MECHANISMS OF VIRULENCE GENE REGULATION IN S. AUREUS

描述(改编自申请人的摘要)：尽管内容密集 过去50年的研究努力，金黄色葡萄球菌仍然是一种 严重威胁人类健康。事实上，最近有报道称， 对万古霉素的敏感性降低表明这种可能性越来越大 金黄色葡萄球菌可能会对目前所有可用的抗菌剂产生抗药性 探员。因此，现在金黄色葡萄球菌对人类健康的威胁比 从抗生素前区域开始的任何时间。中国的长期目标是 研究人员的研究是开发新的抗葡萄球菌疗法 阻止耐药菌株发展的药物。目前的建议是 重点研究了毒力基因的两个全球作用调节子的相互作用 表达：sar和agr。调查人员和其他人之前的工作表明 Sar基因的产物Sara是一种转录因子， 激活agr的表达，并导致有机体的毒力增强。 因为agr、sar和agr/sar突变体在猪传染性支气管炎动物模型中毒性较低。 葡萄球菌病，他们认为SarA/AGR的相互作用是一种非常 寻找新型葡萄球菌毒力抑制剂的前景看好。重要的是 由于sar和agr突变体生长正常，但毒性较小，因此应该有 减少了对这种类型的抑制剂产生抗药性的进化压力 与传统的抑制生长的抗生素相比。此外，还有 是否有报道称sar和agr突变体对现有的 包括甲氧西林在内的抗菌剂。SARA/AGR的抑制剂 因此，交互对于增加 现有的药物。为了为抑制剂的开发提供基础，他们将 首先揭示SARA激活agr基因表达的机制。这个 拟议研究的前三个具体目标是：1)定义独联体 负责SARA激活agr基因的调控元件，2) 定义激活AGR所需的SARA功能结构域 转录，3)确定sARA与agr调控的相互作用 原子水平上的元素。这些目标将通过联合行动来实现 诱变，体外和体内活性分析，x射线结晶学， 和原子力显微镜。第四个具体目标，开始发展 针对这些全球调控因素的抗葡萄球菌抑制剂是 旨在检验Sara-agr是小说的合适目标这一假设 抗葡萄球菌药物。这种基础广泛的方法利用了 协调团队，每个成员都是其所在领域的专家。

DESCRIPTION (Adapted from the Applicant's Abstract): Despite intensive research efforts over the past 50 years, Staphylococcus aureus remains a serious threat to human health. In fact, recent reports of isolates with reduced susceptibility to vancomycin are indicative of the growing likelihood that S. aureus may become resistant to every currently available antimicrobial agent. Therefore, S. aureus represents a bigger threat to human health now than at any time since the pre-antibiotic area. The long-term goal of the investigators' research is to develop novel anti-staphylococcal therapeutic agents to stem the advance of drug-resistant strains. The current proposal is focused on the interaction of two globally-acting regulators of virulence gene expression: sar and agr. Previous work by the investigators and others indicate that the product of the sar gene, SarA, is a transcription factor that activates agr expression and leads to enhanced virulence of the organism. Because agr, sar and agr/sar mutants are less virulent in animal models of staphylococcal disease, they believe that the SarA/agr interaction is a very promising target for novel inhibitors of staphylococcal virulence. Importantly, since sar and agr mutants grow normally, but are less virulent, there should be reduced evolutionary pressure to become resistant to this type of inhibitor in comparison with classical antibiotics that inhibit growth. In addition, there are reports of increased sensitivity of sar and agr mutants to existing antimicrobial agents including methicillin. Inhibitors of the SarA/agr interaction may therefore be useful with respect to increasing the utility of existing drugs. To provide the foundation for inhibitor development, they will first reveal the mechanism by which SarA activates agr gene expression. The first three Specific Aims of the proposed research are: 1) to define the cis regulatory elements responsible for activation of the agr genes by SarA, 2) to define the functional domains of SarA required for activation of agr transcription, 3) to define the interaction of SarA with the agr regulatory elements at the atomic level. These aims will be accomplished by a combination of mutagenesis, in vitro and in vivo activity assays, x-ray crystallography, and atomic force microscopy. The fourth Specific Aim, to begin to develop anti-staphylococcal inhibitors that target these global regulatory factors, is intended to test the hypothesis that SarA-agr is a suitable target for novel anti-staphylococcal drugs. This broad-based approach takes advantage of a coordinated team, each member of which is an expert in his/her field.