Molecular Genetic Analysis of S. mutans Cariogenicity

这项应用将集中在鉴定参与菌斑形成和生长的变形链球菌的必要基因。利用体外模型系统，对变形链球菌GS5进行插入重复诱变后，对生物膜形成所必需的基因进行鉴定和鉴定。此外，我们实验室最近发现的两个在这一过程中起重要作用的基因，comb和sgp，将进一步分析它们在生物被膜形成中的各自作用。涉及这两个基因的潜在信号转导机制将利用基因表达技术进行研究，此外，还将评估COM系统在与基因转移和生物膜形成相关的物种群体感应中的作用。本实验室开发的一种在任何可转化微生物中鉴定必需基因的新方法将被用于鉴定变形链球菌中的这些基因。该方法基于反义RNA诱导，具有识别特异性防龋剂开发的靶点的潜力。此外，这种方法可以很容易地用于识别无处不在的细菌中的必要基因，以开发广谱抗菌剂。这项建议的具体目的是为了提供关于变形链球菌基本毒力因子的新信息，这些信息可以被用来设计新的防龋策略。

This application will focus on characterizing essential genes in Streptococcus mutans involved in plaque formation and growth. Utilizing model in vitro systems, genes essential for biofilm formation will be identified and characterized following insertion duplication mutagenisis of S. mutans GS5. In addition, two genes recently identified in our laboratory as important for this process, comB and sgp, will be further analyzed as to their respective roles in biofilm formation. Potential signal transduction mechanisms involving both genes will be investigated using gene expression techniques in addition, the role of the com system in inraspecies quorum sensing relative to gene transfer and biofilm formation will be assessed. A novel approach developed in this laboratory to identify essential genes in any transformable microorganism will be utilized to identify such genes in S. mutans this approach, based upon antisense RNA induction, has the potential of identifying target sites for the development of specificanticaries agents. In addition, this approach can be readily used to identify essential genes in ubiquitous bacteria for development of broad- spectrum antibacterial agents. The specific aims of this proposal are designed to provide new information regarding essential virulence factors of S. mutans which could be exploited to design novel anticaries strategies.