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

项目概要： 暴露于环境化学品是一个主要的健康风险。不幸的是毒素的有害影响 由于未知的遗传差异，人口中的个体之间的暴露量各不相同。以更好的 了解我们的遗传如何影响毒素反应，我们可以更准确地预测有害的 健康影响。很难确定这些因素，因为人类全基因组关联研究通常 缺乏必要的统计能力和受控的毒素暴露。因此，我们将使用定义 线虫的种群范围内的变异，以实现毒素的精确测量 反应的规模和统计能力的单细胞生物体，但保守的分子，细胞， 以及后生动物的发育特性在目标1中，我们将确定遗传位点的变异， 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 延缓剂我们将使用低成本，高通量， 以及高精度的生长和生育力测定。然后，我们将定义人口范围内的变化， 对这30种毒素的反应，并使用这些数据来映射毒素反应差异的基因，使用两个 映射面板：（1）CeNDR -C. elegans自然多样性资源，一套500株代表 几乎所有已知的遗传变异的物种，和（2）Cephalus-C。多亲实验线虫 进化面板，一组1000个重组近交系，能够映射到单个基因的分辨率。 在目标2中，我们将确定影响毒素反应变异的特定遗传变异和途径。我们将 使用最先进的技术来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 通过绘制另外两种小杆线虫的毒素反应图，探讨毒素反应变异的保守机制 就像老鼠和人类一样基因上彼此不同的物种。创新的比较 数量性状基因座分析将确保识别毒素反应变异的来源， 在多个进化谱系中收敛（因此是可预测的）。我们将通过以下方式扩展这种方法： 进一步比较我们的定位结果与果蝇，啮齿动物和人类的定位结果， 负责毒素反应变异的途径。我们的小杆线虫遗传资源 变异，等位基因频率和与人类相似的表型效应，提供了一个框架，以发现 基因和变异体的特征是人类毒素反应差异的基础。几十年来， 研究C.线虫已经发现了无数的广泛保守的分子机制 潜在的信号，基因调控和代谢，这表明毒素反应机制 尽管在生活史和解剖学上存在明显的差异，但在这里发现的基因将延伸到人类。

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.