B. subtilis PHO REGULON SIGNAL TRANSDUCTION NETWORK

描述（由申请人提供）：2-组分信号传导是原核生物中信号转导的主要形式，在真核生物中具有独特的实例。在对数生长结束时，"过渡状态"芽孢杆菌细胞从环境接收多个信号，这些信号同时报告诸如温度、细胞密度、营养可用性和氧张力的条件。这些信号被处理以确定最合适的基因表达和生存代谢反应。我们正在测试的假设是，“多个信号的处理是由涉及多个2-组件系统的调节网络完成的，这些系统的功能是在系统之间建立依赖关系或层次结构。调节子之间的跨系统相互作用提供了信号整合和放大的机制，该机制导致对给定响应的微调，该给定响应适应生物体在任何时间经历的整个信号输入。Pho信号转导网络由至少3个双组分系统组成：PhoP-PhoR，ResD-ResE和Spo0A，以及全局应激，分解代谢物，过渡态和发育调节剂。我们将通过确定6个phoPR启动子中的哪一个响应于直接AbrB结合以及AbrB是否也通过ScoC具有间接作用来检查Spo0A~P-AbrB通路在Pho信号转导网络中的作用。我们将确定什么未知的监管电路控制phoPR P5启动子调节的情况下，第二个Pi饥饿的全球调节器，SigB。我们将研究正反馈环，这是必不可少的resABCDE转录（ResD和ResE生产）在磷酸盐饥饿过程中通过分析突变，绕过要求的PhoP在resA转录，并通过重建resA转录在体外了解PhoP和ResD的重要但不足的作用。我们将通过确定上游调节器ResD在控制Pi缺陷信号和/或该信号的调制中的作用，来检查通过正反馈回路的跨系统相互作用，该正反馈回路对于Pho调节子的完全诱导是必不可少的。我们将确定如何减少甲基萘醌，抑制phoR的自磷酸化在体外，调节体内磷酸缺乏症的信号，并询问是否氧化还原反应性半胱氨酸发挥作用。这些研究将有助于为革兰氏阳性菌的双组分信号转导系统作为抗菌治疗靶点的知识基础。

DESCRIPTION (provided by applicant): 2-component signaling is the principal form of signal transduction in prokaryotes with distinctive examples in eukaryotes. At the end of logarithmic growth, the "transition state" Bacillus cell receives multiple signals from the environment that are simultaneously reporting conditions such as temperature, cell density, nutrition availability and oxygen tension. These signals are processed to determine the most appropriate gene expression and metabolic response for survival. The hypothesis we are testing is that "The processing of the multiple signals is accomplished by regulatory networks involving multiple 2-component systems that function to establish dependencies or hierarchies between systems. Cross-system interaction between regulons provides a mechanism for signal integration and amplification, a mechanism which results in fine tuning of a given response that accommodates the entire signal input experienced by the organism at any 1 time." The Pho signal transduction network is comprised of at least 3 2-component systems: PhoP-PhoR, ResD-ResE and Spo0A, and global stress, catabolite, transition state and developmental regulators. We will examine the role of the Spo0A~P-AbrB pathway in the Pho signal transduction network by determining which of 6 phoPR promoter(s) respond to direct AbrB binding and if AbrB also has an indirect role via ScoC. We will determine what unknown regulatory circuits control phoPR P5 promoter regulation in the absence of a second Pi starvation global regulator, SigB. We will examine the positive feedback loop that is essential for resABCDE transcription (ResD and ResE production) during phosphate starvation by analyzing mutations that bypass the requirement for PhoP in resA transcription and via reconstruction of resA transcription in vitro to understand the essential but insufficient role of both PhoP and ResD. We will examine the cross-system interaction via the positive feedback loop that is essential for full induction of the Pho regulon by determining the role of upstream regulator, ResD, in controlling the Pi deficiency signal and/or modulation of that signal. We will determine how reduced menaquinones that inhibit the autophosphorylation of PhoR in vitro, modulate the phosphate deficiency signal in vivo and ask if redox-reactive cysteines play a role. These studies will contribute to the knowledge base of two-component signal transduction systems of gram-positive bacteria as targets for antimicrobial therapy.