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

摘要 该项目将通过进行转录组、蛋白质组和基因组规模的研究来关注病原体 球虫属(Coccidioides)种。球孢子虫(C.immitis)和球孢子虫(C.posadasii)在土壤中以菌丝体的形式生长， 在哺乳动物宿主中分化成一种独特的圆形结构，称为球体--这是它们 致病性。球形扩大并在内部分裂形成内生孢子，大约4天后释放。 在哺乳动物的宿主中。球孢子虫分化成球状的机制及毒力因子 在很大程度上仍然不为人知。我们对球体丰富的基因和球体表面的假设很感兴趣- 附着蛋白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，我们的总体目标是确定可能在(1)控制从 从环境到寄生的生长或(2)直接与宿主相互作用以破坏免疫反应。我们会 采用功能基因组学和蛋白质组学方法来确定哪些因子(即转录调节因子)是 小球体特异基因和内孢子特异基因的表达所需的基因，并对它们进行表征 它们在球体生长和球体特异性基因表达谱中的重要性。此外，我们将确定 对于对敏感和耐药小鼠宿主的反应至关重要的真菌基因，识别分泌的 球状球虫球体表面附着和/或GPI锚定的蛋白，并产生敲除突变体 候选基因，将根据这些转录组和蛋白质组学研究以及我们的 初步数据。在细胞培养中表现出明显不同的细胞因子反应的突变株将 在活动下优先接受球孢子菌病小鼠模型的毒力表型测试 计划在模型有机体核心。这些实验的结果将揭示参与其中的基因/蛋白质 调节球孢子虫的寄生生长，并阐明了球孢子虫与球孢子虫相互作用的分子细节 寄主和病原体。

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.