Fig. 6. Cells in the lens and salivary glands absolutely require cis-regulatory elements in intron 2 for activation of ß-gal transcription. (A-F) X-gal staining in lenses of Ecad-In2flox embryos shows high intensities (A,C,E), whereas no expression is found in lenses of Ecad-In2floxdel embryos (B,D,F). Lenses at stages E10.5 (A,B), E12.5 (C,D) and E14.5 (E,F) are shown. (G-P) Analysis of E-cadherin-specific expression in mandibular salivary (arrow) and thyroid (white arrowhead) glands at E16.5 (black arrowhead marks meninges). Heads of Ecad-In2flox (G) and Ecad-In2floxdel embryos (H) were cut prior to X-gal staining and viewed from bottom. In Ecad-In2flox high expression is found in the salivary and thyroid glands (G), but no staining is observed in salivary glands of Ecad-In2floxdel embryos (H). (I-P) Transverse sections of Ecad-In2flox (I-L) and Ecad-In2floxdel heads at E16.5 (M-P). Sections of salivary (I,M) and thyroid glands (J,N), trachea (K,O) and meninges (L,P). Scale bars: 100 µm in A,B,J,N; 250 µm in C,D; 500 µm in E,F; 1 mm in G,H; 50 µm in I,K,L,M,O,P.