Figure 4

Heart and developing lung demonstrate TFII-I expression. A. Heart at E12 (5 ×), B. Lung at E12, C. Lung at E16, D and E. Lung at E15. A low power view of the ED12 embryo shows extensive, largely cytoplasmic TFII-I immunoreactivity in heart. Both E12 and E16 are representative of the pattern of TFII-I expression in lung (64 ×), showing extensive immunoreactivity in developing airway epithelium as well as in endothelial cells lining the vasculature (arrows). Immunoreactivity is present in lung parenchyma with increased intensity and nuclear localization at E16 compared with E12. Immuno-reactivity detected in lung at E15 (Figure 4 E) is competed completely by pre-incubation of the antibody with peptide (Figure 4D). Abbr.: AE-Airway Epithelium, DE- Developing Epithelium, H-Heart, LB-Lobar Bronchus, PC-Pericardial Cavity, VE-Vascular Endothelium, VS-Vascular System,