The Genetic Basis of Virulence in Cryptococcus Neoformans

新型隐球菌毒力的遗传基础

• 批准号: 9389607
• 负责人: JOSEPH HEITMAN
• 金额: $ 38.62万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-05 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9389607
• 关键词: Address; Affect; Alleles; Animals; Antifungal Agents; Architecture; Benign; Cells; Cessation of life; Clinical; Coculture Techniques; Communities; Complement; Complex; Cryptococcus; Cryptococcus gattii; Cryptococcus neoformans; Cryptococcus neoformans infection; DNA; Disease; Environment; Frequencies; Fungal Drug Resistance; Genes; Genetic; Genetic Crosses; Genetic Determinism; Genetic Population Study; Genetic Recombination; Genome; Genomics; Genotype; Geographic Distribution; Geographic Locations; High temperature of physical object; Individual; Infection; Knowledge; Lead; Metabolic; Molecular; Morphology; Online Systems; Outcome; Pathogenesis; Pathogenicity; Pathway interactions; Phenotype; Physiological; Polysaccharides; Population; Population Heterogeneity; Prevention; Prevention strategy; Property; Public Health; Quantitative Trait Loci; Research; Research Personnel; Resources; Sampling; Source; Statistical Models; Surveys; Techniques; Variant; Virulence; Virulent; Yeasts; analytical tool; capsule; design; gene replacement; genetic linkage analysis; genome sequencing; genome wide association study; macrophage; offspring; pathogen; prevent; public health relevance; success; trait; whole genome

Project Summary The fungal pathogen Cryptococcus neoformans is estimated to cause disease in more than 1,000,000 people worldwide every year, resulting in greater than 600,000 deaths. However, not all Cryptococcus isolates cause lethal infections; some are relatively benign while others are hypervir- ulent. Differences in pathogenicity are often correlated with variation in specific morphological and physiological features such as the ability to grow at high temperatures, the size of the pro- tective polysaccharide capsule surrounding the yeast cell, or resistance to antifungal drugs. In order to develop better ways to prevent and treat cryptococcal disease we need to understand the underlying genetic differences that lead to changes in virulence and virulence-related traits. We also need to understand the frequency and distribution of these genetic differences in different parts of the world. To tackle these problems, the proposed research will use a combination of experimental and statistical approaches to dissect the causal genetic basis of variation in virulence and virulence- related traits. In Aim 1 we will employ a statistical technique called Quantitative Trait Locus (QTL) mapping, that exploits genotypic and phenotypic differences among offspring derived from genetic crosses to identify regions of the genome (loci) and DNA changes (alleles) that con- tribute to differences in virulence traits. We will validate the contributions of the loci identified in this manner using gene replacements and related techniques. In Aim 2 we will subject ge- netically diverse populations of Cryptococcus to selection in animal hosts. Following selection, pooled whole genome sequencing will be used to identify loci and alleles that are favored during infection. This technique provides an unbiased approach for discovering loci that contribute to virulence, and will both complement and extend the results of Aim 1. In Aim 3 we will frame our findings in the context of natural populations of Cryptococcus by studying the frequency and geo- graphic distributions of virulence alleles identified in Aims 1 and 2. This aim will employ a large, global sample of Cryptococcus strains isolated from both clinical settings and the natural environ- ment. This information will be used to carry out Genome-Wide Association (GWAS) mapping of virulence traits and to identify regions of the world where there are higher frequencies of virulent genotypes or where there is potential for increased virulence through recombination.

项目概要 据估计，真菌病原体新型隐球菌会导致超过 全世界每年有 1,000,000 人死亡，导致超过 600,000 人死亡。 隐球菌分离株会引起致命的感染；有些是相对良性的，而另一些则是高病毒性的。 致病性的差异通常与特定形态的变化相关。 和生理特征，例如在高温下生长的能力，亲的大小 酵母细胞周围有保护性多糖胶囊，或对抗真菌药物产生抵抗力。 为了开发更好的方法来预防和治疗隐球菌病，我们需要了解 导致毒力和毒力相关性状变化的潜在遗传差异。 还需要了解这些遗传差异在不同人群中的频率和分布 世界部分地区。 为了解决这些问题，拟议的研究将结合实验和 剖析毒力和毒力变异的因果遗传基础的统计方法 在目标 1 中，我们将采用一种称为“数量性状基因座”的统计技术。 (QTL) 作图，利用后代之间的基因型和表型差异 通过遗传杂交来识别基因组区域（位点）和 DNA 变化（等位基因） 我们将验证所确定的基因座的贡献。 以这种方式，使用基因替换和相关技术，在目标 2 中，我们将研究基因。 选择后，在动物宿主中选择明显不同的隐球菌种群， 汇集的全基因组测序将用于识别在 该技术提供了一种公正的方法来发现有助于感染的基因座。 毒力，并且将补充和扩展目标 1 的结果。在目标 3 中，我们将制定我们的目标 通过研究隐球菌自然种群的频率和地理发现 目标 1 和 2 中确定的毒力等位基因的图形分布。该目标将采用大量的、 从临床环境和自然环境中分离出的隐球菌菌株的全球样本 该信息将用于进行全基因组关联（GWAS）映射。 毒力特征并确定世界上毒力频率较高的地区 基因型或通过重组可能增加毒力的地方。