BIOINFORMATICS AND EXPRESSION ANALYSIS OF PLIN2 IN CHINESE PERCH (SINIPERCA CHUATSI) AND ITS ROLE IN LIVER FAT ACCUMULATION

Perlipin2 (plin2) belongs to a family of related proteins named perilipin or PLIN (Perlipin), and is expressed in most tissues. plin2 plays a key role in the formation and stabilization of lipid droplets and fatty liver formation. However, little is known about the function of plin2 in Chinese perch (Siniperca chuatsi). This study identified two subtypes of plin2 gene in Chinese perch (Siniperca chuatsi), named plin2a and plin2b, respectively. Domain analysis found that plin2a and plin2b of Chinese perch included the conserved N-terminal PAT domain and 11-mer repeating domain. plin2 systemic analysis revealed that the genes adjacent to two subtypes of plin2 were strictly conserved in Chinese perch and stickleback. According to the phylogenetic analysis, plin2a and plin2b in Chinese perch had a closer relationship with stickleback, climbing perch and tongue sole. Meanwhile, we tested its mRNA expression of plin2a and plin2b in different tissues using real-time quantitative PCR. Both plin2 genes widely distributed but with some differences. plin2a had the highest level in liver, while plin2b had almost no expression in the liver. plin2b was mainly expressed in kidney, stomach, adipose and brain. To explore the function of plin2 in Chinese perch, we detected plin2a mRNA level in high-carbohydrates diet-fed fish. The result showed that compared with fish fed control diet, high-carbohydrate diet significantly increased the hepatic plin2a level. In addition, we found that plin2a mRNA level was also significantly increased after stimulating with 0.1 mmol/L sodium palmitate in Chinese perch hepatocytes. This study shows that the two subtypes of plin2 genes in Chinese perch may have functional differentiation. plin2a, as an important regulator in liver lipid metabolism, may play an important role in the accumulation of fat in the liver of Chinese perch.