Scc2/Nipbl hops between chromosomal cohesin rings after loading
Abstract
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 of cohesin's ring. Scc2 (Nipbl) stimulates cohesin's ABC-like ATPase and is essential for loading cohesin onto chromosomes. However, it is possible that the stimulation of cohesin's ATPase by Scc2 also has a post-loading function, for example driving loop extrusion. Using fluorescence recovery after photobleaching (FRAP) and single- molecule tracking, we show that Scc2 binds dynamically to chromatin, principally through an association with cohesin. Scc2's movement within chromatin is consistent with a 'stop-and-go' or 'hopping' motion. We suggest that a low diffusion coefficient, a low stoichiometry relative to cohesin, and a high affinity for chromosomal cohesin enables Scc2 to move rapidly from one chromosomal cohesin complex to another, performing a function distinct from loading.
Article and author information
Author details
Funding
Wellcome (091859/Z/10/Z)
- Kim A Nasmyth
H2020 European Research Council (294401)
- Kim A Nasmyth
Cancer Research UK (C573/A12386)
- Kim A Nasmyth
Wellcome (101636/Z/13/Z)
- Stephan Uphoff
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Andrea Musacchio, Max Planck Institute of Molecular Physiology, Germany
Version history
- Received: June 28, 2017
- Accepted: September 8, 2017
- Accepted Manuscript published: September 15, 2017 (version 1)
- Version of Record published: September 29, 2017 (version 2)
Copyright
© 2017, Rhodes et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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