Cloning two PepT1 cDNA fragments of common carp, Cyprynus carpio (Actinopterygii: Cypriniformes: Cyprinidae)

Background. Common carp, Cyprinus carpio, is a model organism within Teleostei. Oligopeptides are a new and promising alternative source of amino acids in animal as well as in human nutrition. In common carp, the membrane protein that transports oligopeptides across the enterocyte membrane is encoded by the gene PepT1 (SLC15A1). The aim of this paper was to sequence the PepT I (SLC15A1) in common carp. Materials and Methods. Intestine samples were isolated from six-week old common carp. Total RNA was isolated using a Trizol method. Reverse transcription was used to synthesize cDNA. Two different pairs of primers were designed, according to the zebrafish (Danio rerio) PepT1 sequence, and used for PCR. The amplified DNA was isolated by electrophoresis, cloned (pCRII-TOPO vectors), sequenced, and subjected to in silico analysis. Results. Two nucleotide fragments of the PepT1 gene were obtained and analyzed using bioinformatic tools. Both fragments showed a high degree of homology with the known PepT I genes of other teleosts, mammals, and birds. High homology of the PepT1 gene, and similar primary protein structure among the aforementioned taxa probably reflects the conservative function of the PepT I protein product. Both fragments of the PepT I gene were deposited in GenBank (FJ556590; FJ529670). Conclusions. The sequenced fragments of the common carp PepT I gene will allow evaluation of PepT1 expression in the intestines of fish fed diets containing various forms of protein, which is an issue of importance regarding fish nutrition and its import for aquaculture.