The minus 35-recognition region of Escherichia coli sigma 70 is inessential for initiation of transcription at an "extended minus 10" promoter.
The minus 35-recognition region of Escherichia coli sigma 70 is inessential for initiation of transcription at an "extended minus 10" promoter.
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大肠杆菌 sigma 70 的负 35 识别区域对于“扩展负 10”启动子处的转录起始不是必需的。
DOI：
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发表时间：
1993
影响因子：
5.6
通讯作者：
R. Hayward
中科院分区：
文献类型：
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作者：
Anil Kumar;R. Malloch;N. Fujita;D. A. Smillie;Akira Ishihama;R. Hayward
已知，具有主要负10共有序列TATAAT但与负35区域中的共有序列缺乏显着相似性的大肠杆菌启动子，如果它们在紧邻负10上游具有额外的TGn基序，则允许体内和体外转录起始。为了确定西格玛70的区域4.2（其正常作用是在负35处的序列识别）对于在这种“扩展负10”启动子处的转录起始是否是不必要的，我们修改了 sigma 70 基因，以产生缺乏最后 84 个氨基酸并因此缺失区域 4.2 的羧基截短的多肽。我们的结果表明，完整和截短的 sigma 70 都允许纯化的 RNA 聚合酶在延伸的负 10 启动子处有效且特异性地启动，而只有完整的 sigma 70 允许在正常启动子（由负 35 和负 10 六聚体序列定义）处有效启动。
It is known that Escherichia coli promoters having the major minus 10 consensus sequence TATAAT, but lacking significant resemblance to consensus in the minus 35 region, allow transcriptional initiation in vivo and in vitro if they have an additional TGn motif immediately upstream of minus 10. To determine whether region 4.2 of sigma 70, whose normal role is sequence recognition at minus 35, is unnecessary for initiation of transcription at such "extended minus 10" promoters, we modified the sigma 70 gene so as to generate a carboxy-truncated polypeptide lacking the last 84 amino acids and therefore missing region 4.2. Our results show that both the intact and truncated sigma 70 allow purified RNA polymerase to initiate efficiently and specifically at an extended minus 10 promoter, whereas only the intact sigma 70 permits efficient initiation at normal promoters (defined by minus 35 and minus 10 hexamer sequences).