Generation and Validation of Tissue-Specific Knockout Strains for Toxicology Research.

Tissue-specific knockout mice are widely used throughout scientific research. A principle method for generating tissue-specific knockout mice is the Cre-loxP system. Here, we give a detailed description of the steps required to generate and validate tissue-specific knockout mice using the Cre-loxP system. The first protocol describes how to use gene targeting in mouse embryonic stem cells to generate mice with conditional alleles. Subsequent protocols describe how to recover Cre transgenic mice from cryopreserved sperm using in vitro fertilization and present a breeding strategy for obtaining tissue-specific knockouts. Finally, methods are provided for validating the knockout mice using PCR of genomic DNA, reverse-transcription PCR and quantitative reverse-transcription PCR of mRNA, and immunoblot analysis of proteins.