LacZ staining of diaphragm, heart and brain from Hprt-targeted mice carrying vWF2-lacZ, vWF3-lacZ, or vWF2-βGIVS2-lacZ. Diaphragms, hearts, and brains were harvested from 6- to 8-week-old F2 male Hprt-targeted mice carrying vWF2-lacZ (vWF sequences between −2182 and +1475), vWF3-lacZ (vWF sequences between −2182 and +246), or vWF2-βGIVS2-lacZ (vWF sequences between −2182 and +246 and intron 2 from the human β-globin gene) and processed in parallel for whole-mount staining with X-Gal. In panels A and E, the diaphragm from the vWF2-lacZ transgenic mouse is on the right, and the diaphragm from the vWF2-βGIVS2-lacZ or vWF3-lacZ mouse is on the left. Panels B and F are higher power images of vWF2-βGIVS2-lacZ and vWF3-lacZ diaphragms, respectively. In panel C, the vWF2-lacZ heart is on the bottom, and the vWF2-βGIVS2-lacZ heart is on the top. In panel G, the vWF2-lacZ heart is on the bottom, and the vWF3-lacZ heart is on the top. In panel D, the vWF2-lacZ brain is on the bottom, and the vWF2-βGIVS2-lacZ brain is on the top. In panel H, the vWF2-lacZ brain is on the right, and the vWF3-lacZ brain is on the left. In panels A through D, vWF2-βGIVS2-lacZ organs reveal a similar pattern (though lower absolute levels) of expression compared with vWF2-lacZ. In E-H, vWF3-lacZ organs show the X-Gal reaction product in brain but not heart or skeletal muscle. Whole-mount tissues were analyzed under a Nikon SMZ-U dissecting microscope, and microphotographs were collected using a Nikon Coolpix 8400 camera.