VIRUS RESISTANCE OF TRANSGENIC TOBACCO PLANTS EXPRESSING TOBACCO MOSAIC VIRUS COAT PROTEIN GENE

An intermediate expressing vector carrying the tobacco mosaic virus (TMV, Chinese common strain) coat protein (CP) gene was constructed by recombinant DNA techniques. The TMV-CP gene was transferred into the tobacco genome via Ti plasmid and a large number of regenerated plants, including both systemic and local lesion hosts for TMV, were obtained. Southern blot analysis revealed that 1-5 copies of the CP gene were integrated into the tobacco genome. RNA and protein analysis demonstrated that the TMV-CP gene was correctly expressed in the transgenic plants. The abundance of TMV-CP mRNA in total leaf RNA accounted for 0.005-0.01%, while the amount of coat proteins reached 0.05-0.2% of the total leaf soluble proteins. Virus challenge experiments showed that the symptom development of virus infection was markedly delayed and the replication as well as the spread of the virus was significantly inhibited in the transgenic plants expressing the TMV-CP gene. Three of these plants were completely protected afte     

表达烟草花叶病毒外壳蛋白的转基因烟草及其对TMV的抗性

利用体外重组DNA技术构建携带烟草花叶病毒(TMV,国内流行的普通株)外壳蛋白基因(CP)的中间表达载体,通过土壤农杆菌(Agrobacterium tumefaciens)Ti质粒,重组TMV-CP基因被转移至烟草细胞,并获得大量再生的转基因烟草。工程烟草的基因组经Southern印迹法分析证明,CP基因在再生工程株染色体中有1—5个拷贝的插入。分子杂交分析确证TMV-CP基因在转基因株中获得正确表达,其mRNA和蛋白产物的丰度分别达0.005—0.01％及0.05—0.2％。攻毒实验表明90％以上的能表达TMV—CP基因的工程烟草能不同程度地抑制病毒的复制、扩散,并显著延缓,减轻系统病状的发生。有3株工程植株直至花期无病状表现,生长正常。这一抗性作用机制在于转化细胞中的外壳蛋白在病毒侵染早期有效地抑制了入侵病毒颗粒的脱壳,从而阻断病毒的复制。     

大骨节病患儿红细胞膜骨架的变化

本文对大骨节病患儿红细胞膜骨架稳定性及红细胞ATP含量进行测定,结果:1.膜骨架蛋白主要组分血影收缩蛋白(Spectrin)与膜的结合程度下降,2.Spectrin本身的聚合状态有变化,3.~(31)P-NMR测试结果表明,大骨节病患者红细胞膜化学位移各向异性增加,提示膜骨架蛋白与膜脂静电作用增加,磷脂‘头部’运动自由度减少,4.大骨节病患儿红细胞膜内含能源物质ATP明显减少,5.大骨节病患儿红细胞硒含量明显低于对照。本文还对硒与红细胞膜骨架,低硒与大骨节病发病机理进行了讨论。