Fig. 5

flt1^ka601 mutants and vegfaa gain-of-function scenarios promote ectopic venous sprouting.

(a–d). Trunk vasculature at 3 dpf in WT (a), flt1^ka601 (b), vhl^hu2114 (c) and ptena^−/−;ptenb^−/− double mutants (d) in Tg(kdrl:EGFP)^s843 background. Note ectopic sprouts originate from vISVs (blue arrowheads) in mutants. aISVs indicated in red, vISVs in blue. (e) Quantification of ectopic sprouting in indicated mutants and inducible neuronal-specific vegfaa gain-of-function. In all models ectopic sprouting preferentially occurs in veins, mean±s.e.m., n=10-13/per group, t-test. (f,g) flt1^ka601 mutants show hyper-branching and knockdown of flt4 in flt1^ka601 mutant rescues hyper-branching; n=21 embryos per group. (h,i) Knockdown of flt4 in flt1^ka601; vhl^hu2114 double mutants (double) rescues hyper-branching; compare yellow dotted box in h,i. The position of vessels is colour-coded. Note: on loss of flt4 the trunk vasculature consists almost exclusively of aISV. (j) Quantification of h,i. Mean±s.e.m., n=12 embryos per group, t-test. (k,l) Loss of dll4 in flt1^ka601 mutants augments ectopic branching compared with untreated flt1^ka601 mutants. Note: on loss of dll4 the trunk vasculature consists almost exclusively of vISV; n=11 embryos per group, t-test. aISV, intersegmental artery; MO, morpholino; vISV, intersegmental vein. Scale bar, 30 μm in a–d,f; 50 μm in f–i,k.