Publications

• A novel fungal omega3-desaturase with wide substrate specificity from arachidonic acid-producing Mortierella alpina 1S-4.

  Sakuradani E., Abe T., Iguchi K., Shimizu S.

  A filamentous fungus, Mortierella alpina 1S-4, is capable of producing not only arachidonic acid (AA; 20:4n-6) but also eicosapentaenoic acid (EPA; 20:5n-3) below a cultural temperature of 20 degrees C. Here, we describe the isolation and characterization of a gene (maw3) that encodes a novel omeg ... >> More

  A filamentous fungus, Mortierella alpina 1S-4, is capable of producing not only arachidonic acid (AA; 20:4n-6) but also eicosapentaenoic acid (EPA; 20:5n-3) below a cultural temperature of 20 degrees C. Here, we describe the isolation and characterization of a gene (maw3) that encodes a novel omega3-desaturase from M. alpina 1S-4. Based on the conserved sequence information for M. alpina 1S-4 Delta12-desaturase and Saccharomyces kluyveri omega3-desaturase, the omega3-desaturase gene from M. alpina 1S-4 was cloned. Homology analysis of protein databases revealed that the amino acid sequence showed 51% identity, at the highest, with M. alpina 1S-4 Delta12-desaturase, whereas it exhibited 36% identity with Sac. kluyveri omega3-desaturase. The cloned cDNA was confirmed to encode the omega3-desaturase by its expression in the yeast Sac. cerevisiae. Analysis of the fatty acid composition of the yeast transformant demonstrated that 18-carbon and 20-carbon n-3 polyunsaturated fatty acids (PUFAs) were accumulated through conversion of exogenous 18-carbon and 20-carbon n-6 PUFAs. The substrate specificity of the M. alpina 1S-4 omega3-desaturase differs from those of the known fungal omega3-desaturases from Sac. kluyveri and Saprolegnia diclina. Plant, cyanobacterial and Sac. kluyveri omega3-desaturases desaturate 18-carbon n-6 PUFAs, Spr. diclina omega3-desaturase desaturates 20-carbon n-6 PUFAs and Caenorhabditis elegans omega3-desaturase prefers 18-carbon n-6 PUFAs as substrates rather than 20-carbon n-6 PUFAs. The substrate specificity of M. alpina 1S-4 omega3-desaturase is rather similar to that of C. elegans omega3-desaturase, but the M. alpina omega3-desaturase can more effectively convert AA into EPA when expressed in yeast. The M. alpina 1S-4 omega3-desaturase is the first known fungal desaturase that uses both 18-carbon and 20-carbon n-6 PUFAs as substrates. << Less

  Appl. Microbiol. Biotechnol. 66:648-654(2005) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Map-based cloning of a gene controlling omega-3 fatty acid desaturation in Arabidopsis.

  Arondel V., Lemieux B., Hwang I., Gibson S., Goodman H.M., Somerville C.R.

  A gene from the flowering plant Arabidopsis thaliana that encodes an omega-3 desaturase was cloned on the basis of the genetic map position of a mutation affecting membrane and storage lipid fatty acid composition. Yeast artificial chromosomes covering the genetic locus were identified and used to ... >> More

  A gene from the flowering plant Arabidopsis thaliana that encodes an omega-3 desaturase was cloned on the basis of the genetic map position of a mutation affecting membrane and storage lipid fatty acid composition. Yeast artificial chromosomes covering the genetic locus were identified and used to probe a seed complementary DNA library. A complementary DNA clone for the desaturase was identified and introduced into roots of both wild-type and mutant plants by Ti plasmid-mediated transformation. Transgenic tissues of both mutant and wild-type plants had significantly increased amounts of the fatty acid produced by this desaturase. << Less

  Science 258:1353-1355(1992) [PubMed] [EuropePMC]

• Mutants of Arabidopsis deficient in the synthesis of alpha-linolenate. Biochemical and genetic characterization of the endoplasmic reticulum linoleoyl desaturase.

  Browse J., McConn M., James D. Jr., Miquel M.

  The overall fatty compositions of leaf and root lipids from a mutant of Arabidopsis thaliana were characterized by reduced levels of linolenate (18:3) and correspondingly elevated levels of linoleate (18:2) as a consequence of a single nuclear mutation at the fad3 locus. Comparison of the fatty ac ... >> More

  The overall fatty compositions of leaf and root lipids from a mutant of Arabidopsis thaliana were characterized by reduced levels of linolenate (18:3) and correspondingly elevated levels of linoleate (18:2) as a consequence of a single nuclear mutation at the fad3 locus. Comparison of the fatty acid compositions of individual lipids from wild type and mutant plants showed that chloroplast lipids were largely unaffected by the mutation, whereas each of the phospholipids synthesized on the endoplasmic reticulum in the mutant exhibited a marked reduction in the proportion of 18:3 relative to wild type. These and other results indicate that the fad3 mutants are deficient in the activity of an endoplasmic reticulum 18:2 desaturase. In root tissues, this enzyme appears to account for over 80% of the 18:3 present. However, in young leaves of the mutant, phosphatidylcholine (the major phospholipid) contains 16% 18:3 compared with 29% in the wild type, and the proportion of 18:3 in this lipid increases with plant age in both wild type and mutant plants. These results reflect an exchange of lipid between the chloroplast and endoplasmic reticulum that allows the chloroplast desaturases to provide highly unsaturated lipids to the extrachloroplast membranes of leaf cells. << Less

  J. Biol. Chem. 268:16345-16351(1993) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.