Figure 7  Aberrant apoptosis of NCCs in Alk5/Wnt1-Cre mutants. TUNEL (A-H) and Cleaved Caspase-3 (I, J) staining at E11.0 demonstrates a notable increase in apoptosis in Alk5/Wnt1-Cre mutants (B, H, J) on the aortic sac level when compared to controls (A, G, I) or Alk2/Wnt1-Cre mutants (C) (frontal sections), while sections on the OFT level do not demonstrate differences between controls (D) and Alk5 (E) or Alk2 (F) mutants. G,H, TUNEL staining of lacZ-stained embryos demonstrates that apoptotic cells are of neural crest origin. G, control; H, mutant. AS, aortic sac, arrows point to clusters of apoptotic cells surrounding the aortic sac.