Molecular cloning and sequence analysis of the Danio rerio catalase gene

Catalase is an antioxidant enzyme that plays a central role in the protecti on against oxidative stress through the metabolism of hydrogen peroxide. Ca talase has been well studied in plants, bacteria, and mammals, but little w ork has been done in other vertebrate species. We have cloned the zebrafish (Danio rerio) catalase cDNA containing the complete coding region and anal yzed expression by both reverse transcription polymerase chain reaction and western blot. The deduced amino acid sequence predicts a protein of 526 am ino acids with both the primary DNA and amino acid sequences highly conserv ed among vertebrate species. The major protein-heme contact points in the c atalase enzyme complex are also well conserved, although several amino acid s associated with the second and third levels of the major substrate channe l are not, suggesting potential differences in substrate access or specific ity. The 3' flanking region of the cDNA contains a dinucleotide repeat near the termination codon consisting of a near perfect CA array that is polymo rphic. The rat and mouse catalase genes also contain a CA repeat sequence i n the 3' untranslated region, which, along with an adjacent 5' stem-loop st ructure, has previously been shown to be a site for mRNA protein binding (C lerch, 1995, Arch. Biochem. Biophys. 317 (1995) 267-274). A stem-loop struc ture is also predicted adjacent to the zebrafish CA repeat, suggesting a si milar role in catalase gene regulation. (C) 2000 Elsevier Science Inc. All rights reserved.