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Fig. 2 The intestinal lymphatics span the entire intestine and its development is closely associated with the intestinal blood vasculature. All the images used in this figure are generated from the lyve1:DsRed2;kdrl:EGFP transgenic. (A,A′) Lateral image of the right-hand side of the embryo showing the initial lyve1-positive vessel (indicated by asterisks) forming along the AMA, SIA and the PA at 4 dpf (A), with schematic diagram of arteries (red), veins (blue) and lymphatics (green) (A′). (B,B′) Dorsolateral image of the right side of the embryo showing the UR-IL and the LR-IL developing along the SIA and the R-SIV, respectively (B), with schematic diagram (B′). (C,C′) Lateral image of the left side of the embryo showing the UL-IL and the LL-IL that develops along the L-SIV (C), with schematic diagram (C′). Asterisks indicate the connection between the L-IL and the R-IL. The posterior regions of the SIA and the UR-IL are also visible. (D) Dorsal view of the intestinal vessels at 5 dpf. Dotted green lines represent proposed vessel connections between the L-IL and the R-IL. (E,E′) Lateral image showing the connections (indicated by asterisks) between the SILs and the TD at 5 dpf. Blue and black asterisks represent connections between the R-SIL and L-SIL with the TD, respectively. (F,F′) Ventral image showing a pair of LR-IL that forms in close proximity along the R-SIV at 6 dpf (F), with schematic diagram (F′). (G-H′) Lateral images of the right (G), and the left (H) side of the embryo showing the intestinal vessels at 7 dpf, with schematic diagrams (G′,H′). The L-IL branch is labelled with an asterisk in H and H′. (I,I′) Lateral image of the left side of the embryo showing the L-IL branches (indicated by asterisks) and branches extending from the R-IL to the left side of the intestine (indicated by pink arrows) at 15 dpf (I), with schematic diagram (I′). (J) Quantification of the number of L-IL branches at 7 dpf (average 1.3, n=22) and 15 dpf (average 4.4, n=10). Error bar represents 95% confidence interval. ***P<0.001. (K,K′) Lateral image of the right side of the embryo showing the intestinal vessels at 15 dpf (K), with schematic diagram (K′). Lymphatic vessels whose positions are variable between individual embryos are in pink. Connection between the L-IL and the R-IL is indicated with an asterisk. (L,L′) Lateral image showing the SIL branches (indicated by asterisks) at 15 dpf (L), with schematic diagram (L′). Only the lyve1:DsRed2 expression was shown for clarity. B,E,G,H,I,K,L are montage images. B,E,G,H,I used two z series stacks. K used six z series stacks. L used four z series stacks. AMA, anterior mesenteric artery; CCV, common cardinal vein; DA, dorsal aorta; DLLV, dorsal longitudinal lymphatic vessel; ISLV, intersegmental lymphatic vessel; L-IL, left intestinal lymphatics; LL-IL, lower-left intestinal lymphatic; LR-IL, lower-right intestinal lymphatic; L-SIL, left supraintestinal lymphatic vessel; L-SIV, left subintestinal vein; PA, pancreatic anlage; PCV, posterior cardinal vein; R-IL, right intestinal lymphatics; R-SIV, right subintestinal vein; SIA, supraintestinal artery; TD, thoracic duct; UL-IL, upper-left intestinal lymphatic; UR-IL, upper-right intestinal lymphatic. Scale bars: 100 μm in A-H; 200 μm in I-L.