FIGURE 10:

Condensin has adapted to perform multiple functions in Tetrahymena’s two nuclei. In the germline nucleus, the conserved functions of condensin are required to condense and segregate chromosomes in meiosis and mitosis. In the presence of condensin, loop formation may compact chromosomes laterally and reduce the interface between sister chromatids. This could drive the action of Topo II toward decatenation, thus allowing chromatids to be separated easily by spindle forces. In the polyploid somatic nucleus, condensin acts as an anti-pairing factor that promotes the separation of newly replicated copies and maintains chromosome territories to prevent interaction between similar DNA molecules. These functions may help to maintain the even spacing of chromosome copies to aid the approximately equal segregation of copies during amitotic nuclear division.