Ultrastructural and tissue-culture studies on the role of fibronectin, collagen and glycosaminoglycans in the migration of neural crest cells in the fowl embryo

1982 ◽  
Vol 221 (3) ◽  
Author(s):  
D.F. Newgreen ◽  
I.L. Gibbins ◽  
J. Sauter ◽  
B. Wallenfels ◽  
R. W�tz
Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 525-538 ◽  
Author(s):  
M.A. Selleck ◽  
M. Bronner-Fraser

We have investigated the lineage and tissue interactions that result in avian neural crest cell formation from the ectoderm. Presumptive neural plate was grafted adjacent to non-neural ectoderm in whole embryo culture to examine the role of tissue interactions in ontogeny of the neural crest. Our results show that juxtaposition of non-neural ectoderm and presumptive neural plate induces the formation of neural crest cells. Quail/chick recombinations demonstrate that both the prospective neural plate and the prospective epidermis can contribute to the neural crest. When similar neural plate/epidermal confrontations are performed in tissue culture to look at the formation of neural crest derivatives, juxtaposition of epidermis with either early (stages 4–5) or later (stages 6–10) neural plate results in the generation of both melanocytes and sympathoadrenal cells. Interestingly, neural plates isolated from early stages form no neural crest cells, whereas those isolated later give rise to melanocytes but not crest-derived sympathoadrenal cells. Single cell lineage analysis was performed to determine the time at which the neural crest lineage diverges from the epidermal lineage and to elucidate the timing of neural plate/epidermis interactions during normal development. Our results from stage 8 to 10+ embryos show that the neural plate/neural crest lineage segregates from the epidermis around the time of neural tube closure, suggesting that neural induction is still underway at open neural plate stages.


2002 ◽  
Vol 159 (5) ◽  
pp. 867-880 ◽  
Author(s):  
Lisette Hari ◽  
Véronique Brault ◽  
Maurice Kléber ◽  
Hye-Youn Lee ◽  
Fabian Ille ◽  
...  

β-Catenin plays a pivotal role in cadherin-mediated cell adhesion. Moreover, it is a downstream signaling component of Wnt that controls multiple developmental processes such as cell proliferation, apoptosis, and fate decisions. To study the role of β-catenin in neural crest development, we used the Cre/loxP system to ablate β-catenin specifically in neural crest stem cells. Although several neural crest–derived structures develop normally, mutant animals lack melanocytes and dorsal root ganglia (DRG). In vivo and in vitro analyses revealed that mutant neural crest cells emigrate but fail to generate an early wave of sensory neurogenesis that is normally marked by the transcription factor neurogenin (ngn) 2. This indicates a role of β-catenin in premigratory or early migratory neural crest and points to heterogeneity of neural crest cells at the earliest stages of crest development. In addition, migratory neural crest cells lateral to the neural tube do not aggregate to form DRG and are unable to produce a later wave of sensory neurogenesis usually marked by the transcription factor ngn1. We propose that the requirement of β-catenin for the specification of melanocytes and sensory neuronal lineages reflects roles of β-catenin both in Wnt signaling and in mediating cell–cell interactions.


Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2963-2971 ◽  
Author(s):  
S. Nakagawa ◽  
M. Takeichi

During the emergence of neural crest cells from the neural tube, the expression of cadherins dynamically changes. In the chicken embryo, the early neural tube expresses two cadherins, N-cadherin and cadherin-6B (cad6B), in the dorsal-most region where neural crest cells are generated. The expression of these two cadherins is, however, downregulated in the neural crest cells migrating from the neural tube; they instead begin expressing cadherin-7 (cad7). As an attempt to investigate the role of these changes in cadherin expression, we overexpressed various cadherin constructs, including N-cadherin, cad7, and a dominant negative N-cadherin (cN390), in neural crest-generating cells. This was achieved by injecting adenoviral expression vectors encoding these molecules into the lumen of the closing neural tube of chicken embryos at stage 14. In neural tubes injected with the viruses, efficient infection was observed at the neural crest-forming area, resulting in the ectopic cadherin expression also in migrating neural crest cells. Notably, the distribution of neural crest cells with the ectopic cadherins changed depending on which constructs were expressed. Many crest cells failed to escape from the neural tube when N-cadherin or cad7 was overexpressed. Moreover, none of the cells with these ectopic cadherins migrated along the dorsolateral (melanocyte) pathway. When these samples were stained for Mitf, an early melanocyte marker, positive cells were found accumulated within the neural tube, suggesting that the failure of their migration was not due to differentiation defects. In contrast to these phenomena, cells expressing non-functional cadherins exhibited a normal migration pattern. Thus, the overexpression of a neuroepithelial cadherin (N-cadherin) and a crest cadherin (cad7) resulted in the same blocking effect on neural crest segregation from neuroepithelial cells, especially for melanocyte precursors. These findings suggest that the regulation of cadherin expression or its activity at the neural crest-forming area plays a critical role in neural crest emigration from the neural tube.


2015 ◽  
Vol 26 (5) ◽  
pp. 978-992 ◽  
Author(s):  
Guang Wang ◽  
Yan Li ◽  
Xiao-Yu Wang ◽  
Manli Chuai ◽  
John Yeuk-Hon Chan ◽  
...  

This is the first study of the role of BRE in embryonic development using early chick embryos. BRE is expressed in the developing neural tube, neural crest cells, and somites. BRE thus plays an important role in regulating neurogenesis and indirectly somitogenesis during early chick embryo development.


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