Functional characterization and differential nutritional regulation of putative Elovl5 and Elovl4 elongases in large yellow croaker (Larimichthys crocea)

• Published in: Scientific reports Vol. 7; no. 1; pp. 2303 - 15
• Main Authors: Li, Songlin, Monroig, Óscar, Wang, Tianjiao, Yuan, Yuhui, Carlos Navarro, Juan, Hontoria, Francisco, Liao, Kai, Tocher, Douglas R., Mai, Kangsen, Xu, Wei, Ai, Qinghui
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23-05-2017; Nature Publishing Group; Nature Portfolio
• Subjects: 13/106; 13/109; 38/39; 38/77; 42; 45; 45/23; 631/337/572/2102; 631/601/1737; Acetyltransferases - classification; Acetyltransferases - genetics; Acetyltransferases - metabolism; Amino Acid Sequence; Amino acids; Animals; Aquaculture; Biosynthesis; Cells, Cultured; Cloning; Cloning, Molecular; DNA, Complementary - chemistry; DNA, Complementary - genetics; Enzymes; Fatty acids; Fatty Acids, Unsaturated - metabolism; Fish; Fish Proteins - genetics; Fish Proteins - metabolism; Gene Expression Regulation, Enzymologic; Gene regulation; HEK293 Cells; Humanities and Social Sciences; Humans; Isoenzymes - genetics; Isoenzymes - metabolism; Laboratories; Larimichthys crocea; Lipid metabolism; Marine fish; Metabolism; Metabolites; multidisciplinary; Nutrition; Perciformes - genetics; Perciformes - metabolism; Phylogenetics; Phylogeny; Science; Science (multidisciplinary); Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sterol regulatory element-binding protein; Sterols; Transcription
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-02646-8

In the present study, two elongases, Elovl4 and Elovl5, were functionally characterized and their transcriptional regulation in response to n-3 LC-PUFA administration were investigated
in vivo
and
in vitro
. We previously described the molecular characterization of croaker
elovl5
. Here, we report the full-length cDNA sequence of croaker
elovl4
, which contained 1794 bp (excluding the polyA tail), including 909 bp of coding region that encoded a polypeptide of 302 amino acids possessing all the characteristic features of Elovl proteins. Functional studies showed that croaker Elovl5, displayed high elongation activity towards C
18
and C
20
PUFA, with only low activity towards C
22
PUFA. In contrast, croaker Elovl4 could effectively convert both C
20
and C
22
PUFA to longer polyenoic products up to C
34
. n-3 LC-PUFA suppressed transcription of the two elongase genes, as well as
srebp
-
1
and
lxrα
, major regulators of hepatic lipid metabolism. The results of dual-luciferase reporter assays and
in vitro
studies both indicated that the transcriptions of
elovl5
and
elovl4
elongases could be regulated by Lxrα. Moreover, Lxrα could mediate the transcription of
elovl4
directly or indirectly through regulating the transcription of
srebp
-
1
. The above findings contribute further insight and understanding of the mechanisms regulating LC-PUFA biosynthesis in marine fish species.