Molecular Genetics of Rhizobium Nodulation Plasmids

根瘤菌结瘤质粒的分子遗传学

• 批准号: 7861402
• 负责人: GRAHAM C WALKER
• 金额: $ 40.78万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-16 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7861402
• 关键词: Anabolism; Antibiotics; Bacteria; Bacterial Genes; Bacterial Physiology; Biochemical; Biochemical Genetics; Biological Assay; Bioterrorism; Brucella; Cells; Chemicals; Chronic; Cyclic AMP; Defect; Detergents; Drug Delivery Systems; Drug resistance; Enzyme Tests; Enzymes; Genes; Genetic; Genome; Goals; Homologous Gene; Infection; Lipopolysaccharides; Mammals; Manganese; Medicago truncatula; Melilotus; Membrane; Microarray Analysis; Modification; Molecular; Molecular Genetics; Nature; Nonhomologous DNA End Joining; Oxidative Stress; Pathogenesis; Pathway interactions; Physiological; Plant Genes; Plants; Plasmids; Play; Protein Secretion; Proteins; Proteome; RNA Interference; Research; Research Personnel; Rhizobium; Role; Screening procedure; Signal Transduction; Sinorhizobium meliloti; Superoxide Dismutase; Superoxides; Symbiosis; Testing; Vitamin B 12; Walkers; base; crosslink; deoxycholate; gene function; insight; mutant; novel; pathogen; programs; response; succinoglycan

DESCRIPTION (provided by applicant): The long-term goal of this research is to develop a detailed, integrated view of how Sinorhizobium meliloti establishes the chronic intracellular infection that underlies symbiosis and to use these findings to gain new insights into molecular mechanisms used by chronic intracellular pathogens of mammals. This research is suggesting possible new drug targets for Brucella, a serious, hard-to-treat pathogen and a bioterrorism threat, offering detailed insights into the roles of lipopolysaccharides and exopolysaccharides in bacterial interactions with their eukaryotic hosts, and also helping elucidate the unknown part of vitamin B12 biosynthesis. We will continue to investigate the biosynthesis and function of vitamin B12 in S. meliloti by analyzing the 5,6-dimethylbenzimidazole biosynthetic pathway and investigating which B12-dependent enzymes are of symbiotic importantance in S. meliloti. We will continue to investigate CbrA, a previously unrecognized master regulator of symbiosis, including identifying regulatory targets through microarray analysis, determining the basis of detergent-sensitivity of cbrA mutants, and determining the role of the Brucella CbrA homolog in pathogenesis. We will determine the molecular basis of the interactions between symbiotically active rhizobial exopolysaccharides and the plant host by utilizing M. truncatula microarrays to identify plant genes regulated in response to succinoglycan and then dissecting the function of these genes using RNAi knockdowns and other approaches. We will continue to investigate the importance of lipopolysaccharide modifications for symbiosis and with a focus on BacA, including comparing plant responses to bacA mutants to that of a succinoglycan-deficient mutant, determining the topology of BacA protein, and screening for proteins that interact with BacA. We will continue to investigate the role of manganese in oxidative stress protection and symbiosis by further characterizing control of superoxide dismutase levels by manganese, investigating additional factors in superoxide sensitivity, testing the possible symbiotic importance of other Mn2+dependent enzymes, and testing the importance of non-homologous end-joining for symbiosis. We will determine the biochemical and physiological function of pmh, a highly conserved bacterial gene and a possible new drug target whose inactivation greatly sensitizes cells to numerous antibiotics that are no longer clinically useful because of acquired drug resistance.

描述（由申请人提供）：本研究的长期目标是开发一个详细的，综合的观点，苜蓿中华根瘤菌如何建立慢性细胞内感染的基础共生，并使用这些发现获得新的见解，由哺乳动物的慢性细胞内病原体的分子机制。这项研究为布鲁氏菌提出了可能的新药靶点，布鲁氏菌是一种严重的，难以治疗的病原体和生物恐怖主义威胁，为脂多糖和胞外多糖在细菌与真核宿主相互作用中的作用提供了详细的见解，并有助于阐明维生素B12生物合成的未知部分。我们将继续研究维生素B12在S.通过分析5，6-二甲基苯并咪唑的生物合成途径和研究B12依赖的酶在苜蓿根瘤菌中的共生重要性。苜蓿草。我们将继续调查CbrA，一个以前未被认识的主调节共生，包括通过微阵列分析确定监管目标，确定基础的洗涤剂敏感性的cbrA突变体，并确定布鲁氏菌CbrA同源物的发病机制中的作用。我们将利用M.利用蒺藜微阵列来鉴定响应琥珀聚糖的植物基因，然后使用RNAi敲除和其他方法来剖析这些基因的功能。我们将继续研究脂多糖修饰对共生的重要性，重点是巴卡，包括比较植物对巴卡突变体和琥珀聚糖缺陷突变体的反应，确定巴卡蛋白的拓扑结构，并筛选与巴卡相互作用的蛋白质。我们将继续研究锰在氧化应激保护和共生中的作用，通过进一步表征锰对超氧化物歧化酶水平的控制，研究超氧化物敏感性的其他因素，测试其他Mn 2+依赖酶的可能共生重要性，并测试非同源末端连接对共生的重要性。我们将确定pmh的生化和生理功能，pmh是一种高度保守的细菌基因，也是一种可能的新药靶点，它的失活极大地使细胞对许多抗生素敏感，而这些抗生素由于获得性耐药性而不再有临床用途。