Fig. 3

(A) Schematic representation of the trunk vasculature with Intersegmental Vessels (ISV) sprouting from the dorsal aorta (DA). The tip cell leads the cell migration and the stalk cell maintains the connection with the DA. CV: cardinal vein. (B, C) Confocal projections of transgenic Tg(fli1a:GFP)^y1 wild-type (B) and prmt5 mutant (C) embryos at 28 hpf. Red rectangles delimit where DA close ups were made. White rectangles delimit the higher magnification (x2) of the DA with red lines indicating the dorsal aorta diameters. White arrows indicate the connection point between two ISVs to form the Dorsal Longitudinal Anastomotic Vessel (DLAV). Scale bar 100 μm. (D, E) Average ISV length in μm (D) and average number of endothelial cells per intersegmental vessel (E) in control and in prmt5 mutant embryos from 3 independent experiments with at least 3 animals per condition. T-test and Mann Whitney test were performed, respectively. ** P<0.01, ***P<0.001. (F, G) Confocal projections of transgenic Tg(fli1a:GFP)^y1 embryos injected by either control morpholino (F) or prmt5 morpholino (G) at 28 hpf. Scale bar 100 μm. (H, I) Average ISV length in μm (H) and average number of endothelial cells per ISV (I) in control and prmt5 morphant embryos, from 4 independent experiments with at least 5 animals per condition. Mann-Whitney test were performed. **** P<0.0001. (J, K) Confocal projections of control morphant (J) and prmt5 morphant (K) transgenic Tg(TP1bglob:VenusPEST)^s940 embryos labelling cells of the DA at 28 hpf. Yellow lines delimit the measured area occupied by the DA. Scale bar 25 μm. (L) Average area occupied by the DA in μm² in control and prmt5 morpholino injected embryos from 2 independent experiments with at least 8 animals per condition. T-test was performed. (M, N) Still images from movies of control (M) and prmt5 morphant (N) Tg(fli1a:GFP)^y1 transgenic embryos from 28 to 38 hpf. Red asterisks label missing connections between tip and stalk cells as well as missing connections between tip cells that should lead to DLAV formation. Red arrows point to connecting ISVs leading to DLAV formation. White arrows indicate supernumerary sprouts. Yellow asterisks label the lumen of ISVs. Scale bar 50 μm.