Chromatin topological transitions

International audienceDNA transaction events occurring during a cell cycle (transcription, repair, replication) are always associated with severe topological constraints on the double helix. However, since nuclear DNA is bound to various proteins (including histones) that control its accessibility and 3D organization, these topological constraints propagate or accumulate on a chromatin substrate. This paper focuses on chromatin fiber response to physiological mechanical constraints expected to occur during transcription elongation. We will show in particular how recent single molecule techniques help us to understand how chromatin conformational dynamics could manage harsh DNA supercoiling changes