title: Neural crest cells organize the eye via TGF-β and canonical Wnt signalling.
abstract: In vertebrates, the lens and retina arise from different embryonic tissues raising the question of how they are aligned to form a functional eye. Neural crest cells are crucial for this process: in their absence, ectopic lenses develop far from the retina. Here we show, using the chick as a model system, that neural crest-derived transforming growth factor-βs activate both Smad3 and canonical Wnt signalling in the adjacent ectoderm to position the lens next to the retina. They do so by controlling Pax6 activity: although Smad3 may inhibit Pax6 protein function, its sustained downregulation requires transcriptional repression by Wnt-initiated β-catenin. We propose that the same neural crest-dependent signalling mechanism is used repeatedly to integrate different components of the eye and suggest a general role for the neural crest in coordinating central and peripheral parts of the sensory nervous system.
authors.affiliation: Department of Craniofacial Development, King's College London, Guy's Campus, London SE1 9RT, UK.
authors.forename: Timothy
authors.initials: T
authors.lastname: Grocott
authors.forename: Samuel
authors.initials: S
authors.lastname: Johnson
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Bailey
authors.forename: Andrea
authors.initials: A
authors.lastname: Streit
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D005123:Eye / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D007908:Lens, Crystalline / Q000196:embryology / Q000378:metabolism; D008954:Models, Biological; D009432:Neural Crest / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D015398:Signal Transduction; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism; D055411:TGF-beta Superfamily Proteins / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D051154:Wnt2 Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051900:Smad3 Protein; D055411:TGF-beta Superfamily Proteins; D016212:Transforming Growth Factor beta; D051154:Wnt2 Protein