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Marianne Bronner-fraser - One of the best experts on this subject based on the ideXlab platform.
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Neural Crest Formation and Diversification
Neural Development and Stem Cells, 2012Co-Authors: Marcos Simões-costa, Houman D. Hemmati, Tanya A. Moreno, Marianne Bronner-fraserAbstract:The Neural Crest is a multipotent embryonic cell population that migrates throughout the embryo and differentiates into a variety of derivatives. Formation of Neural Crest begins at gastrulation and continues throughout neurulation. Bona fide Neural Crest cells then emerge from the Neural tube after its closure and commence migration to many, destinations. During early induction stages, the cells of the Neural plate border are exposed to different environment signals originated from the adjacent tissues. Such signals are responsible for the activation of a gene regulatory network that controls Neural Crest formation. This regulatory network comprises transcription factors and signaling molecules arranged hierarchically and acts to endow these cells with the ability to delaminate, migrate, and differentiate. This chapter is an overview of the molecular mechanisms underlying Neural Crest induction, specification, and migration.
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MANIPULATIONS OF Neural Crest CELLS OR THEIR MIGRATORY PATHWAYS
Methods in cell biology, 2008Co-Authors: Marianne Bronner-fraser, Martín I. García-castroAbstract:This chapter discusses techniques for the isolation, induction, and identification of Neural Crest cells in tissue culture as well as various manipulations of Neural Crest cells and some of the tissues with which they interact in the embryo. The formation of the embryo involves intricate cell movements, cell proliferation, and differentiation. The Neural Crest has long served as a model for the study of these processes because Neural Crest cells undergo extensive migrations and give rise to many diverse derivatives. Neural Crest cells arise from the dorsal portion of the Neural tube. Several unique properties of these cells make the Neural Crest an ideal system for studying cell migration and differentiation. First, these cells migrate extensively along characteristic pathways. Second, they give rise to diverse and numerous derivatives, ranging from pigment cells and cranial cartilage to adrenal chromaffin cells and the ganglia of the peripheral nervous system. Third, the characteristic position of premigratory Neural Crest cells within the dorsal portion of the Neural tube makes them accessible to surgical and molecular manipulations during initial stages in their development. The methods described in this chapter provide a number of techniques that can be applied to the study of Neural Crest specification, migration, and differentiation.
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Recycling signals in the Neural Crest
Journal of Biology, 2006Co-Authors: Lisa A Taneyhill, Marianne Bronner-fraserAbstract:Vertebrate Neural Crest cells are multipotent and differentiate into structures that include cartilage and the bones of the face, as well as much of the peripheral nervous system. Understanding how different model vertebrates utilize signaling pathways reiteratively during various stages of Neural Crest formation and differentiation lends insight into human disorders associated with the Neural Crest.
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Neural Crest inducing signals.
Advances in experimental medicine and biology, 2006Co-Authors: Martin L. Basch, Marianne Bronner-fraserAbstract:The formation of the Neural Crest has been traditionally considered a classic example of secondary induction, where signals form one tissue elicit a response in a competent responding tissue. Interactions of the Neural plate with paraxial mesoderm or nonNeural ectoderm can generate Neural Crest. Several signaling pathways converge at the border between Neural and nonNeural ectoderm where the Neural Crest will form. Among the molecules identified in this process are members of the BMP, Wnt, FGF and Notch signaling pathways. The concerted action of these nals and their downstream targets will define the identity of the Neural Crest.
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Early steps in Neural Crest specification.
Seminars in cell & developmental biology, 2005Co-Authors: Meyer Barembaum, Marianne Bronner-fraserAbstract:The Neural Crest is a multipotent cell population that arise at the border of the Neural plate and non-Neural ectoderm. Studies conducted in a number of model organisms including chickens, frogs, zebrafish and mice have been instrumental in elucidating this molecular mechanisms underlying Neural Crest formation. Signaling molecules of the Wnt, BMP, and FGF families and their downstream effectors have been shown to mediate Neural Crest induction. Transcription factors including members of the Snail and SoxE gene families as well as FoxD3, c-Myc and others have been implicated in specification of the Neural Crest. These studies represent an important step in understanding the regulatory interactions involved in generating this complex and interesting cell type.
