Steroid-mediated Chromatin Remodeling in Developmental Plasticity

发育可塑性是生物体响应外部线索而改变其发育的能力。这一点很重要，因为它使植物和动物能够适应不断变化的环境条件。发育可塑性是一种重要而普遍的现象，然而，对于外部信息如何转化为生物体发育变化的机制基础，人们的理解有限。在某些情况下，动物如何通过产生激素对环境信号做出反应，以及这些激素信号如何转化为发育变化，这一点已经很好地理解。然而，人们不太了解的是，这些环境诱导的激素信号如何转化为特定组织的发育变化。通过这项工作，研究人员将使用七叶树蝴蝶作为模型来研究环境线索如何通过DNA结构的大规模改变来协调基因表达的组织特异性变化。七叶树蝴蝶作为一个强大的模型系统，研究可塑性，因为不同的人口显示在他们的反应变化的季节性线索，从而允许隔离的遗传因素，控制和调整可塑性的自然种群。这项工作的发现将有助于对环境线索如何通过DNA结构的大规模修饰诱导发育变化产生新的理解。这些知识构成了预测生物体对变化环境的反应的基础。对本科生和研究生进行遗传和发育科学的现代生物学调查方面的培训是该项目的组成部分。这包括招聘科学界代表性不足的群体的成员。从发育上讲，表型可塑性可以被描述为一个由三部分组成的过程。首先，一个线索，如营养，温度，光周期，拥挤，或捕食者的存在，被生物体感知，然后转化为内部信号，这往往是内分泌的性质。第二，整个生物体的细胞以通常表现为组织特异性的方式接收信号。第三，细胞内的分子机制处理并响应信号，导致基因调控的变化，从而改变发育。虽然表型可塑性的生理基础已经在许多系统中得到了很好的描述，但只是在最近几年，研究才开始关注发育如何响应可塑性诱导生理信号的分子和遗传机制。这个问题特别引人注目，因为不同的组织对信号的反应不同，不同组织的反应模式和程度可以在世代之间迅速变化。然而，目前还不清楚组织特异性塑料表型如何通过环境诱导的内分泌信号快速调节。通过这项工作，里德和同事们将研究内分泌信号和染色质组织如何相互作用，以诱导七叶树蝴蝶Junonia coenia的季节性发育可塑性。良好表征的内分泌信号，季节性反应规范的自然遗传变异，以及应用包括ATAC-seq和CRISPR基因组编辑在内的实验方法的能力，使该物种成为解决内分泌信号如何介导全基因组染色质重塑的理想模型，以及染色质重塑如何诱导组织-该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响进行评估，被认为值得支持审查标准。

Developmental plasticity is the ability of an organism to alter its development in response to external cues. This is significant because it allows plants and animals to adapt to changing environmental conditions. Developmental plasticity is an important and widespread phenomenon, however there is only limited understanding of the mechanistic basis of how external information is translated into changes in organismal development. In some cases, it is well understood how animals respond to environmental cues through production of hormones, and how these hormone signals are translated into developmental changes. What is less known, however, is how these environmentally induced hormone signals are translated into developmental changes in specific tissues. With this work, the investigators will use buckeye butterflies as a model to examine how environmental cues can coordinate tissue-specific changes in gene expression through the large-scale alteration of DNA structure. The buckeye butterfly serves as a powerful model system for studying plasticity because different populations show variation in their responses to seasonal cues, thus allowing isolation of genetic elements that control and tune plasticity in natural populations. Findings from this work will help in developing a new understanding of how environmental cues can induce developmental changes through large-scale modification of DNA structure. Such knowledge forms the basis for predicting organismal response to changing environments. Training of undergraduate and graduate students in modern biological investigations of genetic and developmental science is integral to the project. This includes the recruitment of members of under-represented groups in science. Developmentally, phenotypic plasticity can be characterized as a three-part process. First, a cue such as nutrition, temperature, photoperiod, crowding, or predator presence, is sensed by the organism and then translated into an internal signal, which is often endocrine in nature. Second, cells throughout the organism receive the signal in a manner that often appears to be tissue-specific. Third, molecular machinery within cells processes and responds to the signal, resulting in changes in gene regulation, thus altering development. While the physiological basis of phenotypic plasticity has been well described in many systems, it is only in recent years that studies have started to look at the molecular and genetic mechanisms of how development responds to plasticity-inducing physiological signals. This question is particularly compelling because different tissues respond differently to signals, and the mode and degree of response of different tissues can change quickly between generations. However, it is still unclear how tissue-specific plastic phenotypes can be rapidly modulated by environmentally induced endocrine signals. With this work Reed and colleagues will study how endocrine signaling and chromatin organization interact to induce seasonal developmental plasticity in the buckeye butterfly Junonia coenia. A well-characterized endocrine signal, natural genetic variation in seasonal reaction norms, and the ability to apply experimental approaches including ATAC-seq and CRISPR genome editing makes this species an ideal model to address how endocrine signaling mediates genome-wide chromatin remodeling, and how chromatin remodeling induces tissue-specific plastic phenotypes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.