Collaborative Research: Aureochromes-light signaling in the sea

Southern Methodist University, Dallas TX

Investigators

Abstract

Photosynthetic organisms rely on light not only to fix CO2, but they also use light information to learn about their environment. The scientific community has a broad understanding of light-regulated responses in organisms living on land. There, blue and red light sensing proteins help land plants determine information such as the presence of neighbor competition or the time of day. However, about 71% of the Earth surface is water, and aquatic environments are strongly enriched in blue light and deprived of red light. How photosynthetic organisms living in freshwater or marine environments harness light quality and quantity information is an open question. As part of this project the PIs will investigate the function of a group of blue light sensing proteins called Aureochromes, which are widely distributed in marine algae. This project will also train undergraduate/graduate students and postdoctoral associates across disciplines (photochemistry, biochemistry, cell/molecular biology, mathematical modeling) and provide visualization tools to teach the use of math in introductory chemistry and biology. School teachers are at the frontline of improving public scientific literacy and this project will continue previously funded work to train preservice educators on science practices and teaching, and identify how these preservice teachers learn, why they learn, and to investigate if their way of thinking changes during the research and teaching training. Using the unicellular microalga Nannochloropsis oceanica, the PIs will investigate the hypothesis that photochemical kinetics, expression patterns and protein-protein interaction networks of protein photoreceptors shape the dynamics of light responses and therefore the organism’s response to changing light fluencies. To achieve this global understanding of aureochrome signaling, the researchers will develop explicit mathematical models of aureochrome signal transduction, where they will experimentally determine kinetic terms regulating the photochemistry of these LOV domain photoreceptors, their competitive dimerization, expression and degradation rates, and DNA binding capacity. Combined, this project will examine how these factors influence transcriptional activity and impact cell physiology. In this manner, this work will enable the construction of a complete model of blue-light regulation of N. oceanica that integrates local photochemistry with organism’s physiology in a predictive, and falsifiable model. 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.