Laura S. Gammill - One of the best experts on this subject based on the ideXlab platform.
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Cytoplasmic protein methylation is essential for Neural Crest migration
The Journal of cell biology, 2013Co-Authors: Katie L. Vermillion, Kevin A. Lidberg, Laura S. GammillAbstract:As they initiate migration in vertebrate embryos, Neural Crest cells are enriched for methylation cycle enzymes, including S-adenosylhomocysteine hydrolase (SAHH), the only known enzyme to hydrolyze the feedback inhibitor of trans-methylation reactions. The importance of methylation in Neural Crest migration is unknown. Here, we show that SAHH is required for emigration of polarized Neural Crest cells, indicating that methylation is essential for Neural Crest migration. Although nuclear histone methylation regulates Neural Crest gene expression, SAHH and lysine-methylated proteins are abundant in the cytoplasm of migratory Neural Crest cells. Proteomic profiling of cytoplasmic, lysine-methylated proteins from migratory Neural Crest cells identified 182 proteins, several of which are cytoskeleton related. A methylation-resistant form of one of these proteins, the actin-binding protein elongation factor 1 alpha 1 (EF1α1), blocks Neural Crest migration. Altogether, these data reveal a novel and essential role for post-translational nonhistone protein methylation during Neural Crest migration and define a previously unknown requirement for EF1α1 methylation in migration.
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DNA Methyltransferase 3b Is Dispensable for Mouse Neural Crest Development
PloS one, 2012Co-Authors: Bridget T. Jacques-fricke, Julaine Roffers-agarwal, Laura S. GammillAbstract:The Neural Crest is a population of multipotent cells that migrates extensively throughout vertebrate embryos to form diverse structures. Mice mutant for the de novo DNA methyltransferase DNMT3b exhibit defects in two Neural Crest derivatives, the craniofacial skeleton and cardiac ventricular septum, suggesting that DNMT3b activity is necessary for Neural Crest development. Nevertheless, the requirement for DNMT3b specifically in Neural Crest cells, as opposed to interacting cell types, has not been determined. Using a conditional DNMT3b allele crossed to the Neural Crest cre drivers Wnt1-cre and Sox10-cre, Neural Crest DNMT3b mutants were generated. In both Neural Crest-specific and fully DNMT3b-mutant embryos, cranial Neural Crest cells exhibited only subtle migration defects, with increased numbers of dispersed cells trailing organized streams in the head. In spite of this, the resulting cranial ganglia, craniofacial skeleton, and heart developed normally when Neural Crest cells lacked DNMT3b. This indicates that DNTM3b is not necessary in cranial Neural Crest cells for their development. We conclude that defects in Neural Crest derivatives in DNMT3b mutant mice reflect a requirement for DNMT3b in lineages such as the branchial arch mesendoderm or the cardiac mesoderm that interact with Neural Crest cells during formation of these structures.
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Division of labor during trunk Neural Crest development
Developmental biology, 2010Co-Authors: Laura S. Gammill, Julaine Roffers-agarwalAbstract:Neural Crest cells, the migratory precursors of numerous cell types including the vertebrate peripheral nervous system, arise in the dorsal Neural tube and follow prescribed routes into the embryonic periphery. While the timing and location of Neural Crest migratory pathways has been well documented in the trunk, a comprehensive collection of signals that guides Neural Crest migration along these paths has only recently been established. In this review, we outline the molecular cascade of events during trunk Neural Crest development. After describing the sequential routes taken by trunk Neural Crest cells, we consider the guidance cues that pattern these Neural Crest trajectories. We pay particular attention to segmental Neural Crest development and the steps and signals that generate a metameric peripheral nervous system, attempting to reconcile conflicting observations in chick and mouse. Finally, we compare cranial and trunk Neural Crest development in order to highlight common themes.
