SMC complexes can traverse physical roadblocks bigger than their ring size

Journal article (2022)

Authors

B. Pradhan BN/Bionanoscience , Kavli institute of nanoscience Delft,
R. Barth Kavli institute of nanoscience Delft,
E. Kim Kavli institute of nanoscience Delft, , BN/Bionanoscience
T. van Laar Kavli institute of nanoscience Delft, BN/Nynke Dekker Lab - AS
W.W.W. Yang BN/Bionanoscience , , Kavli institute of nanoscience Delft
J.K. Ryu Kavli institute of nanoscience Delft,
J. van der Torre , Kavli institute of nanoscience Delft
Jan Michael Peters Research Institute of Molecular Pathology, Vienna
C. Dekker Kavli institute of nanoscience Delft, , BN/Bionanoscience
More Authors... External organisation
Research Group
BN/Nynke Dekker Lab (AS) (TU Delft)
Copyright: © 2022 B. Pradhan, R. Barth, E. Kim, T. van Laar, W.W.W. Yang, J.K. Ryu, J. van der Torre, Jan Michael Peters, C. Dekker, More Authors
DOI: https://doi.org/10.1016/j.celrep.2022.111491
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Published Date

2022

Language

English

Faculty

Applied Sciences

Department

BN/Bionanoscience

Research Group

BN/Nynke Dekker Lab

Abstract

Ring-shaped structural maintenance of chromosomes (SMC) complexes like condensin and cohesin extrude loops of DNA. It remains, however, unclear how they can extrude DNA loops in chromatin that is bound with proteins. Here, we use in vitro single-molecule visualization to show that nucleosomes, RNA polymerase, and dCas9 pose virtually no barrier to loop extrusion by yeast condensin. We find that even DNA-bound nanoparticles as large as 200 nm, much bigger than the SMC ring size, also translocate into DNA loops during extrusion by condensin and cohesin. This even occurs for a single-chain version of cohesin in which the ring-forming subunits are covalently linked and cannot open to entrap DNA. The data show that SMC-driven loop extrusion has surprisingly little difficulty in accommodating large roadblocks into the loop. The findings also show that the extruded DNA does not pass through the SMC ring (pseudo)topologically, hence pointing to a nontopological mechanism for DNA loop extrusion.