Bacterial gene regulation in response to oxidative stress

描述(由申请人提供)：当人类细胞被细菌病原体感染时，会产生活性氧类。这种氧化爆发的目的是杀死潜在的入侵者。几种细菌转录因子已经被描述为对活性氧物种做出反应，以控制基因表达，并对这种氧化爆发进行防御。研究还表明，细菌对宿主衍生的活性氧物种的低效反应降低了传染性。因此，了解宿主-病原体相互作用的全谱，以便能够使用有效的抗菌剂，对人类健康非常重要。在这个节目中，我们关注氧化爆发的一个相关方面，即伴随产生的尿酸盐。之所以产生尿酸盐，是因为负责产生活性氧的两种主要酶之一是黄嘌呤氧化酶，它在嘌呤降解中起作用，将次黄嘌呤转化为黄嘌呤，将黄嘌呤转化为尿酸盐。在我们以前工作的基础上，我们证明了尿酸盐作为植物病原菌编码的转录因子的配体来介导基因调控，现在我们集中在两个具体的假设上：1-尿酸盐作为信号分子作用于某些细菌物种的基因调控，而这些细菌是人类重要的病原体；2-尿酸盐介导的基因调控受属于多重抗生素耐药性调节(MARR)家族的转录调控因子的影响。以泰兰伯克霍尔德氏菌为模型系统，我们计划确定尿酸盐介导的这种转录因子对dna结合的减弱机制以及它所控制的调节子，我们计划确定尿酸对DNA结合的作用。 氧化应激反应中尿酸依赖的转录调控。拟议的实验计划将扩展已知的基因表达调控机制，以应对氧化应激，并相关的潜力，以更深入地了解宿主与病原体的相互作用，并将提供一个环境，学生将接触到生物医学研究。

DESCRIPTION (provided by applicant): Human cells produce reactive oxygen species when infected by a bacterial pathogen. This oxidative burst is intended to kill the would-be invader. Several bacterial transcription factors have been characterized that respond to reactive oxygen species to control gene expression and mount a defense against this oxidative burst. It has also been shown that an inefficient bacterial response to host-derived reactive oxygen species reduces infectivity. It is therefore of importance to human health to understand the full spectrum of host-pathogen interactions to be able to administer effective antimicrobial agents. In this program, we focus on a related aspect of the oxidative burst, namely the concomitant production of urate. Urate is produced because one of the two main enzymes responsible for production of reactive oxygen species is xanthine oxidase, which functions in purine degradation to convert hypoxanthine to xanthine and xanthine to urate. Based on our previous work in which we demonstrated that urate functions as a ligand for a transcription factor encoded by plant pathogens to mediate gene regulation, we now focus on two specific hypotheses: 1-That urate functions as a signaling molecule to effect gene regulation in certain bacterial species that are important human pathogens, and 2- that urate-mediated gene regulation is effected by a subset of transcriptional regulators that belong to the Multiple Antibiotic Resistance Regulator (MarR) family. Using Burkholderia thailandensis as a model system, we plan to identify the mechanism of urate-mediated attenuation of DNA binding by this transcription factor as well as the regulon under its control, and we plan to determine the role of urate-dependent transcriptional regulation in response to oxidative stress. The proposed experimental plan will extend the known mechanisms by which gene expression is regulated in response to oxidative stress with the associated potential for a deeper understanding of host-pathogen interactions, and it will furnish an environment in which students will be exposed to biomedical research.