the paraxial mesoderm. Such paraxial mesodermal signals appear to control the rostrocaudal identity of neural tube cells and the columnar subtype identity of motor neurons. These results suggest that the generation of motor neuron subtypes in the developing spinal cord involves the integration of distinct rostrocaudal and dorsoventral patterning signals that derive, respectively, from paraxial and axial mesodermal cell groups.

A morphometric analysis of extracellular space in the developing spinal cord of the chick embryo

1988 ◽  
Vol 455 (2) ◽  
pp. 324-331 ◽  
Author(s):  
Nozomi Sano ◽  
Seiji Matsuda ◽  
Hiroshi Matsuda ◽  
Yasuo Uehara
Keyword(s):  
Spinal Cord ◽  
Chick Embryo ◽  
Morphometric Analysis ◽  
Extracellular Space ◽  
Developing Spinal Cord

scholarly journals FZD10 regulates cell proliferation and mediates Wnt1 induced neurogenesis in the developing spinal cord

2019 ◽  
Author(s):  
Abdulmajeed Fahad Alrefaei ◽  
Andrea E. Münsterberg ◽  
Grant N. Wheeler
Keyword(s):  
Spinal Cord ◽  
Cell Proliferation ◽  
Neural Tube ◽  
Spinal Cord Development ◽  
Dorsal Neural Tube ◽  
Wnt Ligands ◽  
Frizzled Receptors ◽  
Developmental Contexts ◽  
Developing Spinal Cord

AbstractWnt/FZD signalling activity is required for spinal cord development, including the dorsal-ventral patterning of the neural tube, where it affects proliferation and specification of neurons. Wnt ligands initiate canonical, β-catenin-dependent, signaling by binding to Frizzled receptors. However, in many developmental contexts the cognate FZD receptor for a particular Wnt ligand remains to be identified. Here, we characterized FZD10 expression in the dorsal neural tube where it overlaps with both Wnt1 and Wnt3a, as well as markers of dorsal progenitors and interneurons. We show FZD10 expression is sensitive to Wnt1, but not Wnt3a expression, and FZD10 plays a role in neural tube patterning. Knockdown approaches show that Wnt1 induced ventral expansion of dorsal neural markes, Pax6 and Pax7, requires FZD10. In contrast, Wnt3a induced dorsalization of the neural tube is not affected by FZD10 knockdown. Gain of function experiments show that FZD10 is not sufficient on its own to mediate Wnt1 activity in vivo. Indeed excess FZD10 inhibits the dorsalizing activity of Wnt1. However, addition of the Lrp6 co-receptor dramatically enhances the Wnt1/FZD10 mediated activation of dorsal markers. This suggests that the mechanism by which Wnt1 regulates proliferation and patterning in the neural tube requires both FZD10 and Lrp6.

scholarly journals Differentiation and localization of interneurons in the developing spinal cord depends on DOT1L expression

2020 ◽  
Author(s):  
Angelica Gray de Cristoforis ◽  
Francesco Ferrari ◽  
Frédéric Clotman ◽  
Tanja Vogel
Keyword(s):  
Spinal Cord ◽  
Neural Tube ◽  
Transcriptional Activation ◽  
Neural Tube Closure ◽  
Epigenetic Factors ◽  
Late Developmental Stage ◽  
Neural Tube Closure Defect ◽  
H3k79 Methylation ◽  
Tube Closure ◽  
Developing Spinal Cord

Abstract Genetic and epigenetic factors contribute to the development of the spinal cord. Failure in correct exertion of the developmental programs, including neurulation, neural tube closure and neurogenesis of the diverse spinal cord neuronal subtypes results in clinical phenotypes with variable severity. The histone methyltransferase Disruptor of Telomeric 1 Like (DOT1L), which mediates histone H3 lysine 79 (H3K79) methylation, is fundamental for proper development of the cerebral cortex and cerebellum, and here we report on its essential role for development of the spinal cord. Conditional inactivation of DOT1L using Wnt1-cre as driver in the developing murine spinal cord did not result in neural tube closure defect (NTCD). Transcriptome analysis revealed that DOT1L deficiency favored differentiation over progenitor proliferation. Dot1l -cKO mainly decreased the numbers of dI1 interneurons expressing Lhx2 . Loss of DOT1L affected localization but not generation of dI2, dI3, and dI5 interneurons. The resulting derailed interneuron patterns might be responsible for increased cell death that occurred at the late developmental stage E18.5. Together our data indicate that DOT1L is essential for subtype- specific neurogenesis, migration and localization of interneurons in the developing spinal cord, in part by regulating transcriptional activation of Lhx2 .

scholarly journals HoxB genes regulate neuronal delamination in the trunk neural tube by controlling the expression of Lzts1

Development ◽  
2021 ◽  
Vol 148 (4) ◽  
pp. dev195404
Author(s):  
Axelle Wilmerding ◽  
Lucrezia Rinaldi ◽  
Nathalie Caruso ◽  
Laure Lo Re ◽  
Emilie Bonzom ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neural Tube ◽  
Leucine Zipper ◽  
Hox Genes ◽  
Neuronal Diversity ◽  
Loss Of Function ◽  
Mantle Zone ◽  
Hox Proteins ◽  
Additional Function ◽  
Developing Spinal Cord

