The ECF Sigma Factors of Bacillus anthracis and their connection to virulence

炭疽杆菌的 ECF Sigma 因子及其与毒力的关系

• 批准号: 7652122
• 负责人: NICHOLAS H BERGMAN
• 金额: $ 17.99万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7652122
• 关键词: Anthrax disease; Bacillus anthracis; Bacteria; Bacterial Infections; Communities; Complement; Condition; DNA-Directed RNA Polymerase; Data; Defect; Environment; Family; Gene Expression; Genes; Genome; Growth; Homologous Gene; Individual; Infection; Lead; Link; Mediating; Mind; Numbers; Pathogenesis; Phenotype; Physiology; Play; Process; Proteins; Regulon; Resource Development; Role; Screening procedure; Sigma Factor; Stimulus; Stress; System; Testing; Virulence; Work; abstracting; base; biodefense; comparative; environmental change; insight; mouse model; mutant; novel therapeutics; pathogen; prevent; protein function; research study; response

Abstract Throughout its infection of the mammalian host, Bacillus anthracis is confronted with a number of different hostile environments to which it must adapt its gene expression and physiology. These adaptations are critical for pathogenesis, but they remain poorly understood. The fifteen ECF (extracytoplasmic function) RNA polymerase sigma factors encoded within the B. anthracis genome appear to be possible regulators of these adaptations, since studies in other bacterial species have shown the ECF proteins to be master regulators mediating bacterial responses to the environment. We hypothesize that one or more of these fifteen proteins might play a role in mediating the response of B. anthracis to stresses encountered during infection, and our preliminary experiments showed that three ECF proteins are critical for virulence in a mouse model of inhalational anthrax. Here we propose to characterize these three proteins in more detail, using two parallel approaches. In the first, we will use phenotype microarrays to screen nearly 2000 different environmental stimuli for conditions in which the deletion of a given ECF factor has an effect on growth of B. anthracis. With this approach we can cover every environmental condition previously associated with ECF factors in any bacterium (plus hundreds of others), and we will confirm and more closely define the phenotypic defects of ECF mutants in further growth studies. These data will tell us a great deal about ECF function, and will also point to specific conditions we can use in later experiments examining the roles of each individual protein. In the second set of experiments, we will use comparative transcriptional profiling to define the regulon associated with each of the three ECF proteins; these data will provide important clues about the function of each ECF factor, and will identify downstream effectors. We expect that in defining the stimuli and regulon associated with each of these three B. anthracis ECF proteins, we will gain significant insights into the B. anthracis-host interaction, and that these insights will likely be broadly applicable to other bacterial pathogens, since the ECF family is found throughout the bacterial domain. Further, we anticipate that the proposed work may lead to new strategies for developing new therapeutic options for treating or preventing anthrax and other bacterial infections.

抽象的 在感染哺乳动物宿主的整个过程中，炭疽杆菌面临着许多不同的恶劣环境，它必须适应其基因表达和生理学。这些适应对于发病机制至关重要，但人们对它们仍然知之甚少。炭疽芽孢杆菌基因组中编码的 15 种 ECF（胞质外功能）RNA 聚合酶 σ 因子似乎是这些适应的可能调节因子，因为对其他细菌物种的研究表明 ECF 蛋白是介导细菌对环境反应的主要调节因子。我们假设这 15 种蛋白质中的一种或多种可能在介导炭疽杆菌对感染过程中遇到的应激反应中发挥作用，并且我们的初步实验表明，三种 ECF 蛋白质对于吸入性炭疽小鼠模型的毒力至关重要。在这里，我们建议使用两种并行方法更详细地表征这三种蛋白质。首先，我们将使用表型微阵列来筛选近 2000 种不同的环境刺激，以了解删除给定 ECF 因子会影响炭疽芽孢杆菌生长的条件。通过这种方法，我们可以涵盖以前与任何细菌（以及数百种其他细菌）中的 ECF 因子相关的所有环境条件，并且我们将在进一步的生长研究中确认并更仔细地定义 ECF 突变体的表型缺陷。这些数据将告诉我们很多有关 ECF 功能的信息，并且还将指出我们可以在后续实验中检查每个单独蛋白质的作用时使用的特定条件。在第二组实验中，我们将使用比较转录分析来定义与三种 ECF 蛋白中的每一种相关的调节子；这些数据将提供有关每个 ECF 因子功能的重要线索，并将识别下游效应器。我们预计，在定义与这三种炭疽芽孢杆菌 ECF 蛋白相关的刺激和调节子时，我们将获得对炭疽芽孢杆菌与宿主相互作用的重要见解，并且这些见解可能广泛适用于其他细菌病原体，因为ECF 家族遍布于整个细菌领域。此外，我们预计拟议的工作可能会导致开发新的治疗方案来治疗或预防炭疽和其他细菌感染的新策略。