Heterologous expression of Mucor rouxii Delta(12)-desaturase gene in Saccharomyces cerevisiae

In this study we present the cloning and functional characterization of a g ene whose product is responsible for Delta(12)-desaturase activity and is i nvolved in the metabolic pathway of gamma-linolenic acid (GLA) synthesis of Mucor rouxii. A cDNA encoding for Delta(12)-desaturase of M. rouxii was ob tained using the combination of reverse transcription-polymerase chain reac tion (RT-PCR) and rapid amplification cDNA ends (RACE) techniques. The 1191 bp code for an open reading frame of 396 amino acid residues. The deduced amino acid sequence of the cloned cDNA comprises three conserved histidine regions and two hydrophobic domains and showed similarity with microsomal o mega-3 and omega-6 desaturases of plants. Expression of this open reading f rame in Saccharomyces cerevisiae resulted in the accumulation of linoleic a cid (C18:2), suggesting that this gene encodes for a membrane-bound desatur ase, Delta(12)-desaturase, of M. rouxii that is functional in yeast. (C) 19 99 Academic Press.