Fig. 4

nkx6.1 and ascl1b are first co-expressed in the endocrine precursors of the dorsal bud but rapidly their expression domain moves apart. Immunodetection of endogenous Nkx6.1 and GFP in Tg(ascl1b:eGFP-creER ^T2 ) embryos at 14 hpf (a–a") and 15 hpf (b–b"). All views are ventral with the anterior part to the left and represent confocal projection images. Scale bars = 40 μm. H hypochord, M medial cells