Cohesin mediates DNA loop extrusion and sister chromatid cohesion by distinct mechanisms

Mol Cell. 2023 Sep 7;83(17):3049-3063.e6. doi: 10.1016/j.molcel.2023.07.024. Epub 2023 Aug 16.


Cohesin connects CTCF-binding sites and other genomic loci in cis to form chromatin loops and replicated DNA molecules in trans to mediate sister chromatid cohesion. Whether cohesin uses distinct or related mechanisms to perform these functions is unknown. Here, we describe a cohesin hinge mutant that can extrude DNA into loops but is unable to mediate cohesion in human cells. Our results suggest that the latter defect arises during cohesion establishment. The observation that cohesin's cohesion and loop extrusion activities can be partially separated indicates that cohesin uses distinct mechanisms to perform these two functions. Unexpectedly, the same hinge mutant can also not be stopped by CTCF boundaries as well as wild-type cohesin. This suggests that cohesion establishment and cohesin's interaction with CTCF boundaries depend on related mechanisms and raises the possibility that both require transient hinge opening to entrap DNA inside the cohesin ring.

Keywords: CTCF; DNA loop extrusion; TADs; chromatin architectures; cohesin; cohesion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cell Cycle Proteins* / genetics
  • Chromatids* / genetics
  • Chromosomal Proteins, Non-Histone / genetics
  • Cohesins
  • Humans


  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone