Fig. 1. Expression of Gata6 and Nkx2.1 during lung development. In situ hybridization for Gata6 (A) and Nkx2.1 (B) expression was performed at E16.5. Immunofluorescent staining for Gata6 and Nkx2.1 expression reveals extensive overlap between the expression of both of these proteins at E16.5, including in the distal airway epithelium (C-E, arrowheads) and more proximal bronchiolar airways (C-E, asterisks). Expression of Gata6 at E18.5 in proximal bronchiolar airways is confirmed by co-staining with the Clara cell marker gene CC10 (F-H, asterisks). Scale bars: 500 µm in A,B; and 100 µm in C-H.