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: 8776919
• 负责人: Ian Michael Ehrenreich
• 金额: $ 19.93万
• 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/8776919
• 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; Genetic study; Genomics; Genotype; Glucose; Growth; Health; 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 approach; genetic variant; genome sequencing; human tissue; improved; mouse model; pathogen; research study; tool; trait

DESCRIPTION (provided by applicant): 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 th lab. Isolates of S. cerevisiae exhibit substantial variability in the types of pathogenicity traitsthey 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.

描述（申请人提供）：真菌是临床感染的主要来源，尤其是在免疫系统受损的患者中。真菌用于定殖人类宿主的机制尚未完全了解，但被认为通常涉及侵入性生长。具体而言，许多真菌能够附着并穿透表面，例如人体组织的表面。酿酒酵母，这是众所周知的殖民免疫功能低下的人，是一个有价值的模型，了解环境的触发因素和遗传机制，在真菌侵入性生长的基础。虽然S.虽然酿酒酵母参考菌株S288 C不表现出侵入性生长，但我们发现许多生态和遗传多样性分离株可以侵入性生长，其性状的表达通常取决于特定的环境条件。在这个建议中，（目的1）我们使用基因作图和基因工程相结合，以确定基因，导致变异的侵袭性生长之间的临床分离株的S。啤酒。我们在一组2,880个分离子中进行遗传作图研究，这些分离子来自所有10种可能的成对组合中5种不同菌株的交配。一旦确定了致病基因座，我们将使用基因工程技术将这些基因座解析为特定的基因和遗传变异。(Aim 2）然后，我们通过将野生分离株和工程菌株感染到动物模型中来测试所鉴定的致病变体的潜在相关性。我们将把这些菌株接种到大量的蜡螟幼虫中，这些幼虫通常用于研究微生物的毒力，并测量菌株引起疾病或死亡的程度。拟议研究的完成将提供有关侵入性生长的遗传和环境原因的详细信息，并将揭示已鉴定等位基因的潜在临床相关性。相关性：真菌致病的病例正在增加，迄今为止在人类感染中发现了500多种真菌。遗传学方法为确定真菌致病的分子机制提供了强有力的工具。然而，常见的机会致病菌，如白色念珠菌，由于它们不能在实验室中进行有性繁殖，因此作为遗传系统受到很大的限制。S.酿酒酵母在它们所表现的致病性性状的类型以及这些性状表达的条件方面表现出很大的变异性。为了确定真菌附着和穿透表面所涉及的遗传和环境因素，这被认为是致病的原因，我们将使用多个S.从免疫受损的人中取样的酿酒酵母。这项研究将提高对真菌发病机制的普遍理解，并可能为新的抗真菌药物确定潜在的靶点。