Prokaryotic Light Responses and Regulatory Mechanisms

智力优势：该项目将有助于更好地理解光合微生物如何感知和响应其光环境的变化。人们对这一过程了解甚少，但具有全球重要性，目前正在使用淡水丝状蓝藻freremyella diplosiphon （Tolypothrix PCC 7601）进行研究。先前的研究表明，这种生物体似乎正在使用一种新的基因调控形式，其中涉及多种形式的翻译起始因子IF3。许多蓝藻似乎含有多个if3编码基因，这可能使这种形式的调节在这个群体中广泛存在。该项目将确认if3介导的转录后控制形式是否在称为互补色适应的过程中调节F. diplosiphon对绿光的反应。如果这是真的，这将扩大对IF3活性的理解，从其在翻译起始中的传统作用扩展到对环境信号的基因表达调节。本研究还将进一步确定在F. diplosiphon基因组中编码的一种假定的蓝藻光敏色素光感受器的活性和功能，令人惊讶的是，这种光感受器的表达是由另一种蓝藻光敏色素调节的。探索这种新的排列将为原核生物光敏色素信号通路提供新的见解。更广泛的影响。本研究将在信号转导、分子生物学、微生物学和功能基因组学等领域培养2名博士和12名本科生。根据该实验室之前的学生培训历史，这些学生中有相当一部分可能来自代表性不足的群体。更广泛地说，由于该项目之前的工作也表明，多种形式的IF3可能调节高等植物胚胎发生和衰老期间叶绿体中的基因表达，因此该研究可能会改善农业实践和作物生产。这项研究是由分子和细胞生物科学部（基因和基因组系统）和新兴前沿（生命转型）共同资助的。

Intellectual Merit: This project will contribute to a better understanding of how photosynthetic microorganisms sense and respond to changes in their light environment. This process, which is poorly understood but of global importance, is being examined using the freshwater, filamentous cyanobacterium Fremyella diplosiphon (Tolypothrix PCC 7601). Previous research demonstrated that this organism appears to be using a novel form of gene regulation that involves multiple forms of a translation initiation factor called IF3. Many cyanobacteria appear to contain multiple IF3-encoding genes, making it likely that this form of regulation is widespread within this group. This project will confirm whether an IF3-mediated form of post-transcriptional control regulates the response of F. diplosiphon to the presence of green light during a process called complementary chromatic adaptation. If true, this will expand understanding of IF3 activity from its traditional role in translation initiation to also include the regulation of gene expression in response to environmental cues. This research will also further define the activity and function of a putative cyanobacterial phytochrome photoreceptor encoded within the F. diplosiphon genome whose expression, surprisingly, is regulated by another cyanobacterial phytochrome. Exploration of this novel arrangement will provide new insights into phytochrome signaling pathways in prokaryotes.Broader Impacts. This research will offer two Ph.D. and twelve undergraduate students training in the fields of signal transduction, molecular biology, microbiology and functional genomics. Based on the prior history of student training for this laboratory, a significant number of these students are likely to be from underrepresented groups. More broadly, because previous work on this project has also suggested that multiple forms of IF3 may regulate gene expression in the chloroplasts of higher plants during embryogenesis and senescence, this research may lead to improved agriculture practices and crop production.This research is co-funded by the Divisions of Molecular and Cellular Biosciences (Genes and Genome Systems) and Emerging Frontiers (Life in Transition).