Saito K, Noji M, Ohmori S, Imai Y, Murakoshi I
Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Proc Natl Acad Sci U S A. 1991 Aug 15;88(16):7041-5. doi: 10.1073/pnas.88.16.7041.
Cytochrome P-450 is involved in the oxidative metabolism of a broad range of substrates. We have made a chimeric construct, pSN002, containing the cDNA for rabbit liver cytochrome P-450 (IIC14) under the control of the TR2' promoter for mannopine synthase in the Agrobacterium Ti plasmid. Nicotiana tabacum was transformed with Agrobacterium tumefaciens harboring a cointegrated plasmid pSN002::pGV2260. The presence of mRNA and of the translated protein from the chimeric cytochrome P-450 gene in transgenic plants was confirmed by RNA blot hybridization and by Western blot and immunohistochemical analyses, respectively. The transformants in which the foreign cytochrome P-450 protein is expressed show marked phenotypic changes, notably a tendency rapidly to senesce. We detected 2-propenylpyrrolidine, a degradative metabolite of nicotine alkaloids, in transgenic tobacco showing this pronounced phenotypic change. Such metabolism is likely to be due to the effect of senescence and not directly to the presence of the cytochrome P-450.
细胞色素P - 450参与多种底物的氧化代谢。我们构建了一个嵌合结构pSN002，其含有兔肝细胞色素P - 450（IIC14）的cDNA，该cDNA受农杆菌Ti质粒中甘露碱合成酶TR2'启动子的控制。用携带共整合质粒pSN002::pGV2260的根癌农杆菌转化烟草。分别通过RNA印迹杂交、蛋白质印迹和免疫组织化学分析证实了转基因植物中嵌合细胞色素P - 450基因的mRNA和翻译蛋白的存在。表达外源细胞色素P - 450蛋白的转化体表现出明显的表型变化，尤其是有快速衰老的趋势。在表现出这种明显表型变化的转基因烟草中，我们检测到了尼古丁生物碱的降解代谢产物2 - 丙烯基吡咯烷。这种代谢可能是由于衰老的影响，而不是直接由于细胞色素P - 450的存在。
