The transgene comprises 8.5 kb of upstream flanking DNA and 85 bp of the 5', noncoding exon of the mouse calcium/calmodulin-dependent protein kinase II alpha gene, an artificial intron and splice signal, the coding sequence for the reverse tetracycline-regulated transactivator (rtTA) protein and an SV40 polyadenylation signal. Maximal doxycycline induction of mice bearing both this transgene and a lacZ reporter transgene under control of the tetracycline operator (tetO) demonstrated expression in the CA1 and CA2 regions, but only minimal expression in the CA3 region, of the hippocampus; in the dentate gyrus; in both superficial layers and a deep layer of the cortex; and in the septum and striatum. (J:123059)