Fig. 8. Proximal airway development and gene expression in SP-C/G6en mice. In situ hybridization analysis was performed on wild-type (A,C,E) and SP-C/G6en (B,D,F) embryos at E17.5 (A-D) and E19.5 (E,F) using gene-specific riboprobes for Foxj1 (A,B) and CC10 (C-F). Foxj1 and CC10 are expressed at similar levels in the proximal airways of wild-type and SP-C/G6en mice (A-F). However, the number of individual airways positive for Foxj1 and CC10 hybridization was significantly reduced at both E17.5 and E19.5 (A-F, yellow arrowheads). This decrease was most extreme in the number of smaller CC10- and Foxj1-positive proximal airways while the number of larger, more central airways was similar (A-F, arrows). These data correlated with a decrease in the number of peripheral airways containing thick convoluted epithelium (G, black arrowheads) which is characteristic of proximal airway epithelium while the number of large centralized proximal airways was similar in H+E stained sections from of wild-type and SP-C/G6en E17.5 embryos (G,H, arrows). Scale bar: 250 µm (A-F), 150 µm (G,H).