Collaborative Research: Transcriptional Adaptation and Response to Pressure

地球的深海是数量庞大、种类繁多的生物的家园，其中包括约90%的微生物，它们可以承受高达表面压力1000倍的压力。负责关键生命过程的蛋白质机器，如遗传密码的转录，必须适应在这种极端和恶劣的条件下发挥作用。这种适应的机制仍然是个谜。本项目旨在了解表面和压力适应微生物的转录机制对高压的响应和适应的分子机制。更好地了解这些机制将有助于深入了解地球上生命的进化甚至起源，并使食品科学行业取得新的生物技术进步，例如，提高压力巴氏灭菌的安全性。参与该项目的研究生和博士后将接受多学科研究技能的培训，并有机会指导本科生和高中生。所有学员都将参加一个极端生物学和生物物理学研究协调网络。在中温菌大肠杆菌和中度亲压菌深光杆菌SS9中，转录响应和压力适应的分子基础涉及热休克响应系统。高压诱导大肠杆菌热休克反应，反之，低压诱导深孔疟原虫SS9热休克反应。该研究将研究压力对内务管理和应激反应RNA聚合酶sigma因子转录调节因子的启动子相互作用的影响，以及sigma因子蛋白本身的稳定性。这些反应将在P. profundum SS9和压力适应菌株大肠杆菌中进行比较分析。此外，还将研究与深叶霉SS9转录程序的压力调节有关的ToxR/ToxS转录调节系统。这项研究将包括直接观察和定量转录蛋白的性质和过程，使用新开发的荧光显微镜技术在压力下，并将采用随机建模来深入了解这些过程中特定生化步骤的压力敏感性。该项目的成果有望为地球上高压环境的进化适应提供见解，并可能有助于减轻食品工业中抗压微生物造成的问题。该项目由生物科学局分子和细胞生物科学部的遗传机制和分子生物物理学项目以及地球科学局海洋科学部的生物海洋学项目共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Earth’s deep oceans are home to an enormous amount and diversity of living creatures, including ~90% of the microbes, which can experience pressures as high as 1000 times that on the surface. The protein machines responsible for critical life processes, such as transcription of the genetic code, must be adapted to function under such extreme and inhospitable conditions. The mechanisms of this adaptation remain a mystery. This project is aimed at understanding molecular mechanisms underlying the response and adaptation to high pressure of the transcription machinery of surface- and pressure-adapted microorganisms. Better knowledge of these mechanisms will provide insights into the evolution and even the origins of life on Earth, and enable new biotechnological advances in the food science industry, e.g., to improve the safety of pressure pasteurization. Graduate students and postdoctoral scholars involved in the project will be trained in multidisciplinary research skills, and have the opportunity to mentor undergraduates and high school students. All trainees will participate in a Research Coordination Network on Extreme Biology and Biophysics.In the mesophile, Escherichia coli, and in the moderate piezophile, Photobacterium profundum SS9, the molecular basis of transcriptional response and adaptation to pressure involves the heat shock response system. High pressure induces a heat shock response in E. coli, and conversely, low pressure induces a heat shock response P. profundum SS9. The research will investigate pressure effects on promoter interactions of the transcriptional regulators of housekeeping and stress response RNA polymerase sigma factors, as well as the stability of the sigma factor proteins themselves. These responses will be characterized in P. profundum SS9 and a pressure-adapted strain of E. coli for comparative analysis. The ToxR/ToxS transcriptional regulator system, which is implicated in pressure regulation of the transcriptional program in P. profundum SS9, will also be examined. The research will involve direct observation and quantification of transcriptional protein properties and processes, using newly developed fluorescence microscopy techniques under pressure, and will employ stochastic modeling for deeper insights into the pressure sensitivity of specific biochemical steps in these processes. The project outcomes are expected to provide insights into evolutionary adaptation to high pressure environments on Earth and may help to mitigate problems caused by pressure resistant microorganisms in the food industry.This project is jointly funded by the Genetic Mechanisms and Molecular Biophysics programs of the Molecular and Cellular Biosciences Division in the Biological Sciences Directorate, and the Biological Oceanography program of the Ocean Sciences Division in the Geosciences Directorate.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.