Synergy betweenHoxa1andHoxb1: the relationship between arch patterning and the generation of cranial neural crest

Development ◽  
2001 ◽  
Vol 128 (15) ◽  
pp. 3017-3027 ◽  
Author(s):  
Anthony Gavalas ◽  
Paul Trainor ◽  
Linda Ariza-McNaughton ◽  
Robb Krumlauf
Keyword(s):  
Neural Crest ◽  
Double Mutant ◽  
Hox Genes ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Vital Role ◽  
Cranial Neural Crest ◽  
Double Mutation ◽  
Signalling Molecules ◽  
Arch Neural

Hoxa1 and Hoxb1 have overlapping synergistic roles in patterning the hindbrain and cranial neural crest cells. The combination of an ectoderm-specific regulatory mutation in the Hoxb1 locus and the Hoxa1 mutant genetic background results in an ectoderm-specific double mutation, leaving the other germ layers impaired only in Hoxa1 function. This has allowed us to examine neural crest and arch patterning defects that originate exclusively from the neuroepithelium as a result of the simultaneous loss of Hoxa1 and Hoxb1 in this tissue. Using molecular and lineage analysis in this double mutant background we demonstrate that presumptive rhombomere 4, the major site of origin of the second pharyngeal arch neural crest, is reduced in size and has lost the ability to generate neural crest cells. Grafting experiments using wild-type cells in cultured normal or double mutant mouse embryos demonstrate that this is a cell-autonomous defect, suggesting that the formation or generation of cranial neural crest has been uncoupled from segmental identity in these mutants. Furthermore, we show that loss of the second arch neural crest population does not have any adverse consequences on early patterning of the second arch. Signalling molecules are expressed correctly and pharyngeal pouch and epibranchial placode formation are unaffected. There are no signs of excessive cell death or loss of proliferation in the epithelium of the second arch, suggesting that the neural crest cells are not the source of any indispensable mitogenic or survival signals. These results illustrate that Hox genes are not only necessary for proper axial specification of the neural crest but that they also play a vital role in the generation of this population itself. Furthermore, they demonstrate that early patterning of the separate components of the pharyngeal arches can proceed independently of neural crest cell migration.

Fate of the mammalian cranial neural crest during tooth and mandibular morphogenesis

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1671-1679 ◽  
Author(s):  
Y. Chai ◽  
X. Jiang ◽  
Y. Ito ◽  
P. Bringas ◽  
J. Han ◽  
...  
Keyword(s):  
Neural Crest ◽  
Genetic Manipulation ◽  
Cell Lineage ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Genetic System ◽  
Branchial Arch ◽  
Mouse Line ◽  
Cranial Neural Crest ◽  
Two Component

Neural crest cells are multipotential stem cells that contribute extensively to vertebrate development and give rise to various cell and tissue types. Determination of the fate of mammalian neural crest has been inhibited by the lack of appropriate markers. Here, we make use of a two-component genetic system for indelibly marking the progeny of the cranial neural crest during tooth and mandible development. In the first mouse line, Cre recombinase is expressed under the control of the Wnt1 promoter as a transgene. Significantly, Wnt1 transgene expression is limited to the migrating neural crest cells that are derived from the dorsal CNS. The second mouse line, the ROSA26 conditional reporter (R26R), serves as a substrate for the Cre-mediated recombination. Using this two-component genetic system, we have systematically followed the migration and differentiation of the cranial neural crest (CNC) cells from E9.5 to 6 weeks after birth. Our results demonstrate, for the first time, that CNC cells contribute to the formation of condensed dental mesenchyme, dental papilla, odontoblasts, dentine matrix, pulp, cementum, periodontal ligaments, chondrocytes in Meckel's cartilage, mandible, the articulating disc of temporomandibular joint and branchial arch nerve ganglia. More importantly, there is a dynamic distribution of CNC- and non-CNC-derived cells during tooth and mandibular morphogenesis. These results are a first step towards a comprehensive understanding of neural crest cell migration and differentiation during mammalian craniofacial development. Furthermore, this transgenic model also provides a new tool for cell lineage analysis and genetic manipulation of neural-crest-derived components in normal and abnormal embryogenesis.

