TOPOISOMERASE-I MUTANTS - THE GENE ON PBR322 THAT ENCODES RESISTANCE TO TETRACYCLINE AFFECTS PLASMID DNA SUPERCOILING
TOPOISOMERASE-I MUTANTS - THE GENE ON PBR322 THAT ENCODES RESISTANCE TO TETRACYCLINE AFFECTS PLASMID DNA SUPERCOILING
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DOI：
10.1073/pnas.83.23.8952
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发表时间：
1986-12-01
影响因子：
11.1
通讯作者：
DRLICA, K
中科院分区：
文献类型：
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作者：
PRUSS, GJ;DRLICA, K
从大肠杆菌和鼠伤寒沙门氏菌的拓扑异构酶I突变体中分离的质粒pBR 322 DNA表现出独特的超螺旋分布，其特征在于含有高度负超螺旋拓扑异构体的连接数的极其不均匀的分布。对pBR 322缺失和插入衍生物的超螺旋分布的分析表明，pBR 322上编码四环素抗性的基因的存在是导致不寻常的超螺旋分布的原因。需要完整的启动子和基因的剩余部分的一部分，而不是基因产物。然而，启动子以外的基因没有特定的部分似乎是必要的;只有剩余部分的大小似乎是重要的。这些观察结果表明，该基因的转录可能是负责其对DNA超螺旋的影响。
Plasmid pBR322 DNA isolated from topoisomerase I mutants of Escherichia coli and Salmonella typhimurium exhibits a distinctive supercoiling distribution characterized by an extremely heterogeneous distribution of linking number that contains highly negatively supercoiled topoisomers. Analysis of the supercoiling distributions of deletion and insertion derivatives of pBR322 shows that the presence of the gene on pBR322 encoding resisitance to tetracycline is responsible for the unusual supercoiling distribution. Both an intact promoter and a portion of the remainder of the gene, but not the gene product, are required. However, no particular section the gene outside the promoter appears to be necessary; only the size of the section remaining appears to be important. These observations suggest that transcription of this gene may be responsible for its effect on DNA supercoiling.