Figure 4

Gain- and loss-of-function of activin-like signaling inhibit the sprouting of ISV. One blastomere of two-cell stage embryos was injected with constitutively active activin receptor (CA hALK4) DNA, dominant negative activin receptor (DN hALK4) DNA or dominant negative Smad3 (DN Smad3) DNA together with nuclear β-galactosidase mRNA as a lineage tracer and later subjected to insitu hybridization using Xmsr probe. (A) Uninjected control embryo. (B) CA hALK4 (1 ng)-injected embryo. (C) DN hALK4 (1 ng)-injected embryo. (D) DN Smad3 (1 ng)-injected embryo. (E) The graph showing the effects of CA hALK4, DN hALK4, DN Smad3 and DN Smad2 on the ISV sprouts.