title: Isolation and Expression Profile of the Ca-Activated Chloride Channel-like Membrane Protein 6 Gene in Xenopus laevis.
abstract: To clone the first anion channel from Xenopus laevis (X. laevis), we isolated a calcium-activated chloride channel (CLCA)-like membrane protein 6 gene (CMP6) in X. laevis. As a first step in gene isolation, an expressed sequence tags database was screened to find the partial cDNA fragment. A putative partial cDNA sequence was obtained by comparison with rat CLCAs identified in our laboratory. First stranded cDNA was synthesized by reverse transcription polymerase-chain reaction (RT-PCR) using a specific primer designed for the target cDNA. Repeating the 5' and 3' rapid amplification of cDNA ends, full-length cDNA was constructed from the cDNA pool. The full-length CMP6 cDNA completed via 5'- and 3'-RACE was 2,940 bp long and had an open reading frame (ORF) of 940 amino acids. The predicted 940 polypeptides have four major transmembrane domains and showed about 50% identity with that of rat brain CLCAs in our previously published data. Semi-quantification analysis revealed that CMP6 was most abundantly expressed in small intestine, colon and liver. However, all tissues except small intestine, colon and liver had undetectable levels. This result became more credible after we did real-time PCR quantification for the target gene. In view of all CLCA studies focused on human or murine channels, this finding suggests a hypothetical protein as an ion channel, an X. laevis CLCA.
authors.affiliation: Department of Biochemistry and Molecular Cell Biology, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.
authors.forename: Ra Mi
authors.initials: RM
authors.lastname: Lee
authors.forename: Rae Hyung
authors.initials: RH
authors.lastname: Ryu
authors.forename: Seong Won
authors.initials: SW
authors.lastname: Jeong
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Oh
authors.forename: Hue
authors.initials: H
authors.lastname: Huang
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Han
authors.forename: Chi Ho
authors.initials: CH
authors.lastname: Lee
authors.forename: C Justin
authors.initials: CJ
authors.lastname: Lee
authors.forename: Lily Yeh
authors.initials: LY
authors.lastname: Jan
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Jeong