Fig. S1

Related to Figure 1. Sema-PlxnD1 signaling limits the abundance of arterial angiogenic cells and axial vasculature ECs and is cell-autonomously required in the endothelium.

(A-B) obd have too many ECs in SeA sprouts/DLAVs and in the axial vasculature. Abbreviations: Segmental Artery sprouts (SeAs), Axial vessels (AxV), Dorsal Longitudinal Anastomotic Vessel (DLAV). (A) 21, 23 and 32 hpf trunk vasculatures of WT and obd. EC nuclei, green. EC membranes, red. Somite boundaries, blue. (B) Quantification of EC abundance in WT and obd at 21, 23 and 32 hpf. n=at least 6 embryos per stage per genotype. *p < 0.05, **p < 0.01, ***p < 0.001. Error bars, s.e.m. (C) plxnD1 is required cell autonomously in the endothelium. 32 hpf chimeric trunk vasculatures. Top row, chimera made using an obd donor and a WT host. Bottom row, chimera made using a WT donor and an obd host. ECs of host origin, red. ECs of donor origin, green. Lineage tracer-labeled donor cells, blue. Yellow arrows, examples of somitic muscle fibers of donor origin. (D) Quantification of the frequency with which ECs cells of donor origin form ectopic SeA sprouts in WT-to-obd and obd-to-WT chimeras (n=42 obd to WT, n=56 WT to obd) (E) SeA sprouts are not necessarily of clonal origin. Mosaic SeA sprouts in WT (left) and obd (right) homogenotypic 32 hpf chimeras. Donor ECs, green. Host ECs, red. (A, C, E) Anterior, left; dorsal, up. Scale bars, 30 μm.