Fig. 4

Bmp2a failed to induce a hepatic fate in the hhex and prox1a double mutant. A. WISH using cp and fabp10a two probes on the embryos obtained from the intercrosses of male and female hhex+/− prox1a+/− double heterozygotes at 3dpf after the injection of the bmp2a mRNA at one-cell stage. The number of total embryos genotyped (denominator) and the number of embryos exhibiting the displayed phenotype (numerator) are provided at the bottom right. lv, liver. Scale bar, 200 μm. B. A model depicts the roles of Hhex and Prox1a in dictating the potency of the prospective hepatoblasts to be differentiated into hepatocytes and cholangiocytes. Left, Hhex and Prox1a protects the hepatic fate by transcriptionally inhibiting cdx1b and pdx1. Right, Loss-of-function of hhex leads to intestinalized extrahepatic duct while the prox1a−/− mutant displays an intestinalized liver due to ectopic expression of cdx1b. Combinatory loss-of-function of Hhex and Prox1a leads to a liver less phenotype. Pink color, hepatocytes; green color, cdx1b-positive domain. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)