Production of transgenic mice.

A "transgenic" mouse is identified by the integration of a foreign DNA into its genome. Such animals serve as experimental systems for the study of gene expression and are often generated as models for human diseases. Direct microinjection of DNA into the male pronucleus of a mouse zygote has been the method most extensively used in the production of transgenic mice. Our method is subdivided into three sections: First, Preinjection, where the animals, the donor eggs, and the injection tools are presented. Second, Injection, where the egg handling and micromanipulation is described. Third, Postinjection, where the surgical transfer into pseudopregnant females completes the procedural sequence. Additional sections are provided to include the materials we use and to offer a series of technical tips that cover various aspects of the transgenic process.