Köroğlu Türkan Ebru, Oğülür Ismail, Mutlu Seval, Yazgan-Karataş Ayten, Ozcengiz Gülay
Molecular Biology-Biotechnology and Genetics Research Center (MOBGAM) and Molecular Biology and Genetics Department, Istanbul Technical University, Turkey.
J Mol Microbiol Biotechnol. 2011;20(3):144-55. doi: 10.1159/000328639. Epub 2011 Jun 28.
In Bacillus subtilis, bacilysin is a nonribosomally synthesized dipeptide antibiotic composed of L-alanine and L-anticapsin. The biosynthesis of bacilysin depends on the bacABCDEywfG operon (bac operon)and the adjacent ywfH gene. To elucidate the effects of global regulatory genes on the expression of bac operon, we used the combination of lacZ fusion analysis and the gel mobility shift assays. The cell density-dependent transition state induction of the bac operon was clearly shown. The basal expression level of the bac operon as well as transition state induction of bac is directly ComA dependent. Three Phr peptides, PhrC, PhrF and PhrK, are required for full-level expression of ComA-dependent bac operon expression, but the most important role seemed to be played by PhrC in stimulating bac expression through a RapC-independent manner. Spo0A is another positive regulator which participates in the transition state induction of bac both directly by interacting with the bac promoter and indirectly by repressing abrB expression. AbrB and CodY proteins do not only directly repress the bac promoter, but they also mutually stimulate the transition state induction of bac indirectly, most likely by antagonizing their repressive effects without preventing each other's binding since both proteins can bind to the bac promoter simultaneously.
在枯草芽孢杆菌中，杆菌溶素是一种非核糖体合成的二肽抗生素，由L-丙氨酸和L-抗荚膜素组成。杆菌溶素的生物合成依赖于bacABCDEywfG操纵子（bac操纵子）和相邻的ywfH基因。为了阐明全局调控基因对bac操纵子表达的影响，我们采用了lacZ融合分析和凝胶迁移率变动分析相结合的方法。结果清楚地表明了bac操纵子的细胞密度依赖性过渡态诱导。bac操纵子的基础表达水平以及bac的过渡态诱导直接依赖于ComA。三种Phr肽，即PhrC、PhrF和PhrK，是ComA依赖性bac操纵子表达达到完全水平所必需的，但PhrC似乎在通过不依赖RapC的方式刺激bac表达方面发挥着最重要的作用。Spo0A是另一种正调控因子，它既通过与bac启动子相互作用直接参与bac的过渡态诱导，也通过抑制abrB表达间接参与。AbrB和CodY蛋白不仅直接抑制bac启动子，而且它们还相互间接刺激bac的过渡态诱导，最有可能是通过拮抗它们的抑制作用而不阻止彼此的结合，因为这两种蛋白可以同时结合到bac启动子上。
