用于库-库筛选体系的抗原表达载体的构建

Construction of The Antigen Expression Vector Used for Library-library Screening

选择感染性噬菌体(SIP)技术是研究蛋白质相互作用的良好手段,体内SIP技术在理论上适于库-库筛选,而双载体共包装聚合噬菌体方式是一条有效途径.为构建适合库-库筛选的抗原表达载体,选用TG10载体作为基本载体进行改造,首先克隆噬菌体M13基因间隔区的序列插入TG10中得到质粒pTMI,克隆基因Ⅲ的N1N2区序列,并在其3′端加上一段G4T柔性多肽,将NIN2插入到pTMI载体中Lac启动子的下游得到pTMIN,化学合成Ptrc启动子序列替换pTMIN中的Lac启动子及部分功能基因序列,构建成抗原表达载体pTTMIN,化学合成c-myc的十肽表位插入到G4S后进行融合表达,采用ELISA和SDS-聚丙烯酰胺凝胶电泳检测抗原的表达,结果显示抗原得到了融合表达.用抗体呈现载体对pTTMIN性能进行鉴定,结果表明抗原表达载体可以与抗体呈现载体高效的共包装.综合以上结果说明抗原表达载体构建成功,可望用于库-库筛选体系.

Selectively infective phage （SIP） technology was developed for screening interacting protein-protein pairs. The in vivo SIP strategy would in principle be suitable for ＂library-library＂ selections, and the co-packaged polyphage may be a suitable approach. In order to construct the antigen expression vector which can be co-packaged into polyphage with phage displaying vectors, plasmid TG10 was chosen as the basic vector which is compatible with antibody display vector. The interval sequence of phage genome was amplified with PCR and cloned into TG10 to provide the packaging signal. It was named pTMI and it can be packaged into phage particles in 10^11 level. The N1N2 region ofgene Ⅲ was amplified and cloned into pTMI under the control oflac promoter to give pTMIN. Promoter trc was synthesized and replaced the lac promoter to give pTTMIN which permits the fusion expression of antigen with N1N2. To test its ability for fusion expression, gene code for ten-peptide of c-myc was synthesized and inserted into pTTMIN downstream to N1N2. After induction expression, the results of ELISA and SDS-PAGE showed that it has been expressed successfully. When pTTMIN was transfected into cell carrying antibody display vector p3MHHB3, it was copackaged into phage particles in 0.3% to 55% after rescuing with helper phage VCSM13.From the results it can concluded that the antigen expression vector was constructed successfully and it can be used for library-library screening in theory.