Regulating the onset of mitosis

In eukaryotes, G(2)/M progression is mediated by activation of mitosis prom oting factor (MPF). To ensure faithful chromosome segregation, the activity of key mitotic inducers and inhibitors are coupled with chromosome replica tion, spindle pole duplication, morphogenesis, and DNA damage. Evidence gat hered in the past two years has underscored the importance of positioning M PF and its regulators in the proper place at the proper time to ensure orde rly progression through the G(2)/M transition. Altering the spatial organiz ation of G(2)/M regulators also contributes to prevention of mitosis follow ing DNA damage.