title: The corneal epithelium and lens develop independently from a common pool of precursors.
abstract: BACKGROUND
  The corneal epithelium (CE) overlays a stroma, which is derived from neural crest cells, and appears to be committed during chick development, but appears still labile in adult rabbit. Its specification was hitherto regarded as resolved and dependent upon the lens, although without experimental support. Here, we challenged CE fate by changing its environment at different stages.
  
  
  RESULTS
  Recombination with a dermis showed that CE commitment is linked to stroma formation, which results in Pax6 stabilization in both species. Surgical ablation shows that CE specification has already taken place when the lens placode invaginates, while removal of the early lens placode led to lens renewal. To block lens formation, bone morphogenetic protein (BMP) signaling, one of its last inducing factors, was inhibited by over-expression of Gremlin in the ocular ectoderm. This resulted in lens-less embryos which formed a corneal epithelium if they survived 2 weeks.
  
  
  CONCLUSIONS
  The corneal epithelium and lens share a common pool of precursors. The adoption of the CE fate might be dependent on the loss of a lens placode favoring environment. The corneal fate is definitively stabilized by the migration of Gremlin-expressing neural crest cells in the lens peripheral ectoderm.
authors: FRE CNRS 3405, AGIM, Université Joseph Fourier Grenoble, Site Santé, France.
authors: Elodie
authors: E
authors: Collomb
authors: Ying
authors: Y
authors: Yang
authors: Sarah
authors: S
authors: Foriel
authors: Sébastien
authors: S
authors: Cadau
authors: David J
authors: DJ
authors: Pearton
authors: Danielle
authors: D
authors: Dhouailly
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D019070:Cell Lineage / Q000235:genetics / Q000502:physiology; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology / Q000196:embryology / Q000378:metabolism / Q000502:physiology; D019573:Epithelium, Corneal / Q000166:cytology / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007908:Lens, Crystalline / Q000166:cytology / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins