scholarly journals Secondary neurulation: Fate-mapping and gene manipulation of the neural tube in tail bud

2011 ◽  
Vol 53 (3) ◽  
pp. 401-410 ◽  
Author(s):  
Eisuke Shimokita ◽  
Yoshiko Takahashi
Keyword(s):  
Neural Tube ◽  
Fate Mapping ◽  
Tail Bud ◽  
Gene Manipulation ◽  
Secondary Neurulation

scholarly journals Secondary neurulation-fated cells in the tail bud undergo self-renewal and tubulogenesis regulated by a Sox2 gradient

2018 ◽  
Author(s):  
Teruaki Kawachi ◽  
Eisuke Shimokita ◽  
Ryosuke Tadokoro ◽  
Yoshiko Takahashi
Keyword(s):  
Neural Tube ◽  
Cell Labeling ◽  
Tail Bud ◽  
Self Renewal ◽  
Expression Levels ◽  
Secondary Neurulation ◽  
Mesenchymal To Epithelial Transition ◽  
Direct Cell ◽  
Posterior Elongation ◽  
Critical Structure

AbstractDuring amniote development, anterior and posterior components of the neural tube form by primary neurulation (PN) and secondary neurulation (SN), respectively. Unlike PN, SN proceeds by the mesenchymal-to-epithelial transition of SN precursors in the tail bud, a critical structure for the axial elongation. Our direct cell labeling delineates non-overlapping territories of SN- and mesodermal precursors in the chicken tail bud. SN-fated precursors are further divided into self-renewing and differentiating cells, a decision regulated by graded expression levels of Sox2. Whereas Sox2 is confined to SN precursors, Brachyury (T) is widely and uniformly distributed in the tail bud, indicating that Sox2+/Brachyury+ cells are neural-fated and not mesodermal. These results uncover multiple steps during the neural posterior elongation, including precocious segregation of SN precursors, their self-renewal, and regulation by graded Sox 2.

Comparative remarks on the development of the tail cord among higher vertebrates

Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 355-363
Author(s):  
A. F. Hughes ◽  
R. B. Freeman
Keyword(s):  
Neural Tube ◽  
Tail Bud ◽  
Caudal Region ◽  
Posterior Neuropore ◽  
Irregular Growth

The development of the caudal region of the neural tube is compared in tailed mammals with that of the chick and human. In rat, mouse, opossum and pig, the lumen of the cord extends caudally in an even manner, whereas in the chick and in man the addition of small cavities to the lumen results in a phase of irregular growth. In mammals with unreduced tails, the site of closure of the posterior neuropore is at the tip of the tail, whereas in pig, man and in the chick closure occurs before the formation of the tail-bud. The teratological implications of these findings are discussed.

Genesis and prevention of spinal neural tube defects in the curly tail mutant mouse: involvement of retinoic acid and its nuclear receptors RAR-beta and RAR-gamma

Development ◽  
1995 ◽  
Vol 121 (3) ◽  
pp. 681-691
Author(s):  
W.H. Chen ◽  
G.M. Morriss-Kay ◽  
A.J. Copp
Keyword(s):  
Retinoic Acid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
In Situ Hybridisation ◽  
Tail Bud ◽  
Retinoic Acid Signalling ◽  
All Trans Retinoic Acid ◽  
Posterior Neuropore ◽  
Computerised Image Analysis ◽  
Curly Tail

A role for all-trans-retinoic acid in spinal neurulation is suggested by: (1) the reciprocal domains of expression of the retinoic acid receptors RAR-beta and RAR-gamma in the region of the closed neural tube and open posterior neuropore, respectively, and (2) the preventive effect of maternally administered retinoic acid (5 mg/kg) on spinal neural tube defects in curly tail (ct/ct) mice. Using in situ hybridisation and computerised image analysis we show here that in ct/ct embryos, RAR-beta transcripts are deficient in the hindgut endoderm, a tissue whose proliferation rate is abnormal in the ct mutant, and RAR-gamma transcripts are deficient in the tail bud and posterior neuropore region. The degree of deficiency of RAR-gamma transcripts is correlated with the severity of delay of posterior neuropore closure. As early as 2 hours following RA treatment at 10 days 8 hours post coitum, i.e. well before any morphogenetic effects are detectable, RAR-beta expression is specifically upregulated in the hindgut endoderm, and the abnormal expression pattern of RAR-gamma is also altered. These results suggest that the spinal neural tube defects which characterise the curly tail phenotype may be due to interaction between the ct gene product and one or more aspects of the retinoic acid signalling pathway.

