Genetic basis and pathogenicity of invasive growth in yeast

项目摘要 项目摘要：真菌是临床感染的主要来源，尤其是在患有 免疫系统受损。真菌用来定植人类宿主的机制还不完全清楚， 但被认为经常涉及侵入性增长。具体地说，许多真菌能够附着在和 穿透性的表面，如人体组织的表面酿酒酵母，已知的定植 免疫受损的人类，是一个了解环境触发因素和遗传基因的有价值的模型 真菌入侵生长的基础机制。尽管酿酒酵母参比菌株S288C没有 表现出侵入性生长，我们发现许多生态和遗传多样性的菌株可以生长 侵袭性的，特征的表达通常取决于特定的环境条件。在这份提案中， (目标1)我们使用基因图谱和基因工程相结合的方法来识别导致 酿酒酵母临床分离株侵袭性生长的变异性。我们进行基因图谱研究 在一个由2,880个分离物组成的小组中，这些分离物来自所有10个可能的菌株中的5个不同菌株的交配 组合。一旦确定了原因基因，我们将使用基因工程技术来解决 这些基因座与特定的基因和遗传变异有关。(目标2)然后我们测试已确定的潜在相关性 通过将野生分离株和工程菌株感染到动物模型中而产生的因果变异。我们将为您接种 菌株进入大量的蜡蛾幼虫，这些菌株通常用于研究微生物的毒力， 并测量这些菌株导致疾病或死亡的程度。完成拟议的研究将 提供有关侵入性生长的遗传和环境原因的详细信息，并将 阐明已识别的等位基因的潜在临床相关性。相关性：真菌致病案例有 到目前为止，在人类感染中发现了500多种真菌，这一数字正在上升。遗传方法 为鉴定真菌致病的分子机制提供了有力的工具。然而， 常见的机会性病原体，如白色念珠菌，由于遗传系统的限制而受到重大限制。 因为它们不能在实验室里进行有性繁殖。酿酒酵母的分离株在 它们表现出的致病特性的类型，以及这些特性表达的条件。至 确定真菌附着和穿透表面所涉及的遗传和环境因素， 这被认为与发病机制有关，我们将使用多个 从免疫功能低下的人身上采集的酿酒酵母分离株。拟议的研究将 提高对真菌发病机制的一般了解，并可能确定新的抗真菌药物的潜在靶点 毒品。

Project Summary Project summary: Fungi are a major source of clinical infections, especially among patients with compromised immune systems. The mechanisms fungi use to colonize human hosts are not fully understood, but are thought to often involve invasive growth. Specifically, many fungi are capable of attaching to and penetrating surfaces, such as those of human tissues. Saccharomyces cerevisiae, which is known to colonize immunocompromised humans, is a valuable model for understanding the environmental triggers and genetic mechanisms that underlie invasive growth in fungi. Although the S. cerevisiae reference strain S288C does not exhibit invasive growth, we have found that many ecologically and genetically diverse isolates can grow invasively, with expression of the trait often dependent on specific environmental conditions. In this proposal, (Aim 1) we use a combination of genetic mapping and genetic engineering to identify genes that cause variability in invasive growth among clinical isolates of S. cerevisiae. We conduct our genetic mapping studies in a panel of 2,880 segregants derived from the mating of 5 diverse strains in all 10 possible pairwise combinations. Once causal loci have been identified, we will use genetic engineering techniques to resolve these loci to specific genes and genetic variants. (Aim 2) We then test the potential relevance of the identified causal variants by infecting wild isolates and engineered strains into an animal model. We will inoculate the strains into a large number of wax moth larvae, which are commonly used to study the virulence of microbes, and measure the extent to which the strains cause sickness or death. Completion of the proposed research will provide detailed information about the genetic and environmental causes of invasive growth, and will also shed light on the potential clinical relevance of the identified alleles. Relevance: Cases of fungal pathogenesis are on the rise, with more than 500 species of fungi identified in human infections to date. Genetic approaches provide powerful tools for identifying the molecular mechanisms underlying pathogenesis in fungi. However, common opportunistic pathogens, such as Candida albicans, suffer from major limitations as genetic systems due to their inability to sexually reproduce in the lab. Isolates of S. cerevisiae exhibit substantial variability in the types of pathogenicity traits they exhibit, as well as the conditions in which these traits are expressed. To determine genetic and environmental factors that are involved in fungi attaching to and penetrating surfaces, which is thought to contribute to pathogenesis, we will perform genetic mapping experiments using multiple isolates of S. cerevisiae that were sampled from immunocompromised humans. The proposed research will improve general understanding of fungal pathogenesis and may identify potential targets for new antifungal drugs.