The (tetO)7-FasL transgene was designed with a Tet response element (TRE) upstream of the 943 bp murine Fas ligand (FasL) coding sequence, all followed by a bovine growth hormone intron and polyA sequence. The Tet response element (TRE) contains seven copies of the 42-bp tet operator sequence (tetO) just upstream of a minimal CMV promoter. Five founder lines (A-E) were established. Founder mice from line D were found with 20 copies of the transgene and intermediate levels of doxycycline-induced FasL mRNA up-regulation. (J:137382)