Fig 7
Photoconversion experiments show that delamination defects in gata1 mutants result in misassignment of cells from luminal to abluminal cell fate.
(A) Flow diagram summarizing the method used in this set of photoconversion experiments. At 48 to 50 hpf, embryonic hearts were stopped using BDM and the ventricle and the ventricular side of the AVC were photoconverted. The embryos were then returned to normal media and allowed to grow normally until 65 hpf, when the heart was stopped again using BDM and the valve imaged (first and second columns in (B–C’)). They were then returned to normal media and allowed to grow normally until 98 hpf, when the heart was stopped using BDM and they were imaged again (third and fourth columns in (B–C’)). (B) Representative images of gata1 controls showing that if the superior layer of the abluminal bilayer and the cell deepest in the CJ is photoconverted at 65 hpf, then all abluminal cells will be photoconverted at 98 hpf. (C) Representative images of gata1 mutants showing that if the superior layer of the abluminal bilayer and the cell deepest in the CJ is photoconverted at 65 hpf, then only some abluminal cells near the base of the valve will be photoconverted at 98 hpf. (C’) Representative images of gata1 mutants, showing that if the entire abluminal bilayer is photoconverted at 65 hpf, then all abluminal cells are photoconverted at 98 hpf. (D) Proposed fate map of gata1 mutants. Cells are colored to indicate position and fate over time. Asterisks at 80 hpf denote cells that have been misassigned from luminal to abluminal cell fate and their progeny. AVC, atrioventricular canal; BDM, 2,3-butanedione monoxime; CJ, cardiac jelly; hpf, hours postfertilization; RBC, red blood cell; VIC, valve interstitial cell; WSS, wall shear stress. |