Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Morphological and histoenzymological differences have been observed between intercalated and principal cells of the quail Coturnix coturnix japonica collecting ducts. The present study was designed to shed light on the lectin affinity of the collecting duct cells within cortex and medulla by the use of HRP-labelled lectins combined with glycosidase degradation. Binding of PNA and RCA-I lectins consequent to enzymatic release of sialic acid revealed abundant sialylated carbohydrate moieties within the principal cell cytoplasm. This characteristic binding pattern differed considerably from the staining observed in the intercalated cells. Interesting information also emerged about the presence of sialoglycoconjugates having the terminal disaccharide sialic acid-beta-N-acetylgalactosamine originating from the increased SBA binding and the unmodified DBA labelling after removal of sialic acid. Sequential degradation by sialidase/beta-galactosidase followed by incubation with DBA offered the possibility to suspect that the receptor sugar for the penultimate beta-galactose may be N-acetylgalactosamine. Conversely, we were not able to define the accept sugar for penultimate beta-GalNAc owing to the lack of availability of beta-N-acetylgalactosaminidase enzyme. When although further studies are clearly needed to elucidate the physiological role of the cellular sialoglycoconjugates detected, the present results already provide valuable insight into the carbohydrate composition of intercalated and principal cells in the quail collecting ducts.
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PMID:Mosaic lectin labelling in the quail collecting ducts. 754 Dec 64

Renal medullary prostaglandins are believed to exert an important functional role in antagonizing vasopressin effects in dehydration. Studies were undertaken to determine the effect of hyperosmolality on cyclooxygenase (COX) isoform expression in the renal medulla. COX-1 and COX-2 mRNA and protein levels were determined by RT-PCR or Western blotting in Sprague-Dawley rats on varying water intakes, in Brattleboro rats and in Long-Evans controls. Over a wide range of urinary tonicity, COX-2 expression correlated closely with urine osmolality levels (R = 0.872). COX-1 levels did not vary. Immunolocalization showed that the stimulation of COX-2 expression by dehydration occurred predominantly in the collecting duct. Hypertonicity caused by addition of NaCl produced a dose- and time-dependent stimulation of COX-2 expression in mIMCD-K2 cells as well as in MDCK cells. COX-1 was unaffected. In the same cell lines, mannitol, sucrose, and raffinose also had a stimulatory effect. The tonicity-stimulated COX-2 expression in mIMCD-K2 cells was almost completely blocked by a tyrosine kinase inhibitor, genistein at 100 microM. In MDCK cells transfected with a 2.7-kb COX-2 promoter and lacZ reporter construct, NaCl induced a twofold increase in beta-galactosidase activity. Using mIMCD-K2 cells, hypertonic NaCl (600 mosmol/kgH(2)O for 24 h) induced a 33-fold increase in PGE(2) release determined by enzyme immunoassay, an effect completely blocked by 3 microM indomethacin or the COX-2-specific blocker N-(2-cyclohexy-4-nitrophenyl)methanesulfonamide (NS-398). We conclude that in inner medulla, COX-2 but not COX-1 is upregulated by hyperosmolality.
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PMID:Regulation of cyclooxygenase-2 expression in renal medulla by tonicity in vivo and in vitro. 1040 91

Kidney-specific cadherin (Ksp-cadherin, cadherin 16) is a tissue-specific member of the cadherin superfamily that is expressed exclusively in the basolateral membrane of tubular epithelial cells in the kidney. To determine the basis for tissue-specific expression of Ksp-cadherin in vivo, we evaluated the activity of the promoter in transgenic mice. Transgenic mice containing 3.3 kb of the mouse Ksp-cadherin promoter and an Escherichia coli lacZ reporter gene were generated by pronuclear microinjection. Assays of beta-galactosidase enzyme activity showed that the transgene was expressed exclusively in the kidney in both adult and developing mice. Within the kidney, the transgene was expressed in a subset of renal tubular epithelial cells that endogenously expressed Ksp-cadherin and that were identified as collecting ducts by colabeling with Dolichos biflorus agglutinin. In the developing metanephros, expression of the transgene in the branching ureteric bud correlated with the developmental expression of Ksp-cadherin. Identical patterns of expression were observed in multiple founder mice, indicating that kidney specificity was independent of transgene integration site. However, heterocellular expression was observed consistent with repeat-induced gene silencing. We conclude that the Ksp-cadherin gene promoter directs kidney-specific expression in vivo. Regulatory elements that are sufficient to recapitulate the tissue- and differentiation-specific expression of Ksp-cadherin in the renal collecting duct are located within 3.3 kb upstream to the transcriptional start site.
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PMID:Ksp-cadherin gene promoter. II. Kidney-specific activity in transgenic mice. 1051 85

