Figure 6.

Expression of YAP1 and TAZ proteins in postnatal pituitaries. Immunofluorescence using specific antibodies on frontal sections of dissected postnatal pituitaries at P21. (A) Immunofluorescence using antibodies against the pituitary stem cell marker SOX2 (red, arrowheads) showing positive staining in the periluminal epithelium and in small groups of cells throughout the anterior lobe parenchyma. Antibodies against endomucin mark epithelial cells surrounding blood vessels (green, arrows). (B–D) Immunofluorescence staining against total TAZ protein (B), total YAP1 protein (C) and phosphorylated YAP1 (S127) protein (D) in red. All three are detected in periluminal cells (white arrowheads) as well as structures resembling blood vessels (white arrows). (E–G) Double immunofluorescence staining on pituitary sections from Sox2^Egfp∕+ animals using antibodies against GFP protein in green detecting EGFP and marking SOX2⁺ cells together with antibodies against TAZ protein (E), total YAP1 protein (F) and phosphorylated YAP1 (S127) protein (G) in red. Arrows in (E,F) indicate examples of cells with nuclear TAZ or YAP1 protein. Yellow arrowheads in G note examples of GFP⁺ cells with strong nucleocytoplasmic pYAP1 protein localization and green arrowheads indicate GFP⁺ cells in lower pYAP1 levels in the nucleus. Nuclei are counterstained with DAPI (blue). Abbreviations: pl, posterior lobe; al, anterior lobe; il, intermediate lobe. Axes in (A) applicable to all panels: d, dorsal; v, ventral; ri, right; le, left. Scale bars 100 μm in (A–D), 20 μm in inserts and 50 μm in (E–G).