GLOBAL REGULATION OF VIRULENCE FACTOR IN BORDETELLA PERTUSSIS

我们实验室工作的主要焦点是 百日咳杆菌该位点负责B的调节。 百日咳毒力决定因子（百日咳毒素，丝状 血凝素等）对环境刺激的反应。这个轨迹是 也是可逆移码突变的位点，其导致 相位变化现象。在过去，我们观察到， 与B密切相关的菌株。百日咳经历了阶段性变化. 不同的利率。我们最近扩展了这一观察 通过在卡那霉素抗性中构建确定的移码突变， 基因，并表明这种突变的逆转也发生在 在这两种菌株中有着显著的差异。我们目前正在 从事这种超突变表型的遗传作图， 注意分离出相关基因。这种映射是由 这是可能的，因为我们最近完成了B的物理地图。 百日咳染色体以前分离的基因的物理作图是 一个简单直接的任务，我们有几个合作项目， 与该领域的其他工作人员一起绘制特定基因的图谱。但 该图谱的推导还允许使用遗传工具进行作图。 具体来说，我们设计并构建了新的菌株和新的 这些载体使我们能够使用类似Hfr的菌株进行遗传作图， B。百日咳。 这种做法将使一些人能够孤立起来， 使用标准克隆技术无法获得的有趣基因 技术.染色体图谱的主要科学发现是， B的基因。百日咳毒力决定簇是不连锁的，即 分散在染色体周围。这一发现的含义是 目前正在通过构建B的其他菌株的图谱来扩展。 百日咳和其他种类的博德特氏菌，希望进一步 定义它们的进化关系。

The primary focus of work in our laboratory has been the vir locus of Bordetella pertussis. This locus is responsible for the regulation of B. pertussis virulence determinants (pertussis toxin, filamentous hemagglutinin, etc.) in response to environmental stimuli. This locus is also the site of a reversible frameshift mutation which results in the phenomenon of phase variation. In the past we had observed that two closely related strains of B. pertussis underwent phase variation at dramatically different rates. We have recently extended this observation by constructing a defined frameshift mutation in a kanamycin resistance gene and showing that the reversion of this mutation also occurs at dramatically different rates in these two strains. We are currently engaged in the genetic mapping of this hypermutable phenotype, with an eye to the isolation of the gene(s) responsible. This mapping is made possible because we have recently completed a physical map of the B. pertussis chromosome. Physical mapping of previously isolated genes is a simple and straightforward task, and we have several collaborations with other workers in the field to map specific genes. However, the derivation of this map also allows the use of genetic tools for mapping. Specifically, we have designed and constructed new strains and new vectors which allow us to do genetic mapping using Hfr-like strains of B. pertussis. Such an approach will allow the isolation of some interesting genes which has not been possible using standard cloning techniques. The primary scientific finding of the chromosomal map was that the genes for B. pertussis virulence determinants are unlinked, i.e. are scattered around the chromosome. The implications of this finding are currently being extended by constructing maps of other strains of B. pertussis and other species of Bordetella with the hopes of further defining their evolutionary relationships.