title: An ongoing role for Wnt signaling in differentiating melanocytes in vivo.
abstract: A role for Wnt signaling in melanocyte specification from neural crest is conserved across vertebrates, but possible ongoing roles in melanocyte differentiation have received little attention. Using a systems biology approach to investigate the gene regulatory network underlying stable melanocyte differentiation in zebrafish highlighted a requirement for a positive-feedback loop involving the melanocyte master regulator Mitfa. Here, we test the hypothesis that Wnt signaling contributes to that positive feedback. We show firstly that Wnt signaling remains active in differentiating melanocytes and secondly that enhanced Wnt signaling drives elevated transcription of mitfa. We show that chemical activation of the Wnt signaling pathway at early stages of melanocyte development enhances melanocyte specification as expected, but importantly that at later (differentiation) stages, it results in altered melanocyte morphology, although melanisation is not obviously affected. Downregulation of Wnt signaling also results in altered melanocyte morphology and organization. We conclude that Wnt signaling plays a role in regulating ongoing aspects of melanocyte differentiation in zebrafish.
authors.affiliation: Developmental Biology Programme, Department of Biology and Biochemistry, Centre for Regenerative Medicine, University of Bath, Bath, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Vibert
authors.affiliation: Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Aquino
authors.affiliation: Developmental and Cell Biology School of Biological Sciences, University of California, Irvine, CA, USA.
authors.forename: Ines
authors.initials: I
authors.lastname: Gehring
authors.affiliation: Developmental Biology Programme, Department of Biology and Biochemistry, Centre for Regenerative Medicine, University of Bath, Bath, UK.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Subkankulova
authors.affiliation: Developmental and Cell Biology School of Biological Sciences, University of California, Irvine, CA, USA.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Schilling
authors.affiliation: Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Rocco
authors.affiliation: Developmental Biology Programme, Department of Biology and Biochemistry, Centre for Regenerative Medicine, University of Bath, Bath, UK.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Kelsh
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D004625:Embryo, Nonmammalian / Q000166:cytology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D008544:Melanocytes / Q000166:cytology* / Q000378:metabolism; D060449:Wnt Signaling Pathway; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029961:Zebrafish Proteins
keywords: 
  mitfa
  ; Wnt signaling; Zebrafish; differentiation; melanocyte; neural crest; specification