Condensin-dependent localisation of XXXX to an axial chromosomal structure is required for sister chromatid resolution during mitosis.

@entity70955 @entity238 @entity70954 @entity61717
Assembly of compact mitotic chromosomes and resolution of sister chromatids are two essential processes for the correct segregation of the genome during mitosis. Condensin, a five-subunit protein complex, is thought to be required for chromosome condensation. However, recent genetic analysis suggests that condensin is only essential to resolve sister chromatids. To study further the function of condensin we have depleted @entity70954 , a subunit of the complex, from @entity238 S2 cells by dsRNA-mediated interference. Cells lacking @entity70954 assemble short mitotic chromosomes with unresolved sister chromatids where Barren, a non-SMC subunit of the complex is unable to localise. @entity61717 , however, binds mitotic chromatin after depletion of @entity70954 but it is no longer confined to a central axial structure and becomes diffusely distributed all over the chromatin. Furthermore, cell extracts from @entity70954 dsRNA-treated cells show significantly reduced @entity61717 -dependent DNA decatenation activity in vitro. Nevertheless, @entity70954 -depleted chromosomes have centromeres and kinetochores that are able to segregate, although sister chromatid arms form extensive chromatin bridges during anaphase. These chromatin bridges do not result from inappropriate maintenance of sister chromatid cohesion by @entity70955 , a subunit of the @entity70955 complex. Moreover, depletion of @entity70954 prevents premature sister chromatid separation, caused by removal of @entity70955 , allowing cells to exit mitosis with chromatin bridges. Our results suggest that condensin is required so that an axial chromatid structure can be organised where @entity61717 can effectively promote sister chromatid resolution.
