Effect of the deletion of the σ32‐dependent promoter (P1) of the Escherichia coli topoisomerase I gene on thermotolerance
Effect of the deletion of the σ32‐dependent promoter (P1) of the Escherichia coli topoisomerase I gene on thermotolerance
复制标题
大肠杆菌拓扑异构酶I基因σ32依赖性启动子（P1）缺失对耐热性的影响
作者：
Haiyan Qi;R. Menzel;Y. Tse‐Dinh
Topoisomerase I and DNA gyrase are the major topoisomerase activities responsible for the regulation of DNA supercoiling in the bacterium Escherichia coli. The P1 promoter of topA has previously been shown to be a σ32‐dependent heat‐shock promoter. A mutant strain with a deletion of P1 was constructed. This mutant is >10‐fold more sensitive to heat treatment (52°C) than the wild type. After brief treatment at 42°C, wild‐type Escherichia coli acquires an enhanced resistance to the effects of a subsequent 52°C treatment. This is not the case for the P1 deletion mutant, which, and under these conditions, is about 100‐fold less thermotolerant than the wild type. The presence of a plasmid expressing topoisomerase I restored the heat‐survival level of the mutant to that of the wild type. During heat shock, the superhelical density of a plasmid with the heat‐inducible rpoD promoter is increased in the P1 deletion mutant. We also note that the pulse‐labelling pattern of proteins at 42°C (displayed on SDS–polyacrylamide gels) is different in the mutant, and, most notably, the amounts of DnaK and of GroEL protein are reduced. A model is proposed in order to unify these observations.
DOI：
10.1016/s0021-9258(17)42136-3
发表时间：
1994-01
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
M. Drolet;M. Drolet;X. Bi;Leroy F. Liu
通讯作者：
M. Drolet;M. Drolet;X. Bi;Leroy F. Liu
影响因子：
5.6
作者：
RAHMOUNI, AR;WELLS, RD
通讯作者：
WELLS, RD