Fig. 9

Interaction between stap2b and Notch or bone morphogenetic protein (BMP) signals to control vascular patterning. (A?D) stap2b expression is increased while inactivation of Notch signals, as determined by in situ hybridization of DAPT-treated embryos (B) or knockdown of rbpsuh (D) compared to the wild-type control (C) at 24 hpf. (E and F) Quantification of the relative expression level of stap2b in DMSO control and DAPT-treated embryos (E), and in uninjected wt control and rbpsuh morphants (F). (G?J) DM and DMH1 were used to inhibit BMP signaling. Stap2b expression was reduced in DM- and DMH1-treated embryos (H and I) compared to the DMSO control (G) at 30 hpf. (J) Quantification of the relative expression level of stap2b in control, DM-treated and DMH1-treated embryos at 30 hpf. (K) Quantification of the relative expression level of BMP-regulated genes in stap2b morphants. The expression of id1 (0.68 ± 0.04), eve1 (0.49 ± 0.12), dlx3b (0.68 ± 0.06), and gata2 (0.41 ± 0.03) was reduced in stap2b morphants, but the expression of msx1b (0.94 ± 0.09) was not changed. (L) Western blots and densitometry analysis showed reduced phosphorylation of Smad1/5/8 and Smad1 in stap2b morphants compared to the control, and ?-actin was a loading control. Scale bars are 200 ?m for A?D and G?I. Data are shown as means ± S.D. ***Refers to p < .001 by an unpaired Student's t-test. (M) A schematic drawing of the proposed interaction of stap2b with multiple signaling proteins to control vascular growth in this study.