title: Induction of otic structures by canonical Wnt signalling in medaka.
abstract: The Wnt family of signalling proteins is known to participate in multiple developmental decisions during embryogenesis. We misexpressed Wnt1 in medaka embryos and observed anterior truncations, similar to those described for ectopic activation of canonical Wnt signalling in other species. Interestingly, when we induced a heat-shock Wnt1 transgenic line exactly at 30% epiboly, we observed multiple ectopic otic vesicles in the truncated embryos. The vesicles then fused, forming a single large ear structure. These "cyclopic ears" filled the complete anterior region of the embryos. The ectopic induction of otic development can be explained by the juxtaposition of hindbrain tissue with anterior ectoderm. Fibroblast growth factor (Fgf) ligands are thought to mediate the otic-inducing properties of the hindbrain. However, signals different from Fgf3 and Fgf8 are necessary to explain the formation of the ectopic ear structures, suggesting that Wnt signalling is involved in the otic induction process in medaka.
authors.affiliation: Department for Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria.
authors.forename: Baubak
authors.initials: B
authors.lastname: Bajoghli
authors.forename: Narges
authors.initials: N
authors.lastname: Aghaallaei
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Jung
authors.forename: Thomas
authors.initials: T
authors.lastname: Czerny
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D017849:Animals, Inbred Strains; D004423:Ear / Q000196:embryology*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D009990:Oryzias / Q000196:embryology* / Q000378:metabolism*; D051155:Wnt1 Protein / Q000378:metabolism*
chemical_list: D051155:Wnt1 Protein; D005346:Fibroblast Growth Factors