scholarly journals Connexin 43 impacts the chick premigratory cranial neural crest cell population without affecting the neural crest cell epithelial-to-mesenchymal transition

2019 ◽  
Author(s):  
Karyn Jourdeuil ◽  
Lisa A. Taneyhill
Keyword(s):  
Gap Junctions ◽  
Neural Crest ◽  
Gap Junction ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Cranial Neural Crest ◽  
Mesenchymal Transition ◽  
Junction Protein ◽  
Cranial Neural Crest Cells ◽  
Crest Cell

ABSTRACTGap junctions are intercellular channels that allow for the diffusion of small ions and solutes between coupled cells. Connexin 43 (Cx43), also known as Gap Junction Protein α1, is the most broadly expressed gap junction protein in vertebrate development. Cx43 is strongly expressed in premigratory cranial neural crest cells and is maintained throughout the neural crest cell epithelial-to-mesenchymal transition (EMT), but its function in these cells is not known. To this end, we have used a combination of in vivo and ex vivo live imaging with confocal microscopy, immunohistochemistry, and functional assays to assess gap junction formation, and Cx43 function, in chick premigratory cranial neural crest cells. Our results demonstrate that gap junctions exist between chick premigratory and migratory cranial neural crest cells, with Cx43 depletion inhibiting the function of gap junctions. While a reduction in Cx43 levels just prior to neural crest cell EMT did not affect EMT and subsequent emigration of neural crest cells from the neural tube, the size of the premigratory neural crest cell domain was decreased in the absence of any changes in cell proliferation or death. Collectively, these data identify a role for Cx43 within the chick premigratory cranial neural crest cell population prior to EMT and migration.

5-HT2B receptor-mediated serotonin morphogenetic functions in mouse cranial neural crest and myocardiac cells

Development ◽  
1997 ◽  
Vol 124 (9) ◽  
pp. 1745-1755 ◽  
Author(s):  
D.S. Choi ◽  
S.J. Ward ◽  
N. Messaddeq ◽  
J.M. Launay ◽  
L. Maroteaux
Keyword(s):  
Neural Crest ◽  
Mrna Expression ◽  
Molecular Mechanisms ◽  
In Situ Hybridisation ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Ventricular Myocardium ◽  
Receptor Subtypes ◽  
Cranial Neural Crest ◽  
Receptor Mrna

During embryogenesis, serotonin has been reported to be involved in craniofacial and cardiovascular morphogenesis. The detailed molecular mechanisms underlying these functions, however remain unknown. From mouse and human species, we have recently reported the cloning of 5-HT2B receptors which share signal transduction pathways with other 5-HT2 receptor subtypes (5-HT2A and 5-HT2C). In addition to phospholipase C stimulation, it appears that these three subtypes of receptor transduce a common serotonin-induced mitogenic activity, which could be important for cell differentiation and proliferation. We have first investigated the expression of 5-HT2 receptor mRNAs in the mouse embryo. Interestingly, a peak of 5-HT2B receptor mRNA expression was detected 8–9 days postcoitum, whereas there was only low level 5-HT2A and no 5-HT2C receptor mRNA expression at this stage. Expression of this receptor was confirmed by binding assays using a 5-HT2-specific ligand which revealed a peak of binding to membrane preparations from 9 days postcoitum embryos. In addition, whole mount in situ hybridisation and immunohistochemistry on similar stage embryos detected 5-HT2B expression in neural crest cells, heart myocardium and somites. The requirement for functional 5-HT2B receptors between 8 and 9 days postcoitum is supported by culture of embryos exposed to 5-HT2-specific ligands; 5-HT2B high-affinity antagonist such as ritanserin, induced morphological defects in the cephalic region, heart and neural tube. These antagonistic treatments interfere with cranial neural crest cell migration, induce their apoptosis, and are responsible for abnormal sarcomeric organisation of the subepicardial layer and for the absence of the trabecular cell layer in the ventricular myocardium. This report indicates for the first time that 5-HT2B receptors are actively mediating the action of serotonin on embryonic morphogenesis, probably by preventing the differentiation of cranial neural crest cells and myocardial precursor cells.

