넙치로부터 인지질가수분해효소 C δ4의 특성분석

Abstract

PLCδ4 has a key role in cell proliferation, tumorigenesis, and in an early stage of fertilization. Despite the extensive characterization of the mammalian PLCδ4, it has not been studied in aquatic organisms. Here, we firstly investigate the characterization of olive flounder PLCδ4 to better understand the enzymatic properties and physiological functions. We describe the isolation of cDNA encoding PLCδ4 from olive flounder (PoPLCδ4). The PoPLCδ4 cDNA (2,268 bp) encodes a 755 amino acid polypeptide with an open reading frame of 86 kDa. All of the characteristic domains found in mammalian PLCδ isoforms (PH domain, EF hands, an X–Y catalytic region, and a C2 domain) are present in PoPLCδ4. A homology search revealed that PoPLCδ4 shares most sequence identity with Salmo salar PLCδ4 (67%). Unlike four teleost fishes (zebrafish, stickleback, medaka and cod), olive flounder possess just one gene for PLCδ4 because of a gene-loss event during evolution into orders of Tetraodontiformes and Pleuronectiformes. The mRNA expression analysis of PoPLCδ4 showed that PoPLCδ4 was predominantly expressed in the brain, eye and heart tissues. The recombinant PoPLCδ4 showed a concentration-dependent PLC activity to phosphatidylinositol 4,5-bis-phosphate (PIP2), and its activity was Ca2+-dependent, which was similar to mammalian PLCδ as well as that of the mud loach (Misgurnus mizolepis). Here, we report that the structural features and biochemical characteristics of PoPLCδ4 are similar to that of the other mammalian PLCδ4, and this is the first demonstration of the expression analysis and enzymatic characterization of piscine PLCδ4.