Fig. 1. Expression of Foxp1 and Foxp2 during lung and esophagus development. Previously characterized rabbit polyclonal antibodies were used to perform immunohistochemistry on E14.5 embryonic and adult mouse lung tissue sections to determine the expression pattern of Foxp1 and Foxp2. (A,B) Expression is observed for both proteins in the distal tips of the developing airway epithelium at E14.5 (arrowheads). Foxp1 is expressed at low levels in developing bronchial airways, whereas Foxp2 is not (asterisk). (C,D) In adult lungs, Foxp1 is expressed primarily in AEC-2 cells (C, red arrowheads), whereas Foxp2 is expressed in both AEC-2 (D, red arrowheads) and AEC-1 (D, green arrowheads) cells. (E,F) Foxp1 and Foxp2 are both expressed in the muscular component of the developing esophagus at E14.5, whereas only Foxp1 is expressed in the epithelium. epi, epithelium; mu, muscular layers. Scale bars: 100 µm in A,B; 50 µm in C,D; 10 µm in E,F.