Fig. 7

a Local weakening of EC cortex induces basal bleb. Laser ablation (magenta line) of an arterial ISV was performed in a 3 dpf Tg(kdr-l:ras-mCherry)^s916 embryo. Bleb formation was observed in 18 out of 35 ISVs (n = 15 embryos, 2 independent experiments). Arrow, basal bleb. b, c Short-term inhibition of actin polymerisation in 2 dpf Tg(kdr-l:ras-mCherry)^s916 embryo leads to increased membrane bleb generation at both apical (arrow) and basal (arrowheads) membranes (b). Quantification of basal blebs along the length of ISVs in 49–52 hpf Tg(kdr-l:ras-mCherry)^s916 embryos after treatment with 0.3 µg/ml Latrunculin B for 2.5–3 h (c, 0.03% DMSO treatment: aISVs, n = 37 ISVs/25 embryos; vISVs, n = 39 ISVs/25 embryos; Latrunculin B treatment: aISVs, n = 36 ISVs/22 embryos; vISVs, n = 39 ISVs/24 embryos). Data were collected from three independent experiments. Violin plots represent the entire range of values, dotted lines indicate first and third quartiles, center lines are median. Statistical significance was determined by two-tailed unpaired t-test. d Basal blebs (arrowhead) induced by increased expression of Marcksl1b are suppressed upon decreasing blood flow using 4X tricaine (i and ii, reduced blebbing was observed in 7 out of 8 embryos from 6 independent experiments). Reestablishment of normal blood flow (1X tricaine) increases apical membrane blebbing (arrow in i) and vessel diameter (iii). Triangle, filopodia. 00:00, hh:mm after start of treatment. Dashed boxes, magnified region in b, d. ISV intersegmental vessel; aISV arterial ISV; vISV venous ISV. Scale bars, 5 µm (a, b and iii in d) and 10 µm (i in d). Source data are provided as a Source data file.