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Neural Crest specification: migrating into genomics
Nature Reviews Neuroscience, 2003Co-Authors: Laura S. Gammill, Marianne Bronner-fraserAbstract:The bones in your face, the pigment in your skin and the Neural circuitry that controls your digestive tract have one thing in common: they are all derived from Neural Crest cells. The formation of these migratory multipotent cells poses an interesting developmental problem, as Neural Crest cells are not a distinct cell type until they migrate away from the central nervous system. What defines the pool of cells with Neural Crest potential, and why do only some of these cells become migratory? New genomic approaches in chick, zebrafish and Xenopus might hold the key. Neural Crest cells migrate from the Neural tube to colonize the far reaches of the embryo, where they form peripheral neurons, glia, connective tissue, bone, secretory cells and the outflow tract of the heart. This article provides an overview of early Neural Crest development, and discusses how genomic techniques are helping us to understand this process at the genetic level. During neurulation, the Neural plate border bends to form the Neural folds, which become the dorsal aspect of the Neural tube. Depending on the organism and the axial level, Neural Crest cells initiate migration from the closing Neural folds or the dorsal Neural tube. Although the Neural folds are viewed as 'premigratory' Neural Crest, only a fraction of these cells will actually migrate. Wnt proteins, bone morphogenetic proteins (BMPs) and fibroblast growth factors (FGFs) mimic the tissue interactions that induce Neural Crest. The main Neural Crest-inducing signal from the non-Neural ectoderm seems to be a Wnt protein, although the Wnts, BMPs and FGFs might have different roles in Neural Crest induction and maintenance in different species. Less is known about the events downstream of the signals that induce Neural Crest, although a growing list of genes has been found to be necessary and/or sufficient to initiate Neural Crest development. This list includes epidermal, Neural and Neural Crest markers. The relationships between these genes are not clear. Many Neural Crest genes stimulate proliferation and prevent differentiation ( Zic genes, Pax3 , c-Myc , Ap2 , Msx1 and Msx2 , Id2 , Notch1 and Twist ) or maintain stem cell potential ( Foxd3 and Sox10 ). They include genes for transcriptional repressors (Slug/Snail, Zic1, Msx1 and Msx2, Nbx and Id2) and activators (Sox9 and Sox10, Pax3, c-Myc, Ap2 and Notch1). Genomic level screens could potentially identify all the genes that are involved in early Neural Crest development, which could then be assembled into functional networks. In chick and Xenopus , it is possible to combine powerful array technologies with experimental embryology, and equally enticing is the intersection of genetics, transgenics and genomics in zebrafish.
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Genomic analysis of Neural Crest induction.
Development (Cambridge England), 2002Co-Authors: Laura S. Gammill, Marianne Bronner-fraserAbstract:The vertebrate Neural Crest is a migratory stem cell population that arises within the central nervous system. Here, we combine embryological techniques with array technology to describe 83 genes that provide the first gene expression profile of a newly induced Neural Crest cell. This profile contains numerous novel markers of Neural Crest precursors and reveals previously unrecognized similarities between Neural Crest cells and endothelial cells, another migratory cell population. We have performed a secondary screen using in situ hybridization that allows us to extract temporal information and reconstruct the progression of Neural Crest gene expression as these cells become different from their neighbors and migrate. Our results reveal a sequential `migration activation' process that reflects stages in the transition to a migratory Neural Crest cell and suggests that migratory potential is established in a pool of cells from which a subset are activated to migrate.
Maya Sieber-blum - One of the best experts on this subject based on the ideXlab platform.
