The LoxP/CRE System and Genome Modification

Conventional gene knockout technology by homologous recombination can provide important information toward elucidating the function of some genes; however, the role of many genes cannot be investigated due to early embryonic lethality. Alternatively, the role of a particular gene in adult tissues may be masked by developmental abnormalities in any knockout animals generated. The implementation of site specific recombinases, such as the bacteriophage P1 LoxP/CRE system, enables the development of conditional knockouts that lack a particular gene only in a specific tissue or after a specific stage of development. This system can also be used to facilitate transgene activation/inactivation in vivo, deletions of large stretches of genomic DNA, chromosomal translocation and subtle alterations to genes and/or their regulatory sequences in vivo.