DNA is packaged by histones and associated proteins and RNA into chromatin. Several levels of chromatin organization are required to compact DNA into chromosomes, thereby enabling accurate cell division. The dynamic structure of chromatin modulates other nuclear processes, including transcription and replication, by altering the accessibility of the DNA to regulatory factors. Structural changes in chromatin are affected by the chemical modification of histone proteins and DNA, remodelling of nucleosomes, and by noncoding RNAs and non-histone DNA-binding proteins. Chromatin is subject to proofreading and repair mechanisms during replication and in response to DNA damage, ensuring the faithful inheritance of genetic and epigenetic information and maintaining genome stability. The spatial organization of chromatin in the nucleus reflects another aspect of its dynamic nature. Evidence is emerging that large-scale chromatin interactions, including interactions between chromosomes, have important roles in gene regulation, recombination and other nuclear processes. In addition, chromatin is organized in functional compartments, such as transcription factories and repair centres.

The articles in this series will focus on recent breakthroughs in our understanding of the mechanisms that govern the dynamic structural and spatial organization of chromatin, thereby providing important insights into gene regulation, DNA repair, development and epigenetic inheritance.