FIGURE SUMMARY
Title

roundabout4 is essential for angiogenesis in vivo

Authors
Bedell, V.M., Yeo, S.Y., Park, K.W., Chung, J., Seth, P., Shivalingappa, V., Zhao, J., Obara, T., Sukhatme, V.P., Drummond, I.A., Li, D.Y., and Ramchandran, R.
Source
Full text @ Proc. Natl. Acad. Sci. USA

Expression patterns of robo4 in development. A montage of robo4 whole-mount in situ staining is shown, with 16 (A), 19 (B), 20 (C), 23 (D), 24 (E), and 20 (F) som. (G) High power of F.(H) High power of I.(I) A 22-som telencephalon (t), hindbrain (hb), and neural tube (nt). J is 28-29 hpf. Arrowhead in G indicates expression in angioblasts; asterisk in H shows ISV expression. robo4 (K), G-RCFP (L), DAPI (M), and merge (N) show two-color staining of frozen 20-μm anterior trunk sections of vegfr2-G-RCFP 25-hpf embryos. The arrowhead and asterisk in K-N indicate ISV and axial vessels, respectively. Images were taken with a x20 (A-E), x10 (F, I, and J), x40 (G and H), and x20 (K-N) lens with x2.5 zoom.

EXPRESSION / LABELING:
Gene:
Fish:
Anatomical Terms:
Stage Range: 14-19 somites to Prim-5

Splice MO targeting and endothelial marker analysis of MO-injected embryos. (A) The exon-intron genomic structure from exon 7-12 is shown. Splice MO1 and MO2 target the predicted TM domains. Total RNA was extracted from uninjected (lane 1), MO (lane 2; MO1, upper gel; MO2, lower gel), and msMO (lane 3; msMO1, upper gel; msMO2, lower gel) embryos at 24 hpf, and RT-PCR was performed. Black, gray, and dotted arrows indicate the alternative transcripts that were generated in MO-targeted embryos (lane 2), the black arrowhead indicates a common untargeted bands in lanes 1 and 3, and the gray arrowhead points to 1.5-kb band in lane 2. E, exon. (B) Structural details of predicted protein products generated from aberrant splicing are shown. Hexagons, pentagons, white bar, and black bars represent IgG, FN, TM, and CC domains, respectively. Double staining with flk digoxigenin RNA (blue) and Ab to znp-1 (C-E) (brown) or acetylated tubulin (F and G) in the trunk region of 22-24 som is shown. (C-G) Magnified images of the trunk region, showing WT (C and F), MO1-injected (8 ng) (D and G), and MO2-injected (8 ng) (E) embryos. Asterisk indicates location of ISV. (H) Quantification of embryos with ISV defects. WT (I), MO1 (J), and msMO1 (K) show in situ staining for cdh5 marker at 24 hpf. Anterior is to the left.

EXPRESSION / LABELING:
Genes:
Fish:
Anatomical Terms:
Stage: Prim-5

robo4 overexpression results in misdirected or truncated flk+ ISV from DA. WT (A), YFP (B), and robo4 (C) RNA-injected embryos at 22-24 som are shown. (D) Quantitation of overexpression is shown for WT (n = 36), YFP (n = 29), and robo4 (n = 28). Anterior is to the left.

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.

Unillustrated author statements

EXPRESSION / LABELING:
Gene:
Fish:
Anatomical Term:
Stage: 75%-epiboly
Acknowledgments
This image is the copyrighted work of the attributed author or publisher, and ZFIN has permission only to display this image to its users. Additional permissions should be obtained from the applicable author or publisher of the image. Full text @ Proc. Natl. Acad. Sci. USA