Fig. 4

robo4 gene knockdown affects flk⁺ ISV and rescue of defects by hrobo4. Splice MOs alone (12 ng) or in combination with hrobo4 RNA (150 pg) were microinjected into Tg(vegfr2: G-RCFP)^y10 zebrafish embryos at the one-cell stage, and images were taken at 22-24 som and 48 hpf. From left to right, images are MO, msMO, and MO+hrobo4-injected embryos. A-C and G-I show embryos at 22-24 som, whereas D-F and J-L show embryos at 48 hpf. (A and D) MO1 (n = 31). (G and J) MO2 (n = 28). (B and E) msMO1 (n = 31). (H and K) msMO2 (n = 54). (C and F) MO1+hrobo4 (n = 39). (I and L) MO2+hrobo4 (n = 46). (M) Quantitation for rescue experiments with hrobo4 (A-L). (N) Quantitation of embryos injected for WT (n = 124), MO2 (n = 119), MO2+robo1 (n = 82), MO2+robo2 (n = 115), and MO2+robo4 (n = 91). (O) Quantitation comparison of overexpression experiment for WT (n = 118), hrobo4 (n = 71), and robo4 (n = 91) RNA-injected (150 pg) embryos. A defective embryo was counted as three or more missing ISV. Anterior is to the left.