Fig. 3. ascl1a mutants show decreased expression of the lim3, pitx3 and ascl1a, and fail to initiate expression of neurod, pit1 and all adenohypophyseal hormone genes, whereas the hypothalamus appears unaffected. Columns 1 and 3 show wild-type siblings (wt); columns 2 and 4 show pia mutants. Probes used for whole-mount in situ hybridization are indicated in lower right-hand corners, ages of embryos in the upper right-hand corners of wild types. (A,C,E,F,G,N) Lateral views, anterior towards the right, dorsal upwards. (B,D,H-M) Dorsal views, anterior towards the right. Arrows in A-H indicate expression in the adenohypophysis. Inset in E shows section through pituitary of pia mutant at 120 hpf (see Fig. 2J for wild-type control). h, hypothalamus.