Gretch D G, Sturley S L, Friesen P D, Beckage N E, Attie A D
Department of Biochemistry, University of Wisconsin-Madison 53706.
Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8530-3. doi: 10.1073/pnas.88.19.8530.
Human apolipoprotein E (apoE) is a ligand for the low density lipoprotein (LDL) receptor and mediates the catabolism of several classes of lipoprotein particles. Binding of apoE to the LDL receptor requires association of apoE with lipid in a vesicle or a lipoprotein particle. Because of this requirement, purified apoE or apoE derived directly from bacterial expression systems does not bind to the LDL receptor. To overcome this problem and to facilitate analysis of apoE structure, recombinant baculoviruses containing the human apoE cDNA fused to the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus were constructed. The recombinant viruses were used to infect larvae of the tobacco hornworm Manduca sexta in vivo. High levels of lipoprotein particles containing human apoE were present in the hemolymph of infected larvae. In contrast to apoE produced by recombinant baculovirus-infected insect cells in vitro, these particles were excellent ligands for the LDL receptor.
人载脂蛋白E（apoE）是低密度脂蛋白（LDL）受体的配体，介导几类脂蛋白颗粒的分解代谢。apoE与LDL受体的结合需要apoE与囊泡或脂蛋白颗粒中的脂质缔合。由于这一要求，纯化的apoE或直接源自细菌表达系统的apoE不与LDL受体结合。为克服这一问题并便于对apoE结构进行分析，构建了含有与苜蓿银纹夜蛾核型多角体病毒多角体蛋白启动子融合的人apoE cDNA的重组杆状病毒。这些重组病毒用于在体内感染烟草天蛾Manduca sexta的幼虫。感染幼虫的血淋巴中存在高水平的含人apoE的脂蛋白颗粒。与体外经重组杆状病毒感染的昆虫细胞产生的apoE不同，这些颗粒是LDL受体的优良配体。
