FIGURE 3.

Validation of the labeling of FGF10^Pos cells at E11.5. (A) Fgf10^Ki-v2/+ were crossed with Fgf10^+/+; tdTom^flox/flox mice. Pregnant females received a single IP injection of tamoxifen when the embryos were at E11.5 and sacrificed at E18.5. (B) Head, limbs, lung and cecum of Fgf10^+/+; tdTom^flox/+ and Fgf10^Ki-v2/+; tdTom^flox/+ embryos are shown. Note the absence of fluorescence in the Fgf10^+/+; tdTom^flox/+ indicating that the non-recombined LoxP-Stop-LoxP-tdTomato allele is not leaky. (C) Higher magnification of lung and trachea showing enriched tdTomato expression in the interlobular septa and the lack of tdTomato expression between the cartilage rings, respectively. Scale bar in (B): head: 1.5 mm, Limb: 0.75 mm, Lung: 0.5 mm, cecum: 0.5 mm. Scale bar in (C): 125 μm.