The EGFP-bcl-2 fusion protein blocks developmentally regulated apoptosis at 16 hpf. TUNEL staining of an uninjected embryo (A) or embryos injected with GFP (B) or EGFP-bcl-2 RNA (C). (A-C) Lateral view of embryos at 16 hpf, dorsal to the left. TUNEL-positive apoptotic cells denoted by black staining. (D) Quantification of apoptotic cells in embryos injected with EGFP-bcl-2 RNA (red bar) when compared with uninjected control (beige bar) or GFP-injected control fish (blue bar). The asterisk denotes a significant difference between EGFP-bcl-2-injected (n = 12) and both GFP-injected (n = 12; P = .000 04) and uninjected fish (n = 12; P = .000 04). There were no differences in the mean number of apoptotic cells between the 2 control groups (P = .22). Error bars (1+/- standard deviation). Images A-C photographed at 2×.