Genetic basis and pathogenicity of invasive growth in yeast

酵母菌侵袭性生长的遗传基础和致病性

• 批准号: 8618629
• 负责人: Ian Michael Ehrenreich
• 金额: $ 23.97万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8618629
• 关键词: Alleles; Animal Model; Animals; Antifungal Agents; Backcrossings; Biological Models; Candida; Candida albicans; Carbon; Cause of Death; Cessation of life; Chromosome Mapping; Clinical; Detection; Diploidy; Engineering; Ensure; Environment; Environmental Risk Factor; Ethanol; Exhibits; Gene Targeting; Genes; Genetic; Genetic Engineering; Genetic Polymorphism; Genetic Variation; Genomics; Genotype; Glucose; Growth; Human; Immune system; Immunocompromised Host; Infection; Larva; Light; Measures; Microbe; Microscopy; Modeling; Molecular; Moths; Mus; Mycoses; Organism; Paper; Parents; Partner in relationship; Pathogenesis; Pathogenicity; Patients; Phenotype; Physiological; Ploidies; Relative (related person); Reproduction; Research; Resources; Saccharomyces cerevisiae; Saccharomycetales; Sampling; Source; Surface; System; Techniques; Temperature; Testing; Time; Variant; Virulence; Waxes; Work; Yeasts; base; clinically relevant; fungus; genetic variant; genome sequencing; human tissue; improved; mouse model; pathogen; public health relevance; research study; tool; trait

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.

项目摘要 项目概述：真菌是临床感染的主要来源，特别是在患有 免疫系统受损真菌在人类宿主中定居的机制还不完全清楚， 但被认为通常涉及侵入性生长。具体地说，许多真菌能够附着在 穿透表面，如人体组织的表面。酿酒酵母，这是已知的殖民 免疫功能低下的人类，是了解环境触发因素和遗传因素的有价值的模型。 真菌侵入性生长的机制。虽然S.酿酒酵母参考菌株S288C不 表现出侵入性生长，我们发现许多生态和遗传多样性的分离物可以生长 侵袭性，性状的表达通常取决于特定的环境条件。在这一提议中， (Aim 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 临床分离的S.啤酒。我们进行基因图谱研究 在所有10个可能的配对中，来自5个不同菌株交配的2，880个分离体的面板中， 组合。一旦确定了致病基因座，我们将使用基因工程技术来解决 这些基因座与特定基因和遗传变异有关。(Aim 2）然后我们测试识别的潜在相关性 通过将野生分离株和工程菌株感染到动物模型中，我们将继续努力， 菌株进入大量的蜡螟幼虫，这是通常用于研究微生物的毒力， 并测量菌株导致疾病或死亡的程度。完成拟议的研究将 提供有关入侵性生长的遗传和环境原因的详细信息， 阐明所鉴定的等位基因的潜在临床相关性。相关性：真菌致病的病例是 到目前为止，在人类感染中发现的真菌超过500种。遗传方法 为确定真菌致病的分子机制提供了有力的工具。然而，在这方面， 常见的机会致病菌，如白色念珠菌，受到遗传系统的主要限制， 因为它们无法在实验室里进行有性繁殖S.酿酒酵母表现出显著的变异性， 它们表现出的致病性特征的类型，以及这些特征表达的条件。到 确定真菌附着和穿透表面所涉及的遗传和环境因素， 这被认为是有助于发病机制，我们将进行遗传作图实验，使用多种 S.从免疫受损的人中取样的酿酒酵母。拟议的研究将 提高了对真菌发病机理一般认识，并可能确定新抗真菌药物的潜在靶点 毒品