title: Tissue-specific expression of an 11 beta-hydroxysteroid dehydrogenase with a truncated N-terminal domain. A potential mechanism for differential intracellular localization within mineralocorticoid target cells.
abstract: The enzyme 11 beta-hydroxysteroid dehydrogenase (11-HSD) is thought to confer specificity on the nonselective Type I adrenocorticoid receptor by converting glucocorticoids to receptor-inactive metabolites in mineralocorticoid target tissues. S1 nuclease analyses using a rat liver 11-HSD probe demonstrated tissue-specific expression of the 5' region of the 11-HSD gene in the liver, lung, and kidney not evident in previous studies. Renal tissue contained a unique protected species which mapped to a position within the coding region, consistent with a divergence in liver and kidney protein sequences. Screening of a rat kidney cDNA library resulted in the isolation of several clones (11-HSD1B) noncolinear in their 5' regions with the liver sequence (11-HSD1A). Nucleic acid sequence analysis showed that the divergent clones code for a protein lacking a 26-amino acid NH2-terminal putative membrane-spanning signal peptide. The deletion of the leader sequence from the microsomal 11-HSD1A protein may result in a nuclear localization of the 11-HSD1B isoform. The renal 11-HSD1A and 11-HSD1B species increased coordinately during ontogeny and in parallel with the developmental surge in glucocorticoids. At least three alternate sites of polyadenylation were found to be utilized by the 11-HSD gene. Southern blot analysis showed the presence of a single gene in the rat. This study shows the expression of a kidney-specific 11-HSD isoform which may protect the Type I adrenocorticoid receptor from occupation by glucocorticoids in the nucleus of a mineralocorticoid target cell.
authors.affiliation: Laboratory of Molecular Hypertension, Baker Institute of Medical Research, Prahran, Australia.
authors.forename: Z
authors.initials: Z
authors.lastname: Krozowski
authors.forename: V
authors.initials: V
authors.lastname: Obeyesekere
authors.forename: R
authors.initials: R
authors.lastname: Smith
authors.forename: W
authors.initials: W
authors.lastname: Mercer
mesh_terms: D042842:11-beta-Hydroxysteroid Dehydrogenases; D000818:Animals; D001345:Autoradiography; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D006913:Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D008901:Mineralocorticoids / Q000378:metabolism*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D008901:Mineralocorticoids; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D004247:DNA; D006913:Hydroxysteroid Dehydrogenases; D042842:11-beta-Hydroxysteroid Dehydrogenases