scholarly journals ALKALs are in vivo ligands for ALK family Receptor Tyrosine Kinases in the neural crest and derived cells

2017 ◽  
Author(s):  
Andrey Fadeev ◽  
Patricia Mendoza Garcia ◽  
Uwe Irion ◽  
Jikui Guan ◽  
Kathrin Pfeifer ◽  
...  

AbstractMutations in Anaplastic Lymphoma Kinase (ALK) are implicated in somatic and familial neuroblastoma, a paediatric tumour of neural crest-derived tissues. Recently, biochemical analyses have identified secreted small ALKAL proteins (FAM150, AUG) as potential ligands for human ALK and the related Leukocyte Tyrosine Kinase (LTK). In the zebrafish Danio rerio, DrLtk, which is similar to human ALK in sequence and domain structure, controls the development of iridophores, neural crest-derived pigment cells. Hence, the zebrafish system allows studying Alk/Ltk and Alkals involvement in neural crest regulation in vivo. Using zebrafish pigment pattern formation, Drosophila eye patterning, and cell culture-based assays, we show that zebrafish Alkals potently activate zebrafish Ltk and human ALK driving downstream signalling events. Overexpression of the three Dr Alkals cause ectopic iridophore development whereas loss of function alleles lead to spatially distinct patterns of iridophore loss in zebrafish larvae and adults. alkal loss of function triple mutants completely lack iridophores and are larval lethal as is the case for ltk null mutants. Our results provide the first in vivo evidence of (i) activation of ALK/LTK family receptors by ALKALs and (ii) an involvement of these ligand-receptor complexes in neural crest development.

2018 ◽  
Vol 115 (4) ◽  
pp. E630-E638 ◽  
Author(s):  
Andrey Fadeev ◽  
Patricia Mendoza-Garcia ◽  
Uwe Irion ◽  
Jikui Guan ◽  
Kathrin Pfeifer ◽  
...  

Mutations in anaplastic lymphoma kinase (ALK) are implicated in somatic and familial neuroblastoma, a pediatric tumor of neural crest-derived tissues. Recently, biochemical analyses have identified secreted small ALKAL proteins (FAM150, AUG) as potential ligands for human ALK and the related leukocyte tyrosine kinase (LTK). In the zebrafish Danio rerio, DrLtk, which is similar to human ALK in sequence and domain structure, controls the development of iridophores, neural crest-derived pigment cells. Hence, the zebrafish system allows studying Alk/Ltk and Alkals involvement in neural crest regulation in vivo. Using zebrafish pigment pattern formation, Drosophila eye patterning, and cell culture-based assays, we show that zebrafish Alkals potently activate zebrafish Ltk and human ALK driving downstream signaling events. Overexpression of the three DrAlkals cause ectopic iridophore development, whereas loss-of-function alleles lead to spatially distinct patterns of iridophore loss in zebrafish larvae and adults. alkal loss-of-function triple mutants completely lack iridophores and are larval lethal as is the case for ltk null mutants. Our results provide in vivo evidence of (i) activation of ALK/LTK family receptors by ALKALs and (ii) an involvement of these ligand–receptor complexes in neural crest development.


2018 ◽  
Author(s):  
Sandra G. Gonzalez Malagon ◽  
Anna M. Lopez Muñoz ◽  
Daniel Doro ◽  
Triòna G. Bolger ◽  
Evon Poon ◽  
...  

AbstractMigration of the neural crest lineage is critical to its physiological function. Mechanisms controlling neural crest migration are comparatively unknown, due to difficulties accessing this cell population in vivo. Here, we uncover novel requirements of glycogen synthase kinase 3 (GSK3) in regulating the neural crest. We demonstrate that GSK3 is tyrosine phosphorylated (pY) in neural crest cells and that this activation depends on anaplastic lymphoma kinase (ALK), a protein associated with neuroblastoma. Consistent with this, neuroblastoma cells with pathologically increased ALK activity express high levels of pY-GSK3 and migration of these cells can be inhibited by GSK3 or ALK blockade. In normal neural crest cells, loss of GSK3 leads to increased pFAK and misregulation of Rac1 and lamellipodin, key regulators of cell migration. Genetic reduction of GSK-3 results in failure of migration. All together, this work identifies a role for GSK3 in cell migration during neural crest development and cancer.


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.


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 ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1467-1479 ◽  
Author(s):  
R. Kos ◽  
M.V. Reedy ◽  
R.L. Johnson ◽  
C.A. Erickson

The winged-helix or forkhead class of transcription factors has been shown to play important roles in cell specification and lineage segregation. We have cloned the chicken homolog of FoxD3, a member of the winged-helix class of transcription factors, and analyzed its expression. Based on its expression in the dorsal neural tube and in all neural crest lineages except the late-emigrating melanoblasts, we predicted that FoxD3 might be important in the segregation of the neural crest lineage from the neural epithelium, and for repressing melanogenesis in early-migrating neural crest cells. Misexpression of FoxD3 by electroporation in the lateral neural epithelium early in neural crest development produced an expansion of HNK1 immunoreactivity throughout the neural epithelium, although these cells did not undergo an epithelial/mesenchymal transformation. To test whether FoxD3 represses melanogenesis in early migrating neural crest cells, we knocked down expression in cultured neural crest with antisense oligonucleotides and in vivo by treatment with morpholino antisense oligonucleotides. Both experimental approaches resulted in an expansion of the melanoblast lineage, probably at the expense of neuronal and glial lineages. Conversely, persistent expression of FoxD3 in late-migrating neural crest cells using RCAS viruses resulted in the failure of melanoblasts to develop. We suggest that FoxD3 plays two important roles in neural crest development. First, it is involved in the segregation of the neural crest lineage from the neuroepithelium. Second, it represses melanogenesis, thereby allowing other neural crest derivatives to differentiate during the early stages of neural crest patterning.


