Melanoblast proliferation and apoptosis in bt^9J/+ and bt^9J/bt^9J embryos.

(A–F) Representative immunofluorescence images depicting 16 µm trunk sections from bt^9J/bt^9J E13.5 embryos assayed for proliferation (A–C) and apoptosis (D–F). Proliferating melanoblasts were identified by staining sections for LacZ (cytoplasmic red, A) and PH3 (nuclear green, B), and their co-localization together with nuclear DAPI staining (blue, C). Apoptotic melanoblasts were identified by staining sections for LacZ (cytoplasmic red, D) and CC3 (cytoplasmic green, E), and their co-localization together with DAPI (blue, F). (G–H) The Y axis (%Dct+PH3+ and %Dct+CC3) indicates the average percentage of total melanoblasts per section that are PH3 positive (G) or CC3 positive (H), for bt^9J/+ (blue) and bt^9J/bt^9J (red) E13.5 embryos (n = 5 embryos for each genotype). The total number of sections and melanoblasts analyzed are listed beneath each graph, as well as the standard deviations. Asterisks indicate highly significant P values. The scale bars are: (A–F) 0.5 µM.