Genetic Control of C. albicans Biofilm Formation

描述（由申请人提供）：白色念珠菌是一种主要的人类真菌病原体，可引起粘膜和深部组织感染。白色念珠菌感染的一个重要危险因素是植入医疗装置的存在，它为生物膜的形成提供了表面。生物膜为病原体的生存创造了一个受保护的微环境。这里提出的研究的直接目标是确定关键的白色念珠菌基因和控制生物膜形成的调控途径，长期目标是在此基础上开发新的治疗策略。我们已经实施了一种新的策略来分析独特的白色念珠菌特征：转录因子功能调查。通过这种策略，我们创建了每个转录因子基因都有缺陷的菌株，并测试了菌株的表型缺陷。然后，我们使用微阵列分析来鉴定在研究表型中有直接作用的靶基因。到目前为止，我们已经测试了84种生物膜缺陷转录因子基因中的纯合插入突变体。锌指蛋白bcr1p是生物膜形成和一组表面蛋白基因和粘附素表达所必需的。我们将分析单个和多个目标基因突变以及在生物膜形成试验中过表达的菌株。此外，我们将确定我们在筛选中定义的其他生物膜调节因子的靶基因。目标基因将进行功能分析。最后，我们将用大鼠中心静脉导管模型来测试我们的体外结果，以在体内形成生物膜。将监测包括活负荷、生物膜结构和基因表达谱在内的属性。

DESCRIPTION (provided by applicant): Candida albicans is a major human fungal pathogen, causing both mucosal and deep tissue infections. A significant risk factor for C. albicans infection is the presence of an implanted medical device, which provides a surface for biofilm formation. The biofilm creates a protected microenvironment for survival of the pathogen. The immediate goal of studies here proposed is to define the key C. albicans genes and regulatory pathways that govern biofilm formation, with the long-term objective of developing new treatment strategies based upon this understanding. We have implemented a new strategy for analysis of unique C. albicans traits: a transcription factor function survey. With this strategy, we create strains with defects in each transcription factor gene and test the strains for phenotypic defects. We then use microarray analysis to identify target genes that have a direct role in phenotype under study. We have thus far tested homozygous insertion mutants in each of 84 transcription factor genes for biofilm defects. Zinc-finger protein Bcr1 p is required for biofilm formation and for expression of a group of surface protein genes and adhesins. We will analyze single and multiple target gene mutants as well as over-expressing strains in assays for biofilm formation. In addition, we will identify target genes for additional biofilm regulators that we define in our screen. Target genes will be subjected to functional analysis. Finally, we will test our in vitro results with a rat central venous catheter model for biofilm formation in vivo. Attributes including viable burden, biofilm architecture, and gene expression profiles will be monitored.