Figure 1. Generation of Krt12^R/R/TC/Rosa26^F/GFP mice.

(A) Schematic diagram of Krt12 promoter driven and Cre-mediated GFP expression. The Krt12 promoter drives the expression of rtTA. When bounded to Dox, rtTA/Dox turns on TetO-Cre expression in the Krt12⁺ cells. Cre recombinase then catalyzes the deletion of the loxP flanked STOP sequence to allow the expression of GFP in the Krt12⁺ lineages. Meanwhile, Cre activity also deletes Yap1 exon 3 and abolishes the YAP1 protein expression. The Krt12^R/R/TC/Rosa26^F/GFP mice at 1 month old were intraperitoneally injected with Dox at 80 μg/g body weight in 0.9% aqueous NaCl (10 mg/ml stock) followed by Dox-chow (1 g Dox/kg chow)³⁰. (B) GFP expression at cornea is documented at indicated times after Dox treatment. *indicates the pupil under a fluorescence dissecting microscope. (C–E) Low (C) and high (D,E) magnification of GFP expression at whole mount corneal surface. (F) Corneal epithelium section shows GFP expression induced by Krt12/Cre. A mosaic pattern of GFP expression at cornea basal layer of Krt12^R/R/TC/Rosa26^F/GFP mouse was observed at 7-days of Dox induction. Scale bars = 2 mm in (B), 1 mm in (C), 500 μm in (D), 100 μm in (E), 50 μm in (F). The images shown were representatives from 5 eyes examined.