Fig. 3. Mesenchymal lobes devoid of hepatoblasts are formed in the absence of vHNF1. (A-P) In situ hybridization analysis of early liver differentiation markers at E10.5 (A-F) and E11.5 (G-L), mesenchymal (M,N) and hematopoeitic (O,P) markers at E10.5 in WT (A,C,E,G,I,K,M,O) and vHnf1^-/- (B,D,F,H,J,L,N,P) mouse embryos. Afp, a specification marker, is strongly expressed in WT hepatoblasts at E10.5 (A) and E11.5 (G) but is totally absent from the mutant liver (B,H). Prox1 (C,I) and Hnf4a (E,K) are also expressed in the WT but are not detected in the mutant at these stages (D,J,F,L). Hlx, a mesenchymal marker, is mainly expressed at the periphery of WT hepatic lobes at E10.5 (M). In the mutant, the expanded Hlx expression observed (N) indicates that the lobes are essentially formed by this cell type. Hematopoeitic cells, marked by Gata1, are present in greater numbers in WT (O) than mutant (P) hepatic lobes.