Regulation of nitrogen assimilation in marine diatoms: Investigation of the importance of post-transcriptional processes

硅藻是单细胞光合浮游生物，对全球碳、氮、硅酸盐生物地球化学循环有重要贡献。据估计，硅藻占海洋生态系统中固定碳的40%，占地球初级生产力的20%。在海洋生态系统中，氮的可用性在几个空间尺度（米到公里）和时间尺度（小时到月）上变化。因此，硅藻的生产力和生态成功可以部分归因于它们快速感知和响应氮源和供应波动的能力。在所有活细胞中，基因表达的调控是一个多方面的动态过程。细胞将内在和环境信号整合到多种调节途径中，从而协调基因表达和细胞功能。本项目利用分子方法探讨了在海洋硅藻中，参与氮转运和同化的基因转录后调控是由信使RNA稳定性的变化介导的，并允许对营养来源或供应的变化进行快速代谢反应。硅藻基因组序列的增加和DNA转化能力的进步刺激了利用硅藻的生物技术探索，包括营养和工业应用。在转录后设计和调节基因表达的能力将有助于研究和调节硅藻基因表达所需的新生物技术工具的发展。该研究项目为本科生和研究生以及一名博士后提供培训机会。该项目将通过与克拉克大学雅各布·希亚特城市教育中心的教师合作，开发探索气候变化的K-16“学习进展”，同时为在职和在职公立学校教师提供强化的科学培训，从而促进整个伍斯特社区的教师培训和科学教育。

Diatoms are unicellular photosynthetic plankton that contribute significantly to global carbon, nitrogen, and silicate biogeochemical cycles. Diatoms are estimated to account for 40% of the carbon fixed in marine ecosystems and 20% of the primary productivity on Earth. They exhibit rapid growth in response to increases in nitrogen availability, which in marine ecosystems, varies over several spatial (meters to kms) and temporal (hours to months) scales. Thus, the productivity and ecological success of diatoms can, in part, be attributed to their ability to rapidly sense and respond to fluctuations in nitrogen source and supply. In all living cells, the regulation of gene expression is a multifaceted and dynamic process. Cells integrate intrinsic and environmental signals into multiple regulatory pathways allowing for coordinated gene expression and cellular function. This project uses molecular approaches to explore the hypothesis that in marine diatoms, post-transcriptional regulation of genes involved in nitrogen transport and assimilation is mediated by changes in messenger RNA stability and allows for rapid metabolic response to changes in nutrient source or supply. The increased availability of diatom genome sequences and advances in DNA transformation capabilities have stimulated biotechnological explorations using diatoms, including both nutritional and industrial applications. The ability to engineer and regulate gene expression post-transcriptionally will aid in the development of new biotechnological tools needed to study and regulate gene expression in diatoms. The research program provides training opportunities for undergraduate and graduate students and a post-doctoral scholar. The project will contribute to teacher training, and thus science education throughout the Worcester community, by working collaboratively with faculty in the Jacob Hiatt Center for Urban Education at Clark University to develop a K-16 "learning progression" exploring climate change while providing enhanced science training to pre- and in-service public school teachers.