Cloning and characterization of ∆6/∆5 fatty acyl desaturase (Fad) gene promoter in the marine teleost Siganus canaliculatus



Dong Y, Zhao J, Chen J, Wang S, Liu Y, Zhang Q, You C, Monroig O, Tocher DR & Li Y (2018) Cloning and characterization of ∆6/∆5 fatty acyl desaturase (Fad) gene promoter in the marine teleost Siganus canaliculatus. Gene, 647, pp. 174-180.

The rabbitfish Siganus canaliculatus was the first marine teleost demonstrated to have the ability of biosynthesizing long-chain polyunsaturated fatty acids (LC-PUFA) from C18 PUFA precursors, and all genes encoding the key enzymes for LC-PUFA biosynthesis have been cloned and functionally characterized, which provides us a potential model to study the regulatory mechanisms of LC-PUFA biosynthesis in teleosts. As the primary step to clarify such mechanisms, present research focused on promoter analysis of gene encoding ∆6/∆5 fatty acyl desaturase (Fad), a rate-limiting enzyme catalyzing the first step in the conversion of C18 PUFA to LC-PUFA. First, 2044 bp promoter sequence was cloned by genome walking, and the sequence from -456 bp to + 51bp was determined as core promoter by progressive deletion mutation. Moreover, binding sites of transcription factors (TF) such as CCAAT enhancer binding protein (C/EBP), nuclear factor 1 (NF-1), stimulatory protein 1 (Sp1), nuclear factor Y (NF-Y), activated protein 1 (AP1), sterol regulatory element (SRE), hepatocyte nuclear factor 4α (HNF4α) and peroxisome proliferator activated receptor γ (PPARγ) were identified in the core promoter by site-directed mutation and functional assays. Moreover, NF-1 and HNF4α were confirmed to interact with the core promoter region by gel shift assay and mass spectrometry. This is the first report of the promoter structure of a ∆6/∆5 Fad in a marine teleost, and a novel discovery of NF-1 and HNF4α binding to the ∆6/∆5 Fad promoter.

Fatty acyl desaturase; LC-PUFA biosynthesis; transcriptional regulation mechanism; rabbitfish Siganus canaliculatus; marine teleost; NF-1; HNF4α

Gene: Volume 647

Publication date20/03/2018
Publication date online09/01/2018
Date accepted by journal08/01/2018