Fig. 3.

ErbB2 signaling from 68-72 hpf is required for the initiation of cardiac trabeculation. (A,B) Extensive cardiac trabeculation in wild-type control (A) at 5 dpf and absence of cardiac trabeculation in wild-type larvae (B; data not shown) treated with 5 μM AG1478 from 60, 63 or 68 to 120 hpf. (C-E) Some cardiac trabeculae formed in wild-type larvae that were allowed to develop until 7 dpf after treatment with 5 μM AG1478 from 60-120 hpf. (F) Quantification of cardiac trabecular formation in control and AG1478-treated larvae, as determined by measuring the surface area of the trabecular myocardium and the compact myocardium (larvae treated as in A-E).