Cloning and characterization of estrone sulfate transporter protein (ESTP) from Clonorchis sinensis

초록

The primary cause of clonorchiasis is the consumption of raw or undercooked freshwater fish containing metacercaria of Clonorchis sinensis. The clonorchiasis affects above 20 million people in Korea, Japan, Southern Chiana and other Southeast Asian countries. The long term infection of liver fluke has been shown, both experimentally and epidemiologically, to cause chronic pathological changes, such as cholangitis, cholecystitis, hepatomegaly, hepatic fibrosis, and cholangiocarcinoma. The purpose of this study was to explore the target for the development of new therapeutic drugs of Clonorchis sinensis. Therefore, we tried to cloning and characterization of NCBI recorded bile acid transporter protein (ESTP). The gene was isolated using reverse-transcription polymerase chain reaction from adult clonorchis sinensis and functional analysis was employed Xenopus oocyte expression system. The open reading frame of ESTP cDNA consist of 1641 base pairs that encoded a 546-amino acid residue protein. Hydropathy analysis suggested that ESTP possess 10 putative membrane-spanning domains. When expressed in Xenopus oocytes, ESTP mediated the transport of radiolabeled estrone sulfate in a time- and sodium-dependent manner. There were no uptake of bile acid (taurocholic acid), organic anion and cation transporter substrate (p-aminohippuric acid and tetraethyl ammoniu), respectively. ESTP showed no antiport or cotransport properties by efflux experiments. From above results, this transporter protein is estrone sulfate transporter but not bile acid transporter. It would be necessary kinetic and inhibition experiment to clarify the detail characteristics of this transporter protein.