T-DNA OF AGROBACTERIUM-TUMEFACIENS ENCODES AN ENZYME OF CYTOKININ BIOSYNTHESIS
T-DNA OF AGROBACTERIUM-TUMEFACIENS ENCODES AN ENZYME OF CYTOKININ BIOSYNTHESIS
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DOI：
10.1073/pnas.81.19.5994
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发表时间：
1984-01-01
期刊：
影响因子：
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通讯作者：
GORDON, MP
中科院分区：
文献类型：
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作者：
AKIYOSHI, DE;KLEE, H;GORDON, MP
冠瘿瘤中植物激素的过量产生是由于几个T-DNA基因的表达。这些数据强烈表明，TMR基因（转录本4）是负责细胞分裂素过度生产的编码二甲基烯丙基焦磷酸：AMP二甲基烯丙基转移酶（DMA转移酶），直接参与细胞分裂素的生物合成的酶。含有来自pTiA 6 NC的tmr基因的大肠杆菌菌株的无细胞提取物具有DMA转移酶活性。在仅含有质粒载体的对照菌株中不存在活性。合成的细胞分裂素为异戊烯基腺嘌呤、异戊烯基腺苷和异戊烯基腺苷5 ''-一磷酸。DMA转移酶活性也检测到克隆冠瘿瘤煽动根癌农杆菌野生型A6 NC和tms突变体。E.在tmr基因内插入转座子可以消除大肠杆菌和肿瘤。
Phytohormone overproduction in crown gall tumors is due to the expression of several T-DNA genes. The data strongly suggest that the tmr gene (transcript 4) is responsible for cytokinin overproduction by encoding dimethylallylpyrophosphate:AMP dimethylallyltransferase (DMA transferase), an enzyme directly involved in cytokinin biosynthesis. Cell-free extracts of Escherichia coli strains containing the tmr gene from pTiA6NC had DMA transferase activity. No activity was present in the control strain containing only the plasmid vector. The cytokinins synthesized were isopentenyladenine, isopentenyladenosine and isopentenyladenosine 5''-monophosphate. DMA transferase activity was also detected in cloned crown gall tumors incited by Agrobacterium tumefaciens wild-type A6NC and a tms mutant. Enzymatic activity in cell-free extracts of E. coli and tumors could be abolished by transposon insertion within the tmr gene.