GENETICS OF INTEGRATION HOST FACTOR GENES FROM S MUTANS

突变体整合宿主因子基因的遗传学

• 批准号: 2608315
• 负责人: STEVEN D GOODMAN
• 金额: $ 4.14万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-12-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2608315
• 关键词: DNA primers; DNA replication; Escherichia coli; Streptococcus mutans; bacterial genetics; bacterial proteins; gene complementation; gene expression; genetic recombination; genetic regulation; molecular cloning; mutant; nucleic acid sequence; oral bacteria; phenotype; polymerase chain reaction

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.

变形链球菌是龋齿的病原体。就是能力 造成损害与长链的生产密切相关 葡萄糖聚合物（葡聚糖），使细菌能够成功地 定殖于牙齿的光滑表面。为了合成这些葡聚糖 细菌拥有一系列表达酶的基因，称为 葡萄糖基转移酶。葡萄糖基转移酶基因 gtfB 的表达， gtfC 和 gtfD 受到严格监管。该项目的长期目标 是识别调节其表达的元件，然后 随后描述它们的特征。第一个确定的调制器是 全球原核调节因子，整合宿主因子（IHF）。 IHF网 效果是抑制克隆的 S. mutans gtf 基因高达 6 倍 以大肠杆菌表达。 IHF 密切参与几乎所有形式的类核 操作，即复制、重组和基因表达。在E中。 线圈和其他革兰氏阴性细菌，IHF 会影响基因表达 通过其结合 DNA 的能力进行转录调节 在其同源结合位点。在正式分析IHF功能之前 gtf 表达式可以进行，有必要证明 在大肠杆菌中观察到的表型与在变形链球菌中观察到的表型相似。因此 第一步是建立变形链球菌中 IHF 同源物的遗传学。 这还包括 IHF 基因的克隆和测序 在变形链球菌中构建IHF变形链球菌。 尚未对任何革兰氏阳性菌属的 IHF 进行表征。一旦 编码 IHF 的基因已被克隆，这是一组初步的 将进行互补实验来比较大肠杆菌和链球菌。 直接变形IHF。最后将变形链球菌菌株构建为 可以评估 IHF 缺陷以确定他们的表达能力 他们的gtf基因相对于野生型变形链球菌。