Identification of a novel fatty acid elongase with a wide substrate specificity from arachidonic acid-producing fungus Mortierella alpina 1S-4
The isolation and characterization of a gene (MALCE1) that encodes a fatty acid elongase from arachidonic acid-producing fungus Mortierella alpina 1S-4 are described. MALCE1 was confirmed to encode a fatty acid elongase by its expression in yeast Saccharomyces cerevisiae, resulting in the accumulation of 18-, 19-, and 20-carbon monounsaturated fatty acids and eicosanoic acid. Furthermore, the MALCE1 yeast transformant efficiently elongated exogenous 9-hexadecenoic acid, 9,12-octadecadienoic acid, and 9,12,15-octadecatrienoic acid. The MALCE1 gene-silenced strain obtained from M. alpina 1S-4 exhibited a low content of octadecanoic acid and a high content of hexadecanoic acid, compared with those in the wild strain. The enzyme encoded by MALCE1 was demonstrated to be involved in the conversion of hexadecanoic acid to octadecanoic acid, its main role in M. alpina 1S-4.
KeywordsMortierella alpina Fatty acid elongase RNA interference Gene expression Polyunsaturated fatty acid
This work was supported in part by a Grant-in-Aid for Scientific Research (No. 15658024, to S. S.) from the Ministry of Education, Science, Sports, and Culture, Japan, by the COE for Microbial-Process Development Pioneering Future Production Systems (COE program of the Ministry of Education, Science, Sports, and Culture, Japan to S.S.), and by the Project of the New Energy and Industrial Technology Development Organization, Japan (grant 05A07003d, to E.S.).
- Becker DM, Lundblad V (1994) Manipulation of yeast genes. In: Ausubel FM, Brent R, Kingston RE, Moore DD, Seidman JG, Smith JA, Struhl K (eds) Current protocols in molecular biology. Wiley, New York, pp 13.7.1–13.7.10Google Scholar
- Takeno S, Sakuradani E, Tomi A, Inohara-Ochiai M, Kawashima H, Ashikari T, Shimizu S (2005b) Improvement of the fatty acid composition of an oil-producing filamentous fungus, Mortierella alpina 1S-4, through RNA interference with Δ12-desaturase gene expression. Appl Environ Microbiol 71:5124–5128CrossRefGoogle Scholar
- Yamada H, Shimizu S, Shinmen Y (1987) Production of arachidonic acid by Mortierella elongata 1S-5. Agric Biol Chem 51:785–790Google Scholar