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: 8514644
• 负责人: Joseph Chiung-Chu Chen
• 金额: $ 10.99万
• 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/8514644
• 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 Targeting; 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.

描述（由申请人提供）：尽管细菌细胞尺寸微小，但它们在亚细胞和分子水平上表现出广泛的动态、程序化组织。大量的专用细胞成分在适当的位置和时间定位和组装，以确保适应不断变化的环境条件，包括侵入其他生物体时遇到的环境条件。该项目旨在阐明保守极性因子的功能网络如何控制苜蓿中华根瘤菌中的多个细胞包膜相关活性，该细菌感染豆科植物的根部以形成共生。具体来说，PodJ1 蛋白 (SMc02230) 定位于较新的细胞极，并且 podJ1 基因的删除会干扰鞭毛运动、胞外多糖产生、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，其中大部分与 podJ1 突变体中观察到的表型相关。在 PodJ1 缺失的情况下，表达降低最严重的基因是 tacA (SMc04011)，它编码保守的转录激活因子。此外，抑制子分析还确定了与 podJ1 基因相互作用的九个因子。两个抑制因子（SMc00067 和 SMc03872）的无效突变似乎会消除琥珀聚糖的合成，琥珀聚糖是一种对共生至关重要的胞外多糖。另一个抑制因子编码保守的组氨酸激酶 PleC (SMc02369)。 拟议的研究将 (1) 检查 SMc00067 和 SMc03872 在琥珀酰聚糖生产中的作用，(2) 研究必需的组氨酸激酶 PleC 的调节活性，以及​​ () 确定 TacA 转录激活剂的功能。将使用多种方法评估这些因素如何影响苜蓿中华根瘤菌生理学的不同方面，包括遗传和微阵列分析、表型测定和显微镜检查。调查结果将有助于阐明α-变形菌群中似乎重复的调节回路，其中包括布鲁氏菌和巴尔通体等病原体。产生的见解将有助于更好地理解感染过程中发生的空间和时间协调。