Chromosome conformation capture-based studies reveal novel features of plant nuclear architecture

- Heterochromatin and euchromatin are separated in the 3D nuclear space.
- Topologically associated domains are less prominent in Arabidopsis than metazoa.
- Polycomb proteins may be involved in the regulation of 3D genome organization.
- 3D chromatin loops are associated with many genes they potentially regulate.
- The KNOT is a conspicuous nuclear structure in Arabidopsis involved in TE biology.

Nuclear genome organization has recently received increasing attention due to its manifold functions in basic nuclear processes, such as replication, transcription, and the maintenance of genome integrity. Using technologies based on chromosome conformation capture, such as Hi-C, we now have the possibility to study the three-dimensional organization of the genome at unprecedented resolution, shedding light onto a previously unexplored level of nuclear architecture. In plants, research in this field is still in its infancy but a number of publications provided first insights into basic principles of nuclear genome organization and the factors that influence it. Apart from general aspects, newly discovered three-dimensional conformations, such as the KNOT, raise special interest on how nuclear organization may influence the function of the genome in previously unexpected ways.