Fig. 2. The onset of anaphase is regulated by both Cdk1-CycB activity and the Pim-Thr-Sse complex in a dose-dependent manner. The durations of cell-cycle phases are measured by analyzing timelapse recordings using two-photon microscopy in embryos with different levels of CycB and different components of Pim-Thr-Sse complex between cycles 6 and 11. The duration of prophase-metaphase and anaphase-telophase do not change between cycle 6 and 11 (Ji et al., 2004), thus data are averages of the duration from 10-20 time-lapse recordings of each genotype between cycle 6 and 11. Prophase-metaphase duration is 220 seconds in wild-type embryos (51 measurements from 20 embryos, s.d.=30 seconds); 270 seconds in four cycB embryos (51 measurements from 18 embryos, s.d.=40 seconds); 350 seconds in thr¹/four cycB embryos (24 measurements from 11 embryos, s.d.=60 seconds); 240 seconds in pim¹/four cycB embryos (33 measurements from 10 embryos, s.d.=30 seconds) and 230 seconds in sse^13m/four cycB embryos (52 measurements from 11 embryos, s.d.=30 seconds). When compared with four cycB embryos, the differences caused by lower thr, pim or Sse levels are significant (P<0.0002). There is no significant difference in the duration of anaphase-telophase in the five genotypes (duration varies between 160-180 seconds).