Fig. 5. smp knockdown does not induce apoptosis. (A,B) At late blastula, the nuclear morphology of injected embryos was analyzed by DAPI staining (n=12 for injected-embryos, n=5 for control embryos). Flat-mounts of blastula displayed no evidence of apoptosis, although smpMOI-injected embryos have fewer nuclei. (C-G) TUNEL assay at later stages (dorsal views). No massive induction of apoptosis was detected in smpMOI-injected embryos at late gastrula (D, n=18) or at the 18-somite (G, n=23) stage, when compared with controls (C,F; n=7 and 6, respectively). (E) A few class II embryos displayed an increase in apoptosis, probably resulting from a secondary phenomenon due to epiboly delays. Scale bars: 100 µm.