xCdc4ΔFbox does not affect the cell cycle. xCdc4ΔFbox or xCdc4 mRNA (1 ng) was injected into one cell of two-cell-stage embryos. GFP mRNA (1 ng) was injected as a control, and β-gal mRNA was injected as a lineage tracer (light blue unilateral staining). Whole mount antibody staining against phH3 was performed to detect mitotic cells. The average percentage difference in the number of mitotic cells on the injected side, compared to the uninjected side, was calculated as indicated in Materials and methods. Representative embryos are shown (anterior view, dorsal up, injected side right).