Sequence of events in neural tube closure and the formation of neural crest in the chick embryo

1967 ◽  
Vol 68 (1) ◽  
pp. 127-146 ◽  
Author(s):  
G. di Virgilio ◽  
N. Lavenda ◽  
J.L. Worden
Keyword(s):  
Chick Embryo ◽  
Neural Crest ◽  
Neural Tube ◽  
Neural Tube Closure ◽  
Sequence Of Events ◽  
Tube Closure

Choanal Atresia

1995 ◽  
Vol 16 (12) ◽  
pp. 475-476
Author(s):  
Lisa Menasse-Palmer ◽  
Anna Bogdanow ◽  
Robert W. Marion
Keyword(s):  
Soft Tissue ◽  
Neural Crest ◽  
Neural Tube ◽  
Choanal Atresia ◽  
Neural Tube Closure ◽  
Nasal Airway ◽  
Complete Obstruction ◽  
Live Births ◽  
Choanal Stenosis ◽  
Tube Closure

Choanal atresia is an abnormality of canalization during development of the nasal passages. It involves bone and/or soft tissue and may result in either partial (choanal stenosis) or complete obstruction of the posterior nasal airway. The most widely accepted mechanism for the development of choanal atresia is the persistence of the oronasal membrane beyond the sixth week of gestation, but abnormal migration of cephalic neural crest cells following neural tube closure also has been implicated. The incidence of choanal atresia is 1 in 7000 to 8000 live births. It is more common in females (2:1), more likely to be bony or cartilaginous than membranous (9:1), and more commonly unilateral and right-sided (2:1).

scholarly journals Effects of Shh and Noggin on neural crest formation demonstrate that BMP is required in the neural tube but not ectoderm

Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 4919-4930 ◽  
Author(s):  
M.A. Selleck ◽  
M.I. Garcia-Castro ◽  
K.B. Artinger ◽  
M. Bronner-Fraser
Keyword(s):  
Neural Crest ◽  
Sonic Hedgehog ◽  
Neural Tube ◽  
Neural Crest Cells ◽  
Neural Plate ◽  
Bmp Signaling ◽  
Neural Tube Closure ◽  
Dorsal Neural Tube ◽  
Neural Ectoderm ◽  
Tube Closure

To define the timing of neural crest formation, we challenged the fate of presumptive neural crest cells by grafting notochords, Sonic Hedgehog- (Shh) or Noggin-secreting cells at different stages of neurulation in chick embryos. Notochords or Shh-secreting cells are able to prevent neural crest formation at open neural plate levels, as assayed by DiI-labeling and expression of the transcription factor, Slug, suggesting that neural crest cells are not committed to their fate at this time. In contrast, the BMP signaling antagonist, Noggin, does not repress neural crest formation at the open neural plate stage, but does so if injected into the lumen of the closing neural tube. The period of Noggin sensitivity corresponds to the time when BMPs are expressed in the dorsal neural tube but are down-regulated in the non-neural ectoderm. To confirm the timing of neural crest formation, Shh or Noggin were added to neural folds at defined times in culture. Shh inhibits neural crest production at early stages (0-5 hours in culture), whereas Noggin exerts an effect on neural crest production only later (5-10 hours in culture). Our results suggest three phases of neurulation that relate to neural crest formation: (1) an initial BMP-independent phase that can be prevented by Shh-mediated signals from the notochord; (2) an intermediate BMP-dependent phase around the time of neural tube closure, when BMP-4 is expressed in the dorsal neural tube; and (3) a later pre-migratory phase which is refractory to exogenous Shh and Noggin.

Immunohistochemical localisation of chondroitin sulphate proteoglycans and the effects of chondroitinase ABC in 9- to 11-day rat embryos

Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 787-798
Author(s):  
G. Morriss-Kay ◽  
F. Tuckett
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Chondroitin Sulphate ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Neural Tube Closure ◽  
Chondroitinase Abc ◽  
Rat Embryos ◽  
Crest Cell ◽  
Tube Closure

