A highly efficient ligand-regulated Cre recombinase mouse line shows that LoxP recombination is position dependent.
Conditional gene inactivation using the Cre/loxP system is widely used, but the difficulty in properly regulating Cre expression remains one of the bottlenecks. One approach to regulate Cre activity utilizes a mutant estrogen hormone-binding domain (ERT) to keep Cre inactive unless the non-steroidal estrogen analog 4-hydroxytamoxifen (OHT) is present. Here we describe a mouse strain expressing Cre-ERT from the ubiquitously expressed ROSA26 (R26) locus. We demonstrate efficient temporal and spatial regulation of Cre recombination in vivo and in primary cells derived from these mice. We show the existence of marked differences in recombination frequencies between different substrates within the same cell. This has important consequences when concurrent switching of multiple alleles within the same cell is needed, and highlights one of the difficulties that may be encountered when using reporter mice as indicator strains.
Vooijs
M
M
The Netherlands Cancer Institute, Division of Molecular Genetics, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Jonkers
J
J
Berns
A
A
D000483:Alleles; D000818:Animals; D015139:Blotting, Southern; D004622:Embryo, Mammalian / Q000166:cytology; D004967:Estrogens / Q000378:metabolism; D005821:Genetic Techniques; D005838:Genotype; D019426:Integrases / Q000235:genetics*; D008024:Ligands; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008957:Models, Genetic; D016254:Mutagenesis, Insertional; D009154:Mutation; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic; D013234:Stem Cells / Q000378:metabolism; D013997:Time Factors; D014764:Viral Proteins; D001616:beta-Galactosidase / Q000378:metabolism
D004967:Estrogens; D008024:Ligands; D014764:Viral Proteins; C045073:Cre recombinase; D019426:Integrases; D001616:beta-Galactosidase