Talk:Developmental Signals - Wnt
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Cite this page: Hill, M.A. (2024, April 20) Embryology Developmental Signals - Wnt. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Developmental_Signals_-_Wnt |
2022
Sahebdel F, Parvaneh Tafreshi A, Arefian E, Roussa E, Nadri S & Zeynali B. (2022). Wnt/β-catenin signaling pathway is involved in early dopaminergic differentiation of trabecular meshwork-derived mesenchymal stem cells. J Cell Biochem , 123, 1120-1129. PMID: 35533251 DOI.
Abstract
Permanent degeneration and loss of dopaminergic (DA) neurons in substantia nigra is the main cause of Parkinson's disease. Considering the therapeutic application of stem cells in neurodegeneration, we sought to examine the neurogenic differentiation potential of the newly introduced neural crest originated mesenchymal stem cells (MSCs), namely, trabecular meshwork-derived mesenchymal stem cells (TM-MSCs) compared to two other sources of MSCs, adipose tissue-derived stem cells (ADSCs) and bone marrow-derived mesenchymal stem cells (BM-MSCs). The three types of cells were therefore cultured in the presence and absence of a neural induction medium followed by the analysis of their differentiation potentials. Our results showed that TM-MSCs exhibited enhanced neural morphologies as well as higher expressions of MAP2 as the general neuron marker and Nurr-1 as an early DA marker compared to the adipose tissue-derived mesenchymal stem cells (AD-MSCs) and bone marrow-derived stem cells (BMSCs). Also, analysis of Nurr-1 immunostaining showed more intense Nurr-1 stained nuclei in the neurally induced TM-MSCs compared to those in the AD-MSCs, BMSCs, and noninduced control TM-MSCs. To examine if Wnt/beta-catenin pathway drives TM-MSCs towards a DA fate, we treated them with the Wnt agonist (CHIR, 3 μM) and the Wnt antagonist (IWP-2, 3 μM). Our results showed that the expressions of Nurr-1 and MAP2, as well as the Wnt/beta-catenin target genes, c-Myc and Cyclin D1, were significantly increased in the CHIR-treated TM-MSCs, but significantly reduced in those treated with IWP-2. Altogether, we declare first a higher neural potency of TM-MSCs compared to the more commonly used MSCs, BMSCs and ADSCs, and second that Wnt/beta-catenin activation directs the neurally induced TM-MSCs towards a DA fate.
2019
Hernández-Martínez R, Ramkumar N & Anderson KV. (2019). p120-catenin regulates WNT signaling and EMT in the mouse embryo. Proc. Natl. Acad. Sci. U.S.A. , 116, 16872-16881. PMID: 31371508 DOI.
Proc Natl Acad Sci U S A. 2019 Aug 20;116(34):16872-16881. doi: 10.1073/pnas.1902843116. Epub 2019 Aug 1.
Abstract Epithelial-to-mesenchymal transitions (EMTs) require a complete reorganization of cadherin-based cell-cell junctions. p120-catenin binds to the cytoplasmic juxtamembrane domain of classical cadherins and regulates their stability, suggesting that p120-catenin may play an important role in EMTs. Here, we describe the role of p120-catenin in mouse gastrulation, an EMT that can be imaged at cellular resolution and is accessible to genetic manipulation. Mouse embryos that lack all p120-catenin, or that lack p120-catenin in the embryo proper, survive to midgestation. However, mutants have specific defects in gastrulation, including a high rate of p53-dependent cell death, a bifurcation of the posterior axis, and defects in the migration of mesoderm; all are associated with abnormalities in the primitive streak, the site of the EMT. In embryonic day 7.5 (E7.5) mutants, the domain of expression of the streak marker Brachyury (T) expands more than 3-fold, from a narrow strip of posterior cells to encompass more than one-quarter of the embryo. After E7.5, the enlarged T+ domain splits in 2, separated by a mass of mesoderm cells. Brachyury is a direct target of canonical WNT signaling, and the domain of WNT response in p120-catenin mutant embryos, like the T domain, is first expanded, and then split, and high levels of nuclear β-catenin levels are present in the cells of the posterior embryo that are exposed to high levels of WNT ligand. The data suggest that p120-catenin stabilizes the membrane association of β-catenin, thereby preventing accumulation of nuclear β-catenin and excessive activation of the WNT pathway during EMT. KEYWORDS: WNT signaling; cell migration; epithelial–mesenchymal transition; gastrulation; p53-dependent cell death PMID: 31371508 PMCID: PMC6708312 [Available on 2020-02-01] DOI: 10.1073/pnas.1902843116
Wnt traffic from endoplasmic reticulum to filopodia
PLoS One. 2019 Feb 22;14(2):e0212711. doi: 10.1371/journal.pone.0212711. eCollection 2019.
Moti N1, Yu J1, Boncompain G2, Perez F2, Virshup DM1,3. Author information Abstract Wnts are a family of secreted palmitoleated glycoproteins that play key roles in cell to cell communication during development and regulate stem cell compartments in adults. Wnt receptors, downstream signaling cascades and target pathways have been extensively studied while less is known about how Wnts are secreted and move from producing cells to receiving cells. We used the synchronization system called Retention Using Selective Hook (RUSH) to study Wnt trafficking from endoplasmic reticulum to Golgi and then to plasma membrane and filopodia in real time. Inhibition of porcupine (PORCN) or knockout of Wntless (WLS) blocked Wnt exit from the ER. Wnt-containing vesicles paused at sub-cortical regions of the plasma membrane before exiting the cell. Wnt-containing vesicles were associated with filopodia extending to adjacent cells. These data visualize and confirm the role of WLS and PORCN in ER exit of Wnts and support the role of filopodia in Wnt signaling.
PMID: 30794657 PMCID: PMC6386245 DOI: 10.1371/journal.pone.0212711
2018
Mechanisms of Wnt signaling and control
Wiley Interdiscip Rev Syst Biol Med. 2018 Mar 30:e1422. doi: 10.1002/wsbm.1422. [Epub ahead of print]
Grainger S1, Willert K1.
Abstract
The Wnt signaling pathway is a highly conserved system that regulates complex biological processes across all metazoan species. At the cellular level, secreted Wnt proteins serve to break symmetry and provide cells with positional information that is critical to the patterning of the entire body plan. At the organismal level, Wnt signals are employed to orchestrate fundamental developmental processes, including the specification of the anterior-posterior body axis, induction of the primitive streak and ensuing gastrulation movements, and the generation of cell and tissue diversity. Wnt functions extend into adulthood where they regulate stem cell behavior, tissue homeostasis, and damage repair. Disruption of Wnt signaling activity during embryonic development or in adults results in a spectrum of abnormalities and diseases, including cancer. The molecular mechanisms that underlie the myriad of Wnt-regulated biological effects have been the subject of intense research for over three decades. This review is intended to summarize our current understanding of how Wnt signals are generated and interpreted. This article is categorized under: Biological Mechanisms > Cell Signaling Developmental Biology > Stem Cell Biology and Regeneration. KEYWORDS: WNT; beta-catenin; development; frizzled; signaling; stem cells PMID: 29600540 DOI: 10.1002/wsbm.1422
Novel Mutation of LRP6 Identified in Chinese Han Population Links Canonical WNT Signaling to Neural Tube Defects
Birth Defects Res. 2018 Jan 15;110(1):63-71. doi: 10.1002/bdr2.1122. Epub 2017 Sep 29.
Shi Z1, Yang X1, Li BB1, Chen S1, Yang L1, Cheng L2, Zhang T3, Wang H1,4,5, Zheng Y1,4,6.
Author information
Abstract
BACKGROUND:
Neural tube defects (NTDs), the second most frequent cause of human congenital abnormalities, are debilitating birth defects due to failure of neural tube closure. It has been shown that noncanonical WNT/planar cell polarity (PCP) signaling is required for convergent extension (CE), the initiation step of neural tube closure (NTC). But the effect of canonical WNT//β-catenin signaling during NTC is still elusive. LRP6 (low density lipoprotein receptor related proteins 6) was identified as a co-receptor for WNT/β-catenin signaling, but recent studies showed that it also can mediate WNT/PCP signaling.
METHODS:
In this study, we screened mutations in the LRP6 gene in 343 NTDs and 215 ethnically matched normal controls of Chinese Han population.
RESULTS:
Three rare missense mutations (c.1514A>G, p.Y505C); c.2984A>G, p.D995G; and c.4280C>A, p.P1427Q) of the LRP6 gene were identified in Chinese NTD patients. The Y505C mutation is a loss-of-function mutation on both WNT/β-catenin and PCP signaling. The D995G mutation only partially lost inhibition on PCP signaling without affecting WNT/β-catenin signaling. The P1427Q mutation dramatically increased WNT/β-catenin signaling but only mildly loss of inhibition on PCP signaling. All three mutations failed to rescue CE defects caused by lrp6 morpholino oligos knockdown in zebrafish. Of interest, when overexpressed, D995G did not induce any defects, but Y505C and P1427Q caused more severe CE defects in zebrafish.
CONCLUSION:
Our results suggested that over-active canonical WNT signaling induced by gain-of-function mutation in LRP6 could also contribute to human NTDs, and a balanced WNT/β-catenin and PCP signaling is probably required for proper neural tube development. Birth Defects Research 110:63-71, 2018. © 2017 Wiley Periodicals, Inc.
© 2017 Wiley Periodicals, Inc.
KEYWORDS:
LRP6; PCP signaling; WNT/β-catenin signaling; mutation; neural tube defects
PMID: 28960852 DOI: 10.1002/bdr2.1122
The Pleiotropic Effects of the Canonical Wnt Pathway in Early Development and Pluripotency
Genes (Basel). 2018 Feb 14;9(2). pii: E93. doi: 10.3390/genes9020093.
de Jaime-Soguero A1, Abreu de Oliveira WA2, Lluis F3.
Abstract
The technology to derive embryonic and induced pluripotent stem cells from early embryonic stages and adult somatic cells, respectively, emerged as a powerful resource to enable the establishment of new in vitro models, which recapitulate early developmental processes and disease. Additionally, pluripotent stem cells (PSCs) represent an invaluable source of relevant differentiated cell types with immense potential for regenerative medicine and cell replacement therapies. Pluripotent stem cells support self-renewal, potency and proliferation for extensive periods of culture in vitro. However, the core pathways that rule each of these cellular features specific to PSCs only recently began to be clarified. The Wnt signaling pathway is pivotal during early embryogenesis and is central for the induction and maintenance of the pluripotency of PSCs. Signaling by the Wnt family of ligands is conveyed intracellularly by the stabilization of β-catenin in the cytoplasm and in the nucleus, where it elicits the transcriptional activity of T-cell factor (TCF)/lymphoid enhancer factor (LEF) family of transcription factors. Interestingly, in PSCs, the Wnt/β-catenin-TCF/LEF axis has several unrelated and sometimes opposite cellular functions such as self-renewal, stemness, lineage commitment and cell cycle regulation. In addition, tight control of the Wnt signaling pathway enhances reprogramming of somatic cells to induced pluripotency. Several recent research efforts emphasize the pleiotropic functions of the Wnt signaling pathway in the pluripotent state. Nonetheless, conflicting results and unanswered questions still linger. In this review, we will focus on the diverse functions of the canonical Wnt signaling pathway on the developmental processes preceding embryo implantation, as well as on its roles in pluripotent stem cell biology such as self-renewal and cell cycle regulation and somatic cell reprogramming. KEYWORDS: Wnt/β-catenin pathway; cell cycle; embryonic stem cells; pre-implantation development; somatic cell reprogramming PMID: 29443926 PMCID: PMC5852589 DOI: 10.3390/genes9020093
2016
Wnt9a deficiency discloses a repressive role of Tcf7l2 on endocrine differentiation in the embryonic pancreas
Sci Rep. 2016 Jan 14;6:19223. doi: 10.1038/srep19223.
