title: Asymmetric requirement of surface epithelial β-catenin during the upper and lower jaw development.
abstract: BACKGROUND
  Intercellular communication between epithelial and mesenchymal cells is central to mammalian craniofacial development. β-catenin is the gateway of canonical Wnt signaling, one of the major evolutionarily conserved cell-cell communication pathways in metazoa. In this study, we report an unexpected stage- and tissue-specific function of β-catenin during mammalian jaw development.
  
  
  RESULTS
  Using a unique mouse genetic tool, we have discovered that epithelial β-catenin is essential for lower jaw formation, while attenuation of β-catenin is required for proper upper jaw development. Changes in β-catenin in vivo alter major epithelial Fgf8, Bmp4, Shh, and Edn1 signals, resulting in partial transcriptional reprogramming of the neural crest-derived mesenchyme, the primary source of jawbones.
  
  
  CONCLUSIONS
  The Wnt/β-catenin signal coordinates expression of multiple epithelial signals and has stage-specific asymmetric functions during mammalian upper and lower jaw development. In addition, these findings suggest that evolutionary changes of the canonical Wnt/β-catenin signaling pathway may lead to innovation of jaws.
authors.affiliation: Department of Urology, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
authors.forename: Ye
authors.initials: Y
authors.lastname: Sun
authors.forename: Ian
authors.initials: I
authors.lastname: Teng
authors.forename: Randi
authors.initials: R
authors.lastname: Huo
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rosenfeld
authors.forename: Lorin E
authors.initials: LE
authors.lastname: Olson
authors.forename: Xiaokun
authors.initials: X
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D004848:Epithelium / Q000196:embryology / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D007568:Jaw / Q000196:embryology* / Q000502:physiology; D008648:Mesoderm / Q000196:embryology / Q000502:physiology; D051379:Mice; D009928:Organ Specificity; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000502:physiology*
chemical_list: D051153:Wnt Proteins; D051176:beta Catenin