Cloning and expression of the Δ 6 fatty acyl desaturases of Coilia nasus.

The full-length cDNA of Δ 6 fatty acyl desaturases (FAD6) of Coilia nasus, which was involved in the biosynthesis of highly unsaturated fatty acids ( HUFA), was cloned by RT-PCR ( reverse transcription polymerase chain reaction) and RACE ( rapid- amplification of cDNA ends) methods. The results revealed that the FAD6 cDNA was 2 032 bp,including an ORF( open reading frame) of 1 338 bp specified a protein of 445 amino acids, which contained three histidine-rich regions and two putative transmembrane domains. The deduced amino acid sequence shared 75% - 79% identity with that in Muraenesox cinereus and Rachycentron canadum, and low similarity of freshwater fish. Actually, it was consistent with the results of phylogenetic analysis. The tissue-specific expressions of FAD6 mRNAs were detected in C. nasus. A high expression was observed in the brain and intestine, while relatively high expression was encountered in muscle and liver,and a weak expression in the heart, kidney and gill. [ABSTRACT FROM AUTHOR]