Further characterization of labeled epithelial cells in the Yap/Taz mutant. (A) At E16.5, progenitors (blue) marked by nuclear SOX9 contain more scattered LAMP3 than BFP-Lamp1. At P7, mature AT2 cells (magenta) contain larger, overlapping LAMP3 and BFP-Lamp1 puncta. The intermediate stage lung at E17.5 undergo asynchronous AT2 cell differentiation, featuring developing AT2 cells (yellow) with LAMP3 (arrowhead) concentrating at BFP-Lamp1 puncta (caret) and decreasing SOX9. AT1 cells may also be targeted by Sox9^CreER. To accommodate both LAMP3 and SOX9 immunostaining, SOX9 is in the same channel as EGFP-α-Tubulin, but distinguishable by their subcellular localization. Sox9^CreER/+; ROSA^{Kaleidoscope/+} embryonic lungs were given 500 μg tamoxifen at E12.5 for E16.5 harvest or at E14.5 for E17.5 harvest. Sftpc^CreER/+; Rosa^{Kaleidoscope/+} lungs were given 300 μg tamoxifen at P1 for P7 harvest. Scale: 10 μm. (B) Labeled LAMP3- airway cells still contain BFP-Lamp1 puncta. Tam, 500 μg tamoxifen. Scale: 10 μm. (C) En face view and perimeter quantification of alveolar epithelial cells outlined with E-Cadherin (ECAD) immunostaining. Cells in the Yap/Taz mutant have an intermediate perimeter between AT1 and AT2 cells of the control lung. Tam, 3 mg tamoxifen. Asterisk, P < 0.0001 (ordinary ANOVA with Tukey test; data are mean and standard deviation). Scale: 10 μm.