Influence of genetic variation on fungal MAPK signaling and virulence

描述(申请人提供)：自然遗传变异如何调节与人类疾病相关的细胞生物学特征？许多常见疾病，从自闭症到肥胖症，都受到多个序列变异的影响。全基因组关联(GWA)研究正在产生越来越多的人类疾病风险因素，但这些基因变异如何共同作用来赋予疾病风险仍不清楚。在许多情况下，已识别的基因变异只解释了疾病风险遗传性的一小部分。然而，个性化医学的前景取决于我们能否解释个人基因构成的影响。由于其遗传的柔韧性，芽生酵母是研究复杂性状基因组结构的理想模式系统。莱昂尼德·克鲁格拉克教授和他的实验室此前曾使用两个不同的酿酒酵母分离株来绘制介导各种表型的遗传变异图，包括基因表达的差异。然而，这两个菌株只代表了酿酒酵母全物种遗传和表型差异的一小部分。我正在开发一种方法，它将使我能够从任何两个不同的酿酒酵母分离株开始，生成单个分离物的大型图谱群体。这种方法将使我能够研究遗传变异如何调节核心的MAPK信号级联，即HOG高渗透压信号通路。猪MAPK级联是高度保守的，其人类同行在各种癌症中发挥关键作用，其等价物控制着几种致病真菌的毒力。然而，遗传变异如何影响HOG途径活性尚不清楚。我将确定改变HOG途径活性的序列变体，然后将表征信号是如何具体改变的。我将开发的测量HOG信号的方法稍后可以应用于其他MAPK信号通路的研究。致病真菌新生隐球菌的毒力由几个复杂的特征决定。有趣的是，这种真菌的完全毒力需要猪途径活性。我将确定调节新生葡萄球菌毒力属性的基因变异。特别是，我将描述基因对黑色素产生、包膜大小和器官特异性感染力的影响。这些分析可以扩展到这种病原体的其他医学相关性质，并将有助于其他病原真菌的研究。目的1：建立快速将数量性状基因座(QTL)定位推广到其他酿酒酵母菌株的方法学。目的2：研究基因变异对MAPK信号转导的影响。目的3：寻找调节新生弧菌毒力的QTL。 公共卫生相关性：遗传信息因个人而异。这种自然产生的基因变异在一定程度上决定了我们感染许多常见疾病的风险。为了加深我们对遗传变异对疾病相关细胞过程的影响的理解，我将阐明遗传变异是如何改变细胞信号和真菌毒力的。

DESCRIPTION (provided by applicant): How does naturally genetic variation modulate cell biological traits relevant to human disease? Many common diseases, ranging from autism to obesity, are influenced by multiple sequence variants. Genome-wide association (GWA) studies are yielding more and more human disease risk factors, but how these genetic variants act collectively to confer disease risk remains unclear. In many cases the identified genetic variants only explain a small fraction of the disease risk heritability. Yet, the promise of personalized medicine hinges on whether we can account for the effect of an individual's genetic makeup. Due to its genetic pliability the budding yeast S. cerevisiae is an ideal model system to investigate the genomic architecture of complex traits. Prof. Leonid Kruglyak and his lab have previously used two divergent S. cerevisiae isolates to map the genetic variation mediating various phenotypes, including differences in gene expression. However, these two strains only represent a minute fraction of the S. cerevisiae species-wide genetic and phenotypic variance. I am developing a method that will allow me to generate large mapping populations of individual segregants starting from any two divergent S. cerevisiae isolates. This approach will enable me to investigate how genetic variation modulates a core MAPK signaling cascade, the HOG high osmolarity signaling pathway. The HOG MAPK cascade is highly conserved, with its human counterpart playing a key role in various cancers and its equivalents controlling virulence in several pathogenic fungi. Yet, how genetic variation influences HOG pathway activity is unknown. I will identify sequence variants that alter HOG pathway activity and will then characterize how signaling is altered specifically. The approaches I will develop to measure HOG signaling could later be applied to the study of other MAPK signaling pathways. The virulence of the pathogenic fungus Cryptococcus neoformans is governed by several complex traits. Intriguingly, HOG pathway activity is required for full virulence of this fungus. I will idntify the genetic variations that modulate virulence attributes of C. neoformans. In particular, I will characterize the genetic contributions to melanin production, capsule size and organ-specific infectivity. These analyses could be extended to additional medically relevant properties of this pathogen and will aid the study of other pathogenic fungi. Aim 1: To develop methodology to rapidly extend quantitative trait loci (QTL) mapping to additional S. cerevisiae isolates. Aim 2: T characterize the effect of genetic variation on MAPK signaling. Aim 3: To identify QTL modulating virulence of C. neoformans. PUBLIC HEALTH RELEVANCE: Genetic information varies among individuals. This naturally occurring genetic variation in part determines our risk of contracting many common diseases. To increase our understanding of the effect of genetic variation on disease relevant cellular processes, I will elucidate how genetic variation alters cell signaling and fungal virulence.