Molecular Cloning And Of Tissue Expression Analysis Of Uncoupling Protein 2 Gene In Chinese Perch Siniperca Chuatsi And Silver Carp Hypophthalmichthys Molitrix

The full-length cDNA sequences of uncoupling protein 2 (UCP2) have been cloned from Chinese perch (Siniperca chuatsi) and silver carp (Hypophthalmichthys molitrix). Partial UCP2 cDNA of the two fishes were amplified from liver using RT-PCR and degenerate primers. Rapid amplification of cDNA ends (RACE) method was used to complete the cloning of the 5' and 3' ends of full-length cDNA for both fishes. The full-length UCP2 cDNA of Chinese perch was determined to be 1397 bp in length. Its coding region contains 894 nucleotides, and the deduced protein sequence consists of 297 amino acids. The 5' and 3' untranslated region (UTR) of the Chinese perch UCP2 cDNA is 42 bp and 461 bp, respectively. The full-length UCP2 cDNA of silver carp was determined to be 1452 bp in length. Its coding region contains 933 nucleotides, and the deduced protein sequence consists of 310 amino acids. The 5' and 3' UTR of the silver carp UCP2 cDNA is 337 bp and 182 bp, respectively. In the deduced amino acid sequence of both fishes UCP2 cDNA, three mitochondrial carrier protein motifs, UCP signature motifs, six transmembrane α-helix domains, and the putative purine-nucleotide binding domain (PNBD), were identified.Amino acid sequence alignment shows that, UCP2 proteins of cyprinids have high homology. The similarity of UCP2 amino acid sequences between silver carp and common carp or zebrafish, is 96%～97%, and between silver carp and mammals (human, mouse, rat, pig, dog and cow), is 86%～87%. The similarity of UCP2 amino acid sequences between Chinese perch and largemouth bass, is 95%, and between Chinese perch and mammals (human, mouse, rat, pig, dog and cow), is 75%～78%. However, the homology of cyprinids and percid fishes UCP2 is less than 80%.We generated a phylogenetic tree with 30 sequences of UCP family members. In our tree, UCP2 of Chinese perch and silver carp group together with their respective orthologs, that is, Chinese perch UCP2 clusters firstly with percid UCP2, and silver carp UCP2 clusters firstly with cyprinids UCP2. Those results accorded with morphological classification system. However, UCP2 of the two fishes have a far...