Ds. Knutzon et al., IDENTIFICATION OF DELTA-5-DESATURASE FROM MORTIERELLA-ALPINA BY HETEROLOGOUS EXPRESSION IN BAKERS-YEAST AND CANOLA, The Journal of biological chemistry, 273(45), 1998, pp. 29360-29366
A DNA fragment with homology to Delta 6-desaturases from borage and cy
anobacteria was isolated after polymerase chain reaction amplification
of Mortierella alpina cDNA with oligonucleotide primers corresponding
to the conserved regions of known Delta 6-desaturase genes. This frag
ment was used as a probe to isolate a cDNA clone with an open reading
frame encoding 446 amino acids from a M. alpina library, Expression of
this open reading frame from an inducible promoter in Saccharomyces c
es cerevisiae in the presence of various substrates revealed that the
recombinant product had Delta 5-desaturase activity. The effects of gr
owth and induction conditions as well as host strain on activity of th
e recombinant Delta 5-desaturase in S. cerevisiae were evaluated. Expr
ession of the M. alpina Delta 5-desaturase cDNA in transgenic canola s
eeds resulted in the production of taxoleic acid (Delta 5,9-18:2) and
pinolenic acid (Delta 5,9,12-18: 3), which are the Delta 5-desaturatio
n products of oleic and linoleic acids, respectively.