title: Identification and characterization of Delta12, Delta6, and Delta5 Desaturases from the green microalga Parietochloris incisa.
abstract: The freshwater microalga Parietochloris incisa accumulates, under nitrogen starvation, large amounts of triacylglycerols containing approximately 60% of the omega6 very long-chain polyunsaturated fatty acid (VLC-PUFA), arachidonic acid. Based on sequence homology, we isolated three cDNA sequences from P. incisa, designated PiDesD12, PiDesD6, PiDesD5. The deduced amino acid sequences of the three genes contained three conserved histidine motifs; the front-end desaturases, PiDes6 and PiDes5, contained a fused N-terminal cytochrome b5 domain. By functional characterization in the yeast Saccharomyces cerevisiae, we confirmed that PiDesD6, PiDesD5 cDNA encode membrane bound desaturases with Delta6, and Delta5 activity, respectively. Both PiDes6 and PiDes5 can indiscriminately desaturate both omega6 and omega3 substrates. A phylogenetic analysis showed that the three genes were homologous to the corresponding desaturases from green microalgae and lower plants that were functionally characterized. Quantitative real-time PCR revealed the concerted expression pattern of all three genes in P. incisa cells subjected to nitrogen starvation, featuring maximum expression level on day 3 of starvation, corresponding to the sharpest increase in the share of arachidonic acid.
authors.affiliation: French Associates Institute for Agriculture, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
authors.forename: Umidjon
authors.initials: U
authors.lastname: Iskandarov
authors.forename: Inna
authors.initials: I
authors.lastname: Khozin-Goldberg
authors.forename: Zvi
authors.initials: Z
authors.lastname: Cohen
mesh_terms: D020418:Algal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000460:Chlorophyta / Q000201:enzymology* / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
chemical_list: D020418:Algal Proteins; D018076:DNA, Complementary; D044943:Fatty Acid Desaturases
references.citation: J Biol Chem. 1998 Jul 24;273(30):19055-9
references.pmid: 9668087
references.citation: Can J Biochem Physiol. 1959 Aug;37(8):911-7
references.pmid: 13671378
references.citation: Metab Eng. 2010 May;12(3):233-40
references.pmid: 20004733
references.citation: Biochem J. 2005 Jul 15;389(Pt 2):483-90
references.pmid: 15769252
references.citation: Extremophiles. 2009 Nov;13(6):875-84
references.pmid: 19728010
references.citation: J Biol Chem. 2003 Sep 12;278(37):35115-26
references.pmid: 12835316
references.citation: Prostaglandins Leukot Essent Fatty Acids. 2003 Feb;68(2):73-95
references.pmid: 12538072
references.citation: Lipids. 2002 Feb;37(2):209-16
references.pmid: 11908913
references.citation: Mol Biol Evol. 2007 Aug;24(8):1596-9
references.pmid: 17488738
references.citation: J Biol Chem. 1998 Nov 6;273(45):29360-6
references.pmid: 9792636
references.citation: Nat Biotechnol. 2004 Jun;22(6):739-45
references.pmid: 15146198
references.citation: Plant Mol Biol. 2004 Feb;54(3):335-52
references.pmid: 15284491
references.citation: Biosci Biotechnol Biochem. 2002 Jun;66(6):1314-27
references.pmid: 12162554
references.citation: Plant Physiol. 2002 May;129(1):354-62
references.pmid: 12011365
references.citation: Plant Physiol. 1997 May;114(1):223-230
references.pmid: 12223701
references.citation: Eur J Biochem. 2002 Aug;269(16):4105-13
references.pmid: 12180987
references.citation: Phytochemistry. 2002 May;60(2):135-43
references.pmid: 12009316
references.citation: FEBS Lett. 2003 May 8;542(1-3):100-4
references.pmid: 12729906
references.citation: Am J Clin Nutr. 1997 Oct;66(4 Suppl):1032S-1041S
references.pmid: 9322584
references.citation: Biochem J. 1998 Mar 1;330 ( Pt 2):611-4
references.pmid: 9480865
references.citation: Arch Biochem Biophys. 1999 Feb 1;362(1):175-82
references.pmid: 9917342
references.citation: Plant J. 1998 Jul;15(1):39-48
references.pmid: 9744093
references.citation: Mar Biotechnol (NY). 2010 Aug;12(4):430-8
references.pmid: 19820995
references.citation: Plant Physiol. 1992 Feb;98(2):569-72
references.pmid: 16668678
references.citation: Pharmacol Res. 1999 Sep;40(3):211-25
references.pmid: 10479465
references.citation: Lipids. 2009 Jun;44(6):545-54
references.pmid: 19421794
references.citation: FEBS Lett. 1998 Nov 20;439(3):215-8
references.pmid: 9845325
references.citation: J Biol Chem. 2008 Aug 15;283(33):22352-62
references.pmid: 18556660
references.citation: FEBS J. 2006 Jan;273(2):271-80
references.pmid: 16403015
references.citation: Plant Cell Physiol. 2006 Jan;47(1):64-73
references.pmid: 16267098
references.citation: Yeast. 1995 Apr 15;11(4):355-60
references.pmid: 7785336
references.citation: J Lipid Res. 2004 Jan;45(1):32-40
references.pmid: 14563830
references.citation: J Lipid Res. 2004 Oct;45(10):1899-909
references.pmid: 15292371
references.citation: Gene. 1996 Feb 2;168(1):117-21
references.pmid: 8626057
references.citation: Bacteriol Rev. 1971 Jun;35(2):171-205
references.pmid: 4998365
references.citation: Plant Cell. 2004 Oct;16(10):2734-48
references.pmid: 15377762
references.citation: FEBS J. 2005 Jul;272(13):3401-12
references.pmid: 15978045
references.citation: Eur J Biochem. 1999 May;261(3):812-20
references.pmid: 10215899
references.citation: Phytochemistry. 2002 Jul;60(5):497-503
references.pmid: 12052516
references.citation: Biochim Biophys Acta. 1998 Oct 2;1394(1):3-15
references.pmid: 9767077
references.citation: Plant Cell. 1995 Jul;7(7):957-70
references.pmid: 7640528
references.citation: Prog Lipid Res. 2004 Jan;43(1):36-54
references.pmid: 14636670
references.citation: Prostaglandins Leukot Essent Fatty Acids. 2003 Feb;68(2):135-43
references.pmid: 12538077
references.citation: J Biol Chem. 1999 Dec 24;274(52):37335-9
references.pmid: 10601301
references.citation: Nat Biotechnol. 2005 Aug;23(8):1013-7
references.pmid: 15951804
references.citation: J Biol Chem. 2006 Aug 4;281(31):21988-21997
references.pmid: 16728405
references.citation: Plant Physiol. 1999 Oct;121(2):641-6
references.pmid: 10517856
references.citation: Annu Rev Plant Physiol Plant Mol Biol. 1998 Jun;49:611-641
references.pmid: 15012248
references.citation: Proc Natl Acad Sci U S A. 1997 Apr 15;94(8):4211-6
references.pmid: 9108131