Whole-mount fluorescent in situ hybridization was performed as previously described using the fgf10 probe(16 (link)). Whole mount IF staining was performed as previously described (16 (link)). Antibodies used include rabbit anti-Prox1a (1:100, GTX128354, GeneTex), goat anti-Hnf4a (1:50, sc6556, Santa Cruz), mouse anti-Alcama (1:20, zn-8, DSHB) and mouse anti-Islet1/2 (1:20, 39.4D5, DSHB), rabbit anti-pan-Cadherin (1:5000; Sigma), mouse anti-Anxa4 (1:100, ab71286, aka 2F11, Abcam)(15 (link)), rabbit anti-Bhmt (1:200, ab96415, Abcam), mouse anti-Mdr1(1:200, sc-71557, Santa Cruz), chicken anti-GFP (1:300, GFP1010, Aves Labs), goat anti-mCherry (1:500, LS-C204207, LSBio), rabbit anti-Cytokeratin7 (1:200, ab181598, Abcam), mouse anti-Sox9 (1:200, ab76997, Abcam). Imaging was performed on a Zeiss LSM710 running Zen 2010 (Black) and images were processed with Adobe Photoshop.