Cloning,Functional Characterization and Expression Analysis of the elovl4a Gene in the Large Yellow Croaker(Larimichthys crocea)

摘要

Elovl4 is a fatty acyl elongase which participates in the biosynthesis of long-chain polyunsaturated fatty acids(LCPUFA).Herein we isolated and functionally characterized the elovl4a gene in the large yellow croaker Larimichthys crocea,and investigated the regulatory effects of transcription factors Hnf4α,Lxrα,Pparαon the activity of elovl4a promoter.Tissue expression pattern revealed that elovl4a was widely expressed in several tissues and predominantly in brain.Heterologous expression in yeast showed that L.crocea Elovl4a could effectively elongate both C18 and C20 PUFA substrates to C22 fatty acid.In addition,the affinity of large yellow croaker Elovl4a to n-6 series fatty acids is weak and cannot prolong 18:2n-6 and 18:3n-6.Moreover,L.crocea elovl4a reporter activities were elevated by 1.31-,1.39-and 1.48-fold via over-expression of Lxrα,Pparαand Hnf4α,respectively.The above findings can enrich the knowledge of biosynthesis pathway of LC-PUFA in the large yellow croaker and contribute to elucidate the LC-PUFA anabolism mechanism in fish.