||Figure 2. (A–C) Modulators of tissue compliance applied during stages of early heart development exhibit defects, including pericardial and neural edemas (A) (see arrows; scale bar, 1 mm), altered AP length (B), and increased rates of edema per clutch (C) (n = 30–35 embryos over four clutches).
(D) Compliance measured by microaspiration of HFR.
(E) Compliance at stage 22 confirms that blebbistatin and Y27632 increase and calyculin A decreases compliance (n = 11–17 embryos per treatment over three clutches).
(F) Transverse sections through HFR at stage 28 show changes in polarity (aPKC or ZO-1) within the progenitor population (red). Lower panels show the epithelial marker masked using tropomyosin expression (scale bar, 50 μm).
(G) Apical intensity after small-molecule inhibitor treatment (n = 9–13 embryos over four clutches).
(H) Representative lateral confocal sections of stage 39 tadpole hearts (scale bar, 100 μm).
(I) Cardiac anatomy after stage-specific inhibitor treatments as shown in Figure S2 (n = 5 embryos per treatment per period).
Error bars represent mean ± SEM. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. See also Figures S1, S2, and S3A.