Elongation of very Long-Chain ( & gt;C 24 ) Fatty Acids in Clarias gariepinus : Cloning, Functional Characterization and Tissue Expression of elovl4 Elongases

AbstractElongation of very long-chain fatty acid 4 (Elovl4) proteins participate in the biosynthesis of very long-chain (>C24) saturated and polyunsaturated fatty acids (FA). Previous studies have shown that fish possess two different forms of Elovl4, termed Elovl4a and Elovl4b. The present study aimed to characterize both molecularly and functionally twoelovl4 cDNA from the African catfishClarias gariepinus. The results confirmed thatC. gariepinus possessed twoelovl4-like elongases with high homology to two previously characterized Elovl4 fromDanio rerio, and thus they were termed accordingly as Elovl4a and Elovl4b. TheC. gariepinus Elovl4a and Elovl4b have open reading frames (ORF) of 945 and 915 base pairs, respectively, encoding putative proteins of 314 and 304 amino acids, respectively. Functional characterization in yeast showed both Elovl4 enzymes have activity towards all the PUFA substrates assayed (18:4n-3, 18:3n-6, 20:5n-3, 20:4n-6, 22:5n-3, 22:4n-6 and 22:6n-3), producing elongated products of up to C36. Moreover, theC. gariepinus Elovl4a and Elovl4b were able to elongate very long-chain saturated FA (VLC-SFA) as denoted by increased levels of 28:0 and longer FA in yeast transformed withelovl4 ORF compared to control yeast. These results confirmed thatC. gariepinus Elovl4 play important roles in the biosynthesis of very long-chain FA. Tissue distribution analysis ofelovl4 mRNAs showed both genes were widely expressed in all tissues analyzed, with high expressio...
Source: Lipids - Category: Lipidology Source Type: research