Fig. 1. Fusicoccin (FC) induces heterotaxia. Systemic exposure of Xenopus embryos to FC between fertilization and stage 14, or microinjection of FC into dorsal blastomeres at the four-cell stage, resulted in heterotaxia relative to control embryos (A). Exposed embryos exhibited cardiac inversions (B), heart and gut inversions (C), gut inversions (D), and complete mirror image inversions (E). All embryos are shown in ventral views (thus the embryo's right is the reader's left), with anterior toward the top. Red, yellow and green arrows indicate the asymmetry of the heart, gut and gall bladder, respectively.