Regulation of gene expression in Borrelia burgdorferi

伯氏疏螺旋体基因表达的调控

• 批准号: 7000378
• 负责人: D. SCOTT SAMUELS
• 金额: $ 33.82万
• 依托单位: UNIVERSITY OF MONTANA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-05 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7000378
• 关键词: Regulation; gene; expression; Borrelia; burgdorferi

DESCRIPTION (provided by applicant): The bacterium Borrelia burgdorferi is a causative agent of Lyme disease. B. burgdorferi can synthesize several different outer surface proteins that are involved in pathogenesis or transmission during the enzootic cycle. The regulation of outer surface protein synthesis is not well understood at the molecular level. This application proposes to evaluate the hypothesis that cis-acting factors, such as DNA supercoiling, and trans-acting factors, such as DNA-binding repressor proteins, regulate the expression of outer surface protein genes in response to environmental signals. Production of outer surface proteins OspA and OspC is reciprocally regulated, which may be how B. burgdorferi adapts to the different environments of the tick vector and mammalian host or effects transmission between the environments. An ospAB operon promoter-specific trans-acting protein is hypothesized to repress ospAB transcription. The regulatory protein will be purified and identified. Cis-acting sequences in the ospAB promoter region are hypothesized to mediate transcriptional regulation. These sites will be mapped and characterized. The architectural DNA-binding protein Hbb is hypothesized to facilitate regulation of ospC expression. The function of Hbb will be probed by mutagenesis of the hbb gene and the Hbb binding site in the ospC promoter region. The ospC promoter will be replaced with an inducible promoter system to control cellular OspC levels without perturbing DNA supercoiling so that the coupling of ospC and ospAB transcription can be studied. ospC gene expression from the flac hybrid promoter is hypothesized to be regulated by IPTG and to influence ospAB operon expression. The mechanism by which DNA supercoiling regulates ospC expression is hypothesized to involve Hbb and specific sequence motifs in the ospC promoter region. Mutant ospC promoters will be constructed. The transcriptional response of these mutants to temperature and DNA supercoiling will be assayed in order to define the cis-acting elements responsible for regulation. The long-term objective of these studies is to understand the mechanism of outer surface protein gene regulation in response to environmental signals.

描述（由申请人提供）：Burgdorferi细菌是莱姆病的病因。 B. burgdorferi可以合成几种在enzootic循环中参与发病机理或传播的几种不同的外表面蛋白。外表面蛋白合成的调节在分子水平上尚不清楚。该应用建议评估以下假设：顺式作用因子（例如DNA超螺旋和跨作用因子）（例如DNA结合抑制剂蛋白）调节对环境信号的响应外表面蛋白基因的表达。外表面蛋白OSPA和OSPC的产生经过相互调节，这可能是B. burgdorferi适应tick矢量和哺乳动物宿主的不同环境或环境之间的效果传播的方式。假设Ospab操纵子启动子特异性的跨作用蛋白以抑制OSPAB转录。调节蛋白将被纯化和鉴定。假设Ospab启动子区域中的顺式作用序列介导转录调节。这些站点将被映射和表征。假设结构DNA结合蛋白HBB促进OSPC表达的调节。 HBB的功能将通过OSPC启动子区域中HBB基因的诱变和HBB结合位点进行探测。 OSPC启动子将被诱导的启动子系统替换，以控制细胞OSPC水平，而不会扰动DNA超螺旋，因此可以研究OSPC和OSPAB转录的耦合。 假设来自FLAC杂种启动子的OSPC基因表达由IPTG调节并影响OSPAB操纵子的表达。假设DNA超串联调节OSPC表达的机制涉及OSPC启动子区域中的HBB和特定序列基序。将构建突变的OSPC启动子。这些突变体对温度和DNA超串联的转录响应将被分析，以定义负责调节的顺式作用元件。这些研究的长期目标是了解响应环境信号的外表面蛋白基因调节的机制。