Tanabe H, Yamasaki K, Katoh A, Yoshioka S, Utsumi R
Department of Agricultural Chemistry, Kinki University, Nara, Japan.
Biosci Biotechnol Biochem. 1998 Feb;62(2):286-90. doi: 10.1271/bbb.62.286.
The evgAS operon of Escherichia coli encodes the EvgA response regulator and the EvgS sensory kinase, which are members of one of the two-component signal transduction systems of Escherichia coli. In this study, we identified the evg promoter and the EvgA-responsive element. Primer extension analysis found two evg transcriptional initiation sites, designated P1 (+1) and P2 (-10), and placed them 114 bp and 124 bp upstream of evgA, respectively. A gel retardation assay demonstrated that EvgA specifically bound to an inverted repeat located between -102 and -128 counting from P1. We also did a beta-galactosidase induction experiment using a promoter-probing vector and found that the EvgA-binding sequence was important to stimulate the evg promoter. These results suggest that the expression of evgAS is positively regulated by its own product, EvgA.
大肠杆菌的evgAS操纵子编码EvgA反应调节因子和EvgS传感激酶，它们是大肠杆菌双组分信号转导系统中的两个成员。在本研究中，我们鉴定了evg启动子和EvgA反应元件。引物延伸分析发现了两个evg转录起始位点，分别命名为P1（+1）和P2（-10），并将它们分别置于evgA上游114 bp和124 bp处。凝胶阻滞试验表明，EvgA特异性结合于从P1开始计数位于-102至-128之间的一个反向重复序列。我们还使用启动子探测载体进行了β-半乳糖苷酶诱导实验，发现EvgA结合序列对于刺激evg启动子很重要。这些结果表明，evgAS的表达受到其自身产物EvgA的正调控。
