pRb and condensin--local control of global chromosome structure.

Rb mutants exhibit aneuploidy and aberrant chromosome structure during mitosis. In this issue of Genes & Development, a new paper from Longworth and colleagues (1011-1024) describes both physical and functional interactions between Drosophila Rbf1 and the dCAP-D3 subunit of condensin II. This work directly implicates the Rb family proteins in mitotic chromosome condensation and suggests that a failure in targeting condensin II to chromatin underlies the aneuploidy in rbf1 mutants.