Down-regulation of lung epithelial differentiation markers. Sections of E18.5 (a,c,e,g) wild-type and (b,d,f,h) transgenic lungs after (a,b,e-h) in situ hybridization or (c,d) immunohistochemistry. (a,b) Expression of SftpC (type II cell marker gene). (c,d) Pro-SftpC is strongly expressed in (c) normal, rounded type II cells but in (d) transgenic lungs it is only expressed at low levels in some cuboidal cells (arrow). Expression of Secretoglobin (Scgb1a1 or Cc10; Clara-cell marker gene) is normal in (e) wild-type bronchioles but is reduced in (f) the transgenic lung. The expression of Foxj1 (ciliated-cell marker gene) is slightly diminished in (h) the transgenic lung relative to (g) the wild-type bronchiole. Scale bars, 50 μm.