Transcription-dependent domain-scale three-dimensional genome organization in the dinoflagellate Breviolum minutum

Dinoflagellate chromosomes represent a unique evolutionary experiment, as they exist in a permanently condensed, liquid crystalline state; are not packaged by histones; and contain genes organized into tandem gene arrays, with minimal transcriptional regulation. We analyze the three-dimensional genome of Breviolum minutum, and find large topological domains (dinoflagellate topologically associating domains, which we term 'dinoTADs') without chromatin loops, which are demarcated by convergent gene array boundaries. Transcriptional inhibition disrupts dinoTADs, implicating transcription-induced supercoiling as the primary topological force in dinoflagellates. Analysis of the three-dimensional architecture of the dinoflagellate Breviolum minutum genome identifies large topological domains (dinoTADs) demarcated by convergent gene array boundaries. Transcriptional inhibition disrupts dinoTADs.

Automated summary

Dinoflagellate chromosomes represent a unique evolutionary experiment, existing in a permanently condensed state without histone packaging and minimal transcriptional regulation. Analysis of the three-dimensional genome of Breviolum minutum reveals large topological domains (dinoTADs) demarcated by convergent gene array boundaries, with disruption caused by transcriptional inhibition.