Figure 3.4

Vegfr-signalling is not required for rapid Erk activation following vessel wounding. (A–B’’) Lateral spinning disc confocal images of ISV endothelial cells (ECs) in 28 hours post-fertilisation (hpf) EC-EKC embryos treated for an hour with either 0.5% dimethyl sulfoxide (DMSO) (A–A’’), with active EC Erk-signalling, or 500 nM AV951 (B–B’’), with inactive EC Erk-signalling. Images (A) and (B) show the fli1aep:EKC expression, while images (A’) and (B’) show both the fli1aep:EKC and the fli1a:H2B-mCherry expression. Images (A’’) and (B’’) show the nuclear fli1aep:EKC intensity. (C) Quantification of nucleus/cytoplasm EKC intensity in ISV tip ECs of 28 hpf embryos treated with either 0.5% DMSO (0.849, 65 ECs, n = 14 embryos) or 500 nM AV951 (1.423, 53 ECs, n = 12 embryos). (D–Z’) Vegfr-signalling inhibitors do not block rapid Erk-signalling activation in ablated and adjacent ISVs following vessel wounding. Lateral spinning disc confocal images of ISV ECs in 4 days post-fertilisation (dpf) EC-EKC larvae treated with either 0.5% DMSO (D–I’), 15 μM SL327 (J–M’), 4 μM SU5416 (O–R’), 10 μM SU5416 (S–V’), or 500 nM AV951 (W–Z’). Images (D-E’) show non-ablated control ISV ECs. Images (F-G’), (J-K’), (O-P’), (S-T’), and (W-X’) show ablated ISV ECs. Images (H-I’), (L-M’), (Q-R’), (U-V’), and (Y-Z’) show adjacent ISV ECs. Images (F, H, J, L, O, Q, S, U, W, Y) were taken pre-ablation and images (G, I, K, M, P, R, T, V, X, Z) were taken 15 min post-ablation (mpa). Images (D-Z) show the fli1aep:EKC expression and images (D’-Z’) show the nuclear fli1aep:EKC intensity. White dotted lines show the wounded sites of each larva. ISV: intersegmental vessel. Statistical test: Mann-Whitney test was conducted for graph (C). Error bars represent standard deviation. Scale bars: 25 μm for image (A), 15 μm for image (D).