Homozygous transgenic mice that are also homozygous for Tg(Wnt1-cre)11Rth are viable, fertile, normal in size, and do not display any gross physical or behavioral abnormalities. Both Cre recombinase and the GAL4 transcriptional activator are expressed under the direction of Wnt1 regulatory sequences. Regulated expression initially occurs in the midbrain. After neural tube closure, expression occurs in the dorsal and ventral midlines of the midbrain and caudal diencephalon, the midbrain-hindbrain junction, and in the dorsal spinal cord.