MOLECULAR-CLONING OF A PEROXIDASE MESSENGER-RNA SPECIFICALLY EXPRESSED IN THE INK GLAND OF SEPIA-OFFICINALIS

A full-length cDNA encoding a peroxidase has been assembled from two d ifferent overlapping cDNA clones isolated from the cDNA library of Sep ia officinalis ink gland and 5' RACE procedure. The cDNA of 2898 bp co ntains an open reading frame of 2778 bp corresponding to a protein of 926 amino acids. The protein shows 76% identity with a peroxidase isol ated from the light organ of the squid Euprymna scolopes and approxima tely 30% identity with mammalian peroxidases. Northern blot analysis o f mRNA from various tissues of Sepia officinalis reveals that peroxida se is exclusively expressed in the ink gland. These results represent the first characterization of a melanogenic peroxidase whose possible involvement in the biosynthesis of melanin is discussed. (C) 1997 Else vier Science B.V.