Post-translation regulation of Listeria monocytogenes virulence factors

单增李斯特菌毒力因子的翻译后调控

• 批准号: 8705104
• 负责人: Nancy Elizabeth Freitag
• 金额: $ 9.17万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-05 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8705104
• 关键词: Alleles; Amino Acid Sequence Homology; Antibodies; Antigens; Attenuated; Bacillus subtilis; Bacteria; Bacterial Meningitis; Bacterial Proteins; Binding; Biochemical; Biological Assay; Biological Models; Cell Wall; Cells; Cellular biology; Cessation of life; Cholesterol; Cytolysins; Cytosol; Data; Defect; Development; Disease; Drug Targeting; Environment; Escherichia coli; Exhibits; Family member; Food; Food Safety; Genes; Genetic; Genetic Screening; Goals; Gram-Positive Bacteria; Growth; Health; Homologous Gene; Human; Infection; Lead; Life; Life Style; Listeria monocytogenes; Listeria monocytogenes hlyA protein; Mammalian Cell; Mediating; Membrane; Modeling; Molecular; Molecular Analysis; Molecular Chaperones; Molecular Genetics; Mutation; Nature; North America; Pathogenesis; Peptidylprolyl Isomerase; Phospholipase; Process; Protein Secretion; Proteins; Recording of previous events; Regulation; Research; Role; Secure; Site; Soil; Specificity; Structural Models; Suppressor Mutations; Translations; Virulence; Virulence Factors; base; foodborne infection; foodborne outbreak; genetic analysis; mouse model; pathogen; perforin; phosphatidylcholine-specific phospholipase C; research study; tool; vaccine delivery

DESCRIPTION (provided by applicant): The long-term objective of this research is to understand how the environmental bacterium Listeria monocytogenes (Lm) adapts to life within mammalian cells to become a human pathogen. Lm is a facultative intracellular bacterium that survives as a saprophyte in soil but is capable of transitioning into a pathogen upon entry into a mammalian host. As a pathogen, Lm remains an increasingly important agent of serious food- borne infections and has been responsible for some of the largest food safety recalls in U.S. history. Central to Lm's ability to cause disease is the regulated transport of virulence factors across the bacterial membrane and the rigid cell wall; this critical process has not been well characterized in Gram-positive bacteria. This proposal focuses on molecular and mechanistic analyses of PrsA2, a post-translocation secretion chaperone with peptidyl-prolyl cis/trans isomerase activity that is essential for Lm virulence. Lm strains lacking PrsA2 function are severely attenuated in mouse models of infection and exhibit reduced secretion and activity of at least two key Lm virulence gene products, the cholesterol-dependent cytolysin listeriolysin O (LLO) and the broad specificity phospholipase PC-PLC. Both of these gene products contribute to Lm's ability to gain access to the host cell cytosol and to spread of the bacteria into new host cells. Preliminary experiments indicate that PrsA2 directly regulates LLO stability, and that PrsA2 may be required for the secretion and/or activity of additional Lm factors with important roles in bacterial virulence. The experiments outlined within this proposal will define the role of PrsA2 in regulating the activity of Lm secreted proteins used to secure the bacterium's intracellular replication niche. Aim 1 will determine the molecular mechanism by which PrsA2 regulates the secretion and activity of LLO and PC-PLC. Aim 2 will examine a number of potential PrsA2 substrates with roles in bacterial virulence for direct PrsA2 interactions. Experiments will further determine the nature of a suppressor mutation that partially compensates for PrsA2 function. Aim 3 experiments focus on the molecular analysis of PrsA2 functional domains based on structural modeling of PrsA2. The ultimate goal of the specific aims will be to elucidate how PrsA2 modulates the secretion and/or activity of virulence factors to promote bacterial pathogenesis in mammalian hosts.

描述（由申请人提供）：这项研究的长期目标是了解环境细菌单核细胞增生酸李斯特菌（LM）如何适应哺乳动物细胞内的生命以成为人类病原体。 LM是一种细胞内细菌，可作为土壤中的腐生植物生存，但能够在进入哺乳动物宿主时过渡为病原体。作为病原体，LM仍然是严重食物传播感染的越来越重要的推动者，并负责美国历史上一些最大的食品安全召回。 LM引起疾病能力的中心是毒力因子在整个细菌膜和刚性细胞壁上受到的调节。在革兰氏阳性细菌中，这种关键过程尚未得到很好的特征。该建议的重点是PRSA2的分子和机械分析，PRSA2是一种肽基培养基CIS/反式异构酶活性，是LM毒力必不可少的。缺乏PRSA2功能的LM菌株在感染的小鼠模型中严重减弱，并且表现出至少两个关键LM毒力基因产物的分泌和活性，胆固醇依赖性细胞酚李斯特蛋白listeriolysin O（LLO）和广泛的特异性磷脂酶PC-PC-PC-PC-PLC。这两种基因产物都有助于LM进入宿主细胞细胞质并将细菌传播到新的宿主细胞中。初步实验表明PRSA2直接调节LLO稳定性，并且PRSA2可能需要在细菌毒力中具有重要作用的其他LM因子的分泌和/或活性。该提案中概述的实验将定义PRSA2在调节用于确保细菌细胞内复制生态位的LM分泌蛋白活性中的作用。 AIM 1将确定PRSA2调节LLO和PC-PLC的分泌和活性的分子机制。 AIM 2将检查许多在直接PRSA2相互作用的细菌毒力中具有作用的潜在PRSA2底物。实验将进一步确定部分补偿PRSA2功能的抑制突变的性质。 AIM 3实验集中于基于PRSA2的结构建模的PRSA2功能域的分子分析。特定目的的最终目标是阐明PRSA2如何调节毒力因子的分泌和/或活性以促进哺乳动物宿主中细菌发病机理。