Functions of the REPI Region of Plasmid ColV-K30 in Escherichia coli K12

该项目的目标是确定和表征PColV.K30 REPI区域中存在的与其复制控制相关的功能。这个复制子是我们发现在携带好氧肌动蛋白铁运输系统基因的质粒中保守的复制的好氧肌蛋白铁运输单位的一部分。REPI复制区赋予细胞与IncFI组相对应的不亲和性，并且必须在好氧肌动蛋白铁运输系统的保存和流行病学传播中发挥作用。虽然它是一种复制子，经常在细菌质粒中发现，但对其复制控制机制和导致IncFI不相容表型表达的机制知之甚少。主要进行了以下几个方面的实验：1.含REPI的质粒复制调控产物(S)的分析。2.REPI复制所必需的反式作用蛋白REPI的特性及其作用机制。3.阐明了新的不亲和区INCf和已知的INCE在导致IncFI表型的REPI不亲和性机制中的作用。到目前为止，克罗萨博士在这种细菌质粒上的工作已经建立了元素复制的总体框架，未来拟议的工作涉及他所发现的特征的进一步阐述。了解该复制子的功能，必将促进我们对不同质粒之间的相容和复制的理解。此外，这项研究可能会提高我们对这些质粒如何在细菌群体中传播和保持的理解。

The goal of this project is to identify and characterize the functions present in the PColV.K30 REPI region that are associated with control of its replication. This replicon is part of a replication.aerobactin iron.transport unit that we found to be conserved in plasmid carrying the aerobactin iron-transport system genes. The REPI replication region endows the cells with incompatibility properties corresponding to the IncFI group and must have been instrumental in the preservation and epidemiological spread of the aerobactin iron-transport system. Although it is a replicon frequently found in bacterial plasmid, little is known on the mechanisms controlling its replication and the mechanisms that result in the expression of the IncFI incompatibility phenotype. The following experiments are being performed: 1. Analysis of the product(s) involved in the control of replication of REPI containing plasmid. 2. Characterization of a trans.acting protein RepI which is necessary for REPI replication, and its mechanism of action. 3. Elucidation of the role of the novel incompatibility region incF and the already known incE in the mechanisms of REPI incompatibility that result in the IncFI phenotype. Dr. Crosa's work on this bacterial plasmid to date hasestablished the overall framework of the elements replication, and the proposed future work deals with further elaboration of the features he has found. Understanding of how this replicon functions will certainly advance our understanding of plasmid replication and compatibility between different plasmid. In addition this study may improve our understanding of how these plasmid spread and are maintained in bacterial populations.