Condensin II Counteracts Cohesin and RNA Polymerase II in the Establishment of 3D Chromatin Organization

Publication date: 12 March 2019Source: Cell Reports, Volume 26, Issue 11Author(s): M. Jordan Rowley, Xiaowen Lyu, Vibhuti Rana, Masami Ando-Kuri, Rachael Karns, Giovanni Bosco, Victor G. CorcesSummaryInteraction domains in Drosophila chromosomes form by segregation of active and inactive chromatin in the absence of CTCF loops, but the role of transcription versus other architectural proteins in chromatin organization is unclear. Here, we find that positioning of RNAPII via transcription elongation is essential in the formation of gene loops, which in turn interact to form compartmental domains. Inhibition of transcription elongation or depletion of cohesin decreases gene looping and formation of active compartmental domains. In contrast, depletion of condensin II, which also localizes to active chromatin, causes increased gene looping, formation of compartmental domains, and stronger intra-chromosomal compartmental interactions. Condensin II has a similar role in maintaining inter-chromosomal interactions responsible for pairing between homologous chromosomes, whereas inhibition of transcription elongation or cohesin depletion has little effect on homolog pairing. The results suggest distinct roles for cohesin and condensin II in the establishment of 3D nuclear organization in Drosophila.Graphical Abstract
Source: Cell Reports - Category: Cytology Source Type: research