Figure 1A. Schematic of the intron targeting-mediated strategy for generating hey2zCKOIS zebrafish by using the CRISPR/Cas9 system. Figure 1B. Schematic of the strategy for endothelial cell (EC)-specific KO of hey2. Figure 1C. Projected confocal images (lateral view) of trunk vessels in a hey2zCKOIS/zCKOIS;Ki(flk1-P2A-Cre) embryos at 3.5 dpf. Figure 1D. In the absent of Cre, EGFP was expressed in the DA (arrowheads), and no red fluorescent signal was not detected in the TagRFP channel. Scale bars, 100 μm.