Cloning and bioinformatics analyses of the coding DNA sequence (CDS) of Delta 6 Desaturase gene from Mortierella alpina (CBS 754.68)

Introduction: Membrane-bound desaturases and related enzymes play a pivotal role in the biosynthesis of unsaturated fatty acids. Delta6 desaturase is a key enzyme in the biosynthesis of the unsaturated fatty acids. Mortierella alpina is an oleaginous fungus with active Delta 6 desaturase which hasbeengreatly considered recently. Materials and methods: In order to isolate and clone Δ6D gene from Mortierella alpina, after extraction of total RNA and synthesis cDNA, PCR amplification has been done using gene specific primers. The amplified fragment was cloned into the pBlueScriptSK+ containing seed specific promoter napin. Then the recombinant plasmid was transformed into E.coli DH5a by freezing and thawing method. The confirmed gene construct was cloned into the binary vector pBI121 and transformed into Agrobacterium LBA4404 in order to transform canola plants. Bioinformatics characterization of target gene was investigated by servers TMHMM, ProtParam and Psipred. Results: Correctness of cloning was confirmed by PCR with specific primers, enzymatic digestion and sequencing. The proliferation of a fragment with 830 bp using internal primer of napin promoter and Delta6 desaturase primer confirmed insertion of the gene along with napin promoter. Nucleotide sequencing results showed that cloned CDS includes 1374 nucleotides that will translate to a protein with 448 amino acids. Using bioinformatics analysis, presence of cytochrome b5 domain, three His-box, secondary and spatial structures, transmembrane and conserved domains were confirmed. Discussion and conclusion: Based on the results of BLAST analysis using nucleotide and protein sequences, and also presence of functional domains in the protein, it can be predicted that cloned CDS will show proper enzyme activity after transformation into plants. Confirming these results requires expression analysis of the gene in appropriate plant system and studying its function in the enzyme level.