Conditional mutant mice using tetracycline-controlled gene expression system in the brain.

Generation of knockout mice with targeted mutations in desired genes is one of the most important technologies available for determining the functions of gene products in the brain. However, conventional knockout technology has limitations, such as when conventional knockout results in a lethal phenotype or when gene function at a certain developmental stage must be elucidated. To circumvent these limitations, a tetracycline-controlled gene expression system has been exploited to generate conditional mutant mice in which expression of desired genes can be switched on or off by oral administration of tetracycline derivatives. This up-date article introduces conditional mutant mice obtained using the tetracycline-controlled gene expression system, and presents several examples including our versatile mouse line, the mGluR1 conditional knockout mouse.