Dynamic Characterization of a Model Signal Transduction System

智力价值这项研究的目标是加深我们对细胞如何对环境信号和压力作出反应的理解，特别是对这种反应中的表型变化进行定量研究和建模。为了实现这一目标，本项目将严格研究模式生物大肠杆菌(E.coli)对营养限制(特别是无机磷)形式的环境胁迫的反应动力学。在这些条件下，Phor/Phob双组分系统信号通路被激活，最终反应是激活Phor/Phob双组分系统蛋白质的基因转录，试图由细胞清除日益减少的营养供应。对环境磷酸盐变化的反应将通过直接成像放置在大肠杆菌基因组中的荧光蛋白生物标记物的产生率来监测，该生物标记物受Phor/Phob两组分系统的控制。将使用具有单一荧光蛋白灵敏度的表观荧光视频显微镜来量化蛋白质生产率及其在一组细胞中的变化。除了测量响应，该项目还将开发数学上易于处理的两组分系统的简化模型，并使用随机模拟和有限状态投影方法来预测这些模型中响应的均值和方差。模型的预测可以通过实验进行检验，并指导新的实验方向，而实验结果可能需要对简化的模型进行修改。通过这一点，该项目将获得对细胞对环境信号/压力反应的表型变化机制的新的定量见解。更广泛的影响这个项目为本科生、研究生和博士后实习生提供机会，他们接受过经典的生命科学或物理科学教育，在物理学和生物学的交界处进行多学科研究。主要研究人员通过他们所在的机构以及通过参与REU和MARC项目，参与研究方面的本科教育。该项目的一个主要目标是培养各级多学科科学家。将鼓励学生和博士后实习生参加重要的国内和国际会议并介绍他们的研究成果，使他们接触到生命科学和物理科学领域正在进行的广泛研究，这些研究成果将转化为他们工作中的新想法和新方法。将定期向当地高中班级进行一般性讲座，以激发未来科学家对多学科研究的兴趣。此外，两位首席研究人员都致力于改善生命科学和自然科学领域的多样性和性别平等。

Intellectual meritThe goal of this research is to further our understanding of how cells respond to environmental signals and stresses and specifically to quantitatively investigate and model phenotypic variations in this response. Towards this goal, this project will critically examine the dynamics of the response of the model organism Escherichia coli (E. coli) to environmental stress in the form of nutrient limitation (specifically, inorganic phosphate). Under these conditions, the PhoR/PhoB two-component system signaling pathway is activated with the ultimate response being the activation of gene transcription of the proteins of the PhoR/PhoB two-component system in an attempt by the cell to scavenge the dwindling supply of nutrient. The response to changes in environmental phosphate will be monitored through direct imaging of the production rate of a fluorescent protein biomarker placed in the E. coli genome under control of the PhoR/PhoB two-component system. Quantification of the protein production rate and its variance among a population of cells will be performed using epi-fluorescence video microscopy with single fluorescent protein sensitivity. Beyond measurement of the response, this project will also develop simplified models of the two-component system which are mathematically tractable and use Stochastic Simulation and Finite State Projection methods to predict both the mean and variance of the response in these models. Predictions from models can be tested experimentally and guide new experimental directions while experimental results may necessitate modifications of the simplified models. Through this, the project will obtain new quantitative insight into the mechanism of phenotypic variation in the cellular response to environmental signals/stresses. Broader ImpactsThis project affords opportunities for undergraduate and graduate students and postdoctoral trainees, classically educated in the life or physical sciences, to conduct multidisciplinary research at the interface of physics and biology. The principal investigators are involved in undergraduate education in research both through their institutions and through participation in REU and MARC programs. A primary goal of this project is to train multidisciplinary scientists at all levels. The students and post-doctoral trainees will be encouraged to attend and present their research at major national and international meetings to expose them to the breadth of research being performed in the life and physical sciences which will translate into novel ideas and approaches in their own work. General lectures will be periodically given to local high school classes to pique the interest of tomorrow's scientists in multidisciplinary research. Further, both principal investigators are committed to improving diversity and gender equality in the life and physical sciences.