title: Neural crest cells pattern the surface cephalic ectoderm during FEZ formation.
abstract: BACKGROUND
  Multiple fibroblast growth factor (Fgf) ligands are expressed in the forebrain and facial ectoderm, and vascular endothelial growth factor (VEGF) is expressed in the facial ectoderm. Both pathways activate the MAP kinase cascade and can be suppressed by SU5402. We placed a bead soaked in SU5402 into the brain after emigration of neural crest cells was complete.
  
  
  RESULTS
  Within 24 hr we observed reduced pMEK and pERK staining that persisted for at least 48 hr. This was accompanied by significant apoptosis in the face. By day 15, the upper beaks were truncated. Molecular changes in the FNP were also apparent. Normally, Shh is expressed in the frontonasal ectodermal zone and controls patterned growth of the upper jaw. In treated embryos, Shh expression was reduced. Both the structural and molecular deficits were mitigated after transplantation of FNP-derived mesenchymal cells.
  
  
  CONCLUSIONS
  Thus, mesenchymal cells actively participate in signaling interactions of the face, and the absence of neural crest cells in neurocristopathies may not be merely structural.
authors.affiliation: Department of Orthopaedic Surgery, San Francisco General Hospital, The University of California San Francisco, School of Medicine, San Francisco, California 94110, USA.
authors.forename: Diane
authors.initials: D
authors.lastname: Hu
authors.forename: Ralph S
authors.initials: RS
authors.lastname: Marcucio
mesh_terms: D000818:Animals; D002642:Chick Embryo / Q000196:embryology*; D004475:Ectoderm / Q000166:cytology / Q000196:embryology* / Q000502:physiology; D005145:Face / Q000196:embryology / Q000502:physiology; D005346:Fibroblast Growth Factors / Q000037:antagonists & inhibitors / Q000502:physiology; D053823:Hedgehog Proteins / Q000502:physiology; D008648:Mesoderm / Q000196:embryology / Q000502:physiology; D009432:Neural Crest / Q000166:cytology / Q000196:embryology* / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011758:Pyrroles / Q000494:pharmacology; D011784:Quail; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D053823:Hedgehog Proteins; D011758:Pyrroles; C105686:SU 5402; D005346:Fibroblast Growth Factors; D011505:Protein-Tyrosine Kinases