Production and characterization of human 293 cell lines expressing the site-specific recombinase Cre

We have constructed 293 cell lines expressing the site-specific Cre recombinase from bacteriophage P1, that acts on a 34 bp target sequence calledloxP. Stably transformed cells were obtained by transfection with a plasmid containing Cre and a selectable marker under the control of viral promoters. The resulting 293 Cre cell lines could be used to induce expression from adenovirus vectors containing reporter genes under the control of a Cre responsive “molecular switch” High efficiency recombination was observed for Ad viral DNA containingloxP sites. The Cre expressing cell lines described here are likely to be useful for several purposes: For expression of toxic gene products from Cre inducible viral vectors, to induce recombination betweenloxP sites in transfected plasmids, and to induce deletions or rearrangements of genes defined byloxP sites in viral genomes.