Pujadas G1,2,3, Cervantes S1,2, Tutusaus A1, Ejarque M1,2,3, Sanchez L1, García A1,2, Esteban Y1,2, Fargas L4, Alsina B4, Hartmann C5, Gomis R1,2,3, Gasa R1,2.
Abstract
Transcriptional and signaling networks establish complex cross-regulatory interactions that drive cellular differentiation during development. Using microarrays we identified the gene encoding the ligand Wnt9a as a candidate target of Neurogenin3, a basic helix-loop-helix transcription factor that functions as a master regulator of pancreatic endocrine differentiation. Here we show that Wnt9a is expressed in the embryonic pancreas and that its deficiency enhances activation of the endocrine transcriptional program and increases the number of endocrine cells at birth. We identify the gene encoding the endocrine transcription factor Nkx2-2 as one of the most upregulated genes in Wnt9a-ablated pancreases and associate its activation to reduced expression of the Wnt effector Tcf7l2. Accordingly, in vitro studies confirm that Tcf7l2 represses activation of Nkx2-2 by Neurogenin3 and inhibits Nkx2-2 expression in differentiated β-cells. Further, we report that Tcf7l2 protein levels decline upon initiation of endocrine differentiation in vivo, disclosing the downregulation of this factor in the developing endocrine compartment. These findings highlight the notion that modulation of signalling cues by lineage-promoting factors is pivotal for controlling differentiation programs.
PMID 26771085 PMCID: PMC4725895 DOI: 10.1038/srep19223
2015
WNT3 involvement in human bladder exstrophy and cloaca development in zebrafish
Hum Mol Genet. 2015 Sep 15;24(18):5069-78. doi: 10.1093/hmg/ddv225. Epub 2015 Jun 23.
Baranowska Körberg I1, Hofmeister W2, Markljung E3, Cao J3, Nilsson D4, Ludwig M5, Draaken M6, Holmdahl G7, Barker G8, Reutter H9, Vukojević V10, Clementson Kockum C11, Lundin J1, Lindstrand A12, Nordenskjöld A13.
Abstract
Bladder exstrophy, a severe congenital urological malformation when a child is born with an open urinary bladder, is the most common form of bladder exstrophy-epispadias complex (BEEC) with an incidence of 1:30,000 children of Caucasian descent. Recent studies suggest that WNT genes may contribute to the etiology of bladder exstrophy. Here, we evaluated WNT-pathway genes in 20 bladder exstrophy patients using massively parallel sequencing. In total 13 variants were identified in WNT3, WNT6, WNT7A, WNT8B, WNT10A, WNT11, WNT16, FZD5, LRP1 and LRP10 genes and predicted as potentially disease causing, of which seven variants were novel. One variant, identified in a patient with a de novo nonsynonymous substitution in WNT3 (p.Cys91Arg), was further evaluated in zebrafish. Knock down of wnt3 in zebrafish showed cloaca malformations, including disorganization of the cloaca epithelium and expansion of the cloaca lumen. Our study suggests that the function of the WNT3 p.Cys91Arg variant was altered, since RNA overexpression of mutant Wnt3 RNA does not result in embryonic lethality as seen with wild-type WNT3 mRNA. Finally, we also mutation screened the WNT3 gene further in 410 DNA samples from BEEC cases and identified one additional mutation c.638G>A (p.Gly213Asp), which was paternally inherited. In aggregate our data support the involvement of WNT-pathway genes in BEEC and suggest that WNT3 in itself is a rare cause of BEEC. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
PMID 26105184
Ror2 regulates branching, differentiation, and actin-cytoskeletal dynamics within the mammary epithelium
J Cell Biol. 2015 Feb 2;208(3):351-66. doi: 10.1083/jcb.201408058. Epub 2015 Jan 26.
Roarty K1, Shore AN1, Creighton CJ1, Rosen JM2.
Abstract
Wnt signaling encompasses β-catenin-dependent and -independent networks. How receptor context provides Wnt specificity in vivo to assimilate multiple concurrent Wnt inputs throughout development remains unclear. Here, we identified a refined expression pattern of Wnt/receptor combinations associated with the Wnt/β-catenin-independent pathway in mammary epithelial subpopulations. Moreover, we elucidated the function of the alternative Wnt receptor Ror2 in mammary development and provided evidence for coordination of this pathway with Wnt/β-catenin-dependent signaling in the mammary epithelium. Lentiviral short hairpin RNA (shRNA)-mediated depletion of Ror2 in vivo increased branching and altered the differentiation of the mammary epithelium. Microarray analyses identified distinct gene level alterations within the epithelial compartments in the absence of Ror2, with marked changes observed in genes associated with the actin cytoskeleton. Modeling of branching morphogenesis in vitro defined specific defects in cytoskeletal dynamics accompanied by Rho pathway alterations downstream of Ror2 loss. The current study presents a model of Wnt signaling coordination in vivo and assigns an important role for Ror2 in mammary development. © 2015 Roarty et al.
PMID 25624393
2014
Wnt11 is required for oriented migration of dermogenic progenitor cells from the dorsomedial lip of the avian dermomyotome
PLoS One. 2014 Mar 26;9(3):e92679. doi: 10.1371/journal.pone.0092679. eCollection 2014.
Morosan-Puopolo G1, Balakrishnan-Renuka A1, Yusuf F2, Chen J2, Dai F3, Zoidl G2, Lüdtke TH4, Kispert A4, Theiss C2, Abdelsabour-Khalaf M5, Brand-Saberi B6. Author information
Abstract The embryonic origin of the dermis in vertebrates can be traced back to the dermomyotome of the somites, the lateral plate mesoderm and the neural crest. The dermal precursors directly overlying the neural tube display a unique dense arrangement and are the first to induce skin appendage formation in vertebrate embryos. These dermal precursor cells have been shown to derive from the dorsomedial lip of the dermomyotome (DML). Based on its expression pattern in the DML, Wnt11 is a candidate regulator of dorsal dermis formation. Using EGFP-based cell labelling and time-lapse imaging, we show that the Wnt11 expressing DML is the source of the dense dorsal dermis. Loss-of-function studies in chicken embryos show that Wnt11 is indeed essential for the formation of dense dermis competent to support cutaneous appendage formation. Our findings show that dermogenic progenitors cannot leave the DML to form dense dorsal dermis following Wnt11 silencing. No alterations were noticeable in the patterning or in the epithelial state of the dermomyotome including the DML. Furthermore, we show that Wnt11 expression is regulated in a manner similar to the previously described early dermal marker cDermo-1. The analysis of Wnt11 mutant mice exhibits an underdeveloped dorsal dermis and strongly supports our gene silencing data in chicken embryos. We conclude that Wnt11 is required for dense dermis and subsequent cutaneous appendage formation, by influencing the cell fate decision of the cells in the DML.
PMID 24671096
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092679
2012
Wnt3 and Wnt3a are required for induction of the mid-diencephalic organizer in the caudal forebrain
Neural Dev. 2012 Apr 4;7:12.
Mattes B, Weber S, Peres J, Chen Q, Davidson G, Houart C, Scholpp S. Source Karlsruhe Institute of Technology (KIT), Institute of Toxicology and Genetics (ITG), Karlsruhe, Germany. steffen.scholpp@kit.edu.
