cDNA cloning and expression profile analysis of an ATP-binding cassette transporter in the hepatopancreas and intestine of shrimp Fenneropenaeus chinensis

ATP-binding cassette (ABC) transporters are integral membrane proteins which carry diverse substrates across biological membranes. In this study, we report the cloning of a full-length, 2122-bp cDNA sequence encoding a gene of the ABC transporter subfamily G (ABCG) from the shrimp Fenneropenaeus chinensis. The deduced protein, FcABCG, contains 633 amino acid residues with a theoretical molecular weight of 70.57kDa. Phylogenetic analysis showed that the FcABCG clusters with the shrimp Litopenaeus vannamei ABCG in the same clade and is more closely related to the insect ABC transporter/white proteins than to the ABCG2 of the fish Salmo salar. High-level mRNA expression of FcABCG was detected in the tissues of hepatopancreas and intestine using a real-time quantitative reverse transcriptase PCR. Furthermore, exposure to alkaline pH stress conditions and norfloxacin diets result in the activation of the FcABCG gene in F. chinensis. These results suggest that the ABCG transporter of F. chinensis might play a role in coping high pH stress and in exporting xenobiotics.