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Wednesday 29 October 2003

Eukaryotic sister chromatids remain connected from the time of synthesis until they are separated in anaphase. This cohesion depends on a complex of proteins known as cohesins or cohesin complexes.

In vertebrates, unlike in yeast, the cohesins dissociate from chromosome arms earlier in M phase, during prophase.

Small amounts of cohesin remain near the centromere until metaphase, with complete removal at the beginning of anaphase.

Cohesin complexes contain SMC1 (MIM.300040), SMC3 (CSPG6) (MIM.606062), SCC1 (RAD21), and either SA1 (STAG1) (MIM.604358) or SA2 (STAG2) (MIM.604359).

The cohesin complexes, in turn, interact with PDS5, a protein implicated in chromosome cohesion, condensation, and recombination in yeast

Mitotic chromosome segregation is facilitated by the cohesin complex, which maintains physical connections between sister chromatids until anaphase.

Meiotic cell division is considerably more complex, as cohesion must be released sequentially to facilitate orderly segregation of chromosomes at both meiosis I and meiosis II.

This necessitates meiosis-specific cohesin components; recent studies in rodents suggest that these influence chromosome behavior during both cell division and meiotic prophase.

See also


Pathology of cohesins

- Cornelia de Lange syndrome (CDLS)


- Hodges CA, Revenkova E, Jessberger R, Hassold TJ, Hunt PA. SMC1beta-deficient female mice provide evidence that cohesins are a missing link in age-related nondisjunction.
Nat Genet. 2005 Dec;37(12):1351-5. PMID: 16258540

- Hagstrom KA, Meyer BJ. Condensin and cohesin: more than chromosome compactor and glue. Nat Rev Genet. 2003 Jul;4(7):520-34. PMID: 12838344

Bernard P, Allshire R. Centromeres become unstuck without heterochromatin. Trends Cell Biol. 2002 Sep ;12(9):419-24. PMID : 12220862