Cloning and characterization of carnitine palmitoyltransferase Iα (CPT1α) from obscure puffer (Takifugu obscurus), and its gene expression in response to different lipid sources

•The gene of hepatic CPT Іα from the obscure puffer was cloned and the sequence characterization was analyzed.•The replacement of fish oil (FO) with 50% vegetable oil (VO) in diet does not affect the expression of hepatic CPT Іα.•Different proportion of soybean oil in diet does not affect the expression of CPT Іα gene in the liver of puffer fish. In this study, CPT Іα cDNA of obscure puffer (Takifugu obscurus) was cloned and characterized, and its expression in response to replacement of dietary fish oil with vegetable oil was investigated following a feeding trial. The sequence of obscure puffer CPT Іα cDNA contains a 5’ UTR of 113 bp, a 3’ UTR of 294 bp and an open reading frame of 2316 bp encoding a polypeptide of 771 amino acids with an estimated molecular mass of 88.5 kDa and a predicted isoelectric point of 8.81. Moreover, bioinformatics analysis of CPT Іα sequences indicated that this gene shared 65 %–98 % identity with CPT Іs from other piscine species of which the most closely related one was tiger puffer. And the results of qRT-PCR revealed that CPT Іα gene was ubiquitously expressed in all tested tissues and the highest expression level was found in liver, followed by heart and blood. The lowest expression level of CPT Іα was observed in spleen and eye. Replacing dietary fish oil with 50 % vegetable oil (soybean oil, corn oil and rapeseed oil) or different proportion of soybean oil (0 %, 25 %, 50 % and 75 %) has no significant effect on CPT Іα gene expression in liver of obscure puffer. These results suggest that CPT Іα contains highly-conserved domains and fish oil replacement by vegetable oil has no remarkable effect on hepatic CPT Іα expression. Our results provide the vital data for the further research on the mechanism of lipid catabolism, as the pivotal role of CPT Іα in lipid metabolism.