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Cardiac Neural Crest stem cells
The anatomical record. Part A Discoveries in molecular cellular and evolutionary biology, 2004Co-Authors: Maya Sieber-blumAbstract:Whereas the heart itself is of mesodermal origin, components of the cardiac outflow tract are formed by the Neural Crest, an ectodermal derivative that gives rise to the peripheral nervous system, endocrine cells, melanocytes of the skin and internal organs, and connective tissue, bone, and cartilage of the face and ventral neck, among other tissues. Cardiac Neural Crest cells participate in the septation of the cardiac outflow tract into aorta and pulmonary artery. The migratory cardiac Neural Crest consists of stem cells, fate-restricted cells, and cells that are committed to the smooth muscle cell lineage. During their migration within the posterior branchial arches, the developmental potentials of pluripotent Neural Crest cells become restricted. Conversely, Neural Crest stem cells persist at many locations, including in the cardiac outflow tract. Many aspects of Neural Crest cell differentiation are driven by growth factor action. Neurotrophin-3 (NT-3) and its preferred receptor, TrkC, play important roles not only in nervous system development and function, but also in cardiac development as deletion of these genes causes outflow tract malformations. In vitro clonal analysis has shown a premature commitment of cardiac Neural Crest stem cells in TrkC null mice and a perturbed morphology of the endothelial tube. Norepinephrine transporter (NET) function promotes the differentiation of Neural Crest stem cells into noradrenergic neurons. Surprisingly, many diverse nonneuronal embryonic tissues, in particular in the cardiovascular system, express NET also. It will be of interest to determine whether norepinephrine transport plays a role also in cardiovascular development.
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Neural Crest origin of mammalian Merkel cells.
Developmental biology, 2003Co-Authors: Viktor Szeder, Zdenek Halata, Milos Grim, Maya Sieber-blumAbstract:Here, we provide evidence for the Neural Crest origin of mammalian Merkel cells. Together with nerve terminals, Merkel cells form slowly adapting cutaneous mechanoreceptors that transduce steady indentation in hairy and glabrous skin. We have determined the ontogenetic origin of Merkel cells in Wnt1-cre/R26R compound transgenic mice, in which Neural Crest cells are marked indelibly. Merkel cells in whiskers and interfollicular locations express the transgene, beta-galactosidase, identifying them as Neural Crest descendants. We thus conclude that murine Merkel cells originate from the Neural Crest.
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Mammalian Merkel Cells Are Neural Crest Derivatives
The Merkel Cell, 2003Co-Authors: Maya Sieber-blum, Viktor Szeder, Milos Grim, Zdenek HalataAbstract:We provide evidence for the Neural Crest origin of mammalian Merkel cells. Neural Crest cells originate in the Neural folds during early development of the vertebrate embryo. They delaminate from the dorsal aspect of the forming Neural tube and emigrate to different locations, giving rise to a diverse array of structures in the adult organism. The dorsal Neural tube, including Neural Crest cells, transiently express the protein, Wnt-1. This feature can be used to genetically mark Neural Crest cells and their derivatives. We have thus used the double transgenic Wntl -cre/R26R mouse to determine the ontogenetic origin of mammalian Merkel cells. Merkel cells in the hair follicle epithelium of the whisker pad, interfollicular Merkel cells in touch domes and Merkel cells in the rete ridge express the Neural Crest-specific transgene, s-galactosidase. Our data thus indicate that mammalian Merkel cells are derived from the Neural Crest, resolving a long-standing controversy. Moreover, they suggest that Merkel cell carcinomas are not epithelial tumors, but belong to the neurocristopathies.
