Fig. S4

Nav3a overexpression induces ectopic hepatic gene expression. (A) Cp is expressed in the liver bud of control morpholino-injected embryos at 48 hpf. Nav3a morphants show reduced cp expression in 60% of the analyzed embryos. In each group n=30 embryos were analyzed. (B) In the gain-of-function experiments pDestTol2-sox17-nav3a^ATGmut-mcherry plasmid was injected during single cell stages. Nav3a overexpression induced ectopic endodermal budding and dislocated endodermal cells in the foregut region. Ectopic budding outside of the foregut occurred in the trunk and the yolk sac (left panel). The nav3a positive buds expressed the hepatoblast marker hhex (arrowheads, right panel) (n=20). (C) Nav3a overexpression under control of the endodermal sox17 promoter induces regions of extra endodermal cp-expressing cell clusters. In each group n=50 embryos were analyzed. Ectopic buds were Nav3a-mCherry positive and in 90% of cases we observed cp expression in the ectopic bud (n=20). (D) The vascular marker flt4 (VEGF receptor-3) is not expressed in the ectopic buds (n=5).