Cloning of delta6-desaturase from Mucor circinelloides and its high expression in Saccharomyces cerevisiae.

The aim of this study is to obtain Saccharomyces cerevisiae engineering strain with high gamma-linolenic acid (GLA, gamma-C18:3), which is a nutritionally important fatty acid that plays a vital role in biological structure and cell functions. As the first step,we cloned gamma6-desaturase gene from fungus mucor circinelloides by RT-PCR; delta6-desaturase is responsible for the transformation of linoleic acid into GLA. The PCR product was subcloned into yeast expression vector pYES2 to generate a recombinant plasmid pYES412. Transformation of S. cerevisiae strain INVSc1 was done by the lithium acetate method and the recombinant yeast cells were selected on a uracil-deficient medium. On appropriate medium and temperature,linoleic acid was provided as a substrate to yeast cultures,and the level of gamma-linolenic acid reached 50.07%. So far,the result we obtained is the best in terms of the level of expression of delta6-desaturase gene in Saccharomyces cerevisiae.