LacZ staining of diaphragm from Hprt-targeted mice carrying wild-type or mutant VEGFR1 promoters. Diaphragms were harvested from 6- to 8-week-old F2 male Hprt-targeted mice carrying wild-type (WT) or mutant VEGFR1-lacZ transgenes and processed in parallel for whole-mount staining with X-Gal. In each panel, the diaphragm from WT VEGFR1 transgenic is on the right, and the diaphragm from the mutant mouse is on the left. The exposure time in bottom right panel was reduced compared with other panels. Whole-mount diaphragms were analyzed under a Nikon SMZ-U dissecting microscope, and microphotographs were collected using a Nikon Coolpix 8400 camera.