Fig. 2. Cyclin E localizes to mitotic chromosomes and interphase nuclei throughout early development. Early sea urchin embryos (L. pictus) were fixed at timepoints throughout M-phase of the first cell cycle (A-C), and at the 2- (D-F), 4- (G), and 16-cell stages (H). The embryos were then processed for confocal-immunofluorescence microscopy using antibodies to cyclin E (shown in red) and -tubulin (shown in green). Bars, 25 µm.