Abstract

Chlorella vulgaris had the gene of n-3 fatty acid desaturase (CvFad3) which cansynthesize the precursor of n-3 polyunsaturated fatty acids (PUFAs) or to convert n-6 to n-3 PUFAs. The objective of this study was to examine whether the CvFad3 gene from C. vulgaris can be functionally expressed in mammalian cells and whether its expression can exert a significant effect on cellular fatty acid composition. CvFad3 gene was inserted into plasmid pEGFP-C3 to construct eukaryotic expression vector pEGFP-C3-n-3 and expressed the n-3 Fad gene in mouse breast cancer cells (4T1cells). Transfection of recombinant vector into 4T1 cells resulted in a high expression of n-3 fatty acid desturase. Lipid analysis indicated a remarkable increase in the level of n-3 PUFAs accompanied with a large decrease in the contents of n-6 PUFAs. Accordingly, CvFad3 gene significantly decreased the ratio of n-6/n-3 PUFAs of 4T1 cells membrane. The expression of CvFad3 gene decreased cellular proliferation and promoted cellular apoptosis. This study demonstrates that CvFad3 gene coulddramatically balance the ratio of n-6/n-3 PUFAs. It would be an effective approach to modifying fatty acid composition of mammalian cells and also provided a basis for potential applications of this gene transfer in experimental and clinical settings.

Key words: Chlorella vulgaris, CvFad3 gene, fatty acid desaturase, recombinant expression vector, fatty acid composition.