Fig. 1.

Immunohistochemistry for delta-like 1 homologue (Dlk1) and growth hormone (GH) in the pituitaries of Dlk1-null mice and wild-type littermates. Sections from pituitaries of male wild-type (a–f) and Dlk1-null mutant (g–i) mice stained for Dlk1 (green), Sox2 or GH (red) and 4′,6-diamidino-2-phenylindole (DAPI) (blue). The posterior lobe is orientated at the top of the image, and the anterior at the bottom. Dlk1 is mostly excluded from Sox2-positive cells (a–c), although it is expressed in the majority of somatotrophs in the anterior pituitary (d–f), as previously shown. Expression of Dlk1 is completely lacking in Dlk1-null mutants in the pituitary gland (g–i). Scale bar = 20 μm.