title: Expression of endothelin 3 by mesenchymal cells of embryonic mouse caecum.
abstract: BACKGROUND
  Mutations in endothelin 3 (EDN3) and endothelin B receptor (EDNRB) genes cause terminal colonic aganglionosis in mice, and mutations in these genes have also been linked to the terminal aganglionosis seen in human Hirschsprung's disease. However, details of EDN3 expression during embryogenesis are lacking, and consequently the cellular mechanism by which EDN3 regulates innervation of the terminal gut is unclear.
  
  
  OBJECTIVE
  To localise the expression of EDN3 and EDNRB in the embryonic mouse gut.
  
  
  METHODS
  Expression of EDN3 and EDNRB mRNA was analysed by reverse transcription polymerase chain reaction and in situ hybridisation.
  
  
  RESULTS
  High levels of EDN3 mRNA expression were restricted to mesenchymal cells of the caecum before and after the arrival of neural crest cells. In contrast, EDNRB expression along the gut displayed a time dependent pattern similar to those of the protein tyrosine kinase ret and the neural crest cell marker PGP9.5.
  
  
  CONCLUSIONS
  Mesenchymal cells of the caecum express high levels of EDN3 mRNA during embryogenesis and hence the production of EDN3 at the caecum is likely to act on neural crest cells as a paracrine factor necessary for subsequent innervation of the terminal gut.
authors.affiliation: Department of Human Anatomy and Cell Biology, The University of Liverpool, Ashton Street, Liverpool L69 3GE, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Leibl
authors.forename: T
authors.initials: T
authors.lastname: Ota
authors.forename: M N
authors.initials: MN
authors.lastname: Woodward
authors.forename: S E
authors.initials: SE
authors.lastname: Kenny
authors.forename: D A
authors.initials: DA
authors.lastname: Lloyd
authors.forename: C R
authors.initials: CR
authors.lastname: Vaillant
authors.forename: D H
authors.initials: DH
authors.lastname: Edgar
mesh_terms: D000818:Animals; D002432:Cecum / Q000196:embryology*; D005314:Embryonic and Fetal Development; D019334:Endothelin-3 / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000196:embryology / Q000294:innervation; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D019334:Endothelin-3; D012333:RNA, Messenger; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin