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Fig. 2
Yap1 acts cell autonomously to control trunk lymphangiogenesis in zebrafish.
( A) Overall morphology of sibling (left) and MZ yap1ncv101-/- mutant (right) at 5 dpf. Arrowheads indicate mild craniofacial defects and absent swim bladder. Scale bar 200 μm. ( B–C) Trunk vasculature of sibling and MZ yap1ncv101-/- mutant embryos at 5 dpf. Veins and lymphatics are displayed in white [ Tg(dab2b:EGFP)], erythrocytes show normal blood flow in red [ Tg(gata1:DsRed)]. Asterisks mark absent lymphatic vessels. ( C) Trunk vasculature of sibling and MZ yap1mw48-/- mutant at 6 dpf. Vascular nuclei are marked in green [ Tg(fli1a:nEGFP)], venous and lymphatic vessels in white [ Tg(−5.2lyve1b:DsRed)]. Asterisks indicate absent lymphatic vessels. Scale bars: 50 μm in B and C. ( D) Percentage of TD fragments formed per somite, scored across six somites in total for siblings and MZ yap1ncv101-/-mutants at 5 dpf (sibling: 100% ± 0, n = 23; MZ yap1ncv101-/-: 49% ± 7.33, n = 22; p,0.0001). ( E) Quantification of the total number of LECs across 6 somites at 6 dpf (sibling: 37 ± 1.91, n = 11; MZ yap1mw48-/-: 8 ± 3.79; p<0.0001). ( F) Schematic showing the cell transplantation technique. Blastomere cells are transplanted from donor (EGFP) into host (mCherry) embryos. This results in a chimeric host embryo (right) with randomly located, transplanted EC grafts. ( G) Representative images of host chimeric trunk vessels at 5 dpf. Wildtype (wt) donor ECs contribute to all vascular EC types, while MZ yap1ncv101-/- mutant ECs show reduced propensity to contribute to lymphatic structures. Asterisk marks missing TD. Scale bars: 50 μm. ( H) Graft sizes analysed for vascular grafts. Numbers within bars represent the number of embryos scored for each graft size. ( I) Percentage of embryos with EC grafts contributing to arterial (wt into wt: 96% ± 4; MZ yap1ncv101-/- into wt: 100% ± 0; p=0.31, not significant (ns)), venous (wt into wt: 91% ± 6; MZ yap1ncv101-/- into wt: 67% ± 10; p=0.04 (*)) and lymphatic vessels (wt into wt: 43% ± 10; MZ yap1ncv101-/- into wt: 8% ± 6; p=0.005 (**)). Wildtype into wildtype total number of EC grafts: n = 23; MZ yap1ncv101-/- mutant into wildtype total number of EC grafts: n = 24. Dorsal aorta (DA); Posterior Cardinal Vein (PCV); Thoracic Duct (TD); Intersegmental Lymphatic vessel (ISLV), Dorsal Longitudinal Lymphatic vessel (DLLV).