Fig. 2

Fig. 2 Distinct roles for Hnf1ba in regulating β-cell numbers and ventral pancreas specification. (A) β-Cell nuclei numbers from 80 and 125 hpf wild-type and hnf1ba^s430 mutants, indicating that at either stage, hnf1ba^s430 mutants have significantly fewer β-cells. hnf1ba^s430 mutants (125 hpf) have significantly fewer β-cells than 80 hpf wild-type embryos. Error bars represent s.d. (B-G) Fluorescent confocal microscopy of Tg(ptf1a:eGFP)^jh1 80 hpf wild type (B-D) and 125 hpf hnf1ba^s430 mutant (E-G) pancreas stained for insulin antibodies, SV2 antibodies and DAPI to mark β-cells (red), endocrine cells (white) and nuclei (blue), respectively. Three-dimensional rendering of red and green channels showing an hnf1ba^s430 mutant at 125 hpf with a larger pancreas (E) than wild-type (B). (C,F) Magnification (8×) of B and E (red and white channels only) to show mildly disorganized islet cells. (D,G) Z-focal plane of C and F (with all channels) demonstrating moderately reduced β-cell number in the hnf1ba^s430 mutant islet. For a more severe example, see supplementary material Fig. S2. (H-M) Three-dimensional rendering of 52 hpf Tg(ptf1a:eGFP)^jh1 (pancreas, green) foregut endoderm in wild-type (H), hnf1ba^hi2169 mutants (I) and hnf1ba^s430 embryos (J) stained for Pdx1 to mark the duodenal intestine and cadherin to mark the endoderm epithelium. In contrast to hnf1ba^hi2169 (I), Pdx1 expression (arrowheads) in the intestine and dorsal pancreatic islet (I) is not lost in hnf1ba^s430 embryos (J). (K-M) Three-dimensional rendering of 80 hpf Tg(ptf1a:eGFP)^jh1; Tg(lfabp:dsRed)^gz2 (pancreas, green; liver, red) foregut endoderm in wild-type (K) hnf1ba^hi2169 (L) and hnf1ba^s430 embryos (M) stained for cadherin showing specific loss of ventral pancreas in hnf1ba^s430 hypomorphic mutants. Unlike the hnf1ba^hi2169 (L), liver (L) and swimbladder (SB) are not lost in the hnf1ba^s430 embryos.