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THE Neural Crest AND Neural Crest DEFECTS
Biomedical Reviews, 2002Co-Authors: Maya Sieber-blum, Zhi-jian ZhangAbstract:The Neural Crest is a fascinating embryonic tissue for more than one reason. In the adult organism it gives rise to an array of distinct cell types and tissues. It is responsible for many birth defects, familial diseases and malignancies, and it is amenable to the elucidation of mechanisms that regulate stem cell differentiation. Subsequent to an epithelial-to-mesenchymal transformation, Neural Crest cells emigrate from the dorsal aspect of the Neural tube into the embryo, stop in different places, and eventually give rise to the autonomic and enteric nervous systems, most primary sensory neurons, endocrine cells, and melanocytes of the skin and internal organs. Furthermore, Neural Crest cells are involved in the septation of the cardiac outflow tract and they form the cranial mesenchyme, which gives rise to bone, cartilage, and connective tissue of the face and ventral neck. Environmental insults can lead to Neural Crest defects, including cleft lip/cleft palate and fetal alcohol syndrome. Familial diseases that affect Neural Crest derivatives include Hischsprung's disease and albinism, whereas well-known Neural Crest-related malignancies include melanoma, neuroblastoma, neurofibromatosis and pheochromocytoma. Migratory Neural Crest cells form a heterogeneous population of cells that includes stem cells, cells with restricted developmental potentials, and cells that are committed to a particular lineage. Growth factors play important roles in the survival, proliferation and differentiation of Neural Crest cells. In particular, neurotrophin-3 (NTS), the ligand of the tyrosine kinase receptor, TrkC, promotes the survival of proliferating Neural Crest stem cells. TrkC-deficient mice develop cardiac outflow tract defects that resemble human birth defects, including persistent truncus arteriosus and transposition of the great vessels. In these animals, cardiac Neural Crest stem cells become fate-restricted precociously. Action of stem cell factor (SCF), the ligand of the tyrosine kinase receptor c-kit, affects multiple systems. Heterozygous c-kit deficient mice, termed 'Dominant spotting' (W), have anemia, are sterile and show changes in coat color (white spotting) due to defects in the hemopoietic system, germ cell line and melanogenesis, respectively. Inactivation of the human c-kit gene causes piebaldism, which is characterized by a white forelock, patchy hypopigmentation of the skin and rare sensoryNeural deafness. In the quail Neural Crest, SCF supports the survival of Neural Crest stem cells, promotes their differentiation into small diameter sensory neurons, and, together with a neurotrophin, supports survival of me lanocyte precursors. In c-kit deficient newborn mice, up to one third of substance P-immunoreactive nociceptive sensory neurons are missing, thus confirming across species that SCF signaling is essential for the development of small diameter sensory neurons. In addition, the number of calcitonin gene-related-peptide (CGRP)-immunoreactive putative visceral afferent neurons in the dorsal root ganglion is diminished in these mice. The norepinephrine transporter (NET) is expressed in many embryonic tissues, including premigratory and migratory Neural Crest cells. Norepinephrine (NE) uptake by Neural Crest cells promotes their differentiation into noradrenergic neuroblasts in vitro. In contrast, NE uptake inhibitors, such as tricyclic antidepressants and the drug of abuse, cocaine, inhibit noradrenergic differentiation in vitro and in vivo, suggesting that these drugs can be teratogenic. Since NET is expressed in many embryonic tissues, NE transport may have functions also in non-Neural cells during embryonic development. In summary, growth factors, alone and synergistically as well as NEplay multiple roles in Neural Crest development. Biomedical Reviews 2002; 13: 29-37.
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Factors controlling lineage specification in the Neural Crest.
International review of cytology, 2000Co-Authors: Maya Sieber-blumAbstract:The Neural Crest is a transitory tissue of the vertebrate embryo that originates in the Neural folds, populates the embryo, and gives rise to many different cell types and tissues of the adult organism. When Neural Crest cells initiate their migration, a large fraction of them are still pluripotent, that is, capable of generating progeny that consists of two or more distinct phenotypes. To elucidate the cellular and molecular mechanisms by which Neural Crest cells become committed to a particular lineage is therefore crucial to the understanding of Neural Crest development and represents a major challenge in current Neural Crest research. This chapter discusses selected aspects of Neural Crest cell differentiation into components of the peripheral nervous system. Topics include sympathetic neurons, the adrenal medulla, primary sensory neurons of the spinal ganglia, some of their mechanoreceptive and proprioceptive end organs, and the enteric nervous system.
