Exploring Integrative Conjugative Elements in the Biology and Ecology of Oral Streptococci

项目摘要 必需基因是细菌基因组中最关键的组成部分，是生存所必需的。在……里面 近年来，我们开发了一些技术，使我们能够识别和研究牙齿中的必要基因 龋病病原体变形链球菌。通过这些研究，我们已经确定了几个基因 然而，未知的功能显然是变形链球菌正常生理所不可缺少的。这其中的一个 基因，我们暂时命名为erfr(基本调节因子)，被注释为转录 调整器。该基因的沉默会导致严重的生长和细胞形态缺陷，这表明我们有 发现了变形链球菌生物学中一种新的独特的调节成分。值得注意的是，这种调节蛋白也是 存在于其他病原体的基因组中，包括A组和B组链球菌。自从它被发现以来，我们 已经取得了一些进展，表明ErfR调节一种假定的整合结合词的表达 元素(ICE)称为TnSmu1。这些元素参与遗传物质的水平转移，并且 可以携带理想的特征，如抗菌素耐药性和毒力相关基因。冰可能是一种 该病原菌的基因多样性和表型多样性的重要机制。然而，几乎没有 这些元素在Sm中的深入表征。为了解决这一知识差距，我们将利用TnSmu1和 它被ErfR作为模型ICE进行调控，并制定了三个具体目标：1)功能分析 TnSmu1水平转移的必要性和潜力；2)识别受控制的基因和代谢活动 通过转录组分析TnSmu1的诱导；3)检测冰块对Sm宿主适合性和 进化论。综合这项提案的结果和结论，将使我们更好地理解 ErfR的重要性、TnSmu1功能和对Sm及更广泛的生理影响的机制 这些元素在Sm菌株中的分布。预计结果将把erfR/TnSmu1定位为 口腔细菌接合水平基因转移研究的重要模型。这将填补我们在 了解Sm发病机制中的这些因素及其对口腔生物膜生态的影响。这项建议 还将有助于我们在对Sm的基本流程进行编目方面的长期抱负。

Project Summary Essential genes represent the most critical components of a bacterial genome and are required for survival. In recent years, we developed technologies that allowed us to identify and study essential genes in the dental caries pathogen Streptococcus mutans. Through these studies we have identified several genes that have unknown functions and yet, are clearly indispensable for the normal physiology of S. mutans. One of these genes, that we are provisionally naming erfR (essential regulatory factor), is annotated as a transcriptional regulator. Silencing of this gene causes severe growth and cell morphology defects, suggesting that we have identified a new and unique regulatory component of S. mutans biology. Notably, this regulatory protein is also present in the genome of other pathogens, including Group A and Group B streptococci. Since its discovery we have made advances that show that ErfR regulates the expression of a putative integrative conjugative element (ICE) known as TnSmu1. These elements participate in the horizontal transfer of genetic material, and can carry desirable traits such as antimicrobial resistance, and virulence-associated genes. ICEs could be an important mechanism driving genotypic and phenotypic diversity of this pathogen. However, there is little to no in-depth characterization of these elements in Sm. To address this knowledge gap we will exploit TnSmu1 and its regulation by ErfR as a model ICE and have developed three Specific Aims: 1) Functional analysis of TnSmu1 essentiality and potential for horizontal transfer; 2) Identify genes and metabolic activities controlled by TnSmu1 induction by transcriptome analysis; 3) Examine the impact of ICEs on Sm host fitness and evolution. Combined results and conclusions from this proposal will lead to a greater understanding of the mechanisms of erfR essentiality, TnSmu1 function and physiological effects on Sm, and the broader distribution of these elements among Sm strains. The outcomes are expected to position erfR/TnSmu1 as an important model for studying horizontal gene transfer by conjugation in oral bacteria. This will fill a void in our understanding of these elements in Sm pathogenesis and their impacts on oral biofilm ecology. The proposal will also contribute to our long-term aspirations in cataloging essential processes in Sm.