Figure 1.

The airway epithelium is maintained by Scgb1a1-expressing cells. (A): Schematic illustrating Scgb1a1-CreER^T2; Rosa26R-Confetti constructs. Upon Cre activation by treatment of mice with tamoxifen, the Confetti construct randomly recombines for active expression of fluorescent protein reporters. Scgb1a1-expressing cells were efficiently lineage labeled after treatment of Scgb1a1-CreER^T2; Rosa26R-Confetti mice with tamoxifen (B). Naphthalene-induced lung injury led to clonal expansion of lineage-labeled naphthalene-resistant epithelial progenitor cells within either terminal bronchioles (C) or more proximal bronchioles (D). Scale bars = 50 µm. (E): Schematic illustrating Scgb1a1-CreER^T2; Rosa26-mT/mG (Scgb1a1-mT/mG) mice. (F): Lineage labeled cells (GFP⁺) isolated from Scgb1a1-mT/mG mice were sorted by fluorescence-activated cell sorting and placed in 3D MatriGel culture for 14 days (G). Representative image of the culture shows the formation of type A, B, and C colonies.