CAREER: Evolution and Engineering of Cellular Bet-hedging Devices

该奖项由分子和细胞生物科学部的系统和合成生物学计划资助，解决了进化生物学中的一个经典问题：了解生物体如何适应不断变化的环境。许多生物体依靠赌注对冲策略来应对不可预测和波动的环境。这种广泛的生物学特性是从细菌的抗生素耐受性到哺乳动物免疫多样性等多种现象的基础。例如，微生物种群可以通过允许单个细胞在多种表型之间随机转换来增强其适应性。由此产生的种群多样性确保了一些细胞能够很好地适应不可预见的环境变化。揭示这些适应性转换机制是理解不断变化的环境中微生物进化和生命的关键。最近，有人提出朊病毒--最初被发现是哺乳动物神经退行性疾病的原因--是真菌中的赌注对冲元素，在波动的环境中维持以促进生存。朊病毒蛋白可以在多种构象状态之间转换。转化为朊病毒状态已被证明会产生新的、可遗传的表型，这在许多情况下是有益的。这个项目的首要目标是测试朊病毒赌注对冲假说。根据理论，下注对冲元素的表型转换率会随着环境波动率的变化而变化。该项目的一个中心焦点将是通过研究朊病毒在规定的波动环境选择中的转换来测试这些预测。第二个重点将是使用合成生物学方法重新设计朊病毒下注对冲装置，从而探索适应性特性如何编码在这些元件中。这些研究将需要开发新的遗传工具以及创新技术，如微流体平台，以模拟复杂环境并以超出传统生物实验能力的方式研究细胞。这项工作将对我们对进化、发育和细胞系统的基本理解产生广泛的影响。该项目还将揭示朊病毒的不同作用，朊病毒是微生物世界中常见的独特元素。最后，拟议的工作将对合成生物学产生变革性的影响，使合理设计各种细胞功能的新方案成为可能。对多学科方法的关注，包括实验和理论，将为各个层次的学生提供令人兴奋的机会，为这一基本上未被探索但重要的生物学领域做出贡献。该项目的一个广泛目标是激励和培训从K-12到研究生院的学生从概念上思考定量，跨学科和工程方法如何帮助理解生命。在将要开展的具体活动中，K-12教育将受到为波士顿大学夏季挑战赛（一项针对高中生的住宿夏季计划）开发“系统合成生物学训练营”的影响。开发的实践活动将通过灵感大使计划翻译给广大的高中观众。在本科一级，iGEM活动将扩大，每年将通过该项目指导几名本科生。在研究生一级，将开发一个新的定量系统生物学综合课程。最后，该项目将促进芯片实验室系统内生物实验的自动化和自动化的令人兴奋的技术发展。将实施免费提供设备设计和操作软件的基础设施，以使该技术广泛使用，并使学生有机会随时原型化想法。

The award, funded by the Systems and Synthetic Biology Program in the Division of Molecular and Cellular Biosciences, addresses a classic problem in evolutionary biology: understanding how organisms adapt in ever-changing environments. Many organisms rely on bet-hedging strategies to deal with unpredictable and fluctuating environments. This widespread biological trait underlies diverse phenomena from antibiotic tolerance in bacteria to immune diversity in mammals. For example, a microbial population can enhance its fitness by allowing individual cells to stochastically transition among multiple phenotypes. The resulting population diversity ensures that some cells are well-adapted for an unforeseen environmental change. Uncovering these adaptive switching mechanisms is key to understanding microbial evolution and life in ever-changing environments. Recently, it was proposed that prions - originally discovered as the cause of neurodegenerative diseases in mammals - are bet-hedging elements in fungi, maintained to promote survival in fluctuating environments. Prion proteins can switch between multiple conformational states. Conversion to a prion state has been shown to generate new, heritable phenotypes, which are beneficial in many conditions. The overarching goal of this project is to test the prion bet-hedging hypothesis. According to theory, phenotypic switching rates of bet-hedging elements evolve to be in tune with the rate of environmental fluctuations. A central focus of the project will be to test these predictions by studying prion switching in prescribed, fluctuating environmental selection. A second focus will be to use synthetic biology approaches to de novo engineer prion bet-hedging devices, thereby exploring how adaptive properties might be encoded in these elements. These studies will require the development of new genetic tools, as well as innovative technologies, such as microfluidic platforms, for simulating complex environments and studying cells in ways that are beyond the capabilities of traditional biological experimentation. This work will have broad implications for our basic understanding of evolution, development, and cellular systems. The project will also shed light on the diverse roles of prions, unique elements that are emerging to be common in the microbial world. Finally, the proposed work will have a transformative impact on synthetic biology, enabling new schemes for rationally engineering a wide array of cellular functions.The focus on multidisciplinary approaches, both experimental and theoretical, will provide exciting opportunities for students of all levels to contribute to this largely unexplored, but significant, area of biology. A broad goal of the project is to inspire and train students from K-12 to graduate school to think conceptually about how quantitative, interdisciplinary, and engineering approaches can help in understanding life. Among the specific activities to be pursued, K-12 education will be impacted by developing a 'systems & synthetic biology bootcamp' for Boston University's Summer Challenge, a residential summer program for high school students. The hands-on activities developed will be translated to a broad high school audience via the Inspiration Ambassadors Program. At the undergraduate level, iGEM activities will be expanded and several undergraduates per year will be mentored via the project. At the graduate level, a new integrated course on quantitative systems biology will be developed. Finally, the project will promote exciting technological developments for miniaturizing and automating biological experimentation within lab-on-a-chip systems. Infrastructure for making device designs and operating software freely-available will be implemented in order to make the technology widely accessible and allow students the opportunity to readily prototype ideas.