The long-term objective of this research is to better understand the molecular mechanisms underlying circadian rhythm generation and maintenance in the cyanobacterium Synechococcus elongatus. This understanding will include the metabolic signals used as time markers by the circadian clock, the in vivo clock mechanism itself and the rhythmic patterns of gene expression and metabolism controlled by the circadian clock. Recently, clock-regulated chromosome compaction was identified as a component of clock-generated gene expression rhythms. The circadian clock appears to use this compaction rhythm to establish the rhythmic patterns and phase relationships among clock regulated gene expression patterns. However, this supposition requires more rigorous experimental testing for confirmation. In addition, it was previously found that strains devoid of a critical protein function, SasA protein, lose normal patterns of gene expression despite continued circadian clock function. Recent evidence demonstrates that chromosome compaction rhythms and SasA protein function are each necessary but neither one is sufficient for the generation and maintenance of circadian rhythms in gene expression. The research objectives address the nature of the chromosome compaction rhythm, how specific changes that occur in components of the circadian oscillator affect its interactions with the SasA protein, and how these two circadian clock controlled processes, chromosome compaction and SasA function, work together to generate and maintain rhythmic patterns of gene expression throughout the entire S. elongatus chromosome.
Broader Impact Undergraduate, graduate, and post graduate students will participate in all aspects of the research. A typical student project includes gene cloning, cyanobacterial strain construction, protein purification and assay, and deconvolution fluorescence microscopy of live cells. As part of their training students will also communicate and disseminate their research results to broad audiences. They will meet with other professional scientists during weekly lab meetings to discuss the details of their research progress. They will also discuss their research results during a weekly scientific journal club attended by microbiologists from the University of Utah's Biology Department and School of Medicine. Graduate and post-graduate students will present their work at meetings of the Society for Research on Biological Rhythms and of the Bacterial Locomotion and Signal Transduction group. These are very different types of scientific meetings. The former is attended by medical clinicians and exposes the students to the human impact of their research efforts in circadian biology. The latter is attended by leading signal transduction groups and exposes students to the best of scientific research. The Biology Department at Utah continues to recruit local high school students into research laboratories and funding from the NSF will support efforts to also bring their teachers into the research laboratory environment.