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.


2020 ◽  
Vol 29 (14) ◽  
pp. 2435-2450
Author(s):  
Erica E Davis ◽  
Ravikumar Balasubramanian ◽  
Zachary A Kupchinsky ◽  
David L Keefe ◽  
Lacey Plummer ◽  
...  

Abstract Dysfunction of the gonadotropin-releasing hormone (GnRH) axis causes a range of reproductive phenotypes resulting from defects in the specification, migration and/or function of GnRH neurons. To identify additional molecular components of this system, we initiated a systematic genetic interrogation of families with isolated GnRH deficiency (IGD). Here, we report 13 families (12 autosomal dominant and one autosomal recessive) with an anosmic form of IGD (Kallmann syndrome) with loss-of-function mutations in TCF12, a locus also known to cause syndromic and non-syndromic craniosynostosis. We show that loss of tcf12 in zebrafish larvae perturbs GnRH neuronal patterning with concomitant attenuation of the orthologous expression of tcf3a/b, encoding a binding partner of TCF12, and stub1, a gene that is both mutated in other syndromic forms of IGD and maps to a TCF12 affinity network. Finally, we report that restored STUB1 mRNA rescues loss of tcf12 in vivo. Our data extend the mutational landscape of IGD, highlight the genetic links between craniofacial patterning and GnRH dysfunction and begin to assemble the functional network that regulates the development of the GnRH axis.


2019 ◽  
Author(s):  
Kelly Dew-Budd ◽  
Julie Cheung ◽  
Kyle Palos ◽  
Evan S. Forsythe ◽  
Mark A. Beilstein

AbstractThe telomerase ribonucleoprotein complex (RNP) is essential for genome stability and performs this role through the addition of repetitive DNA to the ends of chromosomes. The telomerase enzyme is composed of a reverse transcriptase (TERT), which utilizes a template domain in an RNA subunit (TER) to reiteratively add telomeric DNA at the ends of chromosomes. Multiple TERs have been identified in the model plant Arabidopsis thaliana. Here we combine a phylogenetic and biochemical approach to understand how the telomerase RNP has evolved in Brassicaceae, the family that includes A. thaliana. Because of the complex phylogenetic pattern of template domain loss and alteration at the previously characterized A. thaliana TER loci, TER1 and TER2, across the plant family Brassicaceae, we bred double mutants from plants with a template deletion at AtTER1 and T-DNA insertion at AtTER2. These double mutants exhibited no telomere length deficiency, a definitive indication that neither of these loci encode a functional telomerase RNA. Moreover, we determined that the telomerase components TERT, Dyskerin, and the KU heterodimer are under strong purifying selection, consistent with the idea that the TER with which they interact is also conserved. To test this hypothesis further, we analyzed the substrate specificity of telomerase from species across Brassicaceae and determined that telomerase from close relatives bind and extend substrates in a similar manner, supporting the idea that TERs in different species are highly similar to one another and are likely encoded from an orthologous locus. Lastly, TERT proteins from across Brassicaceae were able to complement loss of function tert mutants in vivo, indicating TERTs from other species have the ability to recognize the native TER of A. thaliana. Finally, we immunoprecipitated the telomerase complex and identified associated RNAs via RNA-seq. Using our evolutionary data we constrained our analyses to conserved RNAs within Brassicaceae that contained a template domain. These analyses revealed a highly expressed locus whose disruption by a T-DNA resulted in a telomeric phenotype similar to the loss of other telomerase core proteins, indicating that the RNA has an important function in telomere maintenance.


Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1387
Author(s):  
Meihua Ju ◽  
Sofia Ioannidou ◽  
Peter Munro ◽  
Olli Rämö ◽  
Helena Vihinen ◽  
...  

Fenestrae are transcellular plasma membrane pores that mediate blood–tissue exchange in specialised vascular endothelia. The composition and biogenesis of the fenestra remain enigmatic. We isolated and characterised the protein composition of large patches of fenestrated plasma membrane, termed sieve plates. Loss-of-function experiments demonstrated that two components of the sieve plate, moesin and annexin II, were positive and negative regulators of fenestra formation, respectively. Biochemical analyses showed that moesin is involved in the formation of an actin–fodrin submembrane cytoskeleton that was essential for fenestra formation. The link between the fodrin cytoskeleton and the plasma membrane involved the fenestral pore protein PV-1 and Na,K-ATPase, which is a key regulator of signalling during fenestra formation both in vitro and in vivo. These findings provide a conceptual framework for fenestra biogenesis, linking the dynamic changes in plasma membrane remodelling to the formation of a submembrane cytoskeletal signalling complex.


2006 ◽  
Vol 295 (1) ◽  
pp. 410
Author(s):  
Robert N. Kelsh ◽  
Xueyan Yang ◽  
Jeanette Mueller ◽  
Andrew Ward

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