1. University of Oxford, Department of Biochemistry, South Parks Road, Oxford OX1 3QU, UK
2. These authors contributed equally to this work.
3. Present addresses: European Molecular Biology Laboratory (EMBL), Meyerhofstrae 1, 69117 Heidelberg, Germany (C.H.H.); Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK (P.A.).

Correspondence to: Kim Nasmyth¹ Correspondence and requests for materials should be addressed to K.N. (Email: kim.nasmyth@bioch.ox.ac.uk).

Abstract

Sister chromatid cohesion, which is essential for mitosis, is mediated by a multi-subunit protein complex called cohesin. Cohesin's Scc1, Smc1 and Smc3 subunits form a tripartite ring structure, and it has been proposed that cohesin holds sister DNA molecules together by trapping them inside its ring. To test this, we used site-specific crosslinking to create chemical connections at the three interfaces between the three constituent polypeptides of the ring, thereby creating covalently closed cohesin rings. As predicted by the ring entrapment model, this procedure produced dimeric DNA–cohesin structures that are resistant to protein denaturation. We conclude that cohesin rings concatenate individual sister minichromosome DNA molecules.

MORE ARTICLES LIKE THIS

These links to content published by NPG are automatically generated.