GENETICS OF INTEGRATION HOST FACTOR GENES FROM S MUTANS

变形链球菌是一种引起龋齿的病原体。这就是能力 造成损害与生产长链有很强的联系 葡萄糖聚合物(葡聚糖)使细菌能够成功地 定植牙齿光滑的表面。为了合成这些葡聚糖 细菌拥有一组表达酶的基因，称为 葡萄糖基转移酶。葡萄糖转移酶基因GTFB的表达， Gtfc和gtfd受到严格监管。这个项目的长期目标是 就是找出调节其表达的元素，然后 随后描述了它们的特征。第一个确定的调制器是 全球原核生物调节因子，整合宿主因子(IHF)。IHF网 效果是将克隆的变形链球菌GTF基因抑制达6倍 以E.线圈表示。 IHF与几乎所有形式的类核密切相关。 操纵，即复制、重组和基因表达。在E. CoIL和其他革兰氏阴性细菌，IHF可以影响基因表达 通过其结合DNA的能力进行转录调控 在其同源结合部位。在正式分析IHF函数之前 可以进行GTF表达，这将需要证明 在大肠杆菌中观察到的表型与变形链球菌中的表型相似。因此， 第一步是建立变形链球菌IHF同源基因的遗传学。 这将包括IHF基因的克隆和测序。 涉及在变形链球菌中构建IHF突变株。 目前还没有任何革兰氏阳性属的IHF的特征。一旦 编码IHF的基因已经被克隆，这是一组初步的 将进行互补实验以比较E.Coli和S. 直接变种人IHF。最后将变形链球菌菌株构建为 IHF的缺陷可以被评估以确定他们的表达能力 他们的GTF基因与野生型变形链球菌有关。

Streptococcus mutans is a causative agent of dental caries. It's ability to inflict damage is strongly linked to the production of long chain glucose polymers (glucans) which allow the bacteria to successfully colonize the smooth surface of teeth. To synthesize these glucans the bacteria possesses a family of genes that express enzymes called glucosyltransferases. Expression of the glucosyltransferase genes, gtfB, gtfC and gtfD are strongly regulated. The long term goal of this project is to identify elements that regulate their expression and then to subsequently characterize them. The first modulator identified was the global prokaryotic regulator, Integration Host Factor (IHF). IHF's net effect is to repress cloned S. mutans gtf genes as much as 6 fold when expressed in E. coil. IHF is intimately involved in virtually all forms of nucleoid manipulation i.e. replication, recombination and gene expression. In E. coil and other gram negative bacteria, IHF can affect gene expression through either transcriptional regulation through its ability to bind DNA at its cognate binding site. Before a formal analysis of IHF function of gtf expression can be undertaken it will be necessary to demonstrate that the phenotypes observed in E. coli are similar in S. mutans. Thus the first step is to establish the genetics of IHF homologs in S. mutans. This will include the cloning and sequencing of the IHF genes in addition to constructing IHF mutans in S. mutans. No IHF from any gram positive genera has yet been characterized. Once the genes that code for IHF have been cloned, a preliminary set of complementation experiments will be performed to compare E. coli and S. mutans IHF directly. Finally the S. mutans strain constructed to be deficient in IHF can be assessed to determine their ability to express their gtf genes relative to wild type S. mutans.