title: Cloning and functional analysis of Δ6-desaturase gene and its upstream region from Mortierella sp. AGED.
abstract: BACKGROUND
  Δ6-desaturase belonging to membrane-bound enzyme is a key enzyme involved in the synthesis of polyunsaturated fatty acids (PUFAs). This study aimed to clone and characterise Δ6-desaturase gene and its upstream regulatory region of Mortierella sp. AGED.
  
  
  RESULTS
  Glucose and soybean meal are best for lipid and arachidonic acid accumulation of Mortierella sp. AGED. A 1375-bp Δ6-desaturase gene AGfad6 which contains a 1275-bp open reading frame encoding 424 amino acids without signal peptide was cloned. The putative protein contained three conserved histidine-rich motifs and a conserved cytochrome b5 HPGG (H: Histine, P: Proline, G: Glycine, G: Glycine) motif, with a mass of 48.3 kDa and an isoelectric point of 5.96. AGfad6 was successfully expressed in Pichia pastoris GS115, which exerted the effect on converting linoleic acid to γ-linolenic acid. The 1712-bp upstream region contained basic transcriptional elements including TATA, GC and GATA box, putative target-binding sites for transcription factors such as TATA binding protein, transcription activator, CCAAT-enhancer-binding protein, activator protein 1, alcohol dehydrogenase gene regulator 1 and metabolic regulators p40x in fungi, stress-related elements including GT-1 (light-responsive, salicylic acid-inducible), stress response element, heat stress-responsive element, which might participate in regulation of PUFAs synthesis.
  
  
  CONCLUSIONS
  The present finding could enable us to understand the evolution and regulatory mechanism of Δ6-desaturase gene.
authors.affiliation: Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Tan
authors.affiliation: Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
authors.forename: Shue
authors.initials: S
authors.lastname: Li
authors.affiliation: Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
authors.forename: Fuying
authors.initials: F
authors.lastname: Ma
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D016718:Arachidonic Acid / Q000378:metabolism; D003001:Cloning, Molecular; D003470:Culture Media; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D015870:Gene Expression; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D019787:Linoleic Acid / Q000378:metabolism; D050602:Linoleoyl-CoA Desaturase / Q000235:genetics*; D008969:Molecular Sequence Data; D020094:Mortierella / Q000235:genetics* / Q000378:metabolism; D016366:Open Reading Frames; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D017965:gamma-Linolenic Acid / Q000096:biosynthesis
chemical_list: D000596:Amino Acids; D003470:Culture Media; D005231:Fatty Acids, Unsaturated; D005656:Fungal Proteins; D016718:Arachidonic Acid; D017965:gamma-Linolenic Acid; D019787:Linoleic Acid; D050602:Linoleoyl-CoA Desaturase
keywords: arachidonic acid; fatty acid desaturases; gene expression; oleaginous fungus; triglycerides; upstream regulatory region