Localization by in situ hybridization of cells expressing non-lung-specific marker genes. Sections from E18.5 (a,d,g,j,l) wild-type and (b,e,h,k,m) transgenic lungs and from (c,f,i) adult organs were hybridized with the probes indicated. (b, e) Adjacent 7 μm thick sections (for a third adjacent section hybridized with SftpC riboprobe see Additional data file 1, Figure S3. Cryptdin6 is transcribed at high levels (b) by small groups of cells scattered throughout the transgenic epithelium and (c) in Paneth cells at the base of adult intestinal crypts. No expression is seen in (a) normal lung. Dcpp is expressed in (e) transgenic lungs, and by (f) most cells of the submucosal glands of the adult upper trachea but not in (d) wild-type lung. Tff3 RNA is also detected within (h) the transgenic epithelium (arrows) and in (i) the endoderm of intestinal villi. Deltalike3 (Dll3) is ectopically expressed at lower levels in (k) transgenic lung (arrows). Silver grains in the lumen are due to the scatter of 3 particles from the 35S isotope. Scale bars, 50 μm.