Comparative Genomics of Histoplasma and Blastomyces

描述（由申请人提供）：温度诱导的从寄生性霉菌形式到寄生性酵母形式的转变对于通过二型真菌建立疾病是必不可少的，但是对调节这种转变和解释酵母毒力的基因知之甚少。荚膜组织胞浆菌和皮炎芽生菌在遗传学上是引起全世界疾病的二型真菌中最密切相关的，并且代表了日益严重的人类健康问题。分子遗传学工具的发展使这两种真菌在遗传上易于处理，并为酵母阶段上调基因在毒力中的作用提供了第一个确凿的证据--H. capsulatum和BAD 1在B.皮肤炎我们建议在这里确定和比较所有的酵母阶段上调基因从这两个代理商，然后探索这些基因的一个选定的子集的功能作用。我们推测，这两种真菌将表现出进化共享和不同的基因，调节形态发生和致病性。由三个领先实验室组成的联盟将联合收割机将他们的经验与大规模基因组学，分子遗传学和真菌发病机制相结合;由此产生的合作将使用基于微阵列的方法来识别和分析潜在的毒力相关基因。 我们的具体目标是：对B进行排序。与H.荚膜二.使用微阵列和信息学鉴定酵母阶段上调基因，并优先考虑与毒力相关的研究基因。三.在H. capsulatum和B.通过创建用于在动物和细胞培养感染模型中研究的同基因无效突变体，利用lacZ和gfp报告基因监测基因的调控和表达，并采用微阵列鉴定协同调控的其他基因，来筛选优先基因中的16至20个。 这项工作的结果将提供大量的新知识，系统性真菌疾病的生物学和发病机制，并可能在保守基因中发现许多潜在的新的药物靶点。

DESCRIPTION (provided by applicant): The temperature-induced transition from the saprophytic mold form to the parasitic yeast form is essential for the establishment of disease by dimorphic fungi, but the genes that regulate this switch and account for yeast virulence are poorly understood. Histoplasma capsulatum and Blastomyces dermatitidis are phylogenetically the most closely related among the dimorphic fungi that cause disease worldwide and represent a growing human health problem. Development of molecular genetic tools has rendered both these fungi genetically tractable and provided the first firm evidence for the role of yeast phase-upregulated genes in virulence - CBP1 in H. capsulatum and BAD1 in B. dermatitidis. We propose here to identify and compare all of the yeast phase-upregulated genes from these two agents, then explore the functional roles of a selected subset of these genes. We hypothesize that these two fungi will exhibit both evolutionarily shared and distinct genes that regulate morphogenesis and pathogenicity. A consortium of three leading labs will combine their experience with large-scale genomics, molecular genetics, and fungal pathogenesis; the resulting collaboration will use a microarray-based approach to identify and analyze potential virulence-associated genes. Our specific aims are to: I. Sequence the B. dermatitidis genome to approximately 3-fold coverage for comparson to H. capsulatum. II. Identify yeast phase-upregulated genes using microarrays and informatics, and prioritize genes for virulence-related studies. III. Functionally characterize in H. capsulatum and B. dermatitidis 16 to 20 of the prioritized genes by creating isogenic null mutants for investigation in animal and cell culture models of infection, exploiting lacZ and gfp reporters to monitor regulation and expression of the genes, and employing microarrays to identify other genes that are coordinately regulated. Findings from this work will provide substantial new knowledge about the biology and pathogenesis of systemic fungal diseases and may identify among conserved genes many potential new drug targets.