InterPro domain: IPR024324

Condensin is a multi-subunit protein complex that acts as an essential regulator of chromosome condensation [ 1 ]. It contains both SMC (structural maintenance of chromosomes) and non-SMC subunits. Condensin plays an important role during mitosis in the compaction and resolution of chromosomes to remove and prevent catenations that would otherwise inhibit segregation. This is thought to be acheived by the introducion of positive supercoils into relaxed DNA in the presence of type I topoisomerases and converts nicked DNA into positive knotted forms in the presence of type II topoisomerases. During interphase condensin promotes clustering of dispersed loci into subnuclear domains and inhibits associations between homologues. In meiosis, condensin has been shown to influence the number of crossover events by regulating programmed double-strand breaks. Roles in gene regulation and lymphocyte development have also been defined.

Condensin subunit 1 (known as Cnd1 in Schizosaccharomyces pombe (Fission yeast), and XCAP-D2 in Xenopus laevis laevis) represents one of the non-SMC subunits in the complex. This subunit is phosphorylated at several sites by Cdc2. This phosphorylation process increases the supercoiling activity of condensin [ 2 , 3 ].

This entry represents the conserved N-terminal domain of Cnd1.

1. Condensin and cohesin complexity: the expanding repertoire of functions. Nat. Rev. Genet. 11, 391-404
2. Phosphorylation and activation of 13S condensin by Cdc2 in vitro. Science 282, 487-90
3. Fission yeast condensin complex: essential roles of non-SMC subunits for condensation and Cdc2 phosphorylation of Cut3/SMC4. Genes Dev. 13, 2271-83