蜡样芽胞杆菌五组份磷酸糖信号传导途径的研究

细菌通过双组分信号系统感应外界环境各种信号，调控菌体内相关基因的表达，以适应不断变化的环境。前期研究发现蜡样芽胞杆菌通过五组份信号系统(Sps)对宿主体内磷酸糖信号产生应答,该系统包含编码双组份系统的spsR和spsK基因及三个下游基因spsA、spsB和spsC。SpsC的功能是吸收G-6-P；而spsRK、spsA和spsB基因对于Sps的磷酸糖诱导转录是必须的，但它们的作用机制不清楚。本项目在此基础上拟在体外展开Sps系统的作用机制研究：通过分析不同长度启动子的活性,寻找转录调控因子的结合区域,并明确双组份信号系统及其它转录调控因子对Sps系统的调控机制；通过纯化SpsA和SpsB蛋白，研究它们与信号分子的互作及与SpsK信号感应结构域的互作，明确SpsA和SpsB在信号传导系统中的作用机制。为病原菌在宿主环境中对信号应答机制提供理论支撑，对研究病原菌在宿主中的适应性具有重要的意义。

Bacteria sense many different stimuli by two-component systems (TCS) from their environment and such stimuli can rapidly trigger adaptive physiological responses. The ability of bacteria to sense the environment is essential for their adaptation and thus for survival under various conditions including interactions with their respective hosts. Previously study in our group indicated that bacillus cereus responds to sugar phosphate signal by Sps system in vivo and in vitro. Sps system is composed of five genes, which encode a putative two-component system (SpsRK) and three downstream genes spsA, spsB and spsC. The function of SpsC is uptake of glucose-6-phosphate. spsRK, spsA and spsB are necessary to induced transcription of spsABC. However, its regulation mechanisms remain unknown. The regulation mechanism of Sps system will be performed in this study. To determine the transcriptional regulator binding domains and the regulation mechanism of SpsRK and other regulators, the activation of different fragments of promoter will be analyzed. To determine the function of SpsA and SpsB in signal pathway, the interaction of SpsA and SpsB proteins between sugar phosphate signal and sensor domain of SpsK will be analyzed. All achievements in this study will provide fundamental theory in pathogenic bacteria sense to their host environment.