TRANSCRIPTIONAL REGULATION OF BACILLUS-SUBTILIS CITRATE SYNTHASE GENES
TRANSCRIPTIONAL REGULATION OF BACILLUS-SUBTILIS CITRATE SYNTHASE GENES
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DOI：
10.1128/jb.176.15.4680-4690.1994
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发表时间：
1994-08-01
影响因子：
3.2
通讯作者：
SONENSHEIN, AL
中科院分区：
文献类型：
--
作者：
JIN, SF;SONENSHEIN, AL
枯草芽孢杆菌柠檬酸合酶基因citA和citZ在营养肉汤培养基中的早期指数生长期被抑制，并在细胞达到指数期结束时被诱导。这两种基因也可以通过用药物decoyinine处理细胞来诱导。诱导后，citZ mRNA的稳态水平约为citA mRNA的5倍。至少相同的citZ转录物通读到异柠檬酸脱氢酶（citC）基因中。从位于citZ基因3'端附近的明显启动子位点的转录也有助于citC的表达。在基本培养基中，当葡萄糖为唯一碳源时，citA转录比当琥珀酸为碳源时低约6倍。葡萄糖抑制citZ基因的表达2倍，当葡萄糖和谷氨酸同时存在时抑制10倍。后者的协同抑制与葡萄糖和谷氨酸对稳态柠檬酸合成酶活性的影响相似。CitR是LysR家族的一种蛋白质，似乎是citA的阻遏物，但不是citZ的阻遏物。
The Bacillus subtilis citrate synthase genes citA and citZ were repressed during early exponential growth phase in nutrient broth medium and were induced as cells reached the end of exponential phase. Both genes were also induced by treatment of cells with the drug decoyinine. After induction, the steady-state level of citZ mRNA,vas about five times higher than that of citA mRNA. At least same of the citZ transcripts read through into the isocitrate dehydrogenase (citC) gene. Transcription from an apparent promoter site located near the 3' end of the citZ gene also contributed to expression of citC. In minimal medium, citA transcription was about 6-fold lower when glucose was the sole carbon source than it was when succinate was the carbon source. Expression of the citZ gene was repressed 2-fold by glucose and 10-fold when glucose and glutamate were present simultaneously. This latter synergistic repression is similar to the effect of glucose and glutamate on steady-state citrate synthase enzyme activity. CitR, a protein of the LysR family, appeared to be a repressor of citA but not of citZ.