Fig. 2.

The NOTCH1+16 transgene directs arterial endothelial cell-restricted expression in transgenic mice. (A-N) Representative transgenic whole-mount embryos (A-H) and transverse sections (I-N) showing lacZ reporter gene expression (β-galactosidase detected by blue X-gal staining) in arterial endothelial cells throughout embryonic development. The boxed region in J is magnified in K. (O,P) E12 transverse section showing that expression of the venous marker endomucin (Emcn) does not overlap with lacZ reporter gene expression on the same section. cv, cardinal vein; da, dorsal aorta; Emcn, endomucin; en, endocardium; mda, midline dorsal aorta; uv,umbilical vein; v, vein.