Gene Regulation of Fimbriae in Actinomyces naeslundii

内氏放线菌菌毛的基因调控

• 批准号: 6779239
• 负责人: SOPHIA E PINA
• 金额: $ 7.3万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6779239
• 关键词: Actinomyces; bacteria infection mechanism; bacterial genetics; biofilm; biological signal transduction; cell adhesion; gene induction /repression; genetic mapping; genetic promoter element; host organism interaction; microorganism culture; microorganism interaction; oral bacteria; periodontitis; pilus; polymerase chain reaction; reporter genes; transfection /expression vector

Actinomyces naeslundii is a resident of the normal oral flora, however, it also has the potential to cause disease, namely root caries and periodontitis (3, 4). Colonization by A. naeslundii can begin during infancy; it can adhere to salivary proline rich proteins on a tooth surface via type 1 fimbriae and/or to surrounding Streptococcus species such as S. oralis via the type 2 fimbriae. In addition, adherence by type 2 fimbriae is associated with lactose sensitive receptors in the host, such as those on mucosal epithelial cells, erythrocytes, and polymorphonuclear leukocytes (55, 57). Since little is known about the fimbriae associated adherence mechanisms in gram-positive bacteria, studies ofA. naeslundii type 1 and type 2 fimbriae make this organism an ideal model to investigate adherence to host cells as well as aggregation to surrounding bacterial cells in a biofilm. This investigation will examine the effects of environmental signals on the synthesis of type 1 and type 2 fimbriae to test the hypothesis that environmental factors can regulate gene expression of fimbriae. The focus of this proposal will include: Aim 1. Determination of environmental signals that regulate fimbrial biosynthesis Real-time reverse transcriptase PCR will be used to monitor the expression of the type 1 and type 2 fimbrial genes ofA. naeslundii while growing in different conditions in a continuous culture system. Aim 2. Characterization of the type 2 fimbrial promoter The transcriptional start site for the type 2 fimbrial locus will be mapped by primer extension and S 1 nuclease experiments. The type 2 fimbrial promoter regions will then be cloned into a reporter gene vector for use, in future grant periods, in promoter mutation studies.

内氏放线菌是正常口腔植物群的居民，然而，它也有可能引起疾病，即根龋和牙周炎（3，4）。殖民地A。内氏链球菌可开始于婴儿期;它可通过1型菌毛粘附于牙齿表面上的唾液脯氨酸丰富的蛋白质和/或粘附于周围的链球菌物种如链球菌。通过2型菌毛进入口腔。此外，2型菌毛的粘附与宿主中的乳糖敏感性受体相关，例如粘膜上皮细胞、红细胞和多形核白细胞上的受体（55，57）。由于对革兰氏阳性菌菌毛相关粘附机制知之甚少，对A。内氏菌1型和2型菌毛使该生物体成为研究粘附宿主细胞以及聚集周围细菌细胞的理想模型， 生物膜本研究将探讨环境信号对1型和2型菌毛合成的影响，以验证环境因素可以调控菌毛基因表达的假设。本提案的重点将包括： 目标1。确定调节菌毛生物合成的环境信号 采用实时荧光定量PCR技术检测1型和2型菌毛基因的表达。在连续培养系统中，在不同条件下生长时， 目标2. 2型菌毛启动子的表征2型菌毛基因座的转录起始位点将通过引物延伸和S1核酸酶实验作图。然后将2型菌毛启动子区克隆到报告基因载体中，以便在未来的资助期内用于启动子突变研究。