title: Lim 1 is required for nephric duct extension and ureteric bud morphogenesis.
abstract: The nephric duct plays a central role in orchestrating the development of the mammalian urogenital system. Lim 1 is a homeobox gene required for head and urogenital development in the mouse but most Lim 1-deficient embryos die by embryonic day 10. To determine the role of Lim 1 in the development of the nephric duct, we conditionally removed Lim 1 in the nephric epithelium just after the nephric duct begins to form using a floxed allele of Lim 1 and Pax2-cre transgenic mice. We report that Lim 1 conditional knockout mice have renal hypoplasia and hydronephrosis. Developmental studies revealed that the caudal portion of the nephric duct did not reach the urogenital sinus at embryonic day 10.5, formation of the ureteric bud was delayed, the ureteric bud was smaller and branching of the ureteric bud reduced. We also found that the nephric duct was generally not maintained and extension of the Müllerian duct inhibited. Molecular analysis indicated that Pax2 was expressed normally but the expression of Wnt9b and E-cadherin in the nephric duct was markedly altered. These results suggest that Lim 1 influences nephric duct extension and ureteric bud outgrowth by regulating and or maintaining the differentiation of the nephric epithelium.
authors.affiliation: Department of Genetics, Cell Biology and Development and University of Minnesota Developmental Biology Center, University of Minnesota, 6-160 Jackson Hall, 321 Church St. SE, Minneapolis, MN 55455, USA.
authors.forename: Anissa
authors.initials: A
authors.lastname: Pedersen
authors.forename: Christian
authors.initials: C
authors.lastname: Skjong
authors.forename: William
authors.initials: W
authors.lastname: Shawlot
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002454:Cell Differentiation; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D006869:Hydronephrosis / Q000196:embryology / Q000235:genetics / Q000473:pathology; D007668:Kidney / Q000002:abnormalities / Q000196:embryology / Q000378:metabolism; D060850:LIM-Homeodomain Proteins; D051379:Mice; D018345:Mice, Knockout; D009024:Morphogenesis; D051762:PAX2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors; D014513:Ureter / Q000002:abnormalities / Q000196:embryology / Q000378:metabolism; D014566:Urogenital System / Q000196:embryology* / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: D015820:Cadherins; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; C499523:Lhx1 protein, mouse; D051762:PAX2 Transcription Factor; C497319:Pax2 protein, mouse; D014157:Transcription Factors; D051153:Wnt Proteins