Cohesin rings hold chromatids together until the ring is cleaved at anaphase.

Nasmyth

New insight into the structure of cohesin suggests it might lasso sister chromatids to hold them together until anaphase. Stephan Gruber, Christian Haering, and Kim Nasmyth (Research Institute of Molecular Pathology, Vienna, Austria) report interactions between cohesin subunits that reveal a circular structure for the complex.

The ring consists of cohesin subunits Smc1, Smc3, and Scc1. Previous results indicated that Smc heterodimers form a V-shape, with the two proteins joined at the hinge. Now, immunoprecipitation experiments demonstrate that the ends of the V are joined by Scc1 (or by its meiotic replacement, Rec8), forming a ring of cohesin on chromatin in vivo.

Cleavage of the ring by separase released the it from chromatin in vitro and in vivo. “The big question now,” says Nasmyth, “is what is the pathway of the DNA....

The Rockefeller University Press
2003
The Rockefeller University Press
2003
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