Vegfa/Vegfr signalling is necessary for ISV lumenisation maintenance and DLAV formation. (A) Maximum intensity projections at 48 hpf of the trunk of MO-CTL (5 ng) and MO-svep1 (5 ng), Tg(fli1a:eGFP)y7 embryos treated with 1× (0.014%) tricaine, with or without 50 ng ZM32881. Red asterisks indicate gaps in the DLAV. (B) Bilateral quantifications of the percentage of gaps in the DLAV at 48 hpf in MO-CTL (5 ng) [n=29 (0 nM ZM32881), n=28 (50 nM ZM32881)], MO-svep1 (5 ng) [n=29 (0 nM ZM32881), n=26 (50 nM ZM32881)] embryos treated with 1× (0.014%) tricaine and 0 nM or 50 nM ZM32881 from 30 to 48 hpf (N=3). (C) Bilateral quantifications of the percentage of lumenised segments in the DLAV at 48 hpf in MO-CTL (5 ng) [n=29 (0 nM ZM32881), n=28 (50 nM ZM32881)], MO-svep1 (5 ng) [n=29 (0 nM ZM32881), n=26 (50 nM ZM32881)] embryos treated with 1× (0.014%) tricaine and 0 nM or 50 nM ZM32881 from 30 to 48 hpf (N=3). Data are mean±s.d. Mann–Whitney test. n.s., not significant. Scale bars: 50 μm (A).