Figure 8.

Schematic model to explain the mechanism of flare formation. (A) The structural changes experienced by the nucleus and nucleolus of dividing cells. Cell body, gray; the bulk of the DNA mass, blue; nucleolus, green; and spindle pole body, purple. Note that in anaphase, the nucleolus trails behind the bulk of the DNA. The arrow indicates the region of the nuclear membrane that has to be removed after the nucleus divides. In spo7Δ mutants, a flare may form due to incomplete removal of this membrane region at the end of anaphase, or it can form some time after nuclear division. (B) Model. The expansion of the nuclear membrane around the bulk of the DNA is restricted by a tethering mechanism, indicated as red staples, that is excluded from the nucleolus.