Direct cell cycle comparison between embryos injected with Geminin and grp mutant embryos. (A) Either wild-type or grp mutant embryos expressing Histone-GFP were injected with control buffer or Geminin. Time is presented in min:sec. (B) Quantification of interphase chromatin dynamics and mitotic duration from embryos in A. Nuclear envelope formation (NEF) to the beginning of chromatin condensation was measured and the time from chromatin condensation to the onset of mitosis was measured (onset of mitosis was defined by disappearance of the Histone-GFP halo around the chromatin and the first chromatid movements). Average cell cycle times are shown for wild-type (n = 8 embryos), grp (n = 18 embryos), Geminin injected (n = 10 embryos), and Geminin injected into grp (n = 11 embryos). Error bars represent SD.