Cloning and functional analysis of Δ6‐desaturase gene and its upstream region from Mortierella sp. AGED
2015
Tan, Li | Li, Shue | Zhang, Xiaoyu | Ma, Fuying
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. CONCLUSION: The present finding could enable us to understand the evolution and regulatory mechanism of Δ6‐desaturase gene. © 2014 Society of Chemical Industry
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