Figure 2.

Gene knockdown experiments using an antisense morpholino oligonucleotide (antisense-MO) designed on the basis of the sequence at the 5′-untranslated region of zebrafish homologue of nuclear CaMKP-N (zCaMKP-N) mRNA. Zebrafish embryos at the 1–4 cell stage were injected with an antisense-MO or a 5-base mismatch morpholino oligonucleotide (5mis-MO). At 48 hours post-fertilization, embryos were stained with acridine orange and observed by stereoscopic microscopy. Injection of the antisense-MO resulted in abnormal apoptotic cell death during embryogenesis. Arrowheads indicate apoptotic cells stained with acridine orange (white spots). CaMKP, Ca²⁺/calmodulin-dependent protein kinase phosphatase.