Discovery of conserved molecular mechanisms underlying population-wide variation in toxin responses

项目总结： 暴露在环境化学品中是一项重大的健康风险。不幸的是，毒素的有害影响 由于未知的遗传差异，种群中不同的个体暴露在不同的环境中。拥有更好的 了解我们的基因是如何影响毒素反应的，我们可以更准确地预测有害的 对健康的影响。很难确定这些因素，因为人类基因组范围的关联研究经常 缺乏必要的统计能力和受控的毒素暴露。出于这个原因，我们将使用定义的 线虫秀丽线虫种群范围的变异使毒素的精确测量成为可能 单细胞生物体的规模和统计能力的响应，但具有保守的分子，细胞， 以及后生动物的发育特性。在目标1中，我们将确定潜在的变异的遗传位点。 对30种不同毒素的反应，包括金属/类金属、线粒体毒素、杀虫剂和火焰 阻燃剂。我们将使用低成本、高通量、 以及高精度的生长和生育分析。然后，我们将在 响应这30种毒素，并使用这些数据将毒素响应差异映射到使用两种 测绘小组：(1)CENDR--线虫自然多样性资源，由500个菌株组成，代表 几乎所有已知的该物种的遗传变异，以及(2)CeME-线虫多亲实验 进化面板，一组1000个重组自交系，能够定位到单基因的分辨率。 在目标2中，我们将识别影响毒素反应变异的特定遗传变异和途径。我们会 使用最新技术确定毒素反应差异和遗传变异之间的因果关系 育种和基因组编辑技术。然后，我们将使用基因表达分析和假设- 指导实验以确定毒素反应变异的分子基础。在目标3中，我们将阐明 另外两种线虫毒素反应图谱显示毒素反应变异的保守机制 像老鼠和人类一样在基因上彼此不同的物种。一种创新的比较 数量性状基因座分析将确保识别出现的毒素反应变异的来源 在多个进化谱系中汇聚(因此也是可预见的)。我们将通过以下方式扩展此方法 进一步将我们的图谱结果与果蝇、啮齿动物和人类的图谱结果进行比较，发现了保守的 负责毒素反应变化的途径。我们的秀丽线虫遗传资源有 与人类相似的变异、等位基因频率和表型效应，为发现 导致人类毒素反应差异的基因和变种的特征。事实上，几十年来 对线虫的研究已经确定了无数广泛保守的分子机制的例子。 潜在的信号、基因调控和新陈代谢，表明毒素反应机制 在这里发现的将延伸到人类，尽管在生活史和解剖学上有明显的差异。

Project summary: Exposure to environmental chemicals is a major health risk. Unfortunately, the detrimental impacts of toxin exposure vary among individuals in a population because of unknown genetic differences. With a better understanding of how our genetics influence toxin response, we can more accurately predict detrimental health effects. It is difficult to identify these factors because human genome-wide association studies often lack the necessary statistical power and controlled toxin exposures. For this reason, we will use defined population-wide variation in the roundworm Caenorhabditis elegans to enable precise measurements of toxin responses at the scale and statistical power of single-cell organisms but with conserved molecular, cellular, and developmental properties of a metazoan. In Aim 1, we will identify genetic loci underlying variation in response to 30 diverse toxins, including metals/metalloids, mitochondrial toxins, pesticides, and flame retardants. We will define effective toxin doses across diverse individuals using low-cost, high-throughput, and high-accuracy assays of growth and fertility. Then, we will define the population-wide variation in response to these 30 toxins and use these data to map toxin-response differences to genes using two mapping panels: (1) CeNDR - the C. elegans Natural Diversity Resource, a set of 500 strains representing nearly all known genetic variation for the species, and (2) CeMEE - the C. elegans Multiparental Experimental Evolution panel, a set of 1000 recombinant inbred lines that enable mapping to the resolution of single genes. In Aim 2, we will identify specific genetic variants and pathways affecting toxin-response variation. We will define causal relationships between toxin response differences and genetic variants using state-of-the-art breeding and genome-editing techniques. Then, we will use gene expression analyses and hypothesis- directed experiments to determine the molecular basis of toxin-response variation. In Aim 3, we will elucidate conserved mechanisms of toxin-response variation by mapping toxin responses in two other Caenorhabditis species that are as genetically different from each other as mice and humans. An innovative comparative quantitative trait locus analysis will ensure identification of sources of toxin-response variation that arise convergently (and therefore predictably) in multiple evolutionary lineages. We will extend this approach by further comparing our mapping results to those from Drosophila, rodents, and humans, identifying conserved pathways responsible for toxin-response variation. Our Caenorhabditis genetic resources have levels of variation, allele frequencies, and phenotypic effects similar to humans, providing a framework to discover the characteristics of genes and variants that underlie differences in human toxin responses. Indeed, decades of research in C. elegans have identified countless examples of widely conserved molecular mechanisms underlying signaling, gene regulation, and metabolism, suggesting that the toxin-response mechanisms discovered here will extend to humans despite overt differences in life history and anatomy.