ABSTRACT
In this chapter, we describe a high-resolution uorescence anisotropy imaging (FAI) based method to study chromatin structure and dynamics. The rotational mobility of uorescent tagged core histone proteins in live cells detected using FAI provides a measure of the local chromatin structure. The anisotropy-based compaction maps were validated by labeling known epigenetic markers of higher-order chromatin structure. Time lapse FAI combined with image correlation analysis was used to study (a) differential dynamics between heterochromatin and euchromatin regions, (b) impact of cell geometric constraints on chromatin dynamics, and (c) compaction states of chromatin assembly in undifferentiated and differentiated cells. Numerical simulation of image correlation provides a quantitative measure of the relaxation timescales associated with chromatin dynamics in these cases. Taken together, this technique provides us with a handle to analyze the spatiotemporal organization of chromatin in live cells.
