SEX PHEROMONE-INDUCED PLASMID TRANSFER

这项研究的目的是调查和表征分子 肠球菌性信息素诱导交配反应的基础 粪链球菌(原链球菌属)，特别强调结合词 质粒PAD1。PAD1质粒编码一种溶血素(它也有 细菌素活性)以及对紫外线的抵抗力；以及 在小鼠身上的研究表明，该质粒有助于毒力。一个 相当大比例的人肠外肠球菌感染涉及 具有相似或密切关系的粪肠球菌溶血性菌株 质粒。近年来，我们对PAD1了解了很多 信息素反应；拟议的遗传学研究是一种延续 并应提供对机制的进一步洞察 控制这种广泛传播的质粒的细胞间转移。 具体地说，我们将：1)对整个 PAD1 Tra区，利用转座子Tn917lac产生基因 融合和分析信息素响应过程中RNA的产生； 2)对PAD1上的行列式进行(序列)表征 物质“；3)确定染色体携带的决定因素的序列 对于性信息素cad1和质粒携带的决定簇 信息素抑制剂iAD1；4)检查信息素的遗传方面 通过产生和分析在cad1生产中改变的突变体进行生产； 5)对7kb区域进行详细分析，以努力 对这一区域进行完全测序；6)分析新发现的“转换” 与信息素反应无关的现象，并涉及 自发激活或停用传递函数；7)定位 PAD1上的转移原点(ORIT)；和8)确定cAM373的结构 来自金黄色葡萄球菌。

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.