Regulation in Fusobacterium-mediated coaggregation

项目摘要 牙菌斑和相关的牙周疾病是一种常见的传染病， 一半的美国成年人（CDC）。复杂的物种内和物种间的相互作用调节着 多物种口腔微生物群落称为牙菌斑。牙菌斑是由一种有组织的， 高度复杂的微生物社会群落，革兰氏阴性厌氧菌具核梭菌是 这种微生物群凭借其独特的能力与许多早期和晚期殖民者物理聚集。 除了在牙周炎中的作用外，F。核质与几种口腔外疾病有关，包括早产 出生和结肠直肠癌。虽然梭菌与其他细菌的相互作用已被广泛研究， 研究和四个共聚集粘附素鉴定，很少有人知道的机制，调节 梭杆菌介导的共聚集，主要是由于缺乏一个强大的遗传工具包操纵的F。 核质为了克服这一点，我们最近开发了一个方便的基因缺失系统，为F。核质和 产生了具有~10倍基因组覆盖率的随机转座子突变体的大型文库。筛选此 库发现了几个共聚集因子，其中包括一个独特的双组分系统，称为汽车- 卡尔和一个九基因操纵子，编码一个赖氨酸降解途径（LDP），控制数量和 RadD的活性。RadD是一种IV型自身转运蛋白，是一种多功能粘附素， 具有许多早期和一些晚期定殖者的梭菌粘附。根据这些发现，我们计划 深入分析这两个调节因素。我们将第一次展示一种口腔细菌二 组分信号传导组分以细胞密度依赖性方式调节细胞-细胞粘附素的表达 并表征细菌中与赖氨酸催化剂相关的赖氨酸核糖开关。一旦成功完成 这项研究，我们希望有显着的贡献，了解如何多功能粘附素， RadD是通过识别和破译相关的因素和机制来调节的。因为RadD需要F。 核质，以纳入由最初的殖民者组成的已建立的社区，如 链球菌和放线菌，我们的发现将对理解 梭杆菌介导的共聚集作用的发展牙菌斑，将提供新的见解， 开发针对这种重要病原体的有效治疗策略。

PROJECT SUMMARY Dental plaque and associated periodontal diseases represent a common infectious disease afflicting nearly half of American adults (CDC). The complex intra- and interspecies interactions regulate the development of multispecies oral microbial communities called dental plaque. The dental plaque is made of an organized, highly complex microbial social community and the Gram-negative anaerobe F.nucleatum is a key organism of this microbiome by virtue of its unique capability to physically aggregate with many early and late colonizers. Besides its role in periodontitis, F. nucleatum has been linked to several extra-oral diseases including preterm birth and colorectal cancer. Although the fusobacterial interactions with other bacteria have been widely studied and four coaggregation adhesins identified, little is known about mechanisms that regulate Fusobacterium-mediated coaggregation, mainly due to the lack of a robust genetic toolkit for manipulation of F. nucleatum. To overcome this, we recently developed a convenient gene deletion system for F. nucleatum and generated a large library of random transposon mutants with ~10-fold genome coverage. Screening of this library uncovered several coaggregation factors, which include a unique two-component system termed CarS- CarR and a nine-gene-operon that encodes a lysine-degrading pathway (LDP) that controls the amount and activity of RadD, respectively. RadD, a type IV autotransporter, is a versatile adhesin that mediates fusobacterial adhesion with many early and some late colonizers. Based on these findings, we plan to characterize the two regulatory factors in-depth. We will be the first time to show an oral bacterial two component signaling component regulates expression of cell-cell adhesin in a cell density-dependent manner and characterize a lysine riboswitch related to lysine catabolism in bacteria. Upon the successful completion of this research, we expect to have significantly contributed to the understanding of how the versatile adhesin RadD is regulated by identifying and deciphering factors and mechanism involved. Because RadD requires F. nucleatum to incorporate into an established community made of initial commensal colonizers, such as streptococci and actinomyces, our discoveries will have a significant impact on the understanding of fusobacterium-mediated coaggregation role in development of dental plaque, will provide new insights into the development of potent therapeutic strategies against this important pathogen.