Genetic Control of C. albicans Biofilm Formation

描述(申请人提供)：白色念珠菌是一种主要的人类真菌病原体，可引起粘膜和深层组织感染。白色念珠菌感染的一个重要风险因素是植入的医疗设备的存在，该设备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。这里提出的研究的近期目标是确定控制生物膜形成的关键白色念珠菌基因和调控途径，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分析白色念珠菌独特特征的新策略：转录因子功能调查。使用这一策略，我们创建了每个转录因子基因存在缺陷的菌株，并测试这些菌株的表型缺陷。然后，我们使用微阵列分析来确定在所研究的表型中具有直接作用的目标基因。到目前为止，我们已经测试了84个转录因子基因中每一个的纯合子插入突变体的生物膜缺陷。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。我们将在生物被膜形成的检测中分析单个和多个目标基因突变以及过度表达的菌株。此外，我们还将识别我们在屏幕上定义的其他生物膜调节因子的目标基因。将对目标基因进行功能分析。最后，我们将使用大鼠中心静脉导管体内生物膜形成模型来测试我们的体外结果。包括活负荷、生物膜结构和基因表达谱在内的属性将被监测。

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.