Signalling between the hindbrain and paraxial tissues dictates neural crest migration pathways

Development ◽  
2002 ◽  
Vol 129 (2) ◽  
pp. 433-442 ◽  
Author(s):  
Paul A. Trainor ◽  
Dorothy Sobieszczuk ◽  
David Wilkinson ◽  
Robb Krumlauf
Keyword(s):  
Cell Migration ◽  
Neural Crest ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Cranial Neural Crest ◽  
Branchial Arches ◽  
Neural Crest Cell Migration ◽  
And Migration ◽  
Migration Pathways ◽  
Crest Cell

Cranial neural crest cells are a pluripotent population of cells derived from the neural tube that migrate into the branchial arches to generate the distinctive bone, connective tissue and peripheral nervous system components characteristic of the vertebrate head. The highly conserved segmental organisation of the vertebrate hindbrain plays an important role in pattering the pathways of neural crest cell migration and in generating the distinct or separate streams of crest cells that form unique structures in each arch. We have used focal injections of DiI into the developing mouse hindbrain in combination with in vitro whole embryo culture to map the patterns of cranial neural crest cell migration into the developing branchial arches. Our results show that mouse hindbrain-derived neural crest cells migrate in three segregated streams adjacent to the even-numbered rhombomeres into the branchial arches, and each stream contains contributions of cells from three rhombomeres in a pattern very similar to that observed in the chick embryo. There are clear neural crest-free zones adjacent to r3 and r5. Furthermore, using grafting and lineage-tracing techniques in cultured mouse embryos to investigate the differential ability of odd and even-numbered segments to generate neural crest cells, we find that odd and even segments have an intrinsic ability to produce equivalent numbers of neural crest cells. This implies that inter-rhombomeric signalling is less important than combinatorial interactions between the hindbrain and the adjacent arch environment in specific regions, in the process of restricting the generation and migration of neural crest cells. This creates crest-free territories and suggests that tissue interactions established during development and patterning of the branchial arches may set up signals that the neural plate is primed to interpret during the progressive events leading to the delamination and migration of neural crest cells. Using interspecies grafting experiments between mouse and chick embryos, we have shown that this process forms part of a conserved mechanism for generating neural crest-free zones and contributing to the separation of migrating crest populations with distinct Hox expression during vertebrate head development.

scholarly journals Cadherin-6B is proteolytically processed during epithelial-to-mesenchymal transitions of the cranial neural crest

2014 ◽  
Vol 25 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Andrew T. Schiffmacher ◽  
Rangarajan Padmanabhan ◽  
Sharon Jhingory ◽  
Lisa A. Taneyhill
Keyword(s):  
Neural Crest ◽  
Epithelial To Mesenchymal Transition ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Spatiotemporal Pattern ◽  
Cranial Neural Crest ◽  
Mesenchymal Transition ◽  
Crest Cell

The epithelial-to-mesenchymal transition (EMT) is a highly coordinated process underlying both development and disease. Premigratory neural crest cells undergo EMT, migrate away from the neural tube, and differentiate into diverse cell types during vertebrate embryogenesis. Adherens junction disassembly within premigratory neural crest cells is one component of EMT and, in chick cranial neural crest cells, involves cadherin-6B (Cad6B) down-regulation. Whereas Cad6B transcription is repressed by Snail2, the rapid loss of Cad6B protein during EMT is suggestive of posttranslational mechanisms that promote Cad6B turnover. For the first time in vivo, we demonstrate Cad6B proteolysis during neural crest cell EMT, which generates a Cad6B N-terminal fragment (NTF) and two C-terminal fragments (CTF1/2). Coexpression of relevant proteases with Cad6B in vitro shows that a disintegrin and metalloproteinases (ADAMs) ADAM10 and ADAM19, together with γ-secretase, cleave Cad6B to produce the NTF and CTFs previously observed in vivo. Of importance, both ADAMs and γ-secretase are expressed in the appropriate spatiotemporal pattern in vivo to proteolytically process Cad6B. Overexpression or depletion of either ADAM within premigratory neural crest cells prematurely reduces or maintains Cad6B, respectively. Collectively these results suggest a dual mechanism for Cad6B proteolysis involving two ADAMs, along with γ-secretase, during cranial neural crest cell EMT.

