Subregion- and cell type-restricted gene knockout in mouse brain.

Using the phage P1-derived Cre/loxP recombination system, we have developed a method to create mice in which the deletion (knockout) of virtually any gene of interest is restricted to a subregion or a specific cell type in the brain such as the pyramidal cells of the hippocampal CA1 region. The Cre/loxP recombination-based gene deletion appears to require a certain level of Cre protein expression. The brain subregional restricted gene knockout should allow a more precise analysis of the impact of a gene mutation on animal behaviors.