Nogo-B is highly expressed in the lung. (A) Whole-mount X-gal staining of Nogo-A/B KO LacZ mouse lung tissue. Blue indicates positive Nogo-A/B gene expression throughout the lobe. Bar, 0.5 mm. (B) X-gal–stained lung sections from Nogo-A/B^+/− LacZ mice (top). Blue indicates positive Nogo gene expression in epithelium and smooth muscle of airways (A), and endothelial and smooth muscle cells of vessels (V), as well as parenchymal cells. Also shown are lung sections from WT mice stained with Nogo-A/B antibody 1761 (bottom). Brown staining indicates positive Nogo protein expression, and specificity of antibody was confirmed with negative staining of Nogo-A/B KO lung section (inset). Sections were also labeled with anti–E cadherin (Ecad) or α-SMA to delineate epithelium and smooth muscle, respectively. Bars: (top) 200 µm; (bottom) 100 µm. (C) Lysates were immunoblotted with a Nogo-A/B antibody. Brain lysate is as a positive control for Nogo-A. Heart and mouse lung endothelial cells (mlecs) are positive controls for Nogo-B. Lung lysate from Nogo-A/B KO mice is a negative control and hsp90 is a loading control.