As an alternative approach to assessing the actions of DN-ATF5 on glioma cells in vivo, Arias et al. [52] established bi-transgenic “TET-OFF” mice in which expression of DN-ATF5 in cells expressing glial fibrillary protein (GFAP) is inducible by withdrawing doxycycline from the diet. The gene discussed is GFAP; the disease is central nervous system cancer.