How can a conservative site-specific recombination enzyme from bacteria be used to delete specific genes from particular mouse tissues?
a. This approach requires insertion of two specially engineered DNA molecules into the animal’s germ line. The first contains the gene for a recombinase (ex: Cre recombinase from bacteriophage P1) under the control of a tissue-specific promoter, which ensures that the recombinase is expressed only in that tissue. The second DNA molecule contains the gene of interest flanked by recognition sites (loxP sites) for the recombinase. If the recombinase is expressed only in the liver, the gene of interest will be deleted there and only there.