title: Evolutionary functional elaboration of the Elovl2/5 gene family in chordates.
abstract: The biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFA) provides an intriguing example on how multi-enzymatic cascades evolve. Essential LC-PUFA, such as arachidonic, eicosapentaenoic, and docosahexaenoic acids (DHA), can be acquired from the diet but are also endogenously retailored from C18 precursors through consecutive elongations and desaturations catalyzed, respectively, by fatty acyl elongase and desaturase enzymes. The molecular wiring of this enzymatic pathway defines the ability of a species to biosynthesize LC-PUFA. Exactly when and how in animal evolution a functional LC-PUFA pathway emerged is still elusive. Here we examine key components of the LC-PUFA cascade, the Elovl2/Elovl5 elongases, from amphioxus, an invertebrate chordate, the sea lamprey, a representative of agnathans, and the elephant shark, a basal jawed vertebrate. We show that Elovl2 and Elovl5 emerged from genome duplications in vertebrate ancestry. The single Elovl2/5 from amphioxus efficiently elongates C18 and C20 and, to a marked lesser extent, C22 LC-PUFA. Lamprey is incapable of elongating C22 substrates. The elephant shark Elovl2 showed that the ability to efficiently elongate C22 PUFA and thus to synthesize DHA through the Sprecher pathway, emerged in the jawed vertebrate ancestor. Our findings illustrate how non-integrated "metabolic islands" evolve into fully wired pathways upon duplication and neofunctionalization.
authors: Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
authors: Óscar
authors: Ó
authors: Monroig
authors: CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto - University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal.|ICBAS - Institute of Biomedical Sciences Abel Salazar, U. Porto - University of Porto, Rua de José Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors: Mónica
authors: M
authors: Lopes-Marques
authors: Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes 12595, Castellón, Spain.
authors: Juan C
authors: JC
authors: Navarro
authors: Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes 12595, Castellón, Spain.
authors: Francisco
authors: F
authors: Hontoria
authors: CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto - University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal.
authors: Raquel
authors: R
authors: Ruivo
authors: CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto - University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal.|Department of Biology, Faculty of Sciences, U. Porto - University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors: Miguel M
authors: MM
authors: Santos
authors: Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Biopolis, Singapore 138673.
authors: Byrappa
authors: B
authors: Venkatesh
authors: Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
authors: Douglas R
authors: DR
authors: Tocher
authors: CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto - University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal.|Department of Biology, Faculty of Sciences, U. Porto - University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors: L Filipe C
authors: LF
authors: Castro
mesh_terms: D000123:Acetyltransferases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D020440:Gene Duplication; D007798:Lampreys / Q000235:genetics* / Q000378:metabolism; D064175:Lancelets / Q000201:enzymology / Q000235:genetics*; D012754:Sharks / Q000235:genetics* / Q000378:metabolism
chemical_list: D029941:Fish Proteins; D000123:Acetyltransferases