The Cre/loxP transgenic system may be used to achieve temporally and/or spatially regulated gene deletion. The Mx1Cre mouse expresses Cre recombinase under control of the IFN-inducible Mx1 promoter. Mx1Cre mice were crossed with a reporter strain (ROSA26tm1Sor) in which beta-galactosidase activity is expressed only after Cre-mediated recombination to determine the cellular pattern of Cre-mediated genetic recombination in the kidney and other tissues. Widespread recombination was observed in vascular endothelium as well as in the liver and spleen. Recombination was restricted to subsets of stromal cells in uterus, duodenum, colon, aorta, and kidney. In the cortex, chi-galactosidase activity was detected in a subset of tubules and all glomerular cells, including endothelium, mesangium, and podocytes. No chi-galactosidase activity was detected in proximal tubules. Costaining of kidneys with segment-specific markers demonstrated induction of chi-galactosidase activity in collecting duct, with sporadic labeling of the thick ascending limb but no significant labeling of distal convoluted tubules. We conclude that Mx1-driven gene recombination is spatially as well as temporally restricted. The Mx1Cre transgene should prove a useful reagent to achieve temporally regulated recombination in endothelial, glomerular, and distal renal epithelia in mice.
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PMID:Differential, inducible gene targeting in renal epithelia, vascular endothelium, and viscera of Mx1Cre mice. 1252 77

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.
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PMID:UT-A urea transporter promoter, UT-Aalpha, targets principal cells of the renal inner medullary collecting duct. 1609 80

To assess the feasibility of using the renin promoter for expressing Cre recombinase in juxtaglomerular (JG) cells only, we generated five independent transgenic mouse lines (designated hRen-Cre) expressing Cre recombinase under control of a 12.2-kb human renin promoter. In the kidneys of adult mice Cre mRNA (RT-PCR) was found in the renal cortex, with Cre protein (immunohistochemistry) being localized in afferent arterioles and to a lower degree in interlobular arteries. Cre mRNA levels were regulated in a renin-typical fashion by changes in oral salt intake, water restriction, or isoproterenol infusion, indicating the presence of key regulatory elements within 12.2 kb of the 5'-flanking region of the human renin gene. hRen-Cre mice were interbred with both the ROSA26-EGFP and ROSA26-lacZ reporter strains to assess renin promoter activity from Cre-mediated excision of a floxed stop cassette and subsequent enhanced green fluorescent protein (EGFP) and beta-galactosidase (beta-gal) detection. In adult mice, beta-gal staining and EGFP were observed in afferent arterioles and interlobular arteries, overlapping with Cre protein expression. In addition, intense beta-gal staining was found in cortical and medullary collecting ducts where Cre expression was minimal. In embryonic kidneys, beta-gal staining was detected in the developing collecting duct system beginning at embryonic day 12, showing substantial activity of the human renin promoter in the branching ureteric bud. Our data indicate that besides its well-known activity in JG cells and renal vessels the human renin promoter is transiently active in the collecting duct system during kidney development, complicating the use of this approach for JG cell-specific excision of floxed targets.
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PMID:Reporter gene recombination in juxtaglomerular granular and collecting duct cells by human renin promoter-Cre recombinase transgene. 1641 17

Urea movement across plasma membranes is modulated by specialized urea transporter proteins. These proteins are proposed to play key roles in the urinary concentrating mechanism and fluid homeostasis. To date, two urea-transporter genes have been cloned; UT-A (Slc14a2), encoding at least five proteins and UT-B (Slc14a1) encoding a single protein isoform. Recently we engineered mice that lack the inner medullary collecting duct (IMCD) urea transporters, UT-A1 and UT-A3 (UT-A1/3 -/- mice). This article includes 1) a historical review of the role of renal urea transporters in renal function; 2) a review of our studies utilizing the UT-A1/3 -/- mice; 3) description of an additional line of transgenic mice in which beta-galactosidase expression is driven by the alpha-promoter of the UT-A gene, which is allowing better physiological definition of control mechanisms for UT-A expression; and 4) a discussion of the implications of the studies in transgenic mice for the teaching of kidney physiology.
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PMID:Role of collecting duct urea transporters in the kidney--insights from mouse models. 1726 85