scholarly journals The alx3 gene shapes the zebrafish neurocranium by regulating frontonasal neural crest cell differentiation timing

Development ◽  
2021 ◽  
Vol 148 (7) ◽  
Author(s):  
Jennyfer M. Mitchell ◽  
Juliana Sucharov ◽  
Anthony T. Pulvino ◽  
Elliott P. Brooks ◽  
Austin E. Gillen ◽  
...  
Keyword(s):  
Neural Crest ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Developmental Timing ◽  
Cranial Neural Crest ◽  
Different Populations ◽  
Cell Subpopulations ◽  
Cranial Neural Crest Cells ◽  
Discrete Populations ◽  
Crest Cell

ABSTRACT During craniofacial development, different populations of cartilage- and bone-forming cells develop in precise locations in the head. Most of these cells are derived from pluripotent cranial neural crest cells and differentiate with distinct developmental timing and cellular morphologies. The mechanisms that divide neural crest cells into discrete populations are not fully understood. Here, we use single-cell RNA sequencing to transcriptomically define different populations of cranial neural crest cells. We discovered that the gene family encoding the Alx transcription factors is enriched in the frontonasal population of neural crest cells. Genetic mutant analyses indicate that alx3 functions to regulate the distinct differentiation timing and cellular morphologies among frontonasal neural crest cell subpopulations. This study furthers our understanding of how genes controlling developmental timing shape craniofacial skeletal elements.

scholarly journals Cadherin-7 mediates proper neural crest cell-placodal neuron interactions during trigeminal ganglia assembly

2018 ◽  
Author(s):  
Chyong-Yi Wu ◽  
Lisa A. Taneyhill
Keyword(s):  
Neural Crest ◽  
Adherens Junctions ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Trigeminal Ganglia ◽  
Cellular Interactions ◽  
Cranial Neural Crest ◽  
Trigeminal Neurons ◽  
Cranial Neural Crest Cells ◽  
Crest Cell

ABSTRACTThe cranial trigeminal ganglia play a vital role in the peripheral nervous system through their relay of sensory information from the vertebrate head to the brain. These ganglia are generated from the intermixing and coalescence of two distinct cell populations: cranial neural crest cells and placodal neurons. Trigeminal ganglia assembly requires the formation of cadherin-based adherens junctions within the neural crest cell and placodal neuron populations; however, the molecular composition of these adherens junctions is still unknown. Herein, we aimed to define the spatio-temporal expression pattern and function of Cadherin-7 during early chick trigeminal ganglia formation. Our data reveal that Cadherin-7 is expressed exclusively in migratory cranial neural crest cells and is absent from trigeminal neurons. Using molecular perturbation experiments, we demonstrate that modulation of Cadherin-7 in neural crest cells influences trigeminal ganglia assembly, including the organization of neural crest cells and placodal neurons within the ganglionic anlage. Moreover, alterations in Cadherin-7 levels lead to changes in the morphology of trigeminal neurons. Taken together, these findings provide additional insight into the role of cadherin-based adhesion in trigeminal ganglia formation, and, more broadly, the molecular mechanisms that orchestrate the cellular interactions essential for cranial gangliogenesis.

scholarly journals Vital dye analysis of cranial neural crest cell migration in the mouse embryo

Development ◽  
1992 ◽  
Vol 116 (2) ◽  
pp. 297-307 ◽  
Author(s):  
G.N. Serbedzija ◽  
M. Bronner-Fraser ◽  
S.E. Fraser
Keyword(s):  
Cell Migration ◽  
Neural Crest ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Cranial Neural Crest ◽  
Somite Stage ◽  
Cranial Neural Crest Cell ◽  
Neural Crest Cell Migration ◽  
Cranial Neural Crest Cells ◽  
Crest Cell

