Fig. 7: Two classes of extrusion-mediated processes accelerate long-range chromosomal contact formation.

A Schematic representation of both extrusion-mediated acceleration processes (green: large events, blue: small events). Top: Time series of the genomic region around the arrays. Each pair of lines represents the positions of the anchors of a single extruding condensin. Middle: Corresponding effective 1D distance between the arrays (defined schematically), showing shortening due to condensins landing in between. Bottom: Corresponding 3D distance between arrays with 3D contact highlighted. B Top: Average effective 1D distance between the arrays aligned to the onset of large extrusion events (defined as remaining tether <180 kb). Faded lines show individual traces. Bottom: Average contact probability per track aligned to large extrusion event onset (green) compared to random times in simulations without extrusion (gray). High contact probability is present at 3 min (time to extrude to the arrays) following condensin binding. C Same as (B), but for small extrusion events (remaining tether > 180 kb). D CFT simulation with specific extrusion events removed to quantify the contributions of large and small loops. For example, “0–90 kb remaining tether” represents removing all extrusion events with remaining tether > 90 kb.