Regulatory network of a conserved polar factor in Sinorhizobium meliloti

苜蓿中华根瘤菌保守极性因子的调控网络

• 批准号: 8339069
• 负责人: Joseph Chiung-Chu Chen
• 金额: $ 11.33万
• 依托单位: SAN FRANCISCO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8339069
• 关键词: Affect; Alfalfa; Alleles; Alphaproteobacteria; Anabolism; Anti-Bacterial Agents; Antibiotic Therapy; Architecture; Area; Bacteria; Bacterial Proteins; Bartonella; Biological Assay; Brucella; Caulobacter crescentus; Cell Polarity; Cell division; Cells; Detergents; Development; Development Polarity; Drug Delivery Systems; Ensure; Event; Exhibits; Fabaceae; Flagella; Gene Expression Regulation; Genes; Genetic; Glean; Homologous Gene; Infection; Investigation; Knowledge; Life; Location; Measures; Melilotus; Microarray Analysis; Microbe; Microscopy; Modeling; Molecular; Morphology; Nitrogen; Organelles; Organism; Orthologous Gene; Pattern; Phenotype; Physiological; Physiology; Pilum; Plant Roots; Plants; Play; Positioning Attribute; Process; Production; Proteins; Proteobacteria; Recruitment Activity; Research; Resistance; Role; Signal Pathway; Sinorhizobium meliloti; Site; Stress; Structural Protein; Symbiosis; System; Time; Transcription Coactivator; Work; anthropogenesis; antimicrobial; assault; cell envelope; cell motility; coping mechanism; daughter cell; environmental change; fitness; genetic regulatory protein; improved; insight; member; microbial; mutant; null mutation; pathogen; programs; protein-histidine kinase; succinoglycan

DESCRIPTION (provided by applicant): Despite their minute size, bacterial cells exhibit an extensive degree of dynamic, programmed organization at the subcellular and molecular levels. A plethora of dedicated cellular components localize to and assemble at appropriate positions and times to ensure fitness in ever-changing environmental conditions, including those encountered when intruding into other organisms. The proposed project seeks to clarify how the functional network of a conserved polar factor controls multiple cell envelope-associated activities in the alpha- proteobacterium Sinorhizobium meliloti, which infects the roots of legume plants to form symbiosis. Specifically, the PodJ1 protein (SMc02230) localizes to the newer cell pole and deletion of the podJ1 gene interferes with flagellar motility, exopolysaccharide production, cell division, and resistance against detergents and osmotic stress. Microarray analysis indicated that podJ1 affects the expression of 129 genes, the majority of which correlate with phenotypes observed in the podJ1 mutant. In the absence of PodJ1, the gene whose expression was most severely reduced is tacA (SMc04011), which encodes a conserved transcriptional activator. In addition, suppressor analysis led to the identification of nine factos that interact genetically with podJ1. Null mutations in two of the suppressors (SMc00067 and SMc03872) appear to abolish synthesis of succinoglycan, an exopolysaccharide critical for symbiosis. Another suppressor encodes the conserved histidine kinase PleC (SMc02369). The proposed research will (1) examine the roles of SMc00067 and SMc03872 in succinoglycan production, (2) investigate the regulatory activities of the essential histidine kinase PleC, and () determine the function of the TacA transcriptional activator. How these factors contribute to different aspects of S. meliloti physiology will be assessed using multiple approaches, including genetic and microarray analyses, phenotypic assays, and microscopy. Results from the investigation will help elucidate regulatory circuits that appear to be iterated in the alpha-proteobacteria group, which includes pathogens such as Brucella and Bartonella. The insights generated will provide better understanding of the spatial and temporal coordination that occurs during infection. PUBLIC HEALTH RELEVANCE: The proposed research is expected to reveal how conserved proteins, with similar localization patterns in different bacterial species, regulate multiple physiological activities that contribute to effective interaction with eukaryotic host organisms. Advances in this area will enhance the understanding of subcellular architecture in bacteria and ultimately improve analysis and treatment of microbial infections.

描述（由申请人提供）：尽管细菌细胞很小，但它们在亚细胞和分子水平上表现出广泛程度的动态、程序化组织。大量专门的细胞成分定位并在适当的位置和时间组装，以确保在不断变化的环境条件下（包括入侵其他生物体时遇到的环境条件）的适应性。该项目旨在阐明一个保守的极性因子的功能网络如何控制α - Sinorhizobium meliloti中多个细胞包膜相关的活动，该蛋白感染豆科植物的根形成共生。具体来说，PodJ1蛋白（SMc02230）定位于较新的细胞极，PodJ1基因的缺失会干扰鞭毛的运动、胞外多糖的产生、细胞分裂以及对洗涤剂和渗透胁迫的抵抗力。微阵列分析表明，podJ1影响129个基因的表达，其中大多数与podJ1突变体中观察到的表型相关。在PodJ1缺失的情况下，表达减少最严重的基因是tacA (SMc04011)，它编码一个保守的转录激活因子。此外，抑制因子分析鉴定出9个与podJ1基因相互作用的因子。两个抑制子（SMc00067和SMc03872）的零突变似乎会破坏琥珀聚糖的合成，琥珀聚糖是一种对共生至关重要的外多糖。另一个抑制基因编码保守的组氨酸激酶PleC （SMc02369）。拟议的研究将(1)检查SMc00067和SMc03872在琥珀聚糖生产中的作用，(2)研究必需组氨酸激酶PleC的调控活性，以及（）确定TacA转录激活因子的功能。这些因素如何影响S. meliloti生理的不同方面将使用多种方法进行评估，包括遗传和微阵列分析，表型分析和显微镜。调查结果将有助于阐明在α -变形菌群中反复出现的调节回路，其中包括布鲁氏菌和巴尔通体等病原体。由此产生的见解将更好地理解感染期间发生的空间和时间协调。