中枢神经系统靶向性CuZn—SOD的构建和表达

SOD对中风等由氧自由基毒性引起的神经性紊乱有保护作用，但因血脑屏障使血液中的SOD不能进入中枢神经系统。靶向性SOD可能是进入该系统的途径之一。将人CuZn-SODcDNA与破伤风毒素C部分基因融合，分别整合进pET－22b（＋）及pFastBacHTb载体中，并分别在E.coli及粉纹夜蛾Tn-5B1-4细胞中表达。表达产物分子量为68kD,与理论计算值。蛋白质印迹实验证实，其表达产物能与人CuZn－SOD多克隆抗人本及抗破伤毒素全毒互抗体有免疫反应。在Tn细胞中高效表达，表达产物占可溶性总蛋白质的20％，表达产物有SOD活性，且具有逆行轴突运输的能力。这为靶向性SOD的进一步应用创造了条件。

Cloning and Expression of Targeting CuZn-SOD to Central Nervous System

Oxygen derived free radicals are thought to be involved in the pathogenesis of a wide range of neurological disorders. Targeted delivery of CuZn SOD to neurons in central nervous system may have therapeutic value in such diseases. The gene encoding human CuZn SOD was fused to tetanus toxin fragment C gene to construct a fusion gene, then it was cloned into prokaryotic expression vector pET 22b( ) and baculovirus vector pFastBacHTb, and was expressed in E. coli and Tn 5B1 4 cells, respectively. The recombinant fusion protein has a subunit molecular mass of 68 kD and is recognized by both anti CuZn SOD and anti tetanus toxin antibody. By pyrogallol autooxidation assay, it is shown that the CuZn SOD moiety retains substantial enzymatic activity, where the TTC moiety might deliver the fusion protein to neurons in central nervous system. So, CuZn SOD/TTC may be a useful agent for the targeted delivery of CuZn SOD to neurons.