title: Wnt9b plays a central role in the regulation of mesenchymal to epithelial transitions underlying organogenesis of the mammalian urogenital system.
abstract: The vertebrate urogenital system forms due to inductive interactions between the Wolffian duct, its derivative the ureteric bud, and their adjacent mesenchymes. These establish epithelial primordia within the mesonephric (embryonic) and metanephric (adult) kidneys and the Müllerian duct, the anlage of much of the female reproductive tract. We show that Wnt9b is expressed in the inductive epithelia and is essential for the development of mesonephric and metanephric tubules and caudal extension of the Müllerian duct. Wnt9b is required for the earliest inductive response in metanephric mesenchyme. Further, Wnt9b-expressing cells can functionally substitute for the ureteric bud in these interactions. Wnt9b acts upstream of another Wnt, Wnt4, in this process, and our data implicate canonical Wnt signaling as one of the major pathways in the organization of the mammalian urogenital system. Together these findings suggest that Wnt9b is a common organizing signal regulating diverse components of the mammalian urogenital system.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Carroll
authors.forename: Joo-Seop
authors.initials: JS
authors.lastname: Park
authors.forename: Shigemi
authors.initials: S
authors.lastname: Hayashi
authors.forename: Arindam
authors.initials: A
authors.lastname: Majumdar
authors.forename: Andrew P
authors.initials: AP
authors.lastname: McMahon
mesh_terms: D000818:Animals; D018920:Coculture Techniques; D004848:Epithelium / Q000196:embryology / Q000378:metabolism; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000196:embryology / Q000378:metabolism; D008297:Male; D008648:Mesoderm / Q000166:cytology / Q000502:physiology*; D051379:Mice; D009095:Mullerian Ducts / Q000196:embryology; D009154:Mutation; D041681:NIH 3T3 Cells; D038081:Organogenesis / Q000502:physiology; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014566:Urogenital System / Q000196:embryology*; D051153:Wnt Proteins; D060528:Wnt4 Protein; D014928:Wolffian Ducts / Q000196:embryology* / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D060528:Wnt4 Protein; C555582:Wnt4 protein, mouse