COBRE: UID: PROJ 3: MOLECULAR DISSECTION OF ADAPTIVE EVOLUTION

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 微生物进化发生在相对于人类寿命而言迅速的时间尺度上，并可导致毒力、宿主和耐药性的变化。这个项目的长期目标是确定是否有一般原则，可以用来预测短期适应性进化的分子基础。该提案的重点是以二十面体噬菌体为模型系统，深入了解适应性进化的机制基础。具体目标是：1）使用生物化学和生物物理学原理确定蛋白质适应的结构基础; 2）确定调节取代对适应性进化的贡献。为了解决第一个目标，我们将确定增加或减少进化噬菌体的温度范围的氨基酸取代，并剖析这些适应背后的生物物理机制。我们将利用这些信息来建立一个预测模型的热适应和测试这个模型，通过预测的相对温度范围内的细菌从环境中，并通过构建预测的热突变体在相关的噬菌体。为了解决第二个目标，我们将使用基因表达和表型测定，以确定哪些实验观察到的变化，调节区发挥其适应性的影响，通过改变基因表达。我们还将确定变化的幅度和它们适应的背景，并确定促进基因调控变化的选择性条件。这些目标的成功实现将增强我们预测适应性进化可能途径的能力。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Microbial evolution occurs on a time scale that is rapid relative to the human lifespan and can lead to changes in virulence, host and drug resistance. The long term goal of this project is to determine whether there are general principles that can be used to predict the molecular basis of short term adaptive evolution. The focus of the proposal is to develop a deeper understanding of the mechanistic basis of adaptive evolution using icosahedral bacteriophage as a model system. The specific aims are 1) to determine the structural basis of protein adaptation using biochemical and biophysical principles; and 2) to determine the contribution of regulatory substitutions to adaptive evolution. To address the first aim, we will identify amino acid substitutions that increase or decrease temperature range in evolved phage and dissect the biophysical mechanisms underlying these adaptations. We will use this information to build a predictive model of thermal adaptation and test this model by predicting the relative temperature range of phages taken from the environment, and by constructing predicted thermal mutants in a related phage. To address the second aim, we will use gene expression and phenotypic assays to determine which experimentally observed changes in regulatory regions exert their adaptive effects by altering gene expression. We will also determine the magnitude of the changes and the context in which they are adaptive and identify selective conditions that promote changes in gene regulation. Successful achievement of these aims will enhance our ability to predict the probable pathways of adaptive evolution.