Whole-mount in situ hybridization of CD146 in zebrafish. The digoxigenin-labeled antisense probe was derived from the first 0.6 kb of the mRNA. A: Overall staining pattern of CD146 in a 24-hour postfertilization (hpf) embryo. B: A magnification at the trunk-tail region of a 24-hpf embryo. Notice the staining of the intersomitic vessels (green arrow), dorsal aorta (red arrow), caudal artery (red arrowhead), and the caudal vein (blue arrowhead). Staining of the posterior cardinal vein was noticeably absent at this stage (blue arrow). Staining of neuronal cells was also seen at this stage (black arrow). C: Staining pattern in the head region of an embryo at 3 days postfertilization. D: Cross-section of an embryo at 24 hpf at the trunk region showing the expression of CD146 in the artery and a very low level of expression in the vein. E: Expression pattern of CD146 mRNA in a 2-day-old embryo showing endothelial specificity. Notice the expression of CD146 in the posterior cardinal vein. F: Cross-section of a 3-day-old embryo at the trunk region showing expression of CD146 in both the dorsal aorta and posterior cardinal vein.

Effects of morpholino oligonucleotide (MO) in vascular development in zebrafish. A,B: Embryos were injected with 0.8 pmol of either the control MO (A) or splice blocker 1 (B) and examined at 3 dpf. Movie clips of blood circulation (boxed regions) observed under light microscopy were also recorded (see Supplementary Movies 1A and B). C: Histogram showing the distribution of embryos according to percent of functional intersomitic vessels present at 3 days postfertilization (dpf). Amounts of the control MO or splice blocker 1 injected were 1.2 or 0.8 pmol, respectively. Results were the averages of three different experiments. The percentages do not add up to 100% due to rounding errors. D: A 3-day-old embryo injected with splice blocker 1 showing a curvature in the trunk/tail region. Scale bars = 0.1 mm in A,B,D.

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