Fig. 5. Effect of forced expression of ZBP-89 on hematopoietic and vascular development in zebrafish embryos. (A-J) Wild type (A,C,E,G,I) and ZBP-89-overexpressing (B,D,F,H,J) 18 hpf (A-F) or 24 hpf (G-J) zebrafish embryos. In situ hybridization of wild-type embryos overexpressing ZBP-89 reveals a marked increase in the expression of scl (B), lmo2 (D) and gata1 (F), but a marked reduction in intersomitic expression of the endothelial markers flk1 (H) and tie1 (J), when compared with the respective untreated wild-type embryos (A,C,E,G,I), (K,L) Wild-type (K) and ZBP-89-overexpressing (L) Tg (flk1:EGFP) zebrafish embryos examined at 24 hpf. Overexpression of ZBP-89 caused a significant reduction in flk1 expression in the axial (arrows), brain (short arrow) and intersomitic (arrowheads) blood vessels when compared with the control embryo.