Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.22.309146v1?rss=1 Authors: Banigan, E. J., Mirny, L. A. Abstract: Compaction of chromosomes is essential for reliable transmission of genetic information. Experiments suggest that this ~1000-fold compaction is driven by condensin complexes that extrude chromatin loops, i.e., progressively collect chromatin fiber from one or both sides of the complex to form a growing loop. Theory indicates that symmetric two-sided loop extrusion can achieve such compaction, but recent single-molecule studies observed diverse dynamics of condensins that perform one-sided, symmetric two-sided, and asymmetric two-sided extrusion. We use simulations and theory to determine how these molecular properties lead to chromosome compaction. High compaction can be achieved if even a small fraction of condensins have two essential properties: a long residence time and the ability to perform two-sided (not necessarily symmetric) extrusion. In mixtures of condensins I and II, coupling of two-sided extrusion and stable chromatin binding by condensin II promotes compaction. These results provide missing connections between single-molecule observations and chromosome-scale organization. Copy rights belong to original authors. Visit the link for more info