Probing nucleosome dynamics within chromatin fibers using single-molecule fluorescence

Abstract

Nucleosomes form the basic organizational and regulatory units of the genome. They wrap DNA around a histone core, allowing the roughly two meter long genomic DNA to fit inside the micron sized nucleus. Nucleosomes connected by linker DNA assemble into chromatin, a dynamic structure governed by inter-nucleosomal interactions and numerous chromatin-associated proteins. In this thesis, we explored a multitude of biophysical properties of this chromatin. Specifically, we investigated the link between nucleosome repeat length (NRL), internal nucleosome and chromatin fiber structure, and dynamic interchange between multiple conformational states. We established a clear range of timescales for these processes that can be probed using our single-molecule methods. In addition, we observed how local chromatin fiber configuration can influence supramolecular condensate formation behavior.