霍乱毒素B亚单位基因分泌型表达载体的构建及转化烟草的研究

为了探索利用植物分泌特性来表达重组蛋白的可行性，先构建了含钙网蛋白信号肽的植物双元载体pBIcal，再向该载体中插入霍乱毒素B亚单位编码基因，最后得到表达载体pBIcal—ctb。通过根癌农杆菌介导，该表达载体转化烟草，在卡那霉素抗性培养基上筛选，得到30棵抗性植株。经PCR鉴定，霍乱毒素B亚单位基因已经整合到烟草基因组中。初步表达分析表明，转基因烟草中含有具生物活性的霍乱毒素B亚单位蛋白。

Construction and Transference into Tobacco of Expression Vector of Phyto-secretion-type Cholera Toxin B Subunit Gene

Binary phyto-vector pBIcal of calreticulin was first constructed to probe the feasibility to use phyto-secretion to express recombinant proteins,the cholera toxin B subunit gene was then transferred into the vector,and expression vector pBIcal-ctb was finally obtained.By means of Agrobacterium tumefacions ,the expression vector was transferred into tobacco that was cultured on the kanamycin-resistant medium to get 20 resistant plants.PCR identification proved that cholera toxin B subunit gene had been integrated into tobacco genome.The primary analysis indicated the transgenic tobacco contained bioactive cholera toxin B subunit protein.