Fig. 5. Laryngeal-tracheal-bronchial and lung malformations in Rspo2/Lrp6 mutant mice. (A-F) Alcian Blue stained cartilages in the larynx, trachea and bronchi from E18.5 fetuses of indicated genotypes. Asterisks in B and C indicate fusion of the arytenoids to the cricoid cartilage. (C) Arrow indicates the cricoid; cartilage is absent on the dorsal aspect of the ring, also observed in B and D. (F) The SftpC-rtTA transgene does not target cells within the larynx epithelium and only tracheal ring defects were observed. (G-N) Immunohistochemical analysis for pro-SftpC, a type II epithelial cell marker (G-J); and Ccsp, a nonciliated bronchiolar cell marker (K-N). (G,K) Rspo2^+/+;Lrp6^+/+; (H,L) Rspo2^Tg/Tg;Lrp6^+/+; (I,M) Rspo2^Tg/Tg;Lrp6^-/-; (J,N) Rspo2^+/+;Lrp6^-/-. Scale bars: 1 mm in F; 10 µm in J and N.