Figure 3

The branching epithelium expresses basal and bronchial epithelial markers. Confocal sections of immunofluorescently labeled structures in intact Matrigel. Nuclear staining with TO-PRO-3 is shown in blue in all panels. The boxed areas are shown in detail to the right. A. TTF-1 (green) protein is seen in all nuclei with weaker expression towards the core of the structure. CK14 expression (red) is limited to the outermost cells of each structure. B. CK17 in green, E-Cadherin in red. C. p63 is expressed in all cells (green) and pro-SP-C expression (red) is seen throughout the structures, and is most prominent at the outer cell layers. Scale bars 50 μm (left column), 10 μm (right column).