title: Identification of an animal omega-3 fatty acid desaturase by heterologous expression in Arabidopsis.
abstract: In animals, fatty acid desaturases catalyze key reactions in the synthesis of arachidonic acid and other polyunsaturated fatty acids. A search of the Caenorhabditis elegans DNA databases, using the sequences of Arabidopsis genes, identified several putative desaturases. Here we describe the characterization of the first of these genes, fat-1. The predicted protein encoded by a fat-1 cDNA showed 32-35% identity with both FAD2 and FAD3 of Arabidopsis. When expressed in transgenic plants, fat-1 resulted in a 90% increase in the proportion of alpha-linolenic acid in root lipids. Wild-type Arabidopsis incorporated omega-6 fatty acids (delta8,11,14-20:3 and delta5,8,11,14-20:4) into membrane lipids but did not desaturate them. By contrast, fat-1 transgenic plants efficiently desaturated both of these fatty acids to the corresponding omega-3 products. These findings indicate that the C. elegans fat-1 gene encodes the first animal representative of a class of glycerolipid desaturases that have previously been characterized in plants and cyanobacteria. The FAT-1 protein is an omega-3 fatty acyl desaturase that recognizes a range of 18- and 20-carbon omega-6 substrates.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman 99164-6340, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Spychalla
authors.forename: A J
authors.initials: AJ
authors.lastname: Kinney
authors.forename: J
authors.initials: J
authors.lastname: Browse
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D044943:Fatty Acid Desaturases / Q000235:genetics*; D005227:Fatty Acids / Q000032:analysis; D017238:Genes, Helminth; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D005227:Fatty Acids; D044943:Fatty Acid Desaturases; C078565:omega-3 fatty acid desaturase