Clonging and Characterization of Human Organic Anion Transporter 5 and Its Genetic Polymorphism in Osteoporosis Patients in Korea

초록

The organic anion transporters (OATs) are expressed in various tissues, primarily in the liver and kidney, but they are also expressed in the placenta, small intestine, and the choroid plexus, which are all epithelial cells that transport endogenous and exogenous compounds. The OATs also play a role as drug transporters. Here we report cloning and characterization of human organic anion transporter 5 (hOAT5) and its genetic polymorphism in osteoporosis patients in Korea. The hOAT5 was isolated from human kidney cDNA library by hybridization cloning method using isotope labeled probe prepared by PCR. The isolated hOAT5 cDNA was composed of 2327 base pair that encoded 525 amino acid residue protein with 12 putative transmembrane domains. The hOAT5 messanger RNA was expressed in kidney by northern blot analysis. The hOAT5-mediated transport of estrone sulfate, dehydroepiandrosterone sulfate and ochratoxin A was detected time- and concentration-dependent manners. These uptake were inhibited by several steroid sulfate conjugate but not steroid glucuronide conjugates. In order to find genetic polymorphism in female osteoporosis patient in Korea, denaturing gradient gel electrophoresis (DGGE) was employed at every 50 osteoporosis patients and normal women. The six SNPs in hOAT5 were found. Among them, three non-synonymous SNPs were found (R256Q , F426S and P496L). We have succeeded to prepare these mutants. The functional changes of these non-synonymous mutants would be necessary.