Conservation and Adaptation of a Regulon Across Genera

跨属调节子的保护和适应

• 批准号: 6825533
• 负责人: ROBERT MARTIN BLUMENTHAL
• 金额: $ 31.56万
• 依托单位: UNIVERSITY OF TOLEDO HEALTH SCI CAMPUS
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6825533
• 关键词: Escherichia coli; Pasteurella multocida; Proteus; Vibrio cholerae; bacteria infection mechanism; bacterial genetics; binding sites; biochemical evolution; chromatin immunoprecipitation; crosslink; disease /disorder model; gene expression; gene expression profiling; gene mutation; genetic regulatory element; host organism interaction; laboratory rabbit; leucine; microarray technology; pathologic process; polymerase chain reaction; virulence; western blottings

DESCRIPTION (provided by applicant): A primary motivation for determining genome sequences of microbial pathogens is to understand the bases of their pathogenicity. Proper regulation of virulence genes can be as essential to pathogenicity as is possession of these genes, so predicting regulatory networks from genome sequences is a high priority. A plausible but poorly tested assumption underlies many of these predictions. Specifically, the presence in two species of both a conserved regulatory protein and of conserved target genes with candidate upstream binding sites is presumed to imply that their regulatory relationship has been conserved. The two major goals of this project are to test this bioinformatic assumption and, in so doing, better characterize a major bacterial regulatory network (regulon). The leucine-responsive regulatory protein (Lrp) is conserved among many Gram-negative bacteria, and in E. coil affects expression of as many as 400 genes. Recent evidence indicates that many of these genes are preferentially expressed during transition to stationary phase, and may play a role in pathogenicity in related organisms. Three hypotheses will be tested: * The hypothesis that species with conserved Irp genes have conserved Lrp function, to be tested by determining whether Lrp levels vary comparably in these species, and by assessing the extent to which Lrp orthologs are interchangeable. The Irp genes to be tested are from Proteus mirabilis (98% identical to the E. coil protein) V. cholerae (92%), and P. multocida (75%). * The hypothesis that species with highly-conserved Lrp orthologs show a conserved pattern of regulation, to be tested by using microarrays to analyze the effects of Irp mutation in E. coil O157:H7, V. cholerae, and P. multocida. E. coil O157:H7 Lrp is identical to that of E. coil K-12, but the former is a pathogen with -25% more genes, some of which may belong to the Lrp regulon. * The hypothesis that Irp mutations have analogous effects on the virulence of different pathogenic bacteria, to be tested by determining the effects of a Irp null allele in an animal model for V. cholerae.

描述（由申请人提供）：确定微生物病原体基因组序列的主要动机是了解其致病性的基础。毒力基因的正确调控对于致病性来说与拥有这些基因一样重要，因此从基因组序列预测调控网络是重中之重。许多这些预测都是基于一个看似合理但未经充分检验的假设。具体而言，两个物种中保守的调节蛋白和具有候选上游结合位点的保守靶基因的存在被推测意味着它们的调节关系是保守的。该项目的两个主要目标是测试这一生物信息学假设，并在此过程中更好地表征主要细菌调节网络（调节子）。亮氨酸反应调节蛋白 (Lrp) 在许多革兰氏阴性细菌中是保守的，在大肠杆菌中影响多达 400 个基因的表达。最近的证据表明，许多这些基因在向稳定期过渡期间优先表达，并且可能在相关生物体的致病性中发挥作用。将测试三个假设： * 具有保守 Irp 基因的物种具有保守的 Lrp 功能的假设，通过确定这些物种中 Lrp 水平是否有可比性变化以及评估 Lrp 直向同源物可互换的程度来进行测试。待测试的 Irp 基因来自奇异变形杆菌（与大肠杆菌蛋白 98% 相同）、霍乱弧菌 (92%) 和多杀性变形杆菌 (75%)。 * 具有高度保守的 Lrp 直向同源物的物种表现出保守的调节模式的假设，将通过使用微阵列来分析 Irp 突变对大肠杆菌 O157:H7、霍乱弧菌和多杀性巴氏杆菌的影响进行测试。大肠杆菌 O157:H7 Lrp 与大肠杆菌 K-12 相同，但前者是一种多 -25% 基因的病原体，其中一些可能属于 Lrp 调节子。 * Irp 突变对不同病原菌的毒力具有类似影响的假设，通过确定霍乱弧菌动物模型中 Irp 无效等位基因的影响来进行测试。