Fig. 3

hnf1ba and wnt2bb cooperate to specify the hepatopancreas organ system after mid-somitogenesis. (A-F) Three-dimensional rendering of 80 hpf Tg(ptf1a:eGFP)^jh1; Tg(lfabp:dsRed)^gz2 (pancreas, green; liver, red) foregut endoderm in wild type (A), wnt2bb^s404 mutant (B), hnf1ba^s430 mutant (C) and wnt2bb^s404; hnf1ba^s430 double mutants (D-F) stained for cadherin (epithelial endoderm) and with monoclonal antibody 2F11 to mark extra hepatopancreas ducts (^*) (dashed outline). Relative to wild type, the wnt2bb^s404 mutant liver (L) and the hnf1ba^s430 mutant pancreas (P) are reduced in size. The wnt2bb^s404; hnf1ba^s430 double mutant liver and pancreas (arrow) are more severely reduced, or lost. Double mutants can exhibit complete loss of the hepatopancreas system (E,F; white arrowheads). (G,H) Three-dimensional rendering of 80 hpf Tg(ptf1a:eGFP)^jh1 (pancreas, green) foregut endoderm in wild-type (G) and wnt2bb^s404; hnf1ba^s430 double mutants (H) stained for cadherin and Isl1 to mark the hepatopancreas mesenchyme (brackets) and islet (I). Double mutants lacking the entire hepatopancreas system still develop Isl1+ mesenchyme and islet (yellow arrowheads indicate the swimbladder). (I) Merged fluorescent/brightfield micrographs of 4 dpf Tg(ptf1a:eGFP)^jh1; Tg(lfabp:dsRed)^gz2 wnt2bb^s404 mutant (top) and wnt2bb^s404; hnf1ba^s430 double mutants (bottom) showing no obvious body phenotypes other than liver and pancreas agenesis (arrows). (J,K) Three-dimensional rendering of 80 hpf foregut endoderm, heat-shock-induced Tg(hsp70l:dkk1-GFP)^w32; Tg(ptf1a:eGFP)^jh1; Tg(lfabp:dsRed)^gz2 and Tg(hsp70l:dkk1-GFP)^w32; hnf1ba^s430; Tg(ptf1a:eGFP)^jh1; Tg(lfabp:dsRed)^gz2 stained for cadherin and with 2F11. Heat-shock-induced expression of dkk1-GFP in wild-type background does not lead to liver or pancreas agenesis (J), whereas in the hnf1ba^s430 mutant background, the hepatopancreas system is completely lost (K) (white arrow). The swimbladder (yellow arrowhead) is not lost in wnt2bb^s404; hnf1ba^s430 double mutants or in heat-shock-induced Tg(hsp70l:dkk1-GFP)^w32; hnf1ba^s430 mutants (D-F,H,K).