SEX PHEROMONE-INDUCED PLASMID TRANSFER

性信息素诱导的质粒转移

• 批准号: 2177204
• 负责人: DON B CLEWELL
• 金额: $ 34.53万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-03-01 至 1995-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2177204
• 关键词: Enterococcus; Staphylococcus aureus; antibiotics; bacterial DNA; bacterial RNA; bacterial genetics; drug resistance; fusion gene; gel electrophoresis; gene expression; genetic manipulation; genetic transcription; hemolysin; microorganism conjugation; microorganism culture; molecular cloning; mutant; nucleic acid sequence; peptidases; pheromone; plasmids; protein sequence; structural genes; transposon /insertion element

The purpose of this study is to investigate and characterize the molecular basis of the sex-pheromone-induced mating response in Enterococcus (formerly Streptococcus) faecalis, with special emphasis on the conjugative plasmid pAD1. The pAD1 plasmid encodes a hemolysin (which also has bacteriocin activity), as well as resistance to ultraviolet light; and studies in mice have shown that the plasmid contributes to virulence. A significant percentage of human parenteral enterococcal infections involve hemolytic strains of E. faecalis bearing similar or closely related plasmids. In recent years we have learned a great deal about the pAD1 pheromone response; the proposed genetic studies constitute a continuation of our efforts and should provide further insight into mechanisms controlling the intercellular transfer of this widely disseminated plasmid. Specifically we will: 1) Perform a transcriptional analysis of the entire pAD1 Tra region, utilizing the transponson Tn917lac to generate gene fusions and analyzing the production of RNA during the pheromone response; 2) Characterize (sequence) the determinant on pAD1 for "aggregation substance"; 3) Determine the sequence of the chromosome-borne determinant for the sex pheromone cAD1 and the plasmid-borne determinant for the pheromone inhibitor iAD1; 4) Examine genetic aspects of pheromone production by generating and analyzing mutants altered in cAD1 production; 5) Conduct a detailed analysis of the 7 kb region on an effort to completely sequence this region; 6) Analyze a newly discovered "switching phenomenon" that is independent of the pheromone response and involves spontaneously activating or deactivating transfer functions; 7) Locate the transfer origin (oriT) on pAD1; and 8) Determine the structure of cAM373 from Staphylococcus aureus.

本研究的目的是研究和表征分子 肠球菌性信息素诱导的交配反应的基础 （以前称为粪链球菌）粪肠球菌，特别强调接合菌 质粒pAD1。 pAD1 质粒编码溶血素（也具有 细菌素活性），以及对紫外线的抵抗力；和 对小鼠的研究表明，该质粒有助于产生毒力。 一个 相当大比例的人类肠外肠球菌感染涉及 具有相似或密切相关的粪肠球菌溶血菌株 质粒。 近年来我们对 pAD1 有了很多了解 信息素反应；拟议的遗传学研究是一个延续 我们的努力并应提供对机制的进一步见解 控制这种广泛传播的质粒的细胞间转移。 具体来说，我们将：1）对整个内容进行转录分析 pAD1 Tra区域，利用转座子Tn917lac生成基因 融合并分析信息素反应过程中 RNA 的产生； 2) 表征（序列）pAD1 上“聚合”的决定因素 物质”；3)确定染色体携带决定子的序列 性信息素 cAD1 和质粒携带的决定子 信息素抑制剂 iAD1； 4) 检查信息素的遗传方面 通过生成和分析 CAD1 生产中改变的突变体进行生产； 5) 对 7 kb 区域进行详细分析，以期 对该区域进行完整测序； 6）分析新发现的“开关” 现象“独立于信息素反应并涉及 自发激活或停用传递函数； 7) 找到 pAD1 上的转移起点 (oriT)； 8)确定cAM373的结构 来自金黄色葡萄球菌。