Identification of a response regulator gene for catabolite control from a PCB-degrading β-proteobacteria, Acidovorax sp KKS102
Identification of a response regulator gene for catabolite control from a PCB-degrading β-proteobacteria, Acidovorax sp KKS102
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DOI：
10.1111/j.1365-2958.2006.05197.x
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发表时间：
2006-06-01
影响因子：
3.6
通讯作者：
Tsuda, Masataka
中科院分区：
文献类型：
--
作者：
Ohtsubo, Yoshiyuki;Goto, Hiroyuki;Tsuda, Masataka
食酸菌属（以前称为假单胞菌属）菌株KKS 102携带降解PCB/联苯的bph操纵子。发现从pE启动子转录bph操纵子是在分解代谢物控制下，即当向培养物中加入琥珀酸盐、富马酸盐或乙酸盐时，启动子活性处于较低水平。在直接上游区域的pE启动子的一些突变导致分解产物不敏感和组成型低启动子活性，这表明转录激活因子参与分解产物控制。一个pE启动子激活剂的遗传筛选确定了两个串联排列的基因，bphP和bphQ，编码的蛋白质同源的传感器激酶和响应调节器，分别为双组分调节系统。在bphPQ双突变体中，pE启动子活性较弱且对分解产物不敏感，单独供应bphQ基因导致分解产物响应的恢复。KKS 102中分解代谢产物阻遏的机制解释为BphQ抑制活化。与bphQ高度相似的基因是从几种β-变形菌中发现的，如新洋葱伯克霍尔德氏菌J2315，B。multivorans ATCC 17616，B. xenovorans LB 400和青枯雷尔氏菌RS 1085。
Acidovorax sp. (formally Pseudomonas sp.) strain KKS102 carries a bph operon for the degradation of PCB/biphenyl. Transcription from the pE promoter for the bph operon was found to be under catabolite control, i.e. the promoter activity was at a lower level when succinate, fumarate or acetate was added to the culture. Some mutations in the immediate upstream region of the pE promoter resulted in catabolite-insensitive and constitutively low promoter activity, suggesting that a transcriptional activator was involved in catabolite control. A genetic screen for a pE promoter activator identified two tandemly arranged genes, bphP and bphQ, that encoded proteins homologous to the sensor kinases and response regulators, respectively, of two-component regulatory system. In the bphPQ double mutant, pE promoter activity was weak and catabolite-insensitive, and a supply of the bphQ gene alone led to the restoration of the catabolite response. The mechanism of catabolite repression in KKS102 is explained in terms of inhibition of activation by BphQ. The genes highly similar to bphQ were found from several beta-proteobacteria, such as Burkholderia cenocepacia J2315, B. multivorans ATCC17616, B. xenovorans LB400 and Ralstonia solanacearum RS1085.