Temporