scholarly journals Cell Fate Decisions in the Neural Crest, from Pigment Cell to Neural Development

2021 ◽  
Vol 22 (24) ◽  
pp. 13531
Author(s):  
Jonathan H. P. Dawes ◽  
Robert N. Kelsh

The neural crest shows an astonishing multipotency, generating multiple neural derivatives, but also pigment cells, skeletogenic and other cell types. The question of how this process is controlled has been the subject of an ongoing debate for more than 35 years. Based upon new observations of zebrafish pigment cell development, we have recently proposed a novel, dynamic model that we believe goes some way to resolving the controversy. Here, we will firstly summarize the traditional models and the conflicts between them, before outlining our novel model. We will also examine our recent dynamic modelling studies, looking at how these reveal behaviors compatible with the biology proposed. We will then outline some of the implications of our model, looking at how it might modify our views of the processes of fate specification, differentiation, and commitment.

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hyo Sik Jang ◽  
Yujie Chen ◽  
Jiaxin Ge ◽  
Alicia N. Wilkening ◽  
Yiran Hou ◽  
...  

Abstract Background Zebrafish pigment cell differentiation provides an attractive model for studying cell fate progression as a neural crest progenitor engenders diverse cell types, including two morphologically distinct pigment cells: black melanophores and reflective iridophores. Nontrivial classical genetic and transcriptomic approaches have revealed essential molecular mechanisms and gene regulatory circuits that drive neural crest-derived cell fate decisions. However, how the epigenetic landscape contributes to pigment cell differentiation, especially in the context of iridophore cell fate, is poorly understood. Results We chart the global changes in the epigenetic landscape, including DNA methylation and chromatin accessibility, during neural crest differentiation into melanophores and iridophores to identify epigenetic determinants shaping cell type-specific gene expression. Motif enrichment in the epigenetically dynamic regions reveals putative transcription factors that might be responsible for driving pigment cell identity. Through this effort, in the relatively uncharacterized iridophores, we validate alx4a as a necessary and sufficient transcription factor for iridophore differentiation and present evidence on alx4a’s potential regulatory role in guanine synthesis pathway. Conclusions Pigment cell fate is marked by substantial DNA demethylation events coupled with dynamic chromatin accessibility to potentiate gene regulation through cis-regulatory control. Here, we provide a multi-omic resource for neural crest differentiation into melanophores and iridophores. This work led to the discovery and validation of iridophore-specific alx4a transcription factor.


Development ◽  
1999 ◽  
Vol 126 (17) ◽  
pp. 3757-3767 ◽  
Author(s):  
J.A. Lister ◽  
C.P. Robertson ◽  
T. Lepage ◽  
S.L. Johnson ◽  
D.W. Raible

We report the isolation and identification of a new mutation affecting pigment cell fate in the zebrafish neural crest. Homozygous nacre (nac(w2)) mutants lack melanophores throughout development but have increased numbers of iridophores. The non-crest-derived retinal pigment epithelium is normal, suggesting that the mutation does not affect pigment synthesis per se. Expression of early melanoblast markers is absent in nacre mutants and transplant experiments suggested a cell-autonomous function in melanophores. We show that nac(w2) is a mutation in a zebrafish gene encoding a basic helix-loop-helix/leucine zipper transcription factor related to microphthalmia (Mitf), a gene known to be required for development of eye and crest pigment cells in the mouse. Transient expression of the wild-type nacre gene restored melanophore development in nacre(−/−) embryos. Furthermore, misexpression of nacre induced the formation of ectopic melanized cells and caused defects in eye development in wild-type and mutant embryos. These results demonstrate that melanophore development in fish and mammals shares a dependence on the nacre/Mitf transcription factor, but that proper development of the retinal pigment epithelium in the fish is not nacre-dependent, suggesting an evolutionary divergence in the function of this gene.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Lauren M Saunders ◽  
Abhishek K Mishra ◽  
Andrew J Aman ◽  
Victor M Lewis ◽  
Matthew B Toomey ◽  
...  

