Cloning, tissue distribution and nutritional regulation of a Δ6-desaturase-like enzyme in rainbow trout

Abstract

This report describes the cloning, nutritional regulation and tissue distribution of a desaturase-like enzyme in rainbow trout ( Oncorhynchus mykiss). The open reading frame of the trout desaturase-like cDNA encodes a 454-amino acid peptide that contains two membrane-spanning domains, three histidine-rich regions and a cytochrome b 5 domain, which all align perfectly with the same domains located in other recently identified vertebrate Δ5- and Δ6-desaturases. Nutritional regulation of trout desaturase-like gene expression, as well as the tissue expression profile, are also similar to those observed in other vertebrate Δ5- and Δ6-desaturases. Finally, the sequence alignments between the predicted protein sequence of rainbow trout desaturase-like and other Δ6- and Δ5-desaturases revealed a high percentage identity with Δ6-desaturases (64–66% identity with vertebrate Δ6-desaturases). These results demonstrate for the first time the presence and nutritional modulation of a Δ6-desaturase-like cDNA in rainbow trout.