SEX PHEROMONE-INDUCED PLASMID TRANSFER

本研究的目的是调查和表征分子 性信息素诱导肠球菌交配反应的基础 （以前的链球菌）粪，特别强调接合 质粒pAD 1。 pAD 1质粒编码溶血素（其也具有 细菌素活性），以及对紫外线的抗性;以及 对小鼠的研究表明，质粒有助于毒性。 一 相当大比例人胃肠外肠球菌感染涉及 溶血性E.粪生的类似的或密切相关的 质粒。 近年来，我们对pAD 1有了大量的了解。 信息素反应;拟议的遗传研究构成了一个延续 我们的努力，并应提供进一步的深入了解机制 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）对整个基因组进行转录分析， pAD 1 Tra区，利用转座子Tn 917 lac产生基因 融合和分析信息素反应期间RNA的产生; 2)表征pAD 1上“聚集”的决定簇（测序） 3）确定染色体携带的决定簇的序列 性信息素cAD 1的质粒决定子和 信息素抑制剂iAD 1; 4）检查信息素的遗传方面 通过产生和分析cAD 1产生中改变的突变体来产生; 5)对7 kb区域进行详细分析， 6）分析一个新发现的“开关”， 现象”，这是独立的信息素的反应，并涉及 自发激活或停用传递函数; 7）定位 pAD 1上的转移起点（oriT）;和8）确定cAM 373的结构 金黄色葡萄球菌

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.