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Fig. 3
Notch Signaling Is Not Required for Early Arterial Expression of Dll4 (A) Transient transgenesis of wild-type F2:GFP compared to a RBPJk mutant construct (F2ΔRBPJk:GFP). DA, dorsal aorta; PCV, posterior cardinal vein; ISV, intersomitic vessel. (B) Whole-mount images (left), and transverse sections (right) of wild-type and RBPJk-mutated F2-lacZ transgenic embryos. (C) Expression of F2:GFP in control and rbpjk morphant (MO) embryos, demonstrating normal enhancer activity in the DA (arrow) at 20 somites, but decreased expression at 26 hpf. Expression of kdrl:GFP in the DA was unaffected. (D) F2-lacZ expression was reduced but present in the DA of Rpbjk-/- embryos at E8.5 (Rpbjk+/+, n = 25; Rpbjk-/-, n = 5) and E8.25 (Rpbjk+/+, n = 14; Rpbjk-/-, n = 4). (E) F2-lacZ expression was normal at E8.5 (left), and at E9.5 in whole-mount (center) and transverse sections (right) from embryos with endothelial cell-specific loss (ECKO) of Rbpjk, although mutants had a reduced DA diameter (bar) at E9.5, as previously reported (Krebs et al., 2004) E9.5, Rpbjkdel/fl, n = 6; RpbjkECKO, n = 4; E8.5, Rpbjkdel/fl, n = 8; RpbjkECKO, n = 3. (F) In situ hybridization shows that Rbpjk is not absolutely required for Dll4 expression at E8.5 (n = 3 for each genotype). DA, arrows; asterisk, neural tube. Scale bars represent 50 µm (A and C), 500 μm for whole-mounts, and 100 μm for sections (B and D–F). See also Figure S2.
Reprinted from Developmental Cell, 26(1), Wythe, J.D., Dang, L.T., Devine, W.P., Boudreau, E., Artap, S.T., He, D., Schachterle, W., Stainier, D.Y., Oettgen, P., Black, B.L., Bruneau, B.G., and Fish, J.E., ETS Factors Regulate Vegf-Dependent Arterial Specification, 45-58, Copyright (2013) with permission from Elsevier. Full text @ Dev. Cell