Retained Medullary Cord in Humans: Late Arrest of Secondary Neurulation

Neurosurgery ◽  
2011 ◽  
Vol 68 (6) ◽  
pp. 1500-1519 ◽  
Author(s):  
Dachling Pang ◽  
John Zovickian ◽  
Greg S. Moes
Keyword(s):  
Spinal Cord ◽  
Cell Mass ◽  
Tethered Cord ◽  
Underlying Mechanism ◽  
Neurological Deficits ◽  
Tail Bud ◽  
Neural Structure ◽  
Nerve Roots ◽  
Secondary Neurulation ◽  
Caudal Spinal Cord

Abstract BACKGROUND: Formation of the caudal spinal cord in vertebrates is by secondary neurulation, which begins with mesenchyme-epithelium transformation within a pluripotential blastema called the tail bud or caudal cell mass, from thence initiating an event sequence proceeding from the condensation of mesenchyme into a solid medullary cord, intrachordal lumen formation, to eventual partial degeneration of the cavitatory medullary cord until, in human and tailless mammals, only the conus and filum remain. OBJECTIVE: We describe a secondary neurulation malformation probably representing an undegenerated medullary cord that causes tethered cord symptoms. METHOD: We present 7 patients with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac, complete with issuing nerve roots, which, except in 2 infants, produced neurological deficits by tethering. RESULTS: Intraoperative motor root and direct cord stimulation indicated that a large portion of this stout neural structure was “redundant” nonfunctional spinal cord below the true conus. Histopathology of the redundant cord resected at surgery showed a glioneuronal core with ependyma-lined lumen, nerve roots, and dorsal root ganglia, corroborating the picture of a blighted spinal cord. CONCLUSION: We propose that these redundant spinal cords are portions of the medullary cord normally destined to regress but are here retained because of late arrest of secondary neurulation before the degenerative phase. Because programmed cell death almost certainly plays a central role during degeneration, defective apoptosis may be the underlying mechanism.

scholarly journals On The Existence of Regionally Specific Evocators

1952 ◽  
Vol 29 (3) ◽  
pp. 490-495
Author(s):  
C. H. WADDINGTON
Keyword(s):  
Cross Section ◽  
Neural Tube ◽  
Direct Action ◽  
Specific Effect ◽  
Neural Tissue ◽  
Neural Plate ◽  
Normal Embryo ◽  
Tail Bud ◽  
The Brain ◽  
Brain Parts

1. Pieces of the embryonic axis, taken from the anterior and posterior regions of embryos from the open neural plate to the late tail-bud stages which had been coagulated by a few seconds' immersion in water at 90°C, were inserted into flaps of gastrula ectoderm which were then cultivated in Holtfreter solution. No induction of mesoderm occurred, but neural tissue was evoked in a high percentage of cases. 2. In early stages the neural tissue usually formed a more or less chaotic tangle of tubes and rods. At later stages it assumed a variety of forms, some of which were similar to parts of the brain, and such brain-parts might be accompanied by secondary structures such as eyes, nasal pits, ears, etc. No elongated tubes resembling the trunk neural tube were seen, although certain neural vesicles may have a cross-section very like that of the neural tube. 3. The induction of recognizable brain or eye was not uncommon when anterior implants were used, but was not seen at all with posterior implants. There was no other difference between the two sets of experiments. 4. It is suggested that the appearance of such organs is not due to the direct action of a regionally specific inducing factor, but rather that all such definite forms arise by a process of self-individuation which occurs within the induced mass of neural tissue. The direction this self-individuation takes, and thus the nature of the organ finally formed, is supposed to depend on chance resemblances between the mass and shape of parts of the original chaotic mass and some part of the normal embryo. It is argued that this could account for the apparently specific effect of the anterior implants. 5. In other experiments in which mesodermal tissues are also induced (e.g. with implants of adult tissues) it is likely that these take part in the self-individuation processes and tend to direct these towards the formation of posterior organs such as trunk and tail.

scholarly journals Axis elongation during Xenopus tail-bud stage is regulated by GABA expressed in the anterior-to-mid neural tube

