Spatial and Temporal Organization of Chromatin at Small and Large Scales

DNA molecules with a total length of two meters contain the genetic information in every cell in our body. To control access to the genes, to organize its spatial structure in the nucleus, and to duplicate and faithfully separate the genetic material, the cell makes use of sophisticated physical mechanisms. Base pair sequences multiplex various layers of information, chromatin remodelers mobilize nucleosomes via twist defects, loop extruders create a system of nonconcatenated rings to spatially organize chromatin, and biomolecular condensates concentrate proteins and nucleic acids in specialized membraneless compartments. In this review, we discuss the current state of understanding of some of these mechanisms that influence the organization of the genetic material in space and time.