Transcriptional Control of the Helicobacter pylori RpoN Regulon

描述（由申请方提供）：幽门螺杆菌是人类消化性溃疡和多种其他疾病（包括胃癌和粘膜相关淋巴瘤）的病原体。H需要运动。pylori能穿过胃粘膜层并定植于胃上皮;幽门螺杆菌使用一簇极鞭毛来完成这一过程。鞭毛基因在细菌中的表达调控是复杂的，并且涉及将鞭毛基因的表达与鞭毛的组装偶联的转录层级。建议研究的长期目标是确定H。pylori调控鞭毛基因表达。替代σ因子RpoN是几种H. pylori鞭毛基因这些RpoN依赖性基因的转录也需要FlgS/FlgR双组分系统。表达H.幽门螺杆菌RpoN依赖性鞭毛基因与鞭毛蛋白输出装置相连，因为编码输出装置组分的基因突变干扰RpoN调节子的表达。输出装置影响RpoN调节子表达的机制尚不清楚。本项目的目标是确定输出装置控制H. pylori RpoN鞭毛调节子。工作假设是输出装置影响H.通过分泌RpoN调节子的抑制剂或通过蛋白质-蛋白质相互作用影响传感器激酶FlgS的活性来调节pylori RpoN调节子。这一假设将在三个具体目标中得到客观检验。第一个具体目标将确定FlgR的组成型活性形式是否绕过输出装置突变以允许RpoN依赖性报告基因的表达。在第二个具体目标H.将检测具有将输出装置锁定在有利于杆/钩型底物的构象中的突变的幽门螺杆菌菌株，以观察它们如何影响RpoN依赖性报告基因的表达。第三个具体目标将通过破坏编码新蛋白质HP 1042的基因并确定该突变如何影响H.幽门。拟议的工作与NIH促进美国公共卫生的使命有关，因为研究结果可能导致确定控制或检测H的新目标。幽门。这些信息对于开始降低与H相关的发病率和死亡率至关重要。幽门感染 公共卫生相关性：幽门螺杆菌是消化性溃疡疾病和其他胃病的病原体，在美国每年估计造成100万人住院和6,500人死亡。建议的研究结果可能会导致确定新的目标，为控制或检测H。幽门螺杆菌，这对于开始降低与这种重要病原体相关的发病率和死亡率是重要的。

DESCRIPTION (provided by applicant): Helicobacter pylori is the causative agent of peptic ulcer disease and a variety of other diseases in humans, including gastric cancer and mucosal-associated lymphoma. Motility is required for H. pylori to cross the gastric mucous layer and colonize the gastric epithelium, and H. pylori use a cluster of polar flagella to accomplish this. Regulation of flagellar gene expression in bacteria is complex and involves a transcriptional hierarchy that couples the expression of flagellar genes with assembly of the flagellum. The long-term objective of proposed research is to identify mechanisms used by H. pylori to regulate flagellar gene expression. The alternative sigma factor RpoN is needed for transcription of several H. pylori flagellar genes. Transcription of these RpoN-dependent genes also requires the FlgS/FlgR two-component system. Expression of H. pylori RpoN-dependent flagellar genes is linked to the flagellar protein export apparatus as mutations in genes encoding components of the export apparatus interfere with expression the RpoN regulon. The mechanism by which the export apparatus influences expression of the RpoN regulon is unknown. The goal of this project is to identify the molecular mechanism by which the export apparatus controls expression of the H. pylori RpoN flagellar regulon. The working hypothesis is that the export apparatus affects transcription of the H. pylori RpoN regulon by secreting an inhibitor of the RpoN regulon or influencing the activity of the sensor kinase FlgS through protein-protein interactions. This hypothesis will be tested objectively in three specific aims. The first specific aim will determine if a constitutively active form of FlgR bypasses export apparatus mutations to allow expression of RpoN-dependent reporter genes. In the second specific aim H. pylori strains with mutations that lock the export apparatus in a conformation that favors rod-/hook-type substrates will be examined to see how they influence expression of RpoN-dependent reporter genes. The third specific aim will determine if the novel protein HP1042 is an inhibitor of the RpoN regulon by disrupting the gene encoding this protein and determining how this mutation affects expression of RpoN-dependent reporter genes in H. pylori. The proposed work is relevant to NIH's mission of promoting public health in the United States as the results of the studies may lead to identification of new targets for the control or detection of H. pylori. This information is essential to begin to reduce the morbidity and mortality associated with H. pylori infections. PUBLIC HEALTH RELEVANCE: Helicobacter pylori is a causative agent of peptic ulcer disease and other gastric diseases, causing an estimated 1 million hospitalizations and 6,500 deaths each year in the United States. Results of the proposed studies may lead to the identification of new targets for the control or detection of H. pylori, which is important to begin to reduce the morbidity and mortality associated with this significant pathogen.