LacZ staining of diaphragm, heart, and brain from Hprt-targeted mice carrying vWF2-lacZ or vWF2-ETSm-lacZ. Diaphragms, hearts, and brains were harvested from 6- to 8-week-old F2 male Hprt-targeted mice carrying vWF2-lacZ or vWF2-ETSm-lacZ and processed in parallel for whole-mount staining with X-Gal. (A) The diaphragm from the vWF2-lacZ transgenic mouse is on the right, and the diaphragm from the vWF2-ETSm-lacZ mouse is on the left. (B) The vWF2-lacZ heart is on the bottom, and the vWF2-ETSm-lacZ heart is on the top. (C-D) The vWF2-ETSm-lacZ brain at low and high power, respectively (panel D is from the inset shown in panel C). Note the lack of detectable LacZ staining in skeletal muscle (diaphragm) and heart. Whole-mount tissues were analyzed under a Nikon SMZ-U dissecting microscope, and microphotographs were collected using a Nikon Coolpix 8400 camera. Arrows, LacZ-positive blood vessels in posterior brain.