Abstract
Human organic anion transporter (OAT) 3 (SLC22A8) is localized to the basolateral membranes of renal tubular epithelial cells and plays a critical role in the excretion of anionic compounds. We previously reported that interindividual variation in the OAT3 mRNA level corresponded to interindividual differences in the rate of renal excretion of cefazolin. However, there is little information available on the molecular mechanisms regulating the gene expression of OAT3. Therefore, in the present study, we examined the transcriptional regulation of human OAT3. A deletion analysis of the OAT3 promoter suggested that the region spanning -214 to -77 base pairs was essential for basal transcriptional activity. This region contained a perfectly conserved cAMP-response element (CRE), and a mutation here led to a reduction in promoter activity. Electrophoretic mobility shift assays showed that CRE-binding protein (CREB)-1 and activating transcription factor (ATF)-1 bound to CRE. The activity of the OAT3 promoter was increased through the phosphorylation of CREB-1 and ATF-1 by treatment with 8-bromo-cAMP. This paper reports the first characterization of the human OAT3 promoter and shows that CREB-1 and ATF-1 function as constitutive and inducible transcriptional regulators of the human OAT3 gene via CRE.
Footnotes
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This work was supported in part by the 21st Century Center of Excellence (COE) program “Knowledge Information Infrastructure for Genome Science”; a grant-in-aid for scientific research from the Ministry of Education, Culture, Sports, Science and Technology of Japan; and a grant-in-aid for Research on Advanced Medical Technology from the Ministry of Health, Labor and Welfare of Japan. J.A. is supported as a research assistant by the 21st Century COE program “Knowledge Information Infrastructure for Genome Science”.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.106.108233.
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ABBREVIATIONS: OAT, organic anion transporter; OK, opossum kidney; 8-Br-cAMP, 8-bromo-cAMP; RACE, rapid amplification of cDNA ends; PCR, polymerase chain reaction; PKA, protein kinase A; EMSA, electrophoretic mobility shift assay; CRE, cAMP-response element; mut, mutation/mutated; ATF, activating transcription factor; CREB, CRE-binding protein; SNP, single-nucleotide polymorphism; cSNP, coding single-nucleotide polymorphism; rSNP, regulatory single-nucleotide polymorphism.
- Received May 22, 2006.
- Accepted June 28, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
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