Abstract
ABSTRACT: BACKGROUND: A fundamental requirement for development of diverse brain regions is the function of local organizers at morphological boundaries. These organizers are restricted groups of cells that secrete signaling molecules, which in turn regulate the fate of the adjacent neural tissue. The thalamus is located in the caudal diencephalon and is the central relay station between the sense organs and higher brain areas. The mid-diencephalic organizer (MDO) orchestrates the development of the thalamus by releasing secreted signaling molecules such as Shh. RESULTS: Here we show that canonical Wnt signaling in the caudal forebrain is required for the formation of the Shh-secreting MD organizer in zebrafish. Wnt signaling induces the MDO in a narrow time window of 4 hours - between 10 and 14 hours post fertilization. Loss of Wnt3 and Wnt3a prevents induction of the MDO, a phenotype also observed upon blockage of canonical Wnt signaling per se. Pharmaceutical activation of the canonical Wnt pathways in Wnt3/Wnt3a compound morphant embryos is able to restore the lack of the MDO. After blockage of Wnt signaling or knock-down of Wnt3/Wnt3a we find an increase of apoptotic cells specifically within the organizer primordium. Consistently, blockage of apoptosis restores the thalamus organizer MDO in Wnt deficient embryos. CONCLUSION: We have identified canonical Wnt signaling as a novel pathway, that is required for proper formation of the MDO and consequently for the development of the major relay station of the brain - the thalamus. We propose that Wnt ligands are necessary to maintain the primordial tissue of the organizer during somitogenesis by suppressing Tp53-mediated apoptosis.
PMID 22475147
2011
Dissecting Molecular Differences between Wnt Coreceptors LRP5 and LRP6
Low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6) serve as Wnt co-receptors for the canonical β-catenin pathway. While LRP6 is essential for embryogenesis, both LRP5 and LRP6 play critical roles for skeletal remodeling, osteoporosis pathogenesis and cancer formation, making LRP5 and LRP6 key therapeutic targets for cancer and disease treatment. LRP5 and LRP6 each contain in the cytoplasmic domain five conserved PPPSPxS motifs that are pivotal for signaling and serve collectively as phosphorylation-dependent docking sites for the scaffolding protein Axin. However existing data suggest that LRP6 is more effective than LRP5 in transducing the Wnt signal. To understand the molecular basis that accounts for the different signaling activity of LRP5 and LRP6, we generated a series of chimeric receptors via swapping LRP5 and LRP6 cytoplasmic domains, LRP5C and LRP6C, and studied their Wnt signaling activity using biochemical and functional assays. We demonstrate that LRP6C exhibits strong signaling activity while LRP5C is much less active in cells. Recombinant LRP5C and LRP6C upon in vitro phosphorylation exhibit similar Axin-binding capability, suggesting that LRP5 and LRP6 differ in vivo at a step prior to Axin-binding, likely at receiving phosphorylation. We identified between the two most carboxyl PPPSPxS motifs an intervening “gap4” region that appears to account for much of the difference between LRP5C and LRP6C, and showed that alterations in this region are sufficient to enhance LRP5 PPPSPxS phosphorylation and signaling to levels comparable to LRP6 in cells. In addition we provide evidence that binding of phosphorylated LRP5 or LRP6 to Axin is likely direct and does not require the GSK3 kinase as a bridging intermediate as has been proposed. Our studies therefore uncover a new and important molecular tuning mechanism for differential regulation of LRP5 and LRP6 phosphorylation and signaling activity.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0023537
2010
beta-Catenin regulates intercellular signalling networks and cell-type specific transcription in the developing mouse midbrain-rhombomere 1 region
PLoS One. 2010 Jun 3;5(6):e10881.
Chilov D, Sinjushina N, Saarimäki-Vire J, Taketo MM, Partanen J.
