The LytTR Regulatory Systems of Streptococcus mutans

描述(申请人提供)：这项拟议的研究旨在研究LyttR调控系统(LRS)所使用的调控机制，并探索由这些系统在变形链球菌中触发的细胞死亡途径。LRS是一个新发现的基因调控系统，它由LytTR家族转录调节因子和膜蛋白抑制因子组成，可拮抗该调节因子的功能。该项目将通过三个目标来实现：1)确定LRS膜蛋白的抑制机制；2)确定LRS下游负责介导细胞死亡的成分；以及3)发展LRS细胞死亡途径的治疗模型。1)为了确定LRS膜蛋白是如何发挥抑制作用的，我们将研究三种不同的抑制机制：蛋白质稳定、翻译后修饰和隔离。蛋白质-蛋白质相互作用研究将决定LRS膜蛋白是否直接发挥其功能。2)为了确定细胞死亡的介体，我们将使用基因技术来确定突变株的致死表型所需的基因/途径，该突变株构成地激活了LRS细胞死亡途径。3)为了评估LRS细胞死亡途径的治疗潜力，我们将测试三种变形链球菌LRS之间的正反馈调节模型。一个可诱导的细胞死亡系统将在体外和体内进行功能测试 模型系统。这些研究的目标是建立一个在革兰氏阳性细菌中LRS功能的模型系统，并确定LRS细胞死亡途径在抑制素预形成的生物膜群落中的潜在用途。

DESCRIPTION (provided by applicant): The proposed research aims to investigate the regulatory mechanism used by LytTR Regulatory Systems (LRS) as well as explore a cell death pathway triggered by these systems in Streptococcus mutans. LRS are a newly described gene regulatory system that consists of a LytTR family transcription regulator and putative membrane protein inhibitor that antagonizes the function of this regulator. The goals of this project will b achieved in three aims by: 1) determining the inhibitory mechanism employed by LRS membrane proteins; 2) characterizing the components downstream of LRS responsible for mediating cell death; and 3) developing a therapeutic model of the LRS cell death pathway. 1) To determine how LRS membrane proteins function as inhibitors, we will examine three different mechanisms of inhibition: protein stability, posttranslational modification, and sequestration. Protein-protein interaction studies will determine whether LRS membrane proteins exert their function directly. 2) To characterize the mediators of cell death, we will use genetic techniques to determine the genes/pathways required for the lethal phenotype of a mutant strain that constitutively activates the LRS cell death pathway. 3) To assess the therapeutic potential of the LRS cell death pathway, we will test a positive feedback regulatory model between three S. mutans LRS. An inducible cell death system will be tested for functionality in in vitro and in vivo model systems. The goal of these studies is to create a model system for LRS function in Gram positive bacteria and to determine the potential utility of the LRS cell death pathway in inhibitin preformed biofilm communities.