Investigating dynamic chromatin states in a model cell organism*

Chromatin’s biological functions are inextricably linked to its spatial organization and real-time dynamics. I will describe research aimed at gaining new insight into chromatin organization and dynamics, focused on the emerging model of Topologically-Associated Domains (TADs) – 50-100 kb-length regions of the genome that show unusually high contact probability. To date, approaches capable of linking the physical TAD structure to chromatin dynamics have been lacking. I will present a novel data acquisition and analysis pipeline and preliminary results: We label specific gene loci within a model cell organism, S. pombe, with lacO arrays bound by fluorescent LacI-GFP proteins. We then image cell populations over time on a widefield microscope. These movies are used to track the motions of loci for large populations of single cells. Next, we analyze the diffusive behavior of the chromatin loci by determining the mean-square displacement and velocity autocorrelation function. To further investigate the underlying biology that contributes to locus motion, we compare perturbations to a variety of biological inputs, including temperature, the cytoskeleton, and proteins that are hypothesized to have key roles in TAD formation.