Lipase Gene Family In Zebrafish: Expression Pattern, Function And Evolution Analysis

Lipase is the enzyme that can hydrolyze the lipids into fatty acid. Currently, it hasknown that lipases family includes lipoprotein lipase (LPL), hepatic lipase (LIPC),pancreatic lipase (PL), endothelial lipase (EL), phosphatidylserine-specificphospholipaseA1(PLA1A), pancreatic lipase related protein-1(PLRP1) andpancreatic lipase-related protein-2(PLRP2). Members of lipase gene family can bewidely detected in animals, which play a major role in metabolism of fatty acid andsignal transduction. However, little information is known about them in fish.In this article, several biological techniques are used in zebrafish, an importantmodel in scientific research, such as semiquantitative PCR, real-time PCR and in situhybridization. We showed that LPL is highly expressed in liver in zebrafish. This isobviously different to the tissue expression pattern of LPL in mammals, which is notdetected in the adult liver. LIPC was liver-specific expressed, which is consistent withthat in mammals. During embryogenesis, LPL mRNA was increased gradually inabundance from0.5hpf (hour past fertilization) to6dpf (day past fertilization), butLIPC was not expressed at the early stage of the embryo untill at3dpf. In situhybridization further displayed the expression pattern of LPL mainly restricted to thehead region including cells surrounding the mouth opening, branchial arches, pectoralfin and lateral line neuromast; LIPC was mainly restricted to the liver and part of headregions including lens. Moreover, the up-regulation of LPL expression is found byfasting. Researches of other members of lipase gene family, such as EL, PLA1A, LH,were only investigated by tissue distribution and developmental expression. To furtherdiscover the evolution of lipase gene, an amphioxus lipase-like gene was cloned andits protein was recombinantly expressed in E. coli. Tissue distribution of this gene wasalso detected by real-time PCR and in situ hybridization on sections. Our study lays afoundation for further investigation of lipase function and evolution.