Viktor Szeder - One of the best experts on this subject based on the ideXlab platform.
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Neural Crest origin of mammalian Merkel cells.
Developmental biology, 2003Co-Authors: Viktor Szeder, Zdenek Halata, Milos Grim, Maya Sieber-blumAbstract:Here, we provide evidence for the Neural Crest origin of mammalian Merkel cells. Together with nerve terminals, Merkel cells form slowly adapting cutaneous mechanoreceptors that transduce steady indentation in hairy and glabrous skin. We have determined the ontogenetic origin of Merkel cells in Wnt1-cre/R26R compound transgenic mice, in which Neural Crest cells are marked indelibly. Merkel cells in whiskers and interfollicular locations express the transgene, beta-galactosidase, identifying them as Neural Crest descendants. We thus conclude that murine Merkel cells originate from the Neural Crest.
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Mammalian Merkel Cells Are Neural Crest Derivatives
The Merkel Cell, 2003Co-Authors: Maya Sieber-blum, Viktor Szeder, Milos Grim, Zdenek HalataAbstract:We provide evidence for the Neural Crest origin of mammalian Merkel cells. Neural Crest cells originate in the Neural folds during early development of the vertebrate embryo. They delaminate from the dorsal aspect of the forming Neural tube and emigrate to different locations, giving rise to a diverse array of structures in the adult organism. The dorsal Neural tube, including Neural Crest cells, transiently express the protein, Wnt-1. This feature can be used to genetically mark Neural Crest cells and their derivatives. We have thus used the double transgenic Wntl -cre/R26R mouse to determine the ontogenetic origin of mammalian Merkel cells. Merkel cells in the hair follicle epithelium of the whisker pad, interfollicular Merkel cells in touch domes and Merkel cells in the rete ridge express the Neural Crest-specific transgene, s-galactosidase. Our data thus indicate that mammalian Merkel cells are derived from the Neural Crest, resolving a long-standing controversy. Moreover, they suggest that Merkel cell carcinomas are not epithelial tumors, but belong to the neurocristopathies.
Roberto Mayor - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms of Neural Crest Migration
Annual review of genetics, 2018Co-Authors: András Szabó, Roberto MayorAbstract:Neural Crest cells are a transient embryonic cell population that migrate collectively to various locations throughout the embryo to contribute a number of cell types to several organs. After induction, the Neural Crest delaminates and undergoes an epithelial-to-mesenchymal transition before migrating through intricate yet characteristic paths. The Neural Crest exhibits a variety of migratory behaviors ranging from sheet-like mass migration in the cephalic regions to chain migration in the trunk. During their journey, Neural Crest cells rely on a range of signals both from their environment and within the migrating population for navigating through the embryo as a collective. Here we review these interactions and mechanisms, including chemotactic cues of Neural Crest cells' migration.
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Neural Crest Determination and Migration
Principles of Developmental Genetics, 2015Co-Authors: Eric Theveneau, Roberto MayorAbstract:The Neural Crest is induced at the border of the Neural plate by signals that come from the epidermis, the Neural plate, and the underlying mesoderm. Two kinds of signals are required to induce the Neural Crest: an intermediate level of bone morphogenetic protein (BMP) activity and a second signal involving Wnt, fibroblast growth factors (FGF) and retinoic acid (RA). After the Neural Crest has induced, its separation from the surrounding tissues involves an epithelial-mesenchymal transition which is controlled by a network of transcription factors. Neural Crest cells migrate following stereotypical routes that are defined by the availability of permissive extracellular matrix, complementary distribution of negative and positive guidance cues, and cell-cell interactions. Neural Crest cells undergo solitary and collective cell migration. Anterior and posterior Neural Crest gives rise to very different kinds of cells, tissues, and organs. Failure during Neural Crest development is associated with several human pathologies.
