An essential transcription regulator in Pseudomonas aeruginosa

描述（由申请方提供）：铜绿假单胞菌是人类重要的机会致病菌，是囊性纤维化（CF）患者发病和死亡的主要原因。在慢性感染的CF肺中，微生物以生物膜的形式存在，生物膜是包裹在聚合物基质中的表面附着的细菌群落。这种生物膜生长模式增强了铜绿假单胞菌对抗生素的耐药性，并有助于逃避宿主免疫应答。我们已经发现了铜绿假单胞菌中的一个重要的转录调节因子（由PA 0906基因编码），我们已经将其与生物膜形成联系起来。我们已经发现，这种调节剂的基本功能是通过抑制PA 0907基因的表达来防止细胞溶解。PA 0907基因编码另一种调节因子，该调节因子反过来积极控制一组有助于细胞裂解的基因的表达。当我们开始定义由PA 0906的缺失触发的调节级联时，我们利用了这样一个事实，即这种蛋白属于一个经过充分研究的调节因子家族， DNA损伤的反应。特别是，将野生型细胞与含有不可切割的PA 0906突变体的细胞进行比较，使我们能够鉴定出约30个受该调节剂控制的基因。此外，我们发现PA 0906的裂解对于体外生物膜形成是重要的。在这里，我们提出（i）确定哪些基因受到PA 0906的直接控制，哪些基因受到PA 0907的直接控制，（ii）鉴定有助于细胞裂解的PA 0907控制的基因，（iii）测试PA 0906是否影响CF-气道上皮细胞模型中的生物膜形成，以及（iv）确定PA 0906如何影响生物膜形成。我们的研究有望揭示一个以前未被表征的转录调节子的重要性的基础，并阐明该调节子在控制转录过程中的作用。 生物膜的形成。由于这些研究的重点是调节剂是必不可少的，因此是一个潜在的抗生素靶点，我们提出的工作可能有助于开发治疗CF患者的新疗法。

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa is an important opportunistic pathogen of humans that is notorious for being the principal cause of morbidity and mortality in Cystic Fibrosis (CF) patients. In the chronically infected CF lung the organism persists as a biofilm-a surface attached community of bacteria encased in a polymeric matrix. This biofilm mode of growth augments the resistance of P. aeruginosa to antibiotics and facilitates evasion of the host immune response. We have uncovered an essential transcription regulator in P. aeruginosa (encoded by the PA0906 gene) that we have implicated in biofilm formation. We have found that the essential function of this regulator is to prevent cell lysis by repressing the expression of the PA0907 gene. The PA0907 gene encodes another regulator that in turn positively controls the expression of a set of genes that contributes to cell lysis. T begin to define the regulatory cascade that is triggered by the loss of PA0906, we have taken advantage of the fact that this protein belongs to a well-studied family of regulators that undergo cleavage in response to DNA damage. In particular, comparison of wild-type cells with cells containing an uncleavable PA0906 mutant enabled us to identify ~30 genes that are subject to control by this regulator. In addition we have found that cleavage of PA0906 is important for biofilm formation in vitro. Here we propose to (i) determine which genes are subject to direct control by PA0906 and which genes are subject to direct control by PA0907, (ii) identify PA0907-controlled genes that contribute to cell lysis, (iii) test whether or not PA0906 influences biofilm formation in a CF-airway epithelial cell model and (iv) determine how PA0906 influences biofilm formation. Our studies are expected to reveal the basis for the essentiality of a previousl uncharacterized transcription regulator and illuminate the role this regulator plays in the control of biofilm formation. Because the regulator that is the focus of these studies is essential, and thus a potential antibiotic target, it is possible that the work we propose could help in the development of novel therapeutics for the treatment of CF patients.