The expression pattern of the electroneutral Na(+)-HCO(3)(-)cotransporter NBCn1 (slc4a7) was investigated by beta-galactosidase staining of mice with a LacZ insertion into the NBCn1 gene. This method is of particular value because it is independent of immunoreactivity. We find that the NBCn1 promoter is active in a number of tissues where NBCn1 has previously been functionally or immunohistochemically identified, including a broad range of blood vessels (vascular smooth muscle cells and endothelial cells), kidney thick ascending limb and medullary collecting duct epithelial cells, the epithelial lining of the kidney pelvis, duodenal enterocytes, choroid plexus epithelial cells, hippocampus, and retina. Kidney corpuscles, colonic mucosa, and nonvascular smooth muscle cells (from the urinary bladder, trachea, gastrointestinal wall, and uterus) were novel areas of promoter activity. Atrial but not ventricular cardiomyocytes were stained. In the brain, distinct layers of the cerebral cortex and cerebellar Purkinje cells were stained as was the dentate nucleus. No staining of skeletal muscle or cortical collecting ducts was observed. RT-PCR analyses confirmed the expression of NBCn1 and beta-galactosidase in selected tissues. Disruption of the NBCn1 gene resulted in reduced NBCn1 expression, and in bladder smooth muscle cells, reduced amiloride-insensitive Na(+)-dependent HCO(3)(-) influx was observed. Furthermore, disruption of the NBCn1 gene resulted in a lower intracellular steady-state pH of bladder smooth muscle cells in the presence of CO(2)/HCO(3)(-) but not in its nominal absence. We conclude that NBCn1 has a broad expression profile, supporting previous findings based on immunoreactivity, and suggest several new tissues where NBCn1 may be important.
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PMID:Antibody-independent localization of the electroneutral Na+-HCO3- cotransporter NBCn1 (slc4a7) in mice. 1807 6

Recessive inheritance of mutations in ceroid neuronal lipofuscinosis type 3 (CLN3) results in juvenile neuronal ceroid lipofuscinosis (JNCL), a childhood neurodegenerative disease with symptoms including loss of vision, seizures, and motor and mental decline. CLN3p is a transmembrane protein with undefined function. Using a Cln3 reporter mouse harboring a nuclear-localized bacterial beta-galactosidase (beta-Gal) gene driven by the native Cln3 promoter, we detected beta-Gal most prominently in epithelial cells of skin, colon, lung, and kidney. In the kidney, beta-Gal-positive nuclei were predominant in medullary collecting duct principal cells, with increased expression along the medullary osmotic gradient. Quantification of Cln3 transcript levels from kidneys of wild-type (Cln3(+/+)) mice corroborated this expression gradient. Reporter mouse-derived renal epithelial cultures demonstrated a tonicity-dependent increase in beta-Gal expression. RT-quantitative PCR determination of Cln3 transcript levels further supported osmoregulation at the Cln3 locus. In vivo, osmoresponsiveness of Cln3 was demonstrated by reduction of medullary Cln3 transcript abundance after furosemide administration. Primary cultures of epithelial cells of the inner medulla from Cln3(lacZ/lacZ) (CLN3p-null) mice showed no defect in osmolyte accumulation or taurine flux, arguing against a requirement for CLN3p in osmolyte import or synthesis. CLN3p-deficient mice with free access to water showed a mild urine-concentrating defect but, upon water deprivation, were able to concentrate their urine normally. Unexpectedly, we found that CLN3p-deficient mice were hyperkalemic and had a low fractional excretion of K(+). Together, these findings suggest an osmoregulated role for CLN3p in renal control of water and K(+) balance.
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PMID:Osmoregulation of ceroid neuronal lipofuscinosis type 3 in the renal medulla. 2021 47