Conservation and Adaptation of a Regulon Across Genera

跨属调节子的保护和适应

• 批准号: 6909912
• 负责人: ROBERT MARTIN BLUMENTHAL
• 金额: $ 29.7万
• 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/6909912
• 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。毒力基因的适当调节对于致病性与拥有这些基因一样必不可少，因此从基因组序列中预测调节网络是一个很高的优先级。一个合理但测试不佳的假设是许多预测的基础。具体而言，假定在两种保守的调节蛋白和保守的靶基因的存在中存在候选上游结合位点的存在，以暗示其调节关系已得到保留。该项目的两个主要目标是测试这一生物信息学假设，这样做可以更好地表征主要的细菌调节网络（Regulon）。亮氨酸反应性调节蛋白（LRP）在许多革兰氏阴性细菌中保守，并且E.卷积会影响多达400个基因的表达。最近的证据表明，其中许多基因在过渡到固定期的过程中优先表达，并且可能在相关生物的致病性中发挥作用。将测试三个假设： *假设具有保守IRP基因的物种具有保守的LRP功能，可以通过确定LRP水平在这些物种中是否相似，并通过评估LRP直系同源物可以互换的程度来测试。要测试的IRP基因来自Proteus mirabilis（98％与E. coil蛋白相同）V。霍乱（92％）和P. multocida（75％）。 *假设具有高度保存的LRP直系同源物的物种显示了保守的调节模式，可以通过使用微阵列分析E. Coil O157：H7，V。Cholerae和P. multocida对IRP突变的影响进行测试。 E. COIL O157：H7 LRP与E. coil K -12相同，但前者是一种病原体，具有-25％的基因，其中一些可能属于LRP调节剂。 *关于IRP突变对不同致病细菌的毒力具有类似作用的假说，可以通过确定IRP无效等位基因在动物模型中对V.霍乱的动物模型进行测试。