Loop extrusion mechanism. Ring-shaped cohesin complex (blue) is loaded on to chromatin via cohesin-loading factors, such as NIPBL (dark orange). The cohesin complex slides the chromatin string till it encounters convergent CTCF motifs (red triangles), while it extrudes the chromatin outward through the ring-shaped structure. The cohesin-unloading factor, WAPL (purple) unloads the cohesin from the chromatin, recycling the cohesin complexes.