2019 ◽  
Vol 63 (1-2) ◽  
pp. 37-43 ◽  
Author(s):  
Tomoyo Furukawa ◽  
Yuki Yamasaki ◽  
Yusuke Hara ◽  
Chisa Otsuki ◽  
Hiroko Maki ◽  
...  
Keyword(s):  
Neural Tube ◽  
Gaba Receptors ◽  
Early Stage ◽  
Specific Inhibitor ◽  
Early Embryogenesis ◽  
Ligand Molecule ◽  
Metabolome Analysis ◽  
Tail Bud ◽  
Axis Elongation ◽  
Stimulation Of

The receptors of gamma-aminobutyric acid (GABA), which is a well-known neurotransmitter, are expressed in the anterior-to-mid neural tube at an early stage of Xenopus development, but there has been no report on the role of GABA in the presumptive central nervous system. Therefore, we tried to reveal the function of GABA for Xenopus early embryogenesis. We first confirmed that the region expressing a gene encoding glutamate decarboxylase 1 (gad1), which is an enzyme that catalyzes the decarboxylation of L-glutamate to GABA, overlapped with that of several genes encoding GABA receptors (gabr) in the neural tube. Metabolome analysis of culture medium of dorsal tail-bud explants containing the neural tube region of tail-bud stage embryos also revealed that GABA was expressed at this stage. Then, we examined the treatment of pentylenetetrazole (PTZ) and picrotoxin (PTX), which are known as inhibitors of GABA receptors (GABA-R), on the early stages of Xenopus embryogenesis, and found that axis elongation in the tail-bud was inhibited by both treatments, and these phenotypic effects were rescued by co-treatment with GABA. Moreover, our spatial- and temporal-specific inhibitor treatments revealed that the gabr- and gad1-overlapped region, which presents at the anterior-to-mid neural tube during the tail-bud stages, was much more sensitive to PTZ and thus caused severe inhibition of axis elongation. Taken together, our results indicate that the small ligand molecule GABA functions as a regulator to induce the axis elongation event in the tail-bud during early embryogenesis via direct stimulation of the neural tube and indirect stimulation of the surrounding area.

Somite formation in cultured embryos of the snapping turtle, Chelydra serpentina

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 113-130
Author(s):  
David S. Packard
Keyword(s):  
Neural Tube ◽  
In Vitro Cultivation ◽  
Slight Variation ◽  
Chelydra Serpentina ◽  
Tail Bud ◽  
Snapping Turtle ◽  
Wide Range ◽  
Somite Formation ◽  
Full Complement

A simple, reliable method for the in vitro cultivation of snapping turtle embryos was demonstrated. This technique was used to study somite formation in explants containing segmental plates. Segmental plates formed a full complement of somites whether the neural tube or the neural tube and notochord was present. Explanted snapping turtle segmental plates formed an average of 6·6 ± 1·2 somites. Removal of the node region or tail bud from cultured intact embryos led to a cessation of somite formation after an additional 6·1 ± 1·8 somites had formed. These results indicate the number of somites the snapping turtle segmental plate will form. Also, the number of somites formed by explanted segmental plates showed only slight variation over a wide range of segmental plate lengths. It was concluded that while snapping turtle segmental plates formed significantly fewer somites than chicken or Japanese quail segmental plates, they were similar to the avian explants in their ability to form a consistent number of somites regardless of the length of the segmental plate.

The Mode of Growth of the Tail in Urodele Larvae

Development ◽  
1958 ◽  
Vol 6 (3) ◽  
pp. 466-478
Author(s):  
J. Hubertha Bijtel
Keyword(s):  
Spinal Cord ◽  
Neural Tube ◽  
Cell Mass ◽  
Vital Staining ◽  
Neural Plate ◽  
Tail Bud ◽  
Morphogenetic Movements ◽  
Separate Cell ◽  
A Cell ◽  
Axial Organs

The idea that the hinder part of the trunk together with the tail or the tail alone develops by the outgrowth of a cell mass which is in every respect indifferent has been disproved since 1928 for the Amphibia. The results of experiments with vital staining (Bijtel & Woerdeman, 1928; Bijtel, 1929, 1931) and with microsurgical methods (Bijtel, 1936) have shown that the presumptive rudiments of the tail organs (epidermis, spinal cord, muscle segments, tail-gut) are already present in the neural plate stage as more or less separate cell territories. During and immediately after the transformation of the neural plate into the neural tube, these cell territories are brought together into the tail-bud by morphogenetic movements. Holmdahl (1939 a, b, 1947) and Vogt (1939) have criticized this conception. They adhered to the view that the organs of the hinder part of the runk and of the tail (Holmdahl) or only the axial organs of the tail (Vogt, p. 127) originate from an indifferent blastema.

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