Induction of Fungal Dormancy as a Potential Disease Therapy

山谷热病是由一种节孢子（一种无性的土传孢子）引起的。 球孢子菌属被吸入宿主的肺部在抗性和易感宿主中， 一个循环产生含内生孢子的小球，但只有在易感宿主中才有内生孢子 被释放以重复循环。在耐药宿主中，解决疾病的一个重要方面是 真菌停止增殖，进入静止状态，宿主从感染中恢复过来。 感染尽管患者康复，但病原体仍无限期地存在于宿主中， 如果宿主的免疫系统受损，可能会重新激活。该项目将 探讨球孢子菌休眠的遗传基础。调控这一过程的基因 是开发治疗球孢子菌病的新疗法的新靶点。识别这些 基因，目标之一将开发在所有生长阶段的基因表达的体外概况 球孢子菌属（Coccidioides spp.）基因表达系列分析（SAGE）。 在菌丝生长和节孢子发育的污化阶段的基因表达 将与从早期活跃生长开始的疾病周期的几个阶段期间的表达进行比较， 产生模拟体内静止阶段的成熟小球。目标二将使用 SAGE在易感和耐药小鼠体内分析真菌基因表达， 与体外模式进行比较。耐药小鼠中差异表达的基因可能参与了 真菌进入或维持静止状态。目标三将测试功能 静止基因的重要性，通过在球孢子菌属中创建基因置换突变体。 突变体将在体外和体内、在抗性、 易感和免疫小鼠。突变体可能会表现出更敏感的毒性降低 如果静止期对真菌的生存很重要，则可能对宿主防御产生影响，或者如果静止期对真菌的生存很重要， 静止状态是宿主控制感染的重要组成部分。

Valley Fever disease is initiated when an arthroconidium, the asexual soil-borne spore of Coccidioides spp. is inhaled into the host lung. In both resistant and susceptible hosts the disease cycle produces endospore-containing spherules, but only in a susceptible host are endospores released to repeat the cycle. In a resistant host an important aspect of the resolution of illness is that the fungus ceases to proliferate, enters a state of quiescence, and the host recovers from the infection. In spite of patient recovery, the pathogen remains present in the host indefinitely with the potential for re-activation if the host's immune system becomes compromised. This project will explore the genetic basis of quiescence in Coccidioides spp. The genes that regulate this process are novel targets for development of new therapeutics to treat coccidioidomycosis. To identify these genes, objective one will develop an in vitro profile of gene expression during all stages of growth of Coccidioides spp. using the powerful method of serial analysis of gene expression (SAGE). Gene expression during the saprobic stages of mycelial growth, and arthroconidium development will be compared to expression during several stages of the disease cycle from early active growth, to production of mature spherules that mimic the quiescent in vivo stage. Objective two will use SAGE to profile fungal gene expression in vivo, in both susceptible and resistant mice for comparison to in vitro patterns. Genes differentially expressed in resistant mice may be involved in fungal entry into, or maintenance of, the quiescent state. Objective three will test the functional importance of quiescence genes, by creation of gene replacement mutants in Coccidioides. Mutants will be assayed for infectious phase growth, both in vitro and in vivo, in resistant, susceptible and vaccinated mice. Mutants may show reduced virulence by being more susceptible to host defenses if quiescence is important for fungal survival, or may show increased virulence if the quiescent state is an important component of host control of infection.