Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor

Abstract

Currently existing data show that the capability for long-chain PUFA (LC-PUFA) biosynthesis in teleost fi sh is more diverse than in other vertebrates. Such diversity has been primarily linked to the subfunctionalization that teleostei fatty acyl desaturase (Fads)2 desaturases have undergone during evolution. We previously showed that Chirostoma estor , one of the few representatives of freshwater atherinopsids, had the ability for LC-PUFA biosynthesis from C 18 PUFA precursors, in agreement with this species having unusually high contents of DHA. The particular ancestry and pattern of LC-PUFA biosynthesis activity of C. estor make this species an excellent model for study to gain further insight into LC-PUFA biosynthetic abilities among teleosts. The present study aimed to characterize cDNA sequences encoding fatty acyl elongases and desaturases, key genes involved in the LC-PUFA biosynthesis. Results show that C. estor expresses an elongase of very long-chain FA (Elovl)5 elongase and two Fads2 desaturases displaying 4 and 6/5 specifi cities, thus allowing us to conclude that these three genes cover all the enzymatic abilities required for LC-PUFA biosynthesis from C 18 PUFA. In addition, the specifi cities of the C. estor Fads2 enabled us to propose potential evolutionary patterns and mechanisms for subfunctionalization of Fads2 among fi sh lineages. -Fonseca- Madrigal, J., J. C. Navarro, F. Hontoria, D. R. Tocher, C. A. Martínez-Palacios, and Ó. Monroig. Diversifi cation of substrate specifi cities in teleostei Fads2: characterization of 4 and 6 5 desaturases of Chirostoma estor . J. Lipid Res. 2014. 55: 1408 - 1419. © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.