PT - JOURNAL ARTICLE AU - Pia Mach AU - Pavel I. Kos AU - Yinxiu Zhan AU - Julie Cramard AU - Simon Gaudin AU - Jana Tünnermann AU - Edoardo Marchi AU - Jan Eglinger AU - Jessica Zuin AU - Mariya Kryzhanovska AU - Sebastien Smallwood AU - Laurent Gelman AU - Gregory Roth AU - Elphège P. Nora AU - Guido Tiana AU - Luca Giorgetti TI - Live-cell imaging and physical modeling reveal control of chromosome folding dynamics by cohesin and CTCF AID - 10.1101/2022.03.03.482826 DP - 2022 Jan 01 TA - bioRxiv PG - 2022.03.03.482826 4099 - http://biorxiv.org/content/early/2022/03/03/2022.03.03.482826.short 4100 - http://biorxiv.org/content/early/2022/03/03/2022.03.03.482826.full AB - Physical proximity between genomic sequences in mammalian chromosomes controls key biological processes such as transcriptional regulation and DNA repair. Yet it is currently unknown if chromosomal contacts are rare and stable or instead frequent and dynamic, and how they depend on the loop extrusion activity of cohesin or barriers such as CTCF. By imaging chromosomal locations at high spatial and temporal resolution over several hours in living cells, we show that sequences within topological associating domains (TADs) frequently come into physical proximity during the course of a cell cycle and remain close to each other only for a few minutes. Such contacts become nonetheless substantially longer and more frequent in the presence of convergent CTCF sites, resulting in a suppression of variability in chromosome folding in single cells across time. Supported by physical models of chromosome dynamics, our data additionally suggests that individual CTCF-anchored loops last around 10 minutes. The estimates of chromosomal contact dynamics in our study provide a novel quantitative framework to link chromosome structure to function and show that cohesin and CTCF stabilize otherwise highly dynamic chromosome structures to facilitate selected subsets of chromosomal interactions.Competing Interest StatementThe authors have declared no competing interest.