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Updated: Sep 12, 2025
08:53
Strand-Specific Analysis of Proteins at Replicating DNA Strands by Enrichment and Sequencing of Protein-Associated Nascent DNA Method
Published on: May 2, 2025
483
NIPBL and STAG1 enable loop extrusion by providing differential DNA-cohesin affinity
Raman van Wee1,2, Roi Asor1, Yiwen Li1
1Physical and Theoretical Chemistry, Department of Chemistry, Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford OX1 3QU, United Kingdom.
Summary
Cohesin
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- DNA loop extrusion by cohesin is crucial for chromosome organization.
- The exact mechanism of cohesin-mediated loop extrusion remains unclear due to its complex structure.
Purpose of the Study:
- To comprehensively quantify biomolecular interactions in DNA loop extrusion.
- To elucidate the mechanism of cohesin's DNA binding and loop extrusion cycle.
Main Methods:
- Mass photometry was used to quantify interactions.
- Cohesin mutants were analyzed to assess DNA binding roles.
Main Results:
- STAG1 tightly binds the SMC1/SMC3/SCC1 complex, which weakly binds DNA.
- NIPBL acts as a DNA anchor during extrusion.
- An ATP-modulated DNA binding site involving STAG1 is critical for extrusion.
Conclusions:
- Cohesin's DNA binding and loop extrusion mechanism involves specific subunit interactions and ATP modulation.
- The findings necessitate a reevaluation of current models for DNA loop extrusion.
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