Fibrillin-2b regulates endocardial morphogenesis in zebrafish.

scotch tape (sco) is a zebrafish cardiac mutant initially proposed to exhibit a reduced amount of cardiac jelly, the extracellular matrix between the myocardial and endocardial layers. We analyzed sco(te382) mutant hearts in detail using both selective plane illumination microscopy (SPIM) and transmission electron microscopy (TEM), and observed a fascinating endocardial defect. Time-lapse SPIM imaging of wild-type and mutant embryos revealed significant and dynamic gaps between endocardial cells during development.