ABSTRACT
Principles of genome folding and their relationship to function depend on understanding conformational changes of the chromatin fiber. Analysis of bulk chromatin motion at high resolution is still lacking. We developed Hi-D, a method to quantitatively map DNA dynamics for every pixel simultaneously over the entire nucleus from real-time fluorescence images. Hi-D combines reconstruction of chromatin motion using computer vision and classification of local diffusion processes by Bayesian inference. We found that DNA dynamics in the nuclear interior are spatially organized into 0.3 – 3 µm domains of distinct types of diffusion was uncoupled from chromatin compaction. Reorganization of the network of dynamic domains between quiescent and active cells suggest that the microenvironment plays a predominant role in stochastic chromatin motion. Hi-D opens new perspectives towards understanding of chromatin organization placing global motion of nuclear molecules in the context of nuclear architecture.
