Fig. 6

Notch inhibits ectopic arterial sprouting in flt1^ka601 mutants.

(a), flt1^ka601 mutants show ectopic venous sprouts (blue circles), but no arterial sprouts. (b) Inhibiting arterial Notch by endoxifen-induced arterial ISV-specific expression of dominant negative MAML-eGFP (Notch ^i?EC) at 52?hpf under control of the flt1^enh promoter in flt1^ka601 mutant results in the emergence of ectopic arterial sprouts (red circles); representative image from 7 experiments. (c?e) Trunk vasculature of WT (c), flt1^ka601(d) and flt1^ka601 treated with Notch inhibitor LY-411575 (e). LY-411575 was added at 2?dpf. Note the emergence of ectopic arterial sprouts upon LY-411575 treatment. (red arrowhead: arterial sprout; blue arrowhead: venous sprout). (f) Quantification of experiments in (a?e), mean±s.e.m., n=7 for Notch^i?EC, n=10 for LY-41157 treatment, n=10 for flt1^ka601; t-test. (g?i) Imaging of pericytes in TgBAC(pdgfrb:EGFP);Tg(fli1a:myr-mcherry) double transgenic at 54?hpf. (j) Schematic representation of pericyte number counting in ISVs as performed in (k). (k) Quantification of pericyte recruitment in aISVs and vISVs at 54?hpf. (n=246 ISVs from 14 embryos). ISV, intersegmental artery; Notch ^i?EC, inducible ISV-specific loss of Notch; vISV, intersegmental veina. Scale bar, 25??m in a?e,g?i.