The LytTR Regulatory Systems of Streptococcus mutans

描述（由申请人提供）：拟议的研究旨在研究LytTR调控系统（LRS）使用的调控机制，并探索这些系统在变形链球菌中引发的细胞死亡途径。LRS是一种新发现的基因调控系统，由LytTR家族转录调控因子和可能拮抗该调控因子功能的膜蛋白抑制剂组成。本项目的目标将通过以下三个方面来实现：1)确定LRS膜蛋白的抑制机制；2)表征LRS下游负责介导细胞死亡的成分；3)建立LRS细胞死亡通路的治疗模型。1)为了确定LRS膜蛋白作为抑制剂的功能，我们将研究三种不同的抑制机制：蛋白质稳定性、翻译后修饰和隔离。蛋白-蛋白相互作用的研究将决定LRS膜蛋白是否直接发挥其功能。2)为了表征细胞死亡的介质，我们将使用遗传技术来确定突变株的致死表型所需的基因/途径，该突变株可组成性地激活LRS细胞死亡途径。3)为了评估LRS细胞死亡通路的治疗潜力，我们将测试三种S. mutans LRS之间的正反馈调节模型。诱导细胞死亡系统将在体外和体内进行功能测试

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.