cDNA cloning, characterization, and expression analysis of channel catfish (Ictalurus punctatus Rafinesque, 1818) Peroxiredoxin 6 gene

The peroxiredoxin 6 gene (Prdx6) of channel catfish, Ictalurus punctatus, has been cloned and characterized. The sequence of the channel catfish Prdx6 gene consists of 1,003 nucleotides. Analysis of the nucleotide sequence reveals one open reading frame and 55-bp 5' and 276-bp 3'-untranslated regions. The open reading frame potentially encodes 223 amino acids with a calculated molecular mass of 24.6 kDa. The amino acid sequence of channel catfish Prdx6 had 85.2%, 77.7%, 74.1%, 73.7%, 73.7%, 73.7%, 73.2%, and 71.9% identity with that of zebrafish, chicken, human, mouse, Norway rat, pig, cow, and Xenopus laevis, respectively. Channel catfish Prdx6 had four cysteine residues. In addition to one conserved at Cys46, the Cys132 residue seems to be conserved among fish and frog. Channel catfish Prdx6 conserved two reactive motifs with peroxidase and phopholipase A₂ activity. The channel catfish Prdx6 transcript was detected in all the tissues analyzed, suggesting the gene is constitutively expressed and is involved in protecting channel catfish tissues from oxidative damage. This result will not only provide information for further exploration of the role of Prdx6 in fish pathophysiology but also fill the gap in the evolutionary tree.