Fig. 3. SP-C/G6en mice display abnormal lung morphology. Histological sections through E17.5 (A-D), E19.5 (E-H,M-P), or P0 (I-L) SP-C/G6en (A-L) and SP-C/en (M-P) transgenic embryos and neonates. At E17.5, the distal airways of SP-C/G6en embryos are lined with abnormal cuboidal epithelium (D, yellow arrowheads) while the distal airways of wild-type littermates are lined primarily with squamous epithelium (C, black arrowheads). Similar morphological differences are observed at E19.5 (H, yellow arrowheads) and P0 (L, yellow arrowheads). Increased ratio of mesenchyme to airway space is also noted in SP-C/G6en embryos (compare G and H, K and L). However, SP-C/en mice display normal distal epithelial morphology and branching as in the wild-type littermates (M-P). Scale bar: 500 µm (E, F,I,J,M,N), 250 µm (A,B), 125 µm (G,H,K,L,O,P) and 67.5 µm (C,D).