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Wnt11r Is Required for Cranial Neural Crest Migration
Developmental dynamics : an official publication of the American Association of Anatomists, 2008Co-Authors: Helen K. Matthews, Florence Broders-bondon, Jean Paul Thiery, Roberto MayorAbstract:wnt11r is a recently identified member of the Wnt family of genes, which has been proposed to be the true Xenopus homologue to the mammalian wnt11 gene. In this study we have examined the role of wnt11r on Neural Crest development. Expression analysis of wnt11r and comparison with the Neural Crest marker snail2 and the noncanonical Wnt, wnt11, shows wnt11r is expressed at the medial or Neural plate side of the Neural Crest while wnt11 is expressed at the lateral or epidermal side. Injection of wnt11r morpholino leads to strong inhibition of Neural Crest migration with no effect on Neural Crest induction or maintenance. This effect can be rescued by co-injection of Wnt11r but not by Wnt11 mRNA, demonstrating the specificity of the loss of function treatment. Finally, Neural Crest graft experiments show that wnt11r is required in a non-cell-autonomous manner to control Neural Crest migration.
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Induction and development of Neural Crest in Xenopus laevis.
Cell and tissue research, 2001Co-Authors: Roberto Mayor, Manuel J. AybarAbstract:Neural Crest cells are a migratory embryonic cell population that form at the border between the Neural plate and the future epidermis. This border, the Neural plate border, corresponds to the Neural fold. The Neural fold surrounds the entire Neural plate, but only the lateral and posterior portions of the fold give rise to Neural Crest cells, while the anterior Neural fold differentiates as forebrain. This review focuses on Neural Crest development in Xenopus laevis embryos, and analyzes aspects of the induction of the Neural Crest in Xenopus, summarizing available information relating to the expression of several genes in the Neural Crest. Two models for Neural Crest induction are discussed. In the first model, the Neural Crest is induced by the interaction between the Neural plate and the epidermis. In the second, the specification of the Neural plate border arises as a consequence of a gradient of BMP activity. The role of posteriorizing signals on Neural Crest specification is also discussed. Finally, we propose that the specification and differentiation of the Neural Crest is controlled by a cascade of transcription factors, encoded and expressed from a hierarchy of genes. A set of extracellular signals establishes the positional information in the ectoderm, which activates Prepattern genes (Gli, Xiro, Zic, Dlx, etc.) across extended and overlapping domains. A local combination of these genes at the Neural plate border activates the cascade of Neural Crest specification, while different sets of genes are activated at both sides of the Neural folds (in the epidermis and the Neural plate). The genes activated in regions adjacent to the Neural plate border have an inhibitory effect on the Neural Crest transcription program.
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Development of Neural Crest in Xenopus.
Current topics in developmental biology, 1999Co-Authors: Roberto Mayor, Rodrigo M. Young, Alexander O. VargasAbstract:Publisher Summary This chapter discusses a number of different aspects of the Neural Crest development in amphibia, particularly in Xenopus , because of the detailed knowledge of the cellular and molecular aspects of its early development. The chapter discusses the knowledge generated in amphibia since the turn of the century, following the methods, used by experimental embryologists in their attempts not only to establish the structures that originate from the Neural Crest but also to study its properties. The Neural Crest is a unique cell population among embryonic cell types, displaying the properties of both ectodermal and mesodermal lineages. Most of the recent studies, examining the Neural Crest, have been performed in avian embryos. The route of migration and fate of the Neural Crest are described and a new model of Neural Crest induction, in which prospective cells are induced independently of the Neural plate, by a double gradient of a morphogen that patterns the entire ectoderm, is also discussed in the chapter. This model is also discussed in a more general context in connection with the dorsoventral patterning of the Neural tube. Finally, the chapter discusses some ideas concerning the Neural Crest evolution and a novel hypothesis about its phylogenetic origin.
