Phenotype of CMV-GMTag AU⁺ and AU⁻ E14 transgenic embryos.

(A-C) Immunohistochemical detection (black peroxidase staining) of mature granulocytes using Gr1 antibody in CMV-GMTagAU⁻(A), CMV-GMTagAU⁺ (B), or nontransgenic (C) embryos. Gr1⁺ cells appear like black points forming dark areas (magnification × 5). (D-F) Immunohistochemical analysis at greater magnification (× 200) of Gr1⁺ cells (brown peroxidase staining) in vertebra area of CMV-GMTagAU⁻ (D), CMV-GMTagAU⁺ (E), or nontransgenic (F) embryos. (G-I) Immunohistochemical detection of macrophages using F4/80 antibody in CMV-GMTagAU⁻ (G), CMV-GMTagAU⁺ (H), or nontransgenic (I) embryos (black peroxidase staining). (J-L) Detection of endogenous peroxidase activity by histochemistry. Peroxidase-positive cells appear as black spots. (J) CMV-GMTagAU⁻ transgenic embryo; (K) CMV-GMTagAU⁺ transgenic embryo; (L) nontransgenic embryo. (M-O) analysis of peroxidase-positive cells (brown peroxidase staining) at greater magnification (× 200) in the liver of CMV-GMTagAU⁻ (M), CMV-GMTagAU⁺ (N), and nontransgenic (O) embryos. (P,Q) Double staining showing different localization of Gr1⁺ cells (blue alkaline phosphatase staining) and peroxidase-positive cells (brown peroxidase staining), in the liver (P) and close to vertebral bone (Q) of E14 CMV-GMTagAU⁻ transgenic embryo. Arrows point to stained organs (A-C, G-L) or to stained cells (D-F, M-Q). br indicates brain; PM, pia mater; vb, vertebral bone. The phenotypes illustrated in this figure are representative of the different embryos analyzed.