Institute of Biotechnology, University of Helsinki, Helsinki, Finland. Abstract beta-Catenin is a multifunctional protein involved in both signalling by secreted factors of Wnt family and regulation of the cellular architecture. We show that beta-catenin stabilization in mouse midbrain-rhombomere 1 region leads to robust up-regulation of several Wnt signalling target genes, including Fgf8. Suggestive of direct transcriptional regulation of the Fgf8 gene, beta-catenin stabilization resulted in Fgf8 up-regulation also in other tissues, specifically in the ventral limb ectoderm. Interestingly, stabilization of beta-catenin rapidly caused down-regulation of the expression of Wnt1 itself, suggesting a negative feedback loop. The changes in signal molecule expression were concomitant with deregulation of anterior-posterior and dorso-ventral patterning. The transcriptional regulatory functions of beta-catenin were confirmed by beta-catenin loss-of-function experiments. Temporally controlled inactivation of beta-catenin revealed a cell-autonomous role for beta-catenin in the maintenance of cell-type specific gene expression in the progenitors of midbrain dopaminergic neurons. These results highlight the role of beta-catenin in establishment of neuroectodermal signalling centers, promoting region-specific gene expression and regulation of cell fate determination.
PMID: 20532162 http://www.ncbi.nlm.nih.gov/pubmed/20532162
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0010881
Wnt1 signaling has been implicated as one factor involved in neural crest-derived melanocyte (NC-M) development. http://www.ncbi.nlm.nih.gov/pubmed/10963668
Neural crest-directed gene transfer demonstrates Wnt1 role in melanocyte expansion and differentiation during mouse development
Proc Natl Acad Sci U S A. 2000 Aug 29;97(18):10050-5. Dunn KJ, Williams BO, Li Y, Pavan WJ.
Genetic Disease Research Branch, National Human Genome Research Institute, and Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4472, USA. Abstract Wnt1 signaling has been implicated as one factor involved in neural crest-derived melanocyte (NC-M) development. Mice deficient for both Wnt1 and Wnt3a have a marked deficiency in trunk neural crest derivatives including NC-Ms. We have used cell lineage-directed gene targeting of Wnt signaling genes to examine the effects of Wnt signaling in mouse neural crest development. Gene expression was directed to cell lineages by infection with subgroup A avian leukosis virus vectors in lines of transgenic mice that express the retrovirus receptor tv-a. Transgenic mice with tva in either nestin-expressing neural precursor cells (line Ntva) or dopachrome tautomerase (DCT)-expressing melanoblasts (line DCTtva) were analyzed. We overstimulated Wnt signaling in two ways: directed gene transfer of Wnt1 to Ntva(+) cells and transfer of beta-catenin to DCTtva(+) NC-M precursor cells. In both methods, NC-M expansion and differentiation were effected. Significant increases were observed in the number of NC-Ms [melanin(+) and tyrosinase-related protein 1 (TYRP1)(+) cells], the differentiation of melanin(-) TYRP1(+) cells to melanin(+) TYRP1(+) NC-Ms, and the intensity of pigmentation per NC-M. These data are consistent with Wnt1 signaling being involved in both expansion and differentiation of migrating NC-Ms in the developing mouse embryo. The use of lineage-directed gene targeting will allow the dissection of signaling molecules involved in NC development and is adaptable to other mammalian developmental systems.
Endothelial specific stabilization of Wnt/beta-catenin signaling alters early vascular development in the embryo by upregulating Dll4/Notch signaling (Dev Cell, June 2010).
Wnt3a deficiency irreversibly impairs hematopoietic stem cell self-renewal and leads to defects in progenitor cell differentiation (Blood, Jan 2009).
The nuclear import of Frizzled2-C by Importins-beta11 and alpha2 promotes postsynaptic development. Therefore, Wnt-activated growth of the post-synaptic membrane is mediated by the synapse-to-nucleus translocation and active nuclear import of Fz2-C (Nat Neurosci, August 2010).