The spatial and temporal aspects of cranial neural crest cell migration in the mouse are poorly understood because of technical limitations. No reliable cell markers are available and vital staining of embryos in culture has had limited success because they develop normally for only 24 hours. Here, we circumvent these problems by combining vital dye labelling with exo utero embryological techniques. To define better the nature of cranial neural crest cell migration in the mouse embryo, premigratory cranial neural crest cells were labelled by injecting DiI into the amniotic cavity on embryonic day 8. Embryos, allowed to develop an additional 1 to 5 days exo utero in the mother before analysis, showed distinct and characteristic patterns of cranial neural crest cell migration at the different axial levels. Neural crest cells arising at the level of the forebrain migrated ventrally in a contiguous stream through the mesenchyme between the eye and the diencephalon. In the region of the midbrain, the cells migrated ventrolaterally as dispersed cells through the mesenchyme bordered by the lateral surface of the mesencephalon and the ectoderm. At the level of the hindbrain, neural crest cells migrated ventrolaterally in three subectodermal streams that were segmentally distributed. Each stream extended from the dorsal portion of the neural tube into the distal portion of the adjacent branchial arch. The order in which cranial neural crest cells populate their derivatives was determined by labelling embryos at different stages of development. Cranial neural crest cells populated their derivatives in a ventral-to-dorsal order, similar to the pattern observed at trunk levels. In order to confirm and extend the findings obtained with exo utero embryos, DiI (1,1-dioctadecyl-3,3,3′,3′-tetramethylindo-carbocyanine perchlorate) was applied focally to the neural folds of embryos, which were then cultured for 24 hours. Because the culture technique permitted increased control of the timing and location of the DiI injection, it was possible to determine the duration of cranial neural crest cell emigration from the neural tube. Cranial neural crest cell emigration from the neural folds was completed by the 11-somite stage in the region of the rostral hindbrain, the 14-somite stage in the regions of the midbrain and caudal hindbrain and not until the 16-somite stage in the region of the forebrain. At each level, the time between the earliest and latest neural crest cells to emigrate from the neural tube appeared to be 9 hours.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Segmental migration of the hindbrain neural crest does not arise from its segmental generation

Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 691-703 ◽  
Author(s):  
J. Sechrist ◽  
G.N. Serbedzija ◽  
T. Scherson ◽  
S.E. Fraser ◽  
M. Bronner-Fraser
Keyword(s):  
Neural Crest ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Otic Vesicle ◽  
Cranial Neural Crest ◽  
Extrinsic Factors ◽  
Axial Patterning ◽  
Neural Crest Cell Migration ◽  
Neural Crest Migration ◽  
Crest Cell

The proposed pathways of chick cranial neural crest migration and their relationship to the rhombomeres of the hindbrain have been somewhat controversial, with differing results emerging from grafting and DiI-labelling analyses. To resolve this discrepancy, we have examined cranial neural crest migratory pathways using the combination of neurofilament immunocytochemistry, which recognizes early hindbrain neural crest cells, and labelling with the vital dye, DiI. Neurofilament-positive cells with the appearance of premigratory and early-migrating neural crest cells were noted at all axial levels of the hindbrain. At slightly later stages, neural crest cell migration in this region appeared segmented, with no neural crest cells obvious in the mesenchyme lateral to rhombomere 3 (r3) and between the neural tube and the otic vesicle lateral to r5. Focal injections of DiI at the levels of r3 and r5 demonstrated that both of these rhombomeres generated neural crest cells. The segmental distribution of neural crest cells resulted from the DiI-labelled cells that originated in r3 and r5 deviating rostrally or caudally and failing to enter the adjacent preotic mesoderm or otic vesicle region. The observation that neural crest cells originating from r3 and r5 avoided specific neighboring domains raises the intriguing possibility that, as in the trunk, extrinsic factors play a major role in the axial patterning of the cranial neural crest and the neural crest-derived peripheral nervous system.

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