Studies on cell behaviour in vitro have indicated that the chondroitin sulphate proteoglycan (CSPG) family of molecules can participate in the control of cell proliferation, differentiation and adhesion, but its morphogenetic functions had not been investigated in intact embryos. Chondroitin/chondroitin sulphates have been identified in rat embryos at low levels at the start of neurulation (day 9) and at much higher levels on day 10. In this study we have sought evidence for the morphogenetic functions of CSPGs in rat embryos during the period of neurulation and neural crest cell migration by a combination of two approaches: immunocytochemical localization of CSPG by means of an antibody, CS-56, to the chondroitin sulphate component of CSPG, and exposure of embryos to the enzyme chondroitinase ABC. Staining of the CS-56 epitope was poor at the beginning of cranial neurulation; bright staining was at first confined to the primary mesenchyme under the convex neural folds late on day 9. In day 10 embryos, all mesenchyme cells were stained, but at different levels of intensity, so that primary mesenchyme, neural crest and sclerotomal cells could be distinguished from each other. Basement membranes were also stained, particularly bright staining being present where two epithelial were basally apposed, e.g., neural/surface ectoderms, dorsal aorta/neural tube, prior to migration of a population of cells between them. Staining within the neural epithelium was first confined to the dorsolateral edge region, and associated with the onset of neural crest cell emigration; after neural tube closure, neuroepithelial staining was more general. Neural crest cells were stained during migration, but the reaction was absent in areas associated with migration end-points (trigeminal ganglion anlagen, frontonasal mesenchyme). Embryos exposed to chondroitinase ABC in culture showed no abnormalities until early day 10, when cranial neural crest cell emigration from the neural epithelium was inhibited and neural tube closure was retarded. Sclerotomal cells failed to take their normal pathway between the dorsal aorta and neural tube. Correlation of the results of these two methods suggests: (1) that by decreasing adhesiveness within the neural epithelium at specific stages, CSPG facilitates the emigration of neural crest cells and the migratory movement of neuroblasts, and may also provide increased flexibility during the generation of epithelial curvatures; (2) that by decreasing the adhesiveness of fibronectin-containing extracellular matrices, CSPG facilitates the migration of neural crest and sclerotomal cells. This second function is particularly important when migrating cells take pathways between previously apposed tissues.

Transgenic rescue of congenital heart disease and spina bifida in Splotch mice

Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2495-2503 ◽  
Author(s):  
J. Li ◽  
K.C. Liu ◽  
F. Jin ◽  
M.M. Lu ◽  
J.A. Epstein
Keyword(s):  
Transgenic Mice ◽  
Neural Crest ◽  
Neural Tube ◽  
Muscle Development ◽  
Cardiac Development ◽  
Transcriptional Start Site ◽  
Neural Crest Cells ◽  
Regulatory Elements ◽  
Neural Tube Closure ◽  
Tube Closure

Pax3-deficient Splotch mice display neural tube defects and an array of neural crest related abnormalities including defects in the cardiac outflow tract, dorsal root ganglia and pigmentation. Pax3 is expressed in neural crest cells that emerge from the dorsal neural tube. Pax3 is also expressed in the somites, through which neural crest cells migrate, where it is required for hypaxial muscle development. Homozygous mutant Splotch embryos die by embryonic day 14. We have utilized the proximal 1.6 kb Pax3 promoter and upstream regulatory elements to engineer transgenic mice reproducing endogenous Pax3 expression in neural tube and neural crest, but not the somite. Over expression of Pax3 in these tissues reveals no discernible phenotype. Breeding of transgenic mice onto a Splotch background demonstrates that neural tube and neural crest expression of Pax3 is sufficient to rescue neural tube closure, cardiac development and other neural crest related defects. Transgenic Splotch mice survive until birth at which time they succumb to respiratory failure secondary to absence of a muscular diaphragm. Limb muscles are also absent. These results indicate that regulatory elements sufficient for functional expression of Pax3 required for cardiac development and neural tube closure are contained within the region 1.6 kb upstream of the Pax3 transcriptional start site. In addition, the single Pax3 isoform used for this transgene is sufficient to execute these developmental processes. Although the extracellular matrix and the environment of the somites through which neural crest migrates is known to influence neural crest behavior, our results indicate that Pax3-deficient somites are capable of supporting proper neural crest migration and function suggesting a cell autonomous role for Pax3 in neural crest.

scholarly journals Neurogenesis permissive chromatin in neural crest cells as novel epigenetic marks during mouse neural tube closure

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Shunsuke Ichi ◽  
Yueh‐Wei Shen ◽  
Hiromichi Nakazaki ◽  
Sidanth Sapru ◽  
Barbara Mania‐Farnell ◽  
...  
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Neural Crest Cells ◽  
Neural Tube Closure ◽  
Epigenetic Marks ◽  
Tube Closure
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