Moir-Blais T R, Grundy F J, Henkin T M
Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA.
J Bacteriol. 2001 Apr;183(7):2389-93. doi: 10.1128/JB.183.7.2389-2393.2001.
Carbon catabolite protein A (CcpA) is a global regulator of carbon metabolism in gram-positive bacteria, repressing transcription of genes for the utilization of secondary carbon sources in the presence of a readily metabolized carbon source and activating transcription of genes, such as ackA and pta, that are required for carbon excretion. The promoter region of the Bacillus subtilis ackA gene contains two catabolite responsive elements (cre sites), of which only the site closest to the promoter (cre2) binds CcpA to activate transcription. A region immediately upstream of the cre2 site is also important for transcriptional activation. The required elements in this region were further defined by mutagenesis. CcpA binds to the ackA promoter region in gel shift assays even in the presence of mutations in the upstream element that block transcriptional activation, indicating that this region has a function other than promoting binding of CcpA.
碳分解代谢蛋白A（CcpA）是革兰氏阳性菌中碳代谢的全局调节因子，在易代谢碳源存在时抑制次级碳源利用基因的转录，并激活碳排泄所需基因（如ackA和pta）的转录。枯草芽孢杆菌ackA基因的启动子区域包含两个分解代谢物反应元件（cre位点），其中只有最靠近启动子的位点（cre2）结合CcpA以激活转录。cre2位点上游紧邻的区域对转录激活也很重要。通过诱变进一步确定了该区域所需的元件。在凝胶迁移实验中，即使上游元件发生突变阻止转录激活，CcpA仍能与ackA启动子区域结合，这表明该区域除了促进CcpA结合外还有其他功能。
