Genetics of fungal persistence and pathogenicity in mammalian hosts

项目摘要 机会性真菌感染可能危及生命，很难治疗。识别 使真菌在人类体内存活的遗传和分子机制可能有主要的 有益于社会的健康，甚至有可能使发展更有效 抗真菌疗法。模式生物酿酒酵母本身就是一个机会主义者 人类病原体，许多菌株是从临床感染中分离出来的。感染和感染的能力 在人类体内持续存在的情况在酿酒酵母菌株中并不普遍。临床酿酒葡萄球菌 分离物往往是高度杂合的二倍体，可以在更高的温度和 侵入表面。然而，对酿酒酵母坚持不懈和 哺乳动物宿主内的致病性是必要的。为了开始这样的工作，我们使用了染色体- 编码条形码和血统追踪到一组单倍体后代的表型 来自小鼠的发芽酵母杂交。所采用的特定杂交是在单倍体之间 临床分离株和参考菌株的衍生品。连锁作图确定了数十个基因座 影响哺乳动物宿主内真菌持久性的因素，其中许多缺乏先前发现的 候选基因，并显示宿主器官依赖的效应。在我们的工作中，主要问题 仍然没有答案，包括潜在的遗传、分子和生理机制 酵母持久性和酵母-宿主相互作用；因果基因座上的等位基因如何塑造表型 高度杂合的类似临床分离株的二倍体；表面附着和 持久性和致病性方面的侵袭；以及因果基因座的影响是否有助于 真菌的致病力取决于寄主的基因。在这里，我们将延伸我们的工作 通过(1)通过克隆原因研究酵母在特定器官中持续存在的机制 酵母中的基因，以及使用尖端显微镜和RNA-SEQ来分析酵母宿主 相互作用；(2)测试致病等位基因的组合如何在高度 杂合的二倍体酵母菌株；(3)分析酵母细胞的附着和侵袭能力 表面对杂交后代致病性的影响；(4)真菌遗传检测 在遗传上截然不同的小鼠宿主中的致病性。我们的提案将利用未开发的 萌芽酵母模型系统的潜力提供了对遗传学和 机会性真菌致病的分子机制。

Project Summary Opportunistic fungal infections can be life-threatening and difficult to treat. Identifying the genetic and molecular mechanisms that enable fungi to persist in humans could have major health benefits for society, potentially even enabling the development of more effective antifungal therapies. The model organism Saccharomyces cerevisiae is itself an opportunistic human pathogen, with many strains isolated from clinical infections. The ability to infect and persist within humans is not universal among S. cerevisiae strains. Clinical S. cerevisiae isolates tend to be highly heterozygous diploids that can grow at higher temperatures and invade into surfaces. However, rigorous genetic dissection of S. cerevisiae’s persistence and pathogenicity within mammalian hosts is needed. To begin such work, we used chromosomally- encoded barcodes and lineage tracking to phenotype a panel of genotyped haploid progeny from a budding yeast cross in mice. The specific cross employed was between a haploid derivative of a clinical isolate and the reference strain. Linkage mapping identified dozens of loci influencing fungal persistence within a mammalian host, many of which lack previously identified candidate genes and show host organ-dependent effects. Following our work, major questions remain unanswered, including the genetic, molecular, and physiological mechanisms underlying yeast persistence and yeast-host interactions; how alleles at causal loci shape the phenotypes of highly heterozygous diploids resembling clinical isolates; the role of surface attachment and invasion in persistence and pathogenicity; and whether the effects of causal loci contributing to fungal pathogenicity have effects that depend on host genotype. Here, we will extend our work by (1) studying mechanisms causing yeast persistence in particular organs by cloning causal genes in yeast, as well as by using cutting-edge microscopy and RNA-seq to analyze yeast-host interactions; (2) testing how combinations of pathogenicity alleles combine in highly heterozygous diploid yeast strains; (3) analyzing how the ability to attach to and invade into surfaces influences the pathogenicity of cross progeny; and (4) examining the genetics of fungal pathogenicity across genetically distinct mouse hosts. Our proposal will utilize the untapped potential of the budding yeast model system to provide concrete insights into the genetics and molecular mechanisms underlying opportunistic fungal pathogenicity.