Movie S3

Time-lapse imaging of cells labeled at two neighboring anteroposterior levels with DiI (magenta) or DiO (green) in one of the paired heart primordia. This pattern of labeling clearly shows that cells initially arrayed anteroposteriorly reorient mediolaterally during heart tube formation. Selected images are shown in Figure 3B. Annotated, duplicated time-lapse images are shown in the right panel. Red and blue dots depict the original medial and lateral edges of the DiI-labeled cell stripe (magenta), respectively.