Figure 1

Figure 1 (a) Diagram of ~7 wpf zebrafish heart depicting the outflow tract (OFT), ventricle (V) and lymphatics (red). (b) At 10 wpf (fish size 16–24 mm) prox1a-labeled collecting lymphatics are clearly detected in the OFT, but absent on the ventricular surface (n = 9). (c,d) Quantification of 21–34 dpf (fish size 7–14 mm) OFT lymphatic development in prox1a (c) (n21dpf=48, n28dpf=38, n34dpf=19) andlyve1b (d) (n21dpf=12, n28dpf=11, n34dpf=13) transgenic zebrafish. (e) Diagram of adult zebrafish heart depicting ventricular lymphatics (white arrows), fat-associated lymphatics (yellow arrows) and isolated lymphatic clusters (blue arrows). OFT and ventricular lymphatics as well as isolated lymphatic clusters in 22–24 wpf (fish size 25–30 mm) are labeled by the flt4 (f), lyve1b (g), prox1a (f,h) and mrc1a (g,h) (nf = 4, ng = 5, nh = 5) transgenic reporters. (i) 1–5 cells at the tip of ventricular lymphatics are labeled primarily by the flt4 transgene (arrows). Nuclei are labeled by DAPI (blue) (48wpf, fish size 25–30 mm, n = 5). (j) Ventricular lymphatics are not labelled by the blood vessel/endocardial- marker Tg(kdrl:nls-mCherry) (23wpf, fish size 25–30 mm, n = 5). (k) Angiogram of 28 wpf (fish size 28 mm) Tg(flt1_9a_cFos:GFP);Tg(lyve1b:dsRed2) heart. Cardiac lymphatics (arrows) are not labeled following intravascular injection of Qdot705 (blue) (n = 6). Scale bars are 200 µm in b, f-h, j, k; 50 µm in i. Posterior view in b, anterior view in f-k.