During heart formation, cardiac precursors start out as bilateral sheets of cells that move toward the midline, where they converge, surround the central endocardium, and rearrange to create the heart tube. Though the tissue level shape changes that occur during heart tube formation are beginning to be understood, little is known about the cell behaviors or the molecular regulation of this process. Tracking the movement of individual GFP-expressing cardiomyocytes in wild-type zebrafish embryos and in zebrafish mutants with heart tube defects suggests that highly regulated, coordinated cell movements are required to form the heart.

We are currently examining the role of the endoderm, endocardium and yolk in directing the movement of the myocardium.