Scc2/Nipbl hops between chromosomal cohesin rings after loading

• DOI: 10.7554/elife.30000
• Publication Date: 2017-09-15T12:00:13Z
• Authors: James Rhodes; Davide Mazza; Kim Nasmyth; Stephan Uphoff
• Keywords: Condensin

The cohesin complex mediates DNA-DNA interactions both between (sister chromatid cohesion) and within chromosomes (DNA looping). It has been suggested that intra-chromosome loops are generated by extrusion of DNAs through the lumen cohesin’s ring. Scc2 (Nipbl) stimulates ABC-like ATPase is essential for loading onto chromosomes. However, it possible stimulation also a post-loading function, example driving loop extrusion. Using fluorescence recovery after photobleaching (FRAP) single-molecule tracking in human cells, we show binds dynamically to chromatin, principally an association with cohesin. Scc2’s movement chromatin consistent 'stop-and-go' or 'hopping' motion. We suggest low diffusion coefficient, stoichiometry relative cohesin, high affinity chromosomal enables move rapidly from one another, performing function distinct loading.