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).
