Streptococcus gordonii Rgg regulators: gene expression, signaling, oral biofilms

戈登链球菌 Rgg 调节因子：基因表达、信号传导、口腔生物膜

• 批准号: 8825484
• 负责人: M Margaret VICKERMAN
• 金额: $ 19.92万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-20 至 2018-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8825484
• 关键词: Adhesions; Affect; Algorithms; Back; Bacteria; Binding; Biological; Biological Process; Cells; Chromosomes; Chromosomes, Human, Pair 2; Communities; Competence; Complement; Cytoplasm; DNA; Data; Dental Plaque; Development; Dietary Sucrose; Dietary Sugars; Enzymes; Family; Foundations; Future; Gene Expression; Gene Expression Regulation; Gene Family; Gene Targeting; Genes; Genetic; Genetic Transcription; Genome; Glucans; Glucosyltransferase; Goals; Gram-Positive Bacteria; Growth; Health; Helix-Turn-Helix Motifs; In Vitro; Mediating; Methods; Microbial Biofilms; Molecular; Open Reading Frames; Operon; Peptide Signal Sequences; Peptides; Phase; Phenotype; Pheromone; Play; Process; Promoter Regions; Protein Family; Proteins; Reading; Regulation; Regulator Genes; Role; Salivary; Signal Transduction; Signaling Molecule; Staging; Streptococcus gordonii; Streptococcus pyogenes; Structural Genes; Sucrose; Surface; Tooth structure; Transcription Coactivator; Transcriptional Regulation; Virulence; Water; Work; bacteriocin; base; extracellular; family genetics; genetic regulatory protein; genome sequencing; in vivo; insight; member; mutant; novel; oral bacteria; oral biofilm; promoter; quorum sensing; research study; response; stress tolerance; surface coating; synthetic peptide; tooth surface

DESCRIPTION (provided by applicant): Streptococcus gordonii are pioneer colonizers of dental plaque biofilms. Their accumulation on surfaces is facilitated by glucans synthesized from dietary sucrose by the single extracellular glucosyltransferase (Gtf) enzyme. Regulation of the S. gordonii Gtf structural gene, gtfG, is controlled by the upstream gene, rgg which encodes a transcriptional activator that was the first-identified member of the Rgg family of regulatory proteins. There are seven Rgg-family proteins encoded in the S. gordonii chromosome including the partially characterized RggD which may be involved in glucan-independent biofilm formation. Genome sequence data have shown the widespread occurrence of rgg-family genes among Gram-positive bacteria; data are emerging about shared and unique features of the Rgg family. Rgg proteins usually control transcription of adjacent genes which are involved in various biological functions including colonization, virulence and responses to environmental conditions. Rgg-family proteins can increase or decrease expression of their target genes, often in a growth phase-dependent fashion. Some Rggs control not only the expression of adjacent genes, but act as global regulators acting at promoters of multiple genes located throughout the chromosome as occurs in Streptococcus pyogenes. Our data strongly suggest that S. gordonii Rgg may play similar global regulatory roles affecting expression of genes in addition to gtfG. An exciting recent finding in non-oral streptococcal species is that regulation by some Rgg proteins is mediated by peptide signals that function in a pheromone-like manner and act as quorum sensing molecules to coordinate the bacterial community response. These pheromones are processed from pre-peptides that are often encoded by open reading frames located near rgg genes; these peptides can positively or negatively affect the activity of the cognate Rgg. This newly-discovered mechanism of gene regulation holds intriguing possibilities for exploring novel mechanisms of oral biofilm control. Based upon the emerging evidence for pheromone interactions with Rgg proteins, we hypothesize that Rgg-family regulators may share common mechanisms of action and that as-yet-unidentified peptides may influence the activity of the S. gordonii Rgg proteins. The proposed studies will examine this possibility and provide additional insights into the function of S. gordonii Rgg family proteins via the following Specific Aims: 1) t identify and perform a preliminary characterization of selected S. gordonii target genes controlled by rgg-family determinants by comparing gene expression and resulting phenotypes in parental and mutant strains; 2) to determine if activities of S. gordonii Rgg proteins are influenced by potential pheromone-like peptides by examination of Rgg activity in the presence of both culture filtrates and synthetic peptides. Data will be used as a foundation for a future R01 application. It is hoped that these studies will identify novel facets of oral biofilm formatio that may also provide generally- applicable insights into genetic regulation by Rgg-family proteins in other Gram-positive bacteria.

描述（由申请人提供）：戈登链球菌是牙菌斑生物膜的先驱定植者。单胞外葡萄糖基转移酶（Gtf）由膳食蔗糖合成的葡聚糖促进了它们在表面的积累。gordonii Gtf结构基因gtfG的调控由上游基因rgg控制，rgg编码一个转录激活子，该转录激活子是rgg调节蛋白家族中第一个被发现的成员。在S. gordonii染色体中编码有7个rgg家族蛋白，其中包括部分表征的RggD，它可能参与葡聚糖非依赖性生物膜的形成。基因组序列数据显示，rgg家族基因在革兰氏阳性菌中广泛存在；关于Rgg家族的共同和独特特征的数据正在出现。Rgg蛋白通常控制邻近基因的转录，这些基因参与各种生物功能，包括定植、毒力和对环境条件的反应。rgg家族蛋白可以增加或减少其靶基因的表达，通常以生长阶段依赖的方式。一些rgg不仅控制邻近基因的表达，还像在化脓性链球菌中一样，作为位于整个染色体的多个基因启动子的全局调节剂。我们的数据强烈表明，除了gtfG外，gordonii Rgg可能还对其他基因的表达发挥类似的全球调控作用。最近在非口腔链球菌物种中一项令人兴奋的发现是，一些Rgg蛋白的调节是由肽信号介导的，肽信号以类似信息素的方式起作用，并作为群体感应分子来协调细菌群落的反应。这些信息素是由位于rgg基因附近的开放阅读框编码的前肽加工而成的；这些肽可以积极或消极地影响同源Rgg的活性。这一新发现的基因调控机制为探索口腔生物膜控制的新机制提供了有趣的可能性。基于信息素与Rgg蛋白相互作用的新证据，我们假设Rgg家族调节因子可能具有共同的作用机制，并且尚未确定的肽可能影响S. gordonii Rgg蛋白的活性。本研究将通过以下具体目标来检验这种可能性，并对gordonii S. Rgg家族蛋白的功能提供更多的见解：1)通过比较亲本菌株和突变菌株的基因表达和由此产生的表型，鉴定并初步表征选定的gordonii S. Rgg家族决定因素控制的靶基因；2)通过检测培养滤液和合成肽存在下的Rgg活性，确定gordonii S. Rgg蛋白的活性是否受到潜在信息素样肽的影响。数据将用作未来R01应用程序的基础。希望这些研究能够发现口腔生物膜形成的新方面，这也可能为其他革兰氏阳性细菌中rgg家族蛋白的遗传调控提供普遍适用的见解。