S. aureus SarU and Rot regulate virulence factor genes

金黄色葡萄球菌 SarU 和 Rot 调节毒力因子基因

• 批准号: 6774198
• 负责人: PETER JOSEPH MCNAMARA
• 金额: $ 28.83万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6774198
• 关键词: DNA footprinting; Staphylococcus aureus; bacterial toxins; binding proteins; gel mobility shift assay; gene induction /repression; genetic regulation; genetic transcription; immunoprecipitation; intermolecular interaction; microorganism culture; northern blottings; nucleic acid sequence; virulence; virus genetics; western blottings; yeast two hybrid system

DESCRIPTION (provided by applicant): Historically, antimicrobial therapy dramatically reduced the mortality of Staphylococcus aureus infections. Because of multidrug resistance, successful treatment of S. aureus can be difficult to achieve. Novel therapeutic interventions are desperately needed. One promising approach is to develop drugs that target the regulators of virulence factor (VF) expression. A detailed molecular mechanism of action will greatly benefit the search for an appropriate target for regulator-specific drugs. VF regulation in S. aureus is controlled by the cooperative and redundant action of the products of many loci including a family of at least six MarR-family transcriptional regulators, the SarA-homologues. This proposal focuses elucidating the molecular mechanism of two SarA-homologues, Rot and SarU. Genetic evidence suggests that Rot and SarU have a reciprocal effect on the expression of VFs. Using alpha-toxin as an example we will define the molecular interactions that lead to Rot acting as a repressor of the gene encoding alpha-toxin (hlalpha) and SarU acting as an activator of hla transcription. Our hypothesis is that Rot is a constitutively expressed repressor that directly downregulates transcription of hlalpha. This repression is relieved by RNAIII, a riboregulator that is upregulated by both a direct interaction between SarU and the agr promoters and an indirect interaction of SarU on the sarA promoters. To test this hypothesis, we propose: Aim 1. To characterize mechanism(s) of Rot repression of a-toxin production that is antagonized by RNAIII. Aim 2. To characterize mechanism(s) of SarU activation of a-toxin production by demonstrating direct and temporally appropriate interactions between SarU and its target genes.

描述（由申请人提供）：从历史上讲，抗菌治疗大大降低了金黄色葡萄球菌感染的死亡率。由于具有多药耐药性，因此很难获得金黄色葡萄球菌的成功处理。迫切需要新颖的治疗干预措施。一种有希望的方法是开发针对毒力因子（VF）表达调节剂的药物。详细的分子作用机制将极大地有助于寻找适合调节剂特异性药物的目标。金黄色葡萄球菌中的VF调节受许多基因座产品的合作和冗余作用控制，其中包括至少六个MARR家族的转录调节剂Sara-Holdomologues。该提案重点阐明了两个萨拉 - 同源物腐烂和萨鲁的分子机制。遗传证据表明，腐烂和SARU对VF的表达具有相互影响。以α-毒素为例，我们将定义分子相互作用，这些相互作用导致腐烂充当编码α-毒素（Hlalpha）的基因的阻遏物，而SARU充当HLA转录的激活剂。我们的假设是腐烂是一种组成型表达的阻遏物，直接下调了Hlalpha的转录。 RNAIII是一种抑制作用，RNAIII是一种核糖调节剂，它在SARU和AGR启动子之间的直接相互作用以及Saru在Sara启动子上的间接相互作用而上调。为了检验这一假设，我们提出： 目的1。表征由RNAIII拮抗的A毒素产生的腐烂机制。 目的2。通过证明SARU与其靶基因之间的直接和时间适当的相互作用来表征A-Toxin产生的SARU激活机制。