Fig. 2

eya1 is transiently expressed in all adenohypophyseal cells, dependent of Fgf3 and Shh function. All panels show eya1 whole-mount in situ hybridizations at stages indicated in right lower corners (h, hours post-fertilization). All embryos are oriented with anterior to the left; (A) view from animal pole, (B–I, K) lateral view, dorsal up, (J, L–P) ventral view. Arrows in panels A–D point to the anterior neural ridge, where the adenohypophyseal precursor cells are located before placode formation. Arrowheads in panels E, F point to anterior regions of the adenohypophyseal placodes, arrows to posterior lateral regions, which most likely give rise to somatotropes and thyrotropes (compare with Fig. 4A). Arrows in panels I, K, L point to the adenohypophysis, small arrowheads in panels K, L to weak eya1 staining in cells in the fenestra region of the skull, located between the pituitary and the oral cavity epithelium (compare with Fig. 8C). Panels M–P show double in situ hybridizations with eya1 in blue and pomc (M, N) or prl (O, P) in red. Panels N, P show the same embryos as in panels M, O, after the red staining had been washed out. Abbreviations: ear, inner ears; oc, oral cavity; olf, olfactory epithelium. Scale bars are 100 μm.