Fig. 6

Arterial-Venous Differentiation Is Affected by Etv2 Function at Distinct Time Points (A–E) flk1/kdrl expression analysis at 22 hpf stage. Control uninjected (A), MO-injected but never uncaged (B), uncaged at the sphere (C), 10-somite (D), and 15-somite (E) stage embryos. Note that both the dorsal aorta (arrows) and the posterior cardinal vein (arrowheads) are absent in (C); the dorsal aorta is partially (D) or fully present (E), while the vein is greatly reduced or absent. (F–Q) Arterial grl (F, H, J, L, N, and P) and venous mrc1 (G, I, K, M, O, and Q) expression at 24 hpf in photoactivatable etv2 MO-injected embryos. (F and G) Control uninjected, (H and I) uncaged at 30% epiboly, (J and K) 7-somite stage, (L and M) 13 to 14-somite stage, (N and O) 16- to 17-somite stage, and (P and Q) MO-injected but never uncaged embryos. Note that arterial grl expression (arrows) is absent in (H) but is partially present in (J) and not significantly affected when MO is photoactivated at the 13- to 17-somite stages (L and N). Venous mrc1 expression (arrowheads) is absent or strongly reduced in both early (I and K) and late photoactivated embryos (M and O). Scale bar, 100 μm. See also Figure S4.