Fig. 8. itga4;itga5 double mutants have defects in myocardial morphogenesis and anterior endodermal sheet formation. (A–C) ISH for myl7 shows that myocardial cells eventually migrate to the midline in half of the itga4;itga5 double mutants, while the other half of itga4;itga5 double mutants have a cardia bifida phenotype. Arrow indicates trailing myocardial cells. (D–F) ISH for myl7 shows that the myocardial migration defect is weaker in itga5 single mutants than in itga4;itga5 double mutants. (G–L) ISH for axial (foxa2) expression in the anterior endodermal sheet of WT, sibling embryos, and itga4;itga5 double mutants. Parts of the anterior endodermal sheet are narrower or missing in itga4;itga5 double mutants. (M–P) Two-color ISH for foxa2 (blue) and myl7 (red) shows that the myocardial cells can migrate to the midline in about half of itga4;itga5 double mutants that have a very narrow or absent endodermal sheet. Arrowheads indicate myocardium. Scale bar is 20 μm.
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