Transcription of the Escherichia coli rrnB P1 promoter by the heat shock RNA polymerase (E sigma 32) in vitro.
Transcription of the Escherichia coli rrnB P1 promoter by the heat shock RNA polymerase (E sigma 32) in vitro.
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热休克 RNA 聚合酶 (E sigma 32) 体外转录大肠杆菌 rrnB P1 启动子。
DOI：
10.1128/jb.175.3.661-668.1993
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发表时间：
1993
影响因子：
3.2
通讯作者：
Gourse,RL
中科院分区：
文献类型：
--
作者：
Newlands,JT;Gaal,T;Mecsas,J;Gourse,RL
7个大肠杆菌rRNA操纵子的P1启动子含有RNA聚合酶（RNAP）全酶的识别序列，所述全酶含有sigma 70（E sigma 70），其已被证明在体内和体外与rrn P1启动子相互作用并启动转录。rrn P1启动子还含有E sigma 32的推定识别元件，E sigma 32是负责热休克基因转录的RNAP全酶。使用纯化的RNAP全酶的体外转录测定，我们表明，E西格玛32是能够从rrnB P1启动子转录。特异于sigma 70的抗体消除E sigma 70对rrnB P1的转录，但对E sigma 32指导的转录没有影响。E sigma 32-rrnB P1复合物的物理表征表明，E sigma 70和E sigma 32与启动子的相互作用存在差异。E sigma 32响应于Fis介导的和因子独立的上游激活，这两个系统先前显示通过E sigma 70刺激rrnB P1转录。我们发现，E sigma 32是不需要的两个主要控制系统，已知调节rRNA转录起始在正常温度下在体内，严格控制和生长速率依赖性控制。基于E sigma 32在体内热休克启动子转录中的良好作用，我们认为E sigma 32-定向rRNA启动子转录可能在高温下核糖体合成中发挥作用。
The P1 promoters of the seven Escherichia coli rRNA operons contain recognition sequences for the RNA polymerase (RNAP) holoenzyme containing sigma 70 (E sigma 70), which has been shown to interact with and initiate transcription from rrn P1 promoters in vivo and in vitro. The rrn P1 promoters also contain putative recognition elements for E sigma 32, the RNAP holoenzyme responsible for the transcription of heat shock genes. Using in vitro transcription assays with purified RNAP holoenzyme, we show that E sigma 32 is able to transcribe from the rrnB P1 promoter. Antibodies specific to sigma 70 eliminate transcription of rrnB P1 by E sigma 70 but have no effect on E sigma 32-directed transcription. Physical characterization of the E sigma 32-rrnB P1 complex shows that there are differences in the interactions made by E sigma 70 and E sigma 32 with the promoter. E sigma 32 responds to both Fis-mediated and factor-independent upstream activation, two systems shown previously to stimulate rrnB P1 transcription by E sigma 70. We find that E sigma 32 is not required for two major control systems known to regulate rRNA transcription initiation at normal temperatures in vivo, stringent control and growth rate-dependent control. On the basis of the well-characterized role of E sigma 32 in transcription from heat shock promoters in vivo, we suggest that E sigma 32-directed transcription of rRNA promoters might play a role in ribosome synthesis at high temperatures.