Cloning of zebrafish (Danio rerio) seipin gene and its role in D. rerio liver lipid metabolism

Seipin is a key protein regulating lipid storage. Mutation in the bscl2 gene encoding Seipin causes severe congenital generalized lipoatrophy in humans. Patients lose whole-body adipose tissue, accompanied by abnormal liver fat deposition. The function of Seipin in adipose tissue formation and adipocyte differentiation has been widely studied. However, how Seipin regulates lipid storage and metabolism in the liver is still unclear. Therefore, in order to explore the role of fish lipid droplet-related protein Seipin in liver lipid metabolism, the coding sequence of Seipin was cloned for sequence analysis, and the expression of triglyceride (TG) metabolism-related genes in D. rerio liver and liver cells was detected through real-time fluorescence quantitative PCR (qPCR) after interfering and overexpressing Seipin in vivo and in vitro experiments. The results showed that the seipin coding sequence of D. rerio was 1 053 bp in length, encoding 350 amino acids. Bioinformatics analysis showed that D. rerio Seipin protein belongs to alkaline, unstable and hydrophobic transmembrane protein. Real-time quantitative PCR results showed that compared with the control group, the expression of TG synthesis-related gene dgat1b in D. rerio liver and liver cells was significantly increased (P<0.05), the expression of TG transport-related gene mttp was significantly increased (P<0.05), the expression of TG lipolysis related gene lpl was increased (P>0.05), and the expression of atgl was decreased (P>0.05). After 36 h of Seipin interference, the expression of TG synthesis-related gene dgat1a in D. rerio liver and liver cells increased (P>0.05), the expression of mttp decreased significantly (P<0.05), and the expression of lpl decreased significantly (P<0.05). After overexpression of Seipin for 24 h, the expression of TG synthesis-related gene dgat2 in D. rerio liver cells decreased significantly (P<0.05), the expression of mttp decreased significantly (P<0.05), and there was no significant difference in the expression of lpl (P>0.05). After overexpression of Seipin for 36 h, the expression of TG synthesis-related gene dgat2 in D. rerio liver cells increased significantly (P<0.05), the expression of mttp increased significantly (P<0.05), and there was no significant difference in the expression of lpl (P>0.05). The above results indicate that Seipin may participate in D. rerio liver lipid metabolism by affecting the expression of TG metabolism-related genes. This study provides a basis for further study on the mechanism of Seipin regulating lipid storage and metabolism in D. rerio.