Abstract 2254 Unraveling crosstalk between histone acetylation and gene activation in living cells

My lab develops technology to quantify gene expression dynamics with single-molecule precision in living cells. In this talk, I'll describe recently published work imaging single nucleosome mobility in the context of histone H3 acetylation and RNA polymerase II initiation. Contrary to the strong correlation observed between these marks using immunoprecipitation-based assays, we find evidence the two are rarely enriched together. Instead, they appear to mark distinct foci with opposing nucleosome dynamics. In support of this model, I'll present new data from a CRISPR-engineered cell line marking the endogenous MYH9 gene that demonstrates hyperacetylation of MYH9 proceeds its transcriptional activation. Collectively, these data suggest genes oscillate between a highly mobile hyper-acetylated state and a relatively immobile active state. I'll conclude by discussing a new genetically-encoded intrabody we developed to image H3 Lysine 27 acetylation dynamics in living cells. We believe this intrabody will be broadly applicable to the study of enhancer-promoter crosstalk during gene activation. This work was supported by a grant to TJS from the National Institutes of Health (NIGMS grant # R35GM119728).