Fig. 2. lef1 is co-expressed with proneural and neuronal markers in the posterior hypothalamus. White circles outline posterior hypothalamus and inset panels show lef1 mRNA expression from Fast Red fluorescence. Lines in whole-mount images show plane of corresponding cross-sections on the right. In cross-sections, black ovals outline posterior hypothalamus. (A,B) At 19 hpf, sox3 (blue) is not co-expressed with lef1 (red) in the posterior hypothalamus. (C,D) At 24 hpf, zash1a (blue) is not co-expressed with lef1 (red) in the posterior hypothalamus. (E-H) By 30 hpf, sox3 and zash1a are co-expressed with lef1 in both medial progenitors and lateral postmitotic neurons of the posterior hypothalamus. (I-L) By contrast, dlx2 and isl1 are co-expressed only with lef1 in lateral postmitotic neurons.