Fungal Virulence: Identifying the factors that control virulence and the growth in parasitic form of Coccidioides

摘要 本项目将通过转录组学、蛋白质组学和基因组规模的研究， 球孢子菌属。球孢子菌属（Coccidioides species）、球孢子菌C. immitis和C. posadasii，在土壤中生长为菌丝体， 在哺乳动物宿主中分化成一种独特的圆形结构，称为小球-这是它们的标志。 致病性小球扩大并在内部分裂形成内生孢子，约4天后释放 在哺乳动物宿主中。球孢子菌分化成小球的机制及毒力因子 仍然在很大程度上未知。我们对小球富集基因和小球表面- 附着的蛋白质是病原体采取的免疫逃避策略的主要参与者。因此在 在这个项目中，我们的总体目标是识别可能在以下方面发挥作用的基因/蛋白质：（1）控制从 环境-寄生物生长或（2）直接与宿主相互作用以破坏免疫应答。我们将 采用功能基因组学和蛋白质组学方法来鉴定那些 所需的小球特异性基因和内孢子特异性基因的表达，并表征它们， 它们在小球生长和小球特异性基因表达谱中的重要性。此外，我们将确定 对敏感和抗性鼠宿主应答重要的真菌基因，鉴定分泌的， 表面附着和/或GPI锚定的蛋白质，并产生 候选基因，将根据这些转录组学和蛋白质组学研究以及我们的 初步数据。在细胞培养物中引发细胞因子应答方面显示出显著差异的突变体将是 优先在活动下进行球孢子菌病小鼠模型中的毒力表型检测 计划在模型生物核心中。这些实验的结果将揭示相关的基因/蛋白质 在调节球孢子菌属寄生生长中的作用，并揭示了球孢子菌属与 宿主和病原体

Abstract This Project will focus on the pathogen by undertaking transcriptomic, proteomic and genome-scale studies of Coccidioides species. Coccidioides species, C. immitis and C. posadasii, grow as a mycelium in the soil and differentiate into a unique round structure called a spherule in the mammalian host – a hallmark of their pathogenicity. Spherules enlarge and divide internally to form endospores which are released after about 4 days in the mammalian host. The mechanisms of differentiation into spherules and virulence factors of Coccidioides remain largely unknown. We are intrigued by the hypothesis that spherule-enriched genes and spherule surface- attached proteins are major players of the immune evasion strategies adopted by the pathogen. Therefore, in this Project, our overall goal is to identify genes/proteins that may play a role in (1) controlling transition from environmental-to-parasitic growth or (2) directly interacting with the host to subvert immune responses. We will take functional genomics and proteomic approaches to identify factors (i.e. transcriptional regulators) that are required for the expression of spherule-specific genes and endospore-specific genes and characterize them for their importance in spherule growth and spherule-specific gene expression profiles. In addition, we will identify fungal genes that are important for response to susceptible and resistant murine hosts, identify the secreted, surface-attached and/or GPI-anchored proteins from Coccidioides spherules, and generate knockout mutants of the candidate genes, which will be selected based on these transcriptomic and proteomics studies and our preliminary data. Mutants that show significant difference in eliciting cytokine response in cell culture will be prioritized to be tested for virulence phenotypes in mouse model of coccidioidomycosis under the activities planned in the Model Organism Core. Results of these experiments will reveal genes/proteins that are involved in regulating the parasitic growth of Coccidioides and shed light onto the molecular details of interactions between host and the pathogen.