Figure 1.—

Fatty acid composition is altered in Δ9 desaturase double mutants. (A) Simplified scheme of fatty acid desaturation in wild-type C. elegans highlighting the roles of the fatty acid desaturases fat-1–fat-7 (left). (Right) The proposed pathway for generation of the unusual fatty acids produced by the fat-6;fat-7 double mutant. Fatty acid nomenclature: X:YΔZ, as in 18:1Δ11, fatty acid chain of X carbon atoms and Y methylene-interrupted cis double bonds; Z indicates the position of a double bond relative to the carboxyl end of the molecule. (B) Gas chromatography traces showing the fatty acid profiles of wild-type and fat-6;fat-7 double mutants. The fat-6;fat-7 double mutants lack 18:1Δ9 and the 20-carbon PUFAs. In addition, they accumulate higher levels of 18:0 as well as unusual fatty acids, labeled A–D in red. The identities of these fatty acids are A-18:1Δ13, B-18:3(Δ8,11,14), C-18:4(Δ5,8,11,14), and D-18:4(Δ8,11,14,17). (C) Changes in desaturase gene expression in fat-6;fat-7 double mutants compared to wild type. Gene expression was measured by QRT–PCR. (D) Simplified fatty acid composition of Δ9 desaturase double mutants grown in axenic culture. Ole, oleic acid (18:1Δ9); Vac, vaccenic acid (18:1Δ11).