Gene-Targeting Strategies

Gene targeting in mouse embryonic stem (ES) cells has become a routine methodology to study gene function in vivo (1 ). Indeed, gene-targeting core facilities have been established at numerous institutions to facilitate the generation of targeted ES cell lines and the production of mouse chimeras. Although these facilities have centralized many of the unique skills and reagents that are required to generate “knockout”mice, the investigator must still generate a thoughtful strategy to mutate the gene of interest and to subsequently characterize the resulting mutant mice.