Fig. 3

Fig. 3 Zebrafish prl and pomc are expressed in the stomodeal-hypophyseal placode. Single (A, E) and double (B–D, F–H) whole-mount in situ hybridizations with probes indicated in corresponding colors in top right corner. The age of stained embryos is indicated in bottom right corner (hpf, hours after fertilization). (D) A lateral view on the anterior region of the head; all other panels show frontal views. (B–D, F–H) are at a threefold higher magnification than (A) and (E). Frames in (A) and (E) mark magnified region. prl- and pomc-positive cells are intermingled and located in lateral (24 hpf; B, F) or anterior regions (26 hpf; D) of the lim3 domain. At 24 hpf, the number of prl-positive cells is significantly higher than the number of pomc-positive cells (compare F with B). During further development, the number of pomc-positive cells increases, while the number of prl-positive cells remains largely unchanged, so that at 32 hpf, the two cell types are present at similar numbers (H). Also, both prl- and pomc-positive cells converge from lateral regions of the pituitary anlage toward the midline, while lim3-positive cells initially located medially move posteriorly (compare B–D; see also Fig. 7 for schematic illustration; domains I, II, and III are indicated).