PATHOGENESIS OF INFECTION WITH THE LYME DISEASE SPIROCHETE, BORRELIA BURGDORFERI

人类感染伯氏疏螺旋体(BB)可导致 多系统、慢性疾病，表现多样。我们是 从多个层面调查伯氏杆菌以了解 本病病机的某些方面。这些研究包括基因 螺旋体的操作和关键结构的表征 和监管要素。 1.分子特征：Bb的几个特征正在 地址。我们已经描述了同源重组在 编码主要外表面蛋白(OSPs)的基因 删除OSP基因序列并创建嵌合基因融合。bb 表达重组OSP基因可逃脱OSP特异性杀伤 中和抗体。我们还在调查 OSP基因表达的转录调控。隔离和 研究温度过后表达增加的基因 UpShift(热休克基因)将提供有关它们在 细胞生长、发病机制、质粒复制和对应激的适应。 了解线形质粒复制的机制可能会产生 抗生素的新目标，除了揭示 哪些生物体操纵它们的遗传物质。 2.基因转移：为了能够对BB进行遗传分析，一种方法 将基因转移到疏螺旋体的方法正在开发中。的派生函数 BB16kb的线状质粒将作为电穿孔的载体， 从而允许在本地环境中维护转移的DNA。脱氧核糖核酸 编码缺乏中和表位的重组OSP蛋白将 作为一种可选择的标记引入。 3.cDNA文库：BB在体外的延长传代使其功能丧失 感染啮齿动物，蛋白质合成无明显差异。 正在构建高、低传代Bb的cDNA文库， 来自假定低丰度的克隆，差异表达 消息将通过减法进行识别。类似的方法 将被用来识别以不同方式表达的消息 对其他生物相关刺激的反应。

Infection of humans by Borrelia burgdorferi (Bb) can result in a multisystemic, chronic disease with diverse manifestations. We are investigating B. burgdorferi at several levels in order to understand some aspects of the disease pathogenesis. These studies include genetic manipulations of the spirochete and characterization of key structural and regulatory elements. 1. Molecular Characterization: Several features of Bb are being addressed. We have characterized homologous recombination between the genes encoding the major outer surface proteins (Osps) that both deletes osp gene sequences and creates chimeric gene fusions. Bb expressing recombinant osp genes can 'escape' killing by Osp-specific neutralizing antibodies. We are also investigating mechanisms of transcriptional regulation of osp gene expression. Isolating and studying genes whose expression is increased after a temperature upshift (heat shock genes) will provide information about their roles in cell growth, pathogenesis, plasmid replication and adaptation to stress. Understanding the mechanism of linear plasmid replication may yield a new target for antibiotics, in addition to shedding light on ways in which organisms manipulate their genetic material. 2. Gene Transfer: In order to allow genetic analysis of Bb, a method for gene transfer into Borrelia is being developed. A derivative of the Bb 16 kb linear plasmid will be used as a vector for electroporation, allowing for maintenance of transferred DNA in a native setting. DNA encoding recombinant Osp proteins that lack neutralizing epitopes will be introduced as a selectable marker. 3. cDNA Library: Extended passage of Bb in vitro eliminates its ability to infect rodents without any obvious differences in protein synthesis. cDNA libraries of high and low passage Bb are being constructed and clones derived from putative low abundance, differentially expressed messages will be identified by subtractive methods. A similar approach will be taken to identify messages that are differentially expressed in response to other biologically relevant stimuli.