In vivo imaging of gene-trap tTAactivation of a tet-responsive transgene A). Luciferase emission pattern seen in a 03A-0241; Tg(tetL)1Bjd/J doubly transgenic mouse (936) as imaged by an intensified charge-coupled device (CCD) camera. Ventral and dorsal aspects are shown. The intensity of luciferase expression is compared in photons/second/cm2. B) RT-PCR analysis of MacF1 expression in multiple adult tissues, Gapdh was used as a control for sample quality. ES-embryonic stem cells, Lv-liver, Kd-kidney, Br-brain, Lu-lung, Ht-heart, Sp-spleen, St-stomach, BM-bone marrow, SI-small intestine, Co-colon, Ad-adipose, Mu-muscle, Ov-ovary, b-testes, Th-thymus C) Southern analysis of mice from A and B (see Materials and Methods). The donor site concatemer appears as an intense BamHI fragment at 2236 base pairs (arrowhead). The detection of insertion 03A-0241 by three-primer PCR is shown below each lane. Three bands marked by arrows segregate with insertion 03A-0241 genotyping and the concatemer.D) Pattern inheritance by offspring of mouse 936. Mice were imaged and scaled to different ranges of intensity that ranged from 1x104 to 1×108 photons/second/cm2 (scale bars). E) Repression of in vivo luciferase activation after six days of treatment with doxycycline in the same mice from D.