xCdc4ΔFbox does not reduce neural crest by inducing apoptosis. (A,B) xCdc4ΔFbox or xCdc4 mRNA (1 ng) was injected into one cell of two-cell-stage embryos. (C) GFP mRNA (1 ng) was injected as a control, and β-gal mRNA was injected as a lineage tracer (light blue unilateral staining). Apoptosis was assessed using TUNEL staining. Arrow indicates TUNEL-positive cells. Representative embryos are shown (anterior view, dorsal up, injected side right). (D) The area of Snail2 staining on the injected side was expressed as a ratio of the area on the uninjected side, and for each experiment an average ratio was obtained (see Materials and methods). Mean ± standard error of the mean ratio from two independent experiments are shown (n = 57-82). (E-J) xCdc4ΔFbox, xCdc4 or GFP mRNA (1 ng) was injected into one cell of two-cell-stage embryos, along with 1 ng of hBclXL or 1 ng of GFP mRNA as indicated, with β-gal mRNA as a lineage tracer (light blue unilateral staining). Whole mount ISH for Snail2 was performed on stage 18 embryos. The reduction in expression of Snail2 on the injected side of xCdc4ΔFbox expressing embryos is not rescued by co-injection of hBclXL (arrowheads). Representative embryos from the indicated injections are shown (anterior view, dorsal up, injected side right).