ABSTRACTDifferential Hox gene expression is central for specification of axial neuronal diversity in the spinal cord. Here, we uncover an additional function of Hox proteins in the developing spinal cord, restricted to B cluster Hox genes. We found that members of the HoxB cluster are expressed in the trunk neural tube of chicken embryo earlier than Hox from the other clusters, with poor antero-posterior axial specificity and with overlapping expression in the intermediate zone (IZ). Gain-of-function experiments of HoxB4, HoxB8 and HoxB9, respectively, representative of anterior, central and posterior HoxB genes, resulted in ectopic progenitor cells in the mantle zone. The search for HoxB8 downstream targets in the early neural tube identified the leucine zipper tumor suppressor 1 gene (Lzts1), the expression of which is also activated by HoxB4 and HoxB9. Gain- and loss-of-function experiments showed that Lzts1, which is expressed endogenously in the IZ, controls neuronal delamination. These data collectively indicate that HoxB genes have a generic function in the developing spinal cord, controlling the expression of Lzts1 and neuronal delamination.

Identification of early developing axon projections from spinal interneurons in the chick embryo with a neuron specific beta-tubulin antibody: evidence for a new ‘pioneer’ pathway in the spinal cord

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 705-716 ◽  
Author(s):  
H. Yaginuma ◽  
T. Shiga ◽  
S. Homma ◽  
R. Ishihara ◽  
R.W. Oppenheim
Keyword(s):  
Spinal Cord ◽  
Chick Embryo ◽  
Neural Tube ◽  
Floor Plate ◽  
C Cells ◽  
Beta Tubulin ◽  
Cell Groups ◽  
Neuronal Processes ◽  
Longitudinal Association ◽  
Chick Spinal Cord

The early development of interneurons in the chick embryo spinal cord was studied using a monoclonal antibody against a neuron-specific beta-tubulin isoform. Early developing interneurons were divided into two cell groups on the basis of their location and the pattern of growth of their axons. One group is composed of cells that establish a primitive longitudinal pathway (PL-cells), whereas the other group contains cells constituting a circumferential pathway (C-cells). The onset of axonal development in both cell groups occurs at stage (st.) 15 (embryonic day, (E), 2) in the branchial segments, which is prior to axonogenesis of motoneurons. PL-cells develop in the region between the floor plate and the motoneuron nucleus. Their axons are the first neuronal processes (‘pioneer axons’) to arrive in the ventrolateral marginal zone and they project both rostrally and caudally to establish a primitive longitudinal association pathway at the ventrolateral surface of the neural tube. This pathway is formed before axons of C-cells arrive in the ventrolateral region. The first C-cells are initially located in the most dorsal portion of the neural tube, whereas later appearing C-cells are also located in both intermediate and ventral regions of the neural tube. The axons of C-cells project ventrally, without fasciculating, along the lateral border of the neural tube. Some of their axons enter the ipsilateral ventrolateral longitudinal pathway at st. 17. We often observed apparent contacts and interactions between preexisting axons of PL-cells and newly arriving axons of C-cells. The axons of commissural C-cells first enter the floor plate at st. 17 and cross the midline at st. 18. Axons of C cells begin to join the contralateral ventrolateral longitudinal pathway at st. 18+ to st. 19. In the floor plate region, contacts between growth cones and axons were often observed. However, axons in the floor plate at these stages were not fasciculated. These observations establish the timing and pattern of growth of axons from two specific populations of early developing interneurons in the chick spinal cord. Additionally, we have identified an early and apparently previously undescribed ‘pioneer’ pathway that constitutes the first longitudinal pathway in the chick spinal cord.

Open brain, a new mouse mutant with severe neural tube defects, shows altered gene expression patterns in the developing spinal cord

Development ◽  
1994 ◽  
Vol 120 (11) ◽  
pp. 3119-3130 ◽  
Author(s):  
T. Gunther ◽  
M. Struwe ◽  
A. Aguzzi ◽  
K. Schughart
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Dorsal Root Ganglia ◽  
Neural Tube ◽  
Dorsal Root ◽  
Expression Patterns ◽  
Axial Skeleton ◽  
Neural Tube Closure ◽  
Primary Defect ◽  
Developing Spinal Cord

We describe a new mouse mutation, designated open brain (opb), which results in severe defects in the developing neural tube. Homozygous opb embryos exhibited an exencephalic malformation involving the forebrain, midbrain and hindbrain regions. The primary defect of the exencephaly could be traced back to a failure to initiate neural tube closure at the midbrain-forebrain boundary. Severe malformations in the spinal cord and dorsal root ganglia were observed in the thoracic region. The spinal cord of opb mutant embryos exhibited an abnormal circular to oval shape and showed defects in both ventral and dorsal regions. In severely affected spinal cord regions, a dorsalmost region of cells negative for Wnt-3a, Msx-2, Pax-3 and Pax-6 gene expression was detected and dorsal expression of Pax-6 was increased. In ventral regions, the area of Shh and HNF-3 beta expression was enlarged and the future motor neuron horns appeared to be reduced in size. These observations indicate that opb embryos exhibit defects in the specification of cells along the dorsoventral axis of the developing spinal cord. Although small dorsal root ganglia were formed in opb mutants, their metameric organization was lost. In addition, defects in eye development and malformations in the axial skeleton and developing limbs were observed. The implications of these findings are discussed in the context of dorsoventral patterning of the developing neural tube and compared with known mouse mutants exhibiting similar defects.

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