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

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 微生物的进化发生在相对于人类寿命的快速时间尺度上，并可能导致毒力、宿主和耐药性的变化。该项目的长期目标是确定是否存在可用于预测短期适应性进化的分子基础的一般原则。该提案的重点是更深入地理解以二十面体噬菌体为模型系统的适应性进化的机制基础。具体目标是：1)利用生化和生物物理原理确定蛋白质适应的结构基础；2)确定调节替代对适应进化的贡献。为了达到第一个目标，我们将确定在进化噬菌体中增加或降低温度范围的氨基酸替换，并剖析这些适应的生物物理机制。我们将使用这些信息来建立热适应的预测模型，并通过预测从环境中获取的噬菌体的相对温度范围，以及通过在相关噬菌体中构建预测的热突变体来测试该模型。为了达到第二个目标，我们将使用基因表达和表型分析来确定在实验中观察到的调控区域的哪些变化通过改变基因表达来发挥其适应效果。我们还将确定这些变化的大小和适应它们的背景，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路径的能力。

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.