[Transgenic mouse and gene targeting].

Transgenic mouse technology has proved to be a powerful tool for medical research. So far, a large number of transgenic mice have been generated expressing, e.g. oncogenes, viral genes, immunoglobulins, lymphokines and MHC antigens, and have provided much valuable information. Furthermore, gene targeting technology (homologous recombination between specific chromosomal DNA sequences and exogenously introduced DNA sequences) has been improved and applied to pluripotent, mouse embryonic stem (ES) cells, providing the means to create mice of specifically altered genotype. In this review, some of the background and recent advances of transgenic mouse technology and gene targeting in mouse ES cells are described.