Antisense knockdown of flk1 in zebrafish abolishes ORF48R-induced effects. The wild-type embryos are shown in panels A and a (48 hpf), B and b (72 hpf), and C and c (4 dpf). The NC-Mo-injected embryos are shown in panels D and d (48 hpf), E and e (72 hpf), and F and f (4 dpf). The anti-flk1-Mo- and NC-Mo-coinjected embryos are shown in panels G and g (48 hpf), H and h (72 hpf), and I and i (4 dpf). The pG48R- and anti-flk1-Mo-coinjected embryos are shown in panels J and j (48 hpf), K and k (72 hpf), and L and l (4 dpf). The pG48R-injected embryos are shown in panels M and m (48 hpf), N and n (72 hpf), and O and o (4 dpf). Normal (upper panels) and fluorescence (lower panels) images of zebrafish embryos expressing the fusion gene were recorded continuously for 3 days after embryonic injection. Bar, 300 μm for all panels.