title: UT-A urea transporter promoter, UT-Aalpha, targets principal cells of the renal inner medullary collecting duct.
abstract: The urea transporters, UT-A1 and UT-A3, two members of the UT-A gene family, are localized to the terminal portion of the inner medullary collecting duct (IMCD). In this manuscript, we demonstrate that 4.2 kb of the 5'-flanking region of the UT-A gene (UT-Aalpha promoter) is sufficient to drive the IMCD-specific expression of a heterologous reporter gene, beta-galactosidase (beta-Gal), in transgenic mice. RT-PCR, immunoblotting, and immunohistochemistry demonstrate that within the kidney, transgene expression is confined to the terminal portion of the IMCD. Colocalization studies with aquaporin-2 show that expression is localized to the principal cells of the IMCD2 and IMCD3 regions. Utilizing beta-Gal activity assays, we further show that within the kidney, the beta-Gal transgene can be regulated by both water restriction and glucocorticoids, similar to the regulation of the endogenous UT-A gene. These results demonstrate that 4.2 kb of the UT-Aalpha promoter is sufficient to drive expression of a heterologous reporter gene in a tissue-specific and cell-specific fashion in transgenic mice.
authors.affiliation: Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA. ROFE@ana.au.dk
authors.forename: Robert A
authors.initials: RA
authors.lastname: Fenton
authors.forename: Adetola
authors.initials: A
authors.lastname: Shodeinde
authors.forename: Mark A
authors.initials: MA
authors.lastname: Knepper
mesh_terms: D000818:Animals; D005938:Glucocorticoids / Q000502:physiology; D007679:Kidney Medulla / Q000166:cytology* / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D001616:beta-Galactosidase / Q000502:physiology; D000096982:Urea Transporters
chemical_list: D005938:Glucocorticoids; D026901:Membrane Transport Proteins; D001616:beta-Galactosidase; D000096982:Urea Transporters