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. 1994 Jan;6(1):147–158. doi: 10.1105/tpc.6.1.147

Arabidopsis FAD2 gene encodes the enzyme that is essential for polyunsaturated lipid synthesis.

J Okuley 1, J Lightner 1, K Feldmann 1, N Yadav 1, E Lark 1, J Browse 1
PMCID: PMC160423  PMID: 7907506

Abstract

The polyunsaturated fatty acids linoleate and alpha-linolenate are important membrane components and are the essential fatty acids of human nutrition. The major enzyme responsible for the synthesis of these compounds is the plant oleate desaturase of the endoplasmic reticulum, and its activity is controlled in Arabidopsis by the fatty acid desaturation 2 (fad2) locus. A fad2 allele was identified in a population of Arabidopsis in which mutations had been created by T-DNA insertions. Genomic DNA flanking the T-DNA was cloned by plasmid rescue and used to isolate cDNA and genomic clones of FAD2. A cDNA containing the entire FAD2 coding sequence was expressed in fad2 mutant plants and shown to complement the mutant fatty acid phenotype. The deduced amino acid sequence from the cDNA showed homology to other plant desaturases, and this confirmed that FAD2 is the structural gene for the desaturase. Gel blot analyses of FAD2 mRNA levels showed that the gene is expressed throughout the plant and suggest that transcript levels are in excess of the amount needed to account for oleate desaturation. Sequence analysis identified histidine-rich motifs that could contribute to an iron binding site in the cytoplasmic domain of the protein. Such a position would facilitate interaction between the desaturase and cytochrome b5, which is the direct source of electrons for the desaturation reaction, but would limit interaction of the active site with the fatty acyl substrate.

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Selected References

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  1. Cahoon E. B., Shanklin J., Ohlrogge J. B. Expression of a coriander desaturase results in petroselinic acid production in transgenic tobacco. Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11184–11188. doi: 10.1073/pnas.89.23.11184. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Devereux J., Haeberli P., Smithies O. A comprehensive set of sequence analysis programs for the VAX. Nucleic Acids Res. 1984 Jan 11;12(1 Pt 1):387–395. doi: 10.1093/nar/12.1part1.387. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Elledge S. J., Mulligan J. T., Ramer S. W., Spottswood M., Davis R. W. Lambda YES: a multifunctional cDNA expression vector for the isolation of genes by complementation of yeast and Escherichia coli mutations. Proc Natl Acad Sci U S A. 1991 Mar 1;88(5):1731–1735. doi: 10.1073/pnas.88.5.1731. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Feldmann K. A., Marks M. D., Christianson M. L., Quatrano R. S. A Dwarf Mutant of Arabidopsis Generated by T-DNA Insertion Mutagenesis. Science. 1989 Mar 10;243(4896):1351–1354. doi: 10.1126/science.243.4896.1351. [DOI] [PubMed] [Google Scholar]
  5. Fox B. G., Shanklin J., Somerville C., Münck E. Stearoyl-acyl carrier protein delta 9 desaturase from Ricinus communis is a diiron-oxo protein. Proc Natl Acad Sci U S A. 1993 Mar 15;90(6):2486–2490. doi: 10.1073/pnas.90.6.2486. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Holsters M., de Waele D., Depicker A., Messens E., van Montagu M., Schell J. Transfection and transformation of Agrobacterium tumefaciens. Mol Gen Genet. 1978 Jul 11;163(2):181–187. doi: 10.1007/BF00267408. [DOI] [PubMed] [Google Scholar]
  7. Hugly S., Somerville C. A role for membrane lipid polyunsaturation in chloroplast biogenesis at low temperature. Plant Physiol. 1992 May;99(1):197–202. doi: 10.1104/pp.99.1.197. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Iba K., Gibson S., Nishiuchi T., Fuse T., Nishimura M., Arondel V., Hugly S., Somerville C. A gene encoding a chloroplast omega-3 fatty acid desaturase complements alterations in fatty acid desaturation and chloroplast copy number of the fad7 mutant of Arabidopsis thaliana. J Biol Chem. 1993 Nov 15;268(32):24099–24105. [PubMed] [Google Scholar]
  9. Jackson M. R., Nilsson T., Peterson P. A. Identification of a consensus motif for retention of transmembrane proteins in the endoplasmic reticulum. EMBO J. 1990 Oct;9(10):3153–3162. doi: 10.1002/j.1460-2075.1990.tb07513.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Jennings M. L. Topography of membrane proteins. Annu Rev Biochem. 1989;58:999–1027. doi: 10.1146/annurev.bi.58.070189.005031. [DOI] [PubMed] [Google Scholar]
  11. Miquel M., Browse J. Arabidopsis mutants deficient in polyunsaturated fatty acid synthesis. Biochemical and genetic characterization of a plant oleoyl-phosphatidylcholine desaturase. J Biol Chem. 1992 Jan 25;267(3):1502–1509. [PubMed] [Google Scholar]
  12. Miquel M., James D., Jr, Dooner H., Browse J. Arabidopsis requires polyunsaturated lipids for low-temperature survival. Proc Natl Acad Sci U S A. 1993 Jul 1;90(13):6208–6212. doi: 10.1073/pnas.90.13.6208. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Nordlund P., Sjöberg B. M., Eklund H. Three-dimensional structure of the free radical protein of ribonucleotide reductase. Nature. 1990 Jun 14;345(6276):593–598. doi: 10.1038/345593a0. [DOI] [PubMed] [Google Scholar]
  14. Reddy A. S., Nuccio M. L., Gross L. M., Thomas T. L. Isolation of a delta 6-desaturase gene from the cyanobacterium Synechocystis sp. strain PCC 6803 by gain-of-function expression in Anabaena sp. strain PCC 7120. Plant Mol Biol. 1993 May;22(2):293–300. doi: 10.1007/BF00014936. [DOI] [PubMed] [Google Scholar]
  15. Scott D. L., White S. P., Otwinowski Z., Yuan W., Gelb M. H., Sigler P. B. Interfacial catalysis: the mechanism of phospholipase A2. Science. 1990 Dec 14;250(4987):1541–1546. doi: 10.1126/science.2274785. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Strittmatter P., Spatz L., Corcoran D., Rogers M. J., Setlow B., Redline R. Purification and properties of rat liver microsomal stearyl coenzyme A desaturase. Proc Natl Acad Sci U S A. 1974 Nov;71(11):4565–4569. doi: 10.1073/pnas.71.11.4565. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Stukey J. E., McDonough V. M., Martin C. E. The OLE1 gene of Saccharomyces cerevisiae encodes the delta 9 fatty acid desaturase and can be functionally replaced by the rat stearoyl-CoA desaturase gene. J Biol Chem. 1990 Nov 25;265(33):20144–20149. [PubMed] [Google Scholar]
  18. Thiede M. A., Strittmatter P. The induction and characterization of rat liver stearyl-CoA desaturase mRNA. J Biol Chem. 1985 Nov 25;260(27):14459–14463. [PubMed] [Google Scholar]
  19. Venable R. M., Zhang Y., Hardy B. J., Pastor R. W. Molecular dynamics simulations of a lipid bilayer and of hexadecane: an investigation of membrane fluidity. Science. 1993 Oct 8;262(5131):223–226. doi: 10.1126/science.8211140. [DOI] [PubMed] [Google Scholar]
  20. Wada H., Gombos Z., Murata N. Enhancement of chilling tolerance of a cyanobacterium by genetic manipulation of fatty acid desaturation. Nature. 1990 Sep 13;347(6289):200–203. doi: 10.1038/347200a0. [DOI] [PubMed] [Google Scholar]

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