黑胸大蠊浓核病毒NS2蛋白的表达、抗体制备及亚细胞定位

Expression, Purification, Preparation of Polyclonal Antibody and Subcelluar Localization of the NS2 Protein of Periplaneta fuliginosa Densovirus

摘要:

ns2是黑胸大蠊浓核病毒的一个非结构基因, 所编码的蛋白质大小为30 kD, 是一个功能未知的基因。为了对该基因进行深入的功能研究, 从感染了黑胸大蠊浓核病毒的蟑螂的后肠组织中通过RT-PCR得到ns2基因编码序列, 将其构建于原核表达载体pET-28a, 转化大肠杆菌BL21(DE3) 获得融合表达产物。此融合蛋白经分离纯化后, 免疫新西兰大白兔, 制备其多克隆抗体。采用Western印迹技术, 用该抗体检测ns2基因的真核表达产物, 证明该抗体有较好的针对NS2蛋白的专一性, 可用于对NS2结构和功能的研究。同时, 将此编码序列克隆至果蝇细胞表达载体pAC, 得到重组质粒后转染果蝇S2细胞表达重组蛋白, 通过共聚焦显微镜用该抗体检测该蛋白在S2细胞中的亚细胞定位, 发现NS2蛋白主要定位于细胞质, 核内仅有少量分布。

Abstract:

NS2 is a nonstructural protein of Periplaneta fuliginosa densovirus (PfDNV) with a molecular mass of 30 kD, whose function is not yet clearly understood. In order to study the expression, subcellular distribution and the function of NS2 protein, the coding region of NS2 was amplified from the hindgut tissue of cockroaches infected with PfDNV by RT-PCR and then the recombinant prokaryotic expression vector pET28a-NS2 was constructed. The recombinant plasmid was transformed into E. coli BL21 (DE3) to express the 6×His fusion protein in the bacteria. After purification, the fusion protein was injected into New Zealand rabbits to prepare polyclonal antibody. The specificity of the anti-NS2 antibody was successfully proved by western blotting on the eukaryotic expressed products of NS2 protein．Meanwhile, the full sequence of ns2 gene was also cloned into the eukaryotic expression vector pAC. The recombinant plasmid pAC-NS2 was then transfected into Schneider line 2 (S2) cells to express NS2 protein in the insect cells. The subcellular localization of NS2 in the insect cells was then investigated by indirect immunofluorescence technique using the anti-NS2 polyclonal antiserum. The confocal laser scanning microscope observation showed that NS2 protein was located primarily in the cytoplasm with some punctate nuclear staining.