Koncz C, De Greve H, André D, Deboeck F, Van Montagu M, Schell J
Max-Planck-Institut für Züchtungsforschung, Köln, FRG.
EMBO J. 1983;2(9):1597-603. doi: 10.1002/j.1460-2075.1983.tb01630.x.
Signals necessary for in vivo expression of Ti plasmid T-DNA-encoded octopine and nopaline synthase genes were studied in crown gall tumors by constructing mutated genes carrying various lengths of sequences upstream of the 5' initiation site of their mRNAs. Deletions upstream of position -294 did not interfere with expression of the octopine synthase gene while those extending upstream of position -170 greatly reduced the gene expression. The estimated size of the octopine synthase promoter is therefore 295 bp. The maximal length of 5' upstream sequences involved in the in vivo expression of the nopaline synthase gene is 261 bp. Our results also demonstrated that Ti plasmid-derived sequences contain all signals essential for expression of opine synthase genes in plants. Expression of these genes, therefore, is independent of the direct vicinity of the plant DNA sequences and is not activated by formation of plant DNA and T-DNA border junction.
通过构建携带其mRNA 5'起始位点上游不同长度序列的突变基因，研究了Ti质粒T-DNA编码的章鱼碱和胭脂碱合成酶基因在体内表达所需的信号。-294位点上游的缺失不影响章鱼碱合成酶基因的表达，而延伸至-170位点上游的缺失则大大降低了该基因的表达。因此，章鱼碱合成酶启动子的估计大小为295 bp。参与胭脂碱合成酶基因体内表达的5'上游序列的最大长度为261 bp。我们的结果还表明，Ti质粒衍生序列包含植物中表达章鱼碱合成酶基因所需的所有信号。因此，这些基因的表达独立于植物DNA序列的直接邻近区域，并且不会因植物DNA和T-DNA边界连接的形成而被激活。
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