Fig. 1

Elf-1 gene expression during murine embryogenesis. In situ hybridization analyses were performed using the control Elf-1 sense riboprobe (A, C) or the Elf-1 anti-sense riboprobe (B, D) on staged ED 14 (A, B) and ED20 (C, D) murine embryos. Original magnification, ×1.25. In the ED 14 embryo, the Elf-1 riboprobe hybridized (white staining) specifically to the thymus (T) (see also Fig. 2B, D) and to the epithelial lining of the nose (N), mouth (M) (see also Fig. 2B), lungs (L) (see also Fig. 2C), and gut (Gu) as well as to cells lining the primitive ventricles in the brain. In the ED20 embryo, the Elf-1 riboprobe hybridized specifically to the thymus (T), mouth, lung (L), bladder (Bl), and the epithelial and mucosal layers of the esophagus (Eo), stomach (St) (see also Fig. 2F), small intestine (Si), and colon (Co). Lower-intensity hybridization was also observed in the skin epithelia (Se) and in the kidney (K). Elf-1 expression was not observed in the developing heart (He). The liver (Li), thyroid (Th), and adrenal gland (Ad) hybridized to both the anti-sense and sense probes. Note that the intense fluorescence due to erythrocytes (Er) is the result of the refractile property of these cells under dark-field microscopy and does not represent Elf-1-specific gene expression.