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 ^iΔEC) 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^iΔEC, 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 ^iΔEC, inducible ISV-specific loss of Notch; vISV, intersegmental veina. Scale bar, 25 μm in a–e,g–i.