Thyroid hormone (TH) regulates diverse developmental events and can drive disparate cellular outcomes. In zebrafish, TH has opposite effects on neural crest derived pigment cells of the adult stripe pattern, limiting melanophore population expansion, yet increasing yellow/orange xanthophore numbers. To learn how TH elicits seemingly opposite responses in cells having a common embryological origin, we analyzed individual transcriptomes from thousands of neural crest-derived cells, reconstructed developmental trajectories, identified pigment cell-lineage specific responses to TH, and assessed roles for TH receptors. We show that TH promotes maturation of both cell types but in distinct ways. In melanophores, TH drives terminal differentiation, limiting final cell numbers. In xanthophores, TH promotes accumulation of orange carotenoids, making the cells visible. TH receptors act primarily to repress these programs when TH is limiting. Our findings show how a single endocrine factor integrates very different cellular activities during the generation of adult form.


Science ◽  
2019 ◽  
Vol 364 (6444) ◽  
pp. eaas9536 ◽  
Author(s):  
Ruslan Soldatov ◽  
Marketa Kaucka ◽  
Maria Eleni Kastriti ◽  
Julian Petersen ◽  
Tatiana Chontorotzea ◽  
...  

Neural crest cells are embryonic progenitors that generate numerous cell types in vertebrates. With single-cell analysis, we show that mouse trunk neural crest cells become biased toward neuronal lineages when they delaminate from the neural tube, whereas cranial neural crest cells acquire ectomesenchyme potential dependent on activation of the transcription factor Twist1. The choices that neural crest cells make to become sensory, glial, autonomic, or mesenchymal cells can be formalized as a series of sequential binary decisions. Each branch of the decision tree involves initial coactivation of bipotential properties followed by gradual shifts toward commitment. Competing fate programs are coactivated before cells acquire fate-specific phenotypic traits. Determination of a specific fate is achieved by increased synchronization of relevant programs and concurrent repression of competing fate programs.


Author(s):  
Karolina Punovuori ◽  
Mattias Malaguti ◽  
Sally Lowell

AbstractDuring early neural development, changes in signalling inform the expression of transcription factors that in turn instruct changes in cell identity. At the same time, switches in adhesion molecule expression result in cellular rearrangements that define the morphology of the emerging neural tube. It is becoming increasingly clear that these two processes influence each other; adhesion molecules do not simply operate downstream of or in parallel with changes in cell identity but rather actively feed into cell fate decisions. Why are differentiation and adhesion so tightly linked? It is now over 60 years since Conrad Waddington noted the remarkable "Constancy of the Wild Type” (Waddington in Nature 183: 1654–1655, 1959) yet we still do not fully understand the mechanisms that make development so reproducible. Conversely, we do not understand why directed differentiation of cells in a dish is sometimes unpredictable and difficult to control. It has long been suggested that cells make decisions as 'local cooperatives' rather than as individuals (Gurdon in Nature 336: 772–774, 1988; Lander in Cell 144: 955–969, 2011). Given that the cadherin family of adhesion molecules can simultaneously influence morphogenesis and signalling, it is tempting to speculate that they may help coordinate cell fate decisions between neighbouring cells in the embryo to ensure fidelity of patterning, and that the uncoupling of these processes in a culture dish might underlie some of the problems with controlling cell fate decisions ex-vivo. Here we review the expression and function of cadherins during early neural development and discuss how and why they might modulate signalling and differentiation as neural tissues are formed.


2021 ◽  
Vol 7 (1) ◽  
pp. 37
Author(s):  
Mohammad N. Qasim ◽  
Ashley Valle Arevalo ◽  
Clarissa J. Nobile ◽  
Aaron D. Hernday

Candida albicans, a diploid polymorphic fungus, has evolved a unique heritable epigenetic program that enables reversible phenotypic switching between two cell types, referred to as “white” and “opaque”. These cell types are established and maintained by distinct transcriptional programs that lead to differences in metabolic preferences, mating competencies, cellular morphologies, responses to environmental signals, interactions with the host innate immune system, and expression of approximately 20% of genes in the genome. Transcription factors (defined as sequence specific DNA-binding proteins) that regulate the establishment and heritable maintenance of the white and opaque cell types have been a primary focus of investigation in the field; however, other factors that impact chromatin accessibility, such as histone modifying enzymes, chromatin remodelers, and histone chaperone complexes, also modulate the dynamics of the white-opaque switch and have been much less studied to date. Overall, the white-opaque switch represents an attractive and relatively “simple” model system for understanding the logic and regulatory mechanisms by which heritable cell fate decisions are determined in higher eukaryotes. Here we review recent discoveries on the roles of chromatin accessibility in regulating the C. albicans white-opaque phenotypic switch.


Author(s):  
Gemma Sutton ◽  
Robert N. Kelsh ◽  
Steffen Scholpp

The neural crest (NC) is a multipotent cell population in vertebrate embryos with extraordinary migratory capacity. The NC is crucial for vertebrate development and forms a myriad of cell derivatives throughout the body, including pigment cells, neuronal cells of the peripheral nervous system, cardiomyocytes and skeletogenic cells in craniofacial tissue. NC induction occurs at the end of gastrulation when the multipotent population of NC progenitors emerges in the ectodermal germ layer in the neural plate border region. In the process of NC fate specification, fate-specific markers are expressed in multipotent progenitors, which subsequently adopt a specific fate. Thus, NC cells delaminate from the neural plate border and migrate extensively throughout the embryo until they differentiate into various cell derivatives. Multiple signalling pathways regulate the processes of NC induction and specification. This review explores the ongoing role of the Wnt/β-catenin signalling pathway during NC development, focusing on research undertaken in the Teleost model organism, zebrafish (Danio rerio). We discuss the function of the Wnt/β-catenin signalling pathway in inducing the NC within the neural plate border and the specification of melanocytes from the NC. The current understanding of NC development suggests a continual role of Wnt/β-catenin signalling in activating and maintaining the gene regulatory network during NC induction and pigment cell specification. We relate this to emerging models and hypotheses on NC fate restriction. Finally, we highlight the ongoing challenges facing NC research, current gaps in knowledge, and this field’s potential future directions.


2019 ◽  
Author(s):  
Alec K. Gramann ◽  
Arvind M. Venkatesan ◽  
Melissa Guerin ◽  
Craig J. Ceol

AbstractPreventing terminal differentiation is important in the development and progression of many cancers including melanoma. Recent identification of the BMP ligand GDF6 as a novel melanoma oncogene showed GDF6-activated BMP signaling suppresses differentiation of melanoma cells. Previous studies have identified roles for GDF6 orthologs during early embryonic and neural crest development, but have not identified direct regulation of melanocyte development by GDF6. Here, we investigate the BMP ligand gdf6a, a zebrafish ortholog of human GDF6, during the development of melanocytes from the neural crest. We establish that the loss of gdf6a or inhibition of BMP signaling during neural crest development disrupts normal pigment cell development, leading to an increase in the number of melanocytes and a corresponding decrease in iridophores, another neural crest-derived pigment cell type in zebrafish. This shift occurs as pigment cells arise from the neural crest and depends on mitfa, an ortholog of MITF, a key regulator of melanocyte development that is also targeted by oncogenic BMP signaling. Together, these results indicate that the oncogenic role ligand-dependent BMP signaling plays in suppressing differentiation in melanoma is a reiteration of its physiological roles during melanocyte development.


Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 301-305 ◽  
Author(s):  
A. Baroffio ◽  
E. Dupin ◽  
N.M. Le Douarin

The cephalic neural crest (NC) of vertebrate embryos yields a variety of cell types belonging to the neuronal, glial, melanocytic and mesectodermal lineages. Using clonal cultures of quail migrating cephalic NC cells, we demonstrated that neurons and glial cells of the peripheral nervous system can originate from the same progenitors as cartilage, one of the mesectodermal derivatives of the NC. Moreover, we obtained evidence that the migrating cephalic NC contains a few highly multipotent precursors that are common to neurons, glia, cartilage and pigment cells and which we interprete as representative of a stem cell population. In contrast, other NC cells, although provided with identical culture conditions, give rise to clones composed of only one or some of these cell types. These cells thus appear restricted in their developmental potentialities compared to multipotent cells. It is therefore proposed that, in vivo, the active proliferation of pluripotent NC cells during the migration process generates distinct subpopulations of cells that become progressively committed to different developmental fates.


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