Mechanisms of shadow enhancer robustness during development

项目摘要 动物的发育对各种干扰都有很强的抵抗力。动物能够 尽管种群中存在大量的遗传变异，但仍成功发育成健康的成年人 以及胚胎在发育过程中暴露在环境和内在波动中。 然而，发展不是无限强健的，甚至是微小的变化，例如发展中的SNP 增强剂，会导致发育缺陷。我的长期研究目标是阐明 对编码发育程序的调控DNA的一些改变是可以容忍的， 而另一些则具有戏剧性的表型效应。 该提案描述了确定阴影增强器提供的机制的工作 发育系统具有抵御扰动的能力。阴影增强器是一组 看似多余的增强子，控制单个基因并驱动相同的时空 表达模式。由多组阴影增强剂控制的发育基因可以更好地抵御 而不是由单个增强子控制的基因。阴影增强器是一种普遍存在的功能 已经在昆虫、哺乳动物和植物中发现。一项约1000人的调查 果蝇的发育基因发现，近三分之二的被检查基因座包含一组 阴影增强剂。尽管它们很重要，但还没有经过验证的机制来解释阴影如何 增强剂缓冲扰动以驱动强大的基因表达模式。剖析这些机制 的稳健性将使我们能够预测发育系统可能发生的扰动类型 成功缓冲以及哪些类型是无法容忍的，以及合理解释为什么开发中的某些步骤 可能比其他人更脆弱。 为了确定阴影增强器健壮性的机制，本提案描述了一种 阴影的定量实验测量与数学建模相结合 在正常情况下和扰动下的增强子功能。这项工作的结果将有别于 在解释阴影增强剂如何驱动基因表达强健模式的两个假说之间 面对来自离散分子过程和外部环境的不可避免的噪音 对系统的扰动。这些项目的成功还将使您深入了解特定功能 可以调整阴影增强器的大小以缓冲在 发展过程。鉴于阴影增强剂在控制发育中的盛行 神经脊规范和胸腺细胞发育等过程，了解其机制 可能会让我们深入了解为什么某些发育系统比其他系统更脆弱 可能指导人们努力寻找非编码DNA中发育缺陷的致病突变。

Project Summary Animal development is remarkably robust to many kinds of perturbations. Animals are able to successfully develop into healthy adults despite the large amount of genetic variation in the population and the environmental and intrinsic fluctuations to which the embryo is exposed during development. However, development is not infinitely robust, and even small changes, e.g. a SNP in a developmental enhancer, can lead to developmental defects. My long-term research goal is to elucidate how some changes to the regulatory DNA that encodes the developmental program are tolerated, while others have dramatic phenotypic effects. This proposal describes work to identify the mechanisms by which shadow enhancers provide developmental systems the capability to withstand perturbations. Shadow enhancers are sets of seemingly redundant enhancers that control a single gene and drive the same spatio-temporal expression pattern. Developmental genes controlled by sets of shadow enhancers can better withstand perturbations than genes controlled by a single enhancer. Shadow enhancers are a pervasive feature of development and have been found in insects, mammals, and plants. A survey of ~1000 developmental genes in Drosophila found that nearly two-thirds of examined loci contained a set of shadow enhancers. Despite their importance, there is no proven mechanism for how shadow enhancers buffer perturbations to drive robust gene expression patterns. Dissecting these mechanisms of robustness will allow us to predict what types of perturbations developmental systems can successfully buffer and what types are intolerable, and to rationalize why certain steps in development may be more fragile than others. To identify the mechanisms of shadow enhancer robustness, this proposal describes a combination of quantitative experimental measurements and mathematical modeling of shadow enhancer function under normal conditions and perturbation. The results of this work will distinguish between two hypotheses that explain how shadow enhancers drive robust patterns of gene expression in the face of both the inevitable noise that arises from discrete molecular processes and external perturbations to the system. Success in these projects will also yield insight into how specific features of shadow enhancers may be tuned to buffer specific types and amplitudes of perturbations during the developmental process. Given the prevalence of shadow enhancers in controlling developmental processes like neural crest specification and thymocyte development, understanding their mechanisms of action may give insights in to why some developmental systems are more fragile than others and may guide efforts to find causative mutations for developmental defects in non-coding DNA.