Fig. 8

Ang2 gain and loss of function in neural crest alters endothelial cell migration. Stills from time-lapse movies of Tie1:H2B-YFP quail embryos where the premigratory neural crest has been electroporated with control vector (a), Ang2-FL (b), or Ang2-shRNA (c). Lead neural crest cell marked with asterisk in all images except control at 9 h, where the front of the stream has migrated past the image area. Endothelial cells cluster near the dorsal aorta (white circle) and sprout after the lead neural crest passes the dorsal aorta in control. This event occurs early in Ang2-FL. In addition, the sprout created in the Ang2-FL embryo collapses and retreats back to the dorsal aorta before it reaches the perineural vascular plexus (triangle). c Without Ang2 expression, the lead neural crest cells reach their position near the dorsal aorta, but no endothelial cells sprout. In this example, endothelial cells from below the otic vesicle emerge in a plexus to the posterior side of the neural crest stream (white arrow). In addition, some endothelial cells invade the stream, disrupting the neural crest migration. Isolated neural crest marked with asterisk. Scale bars 20 μm. d Example MSD curves. e Mean MSD curves for endothelial cells from same movies in Fig. 6. Control: 14 cells, Ang2-FL: 46 cells, and Ang2-shRNA: 14 cells. f Bayesian analysis of in vivo endothelial cells’ MSD curves, legend at bottom