Expression of scl-β labels hemogenic endothelium that undergoes EHT. Time-lapse confocal imaging of a live Tg(scl-β:d2eGFP; kdrl:Ras-mcherry) zebrafish embryo from 30 to 43 hpf. (A-A′) Global views of the trunk region at 30 hpf. (B-K) Three VAE cells expressing scl-β:d2eGFP are seen to undergo EHT and subsequently enter circulation through the axial vein. Also see supplementary material Movie 2. Dashed circles and arrows (F,J,K) indicate HSCs that disappear from the AGM and enter into circulation. White arrows (A′,K) indicate the direction of the blood stream in the dorsal aorta. Scale bars: 30 μm in A-A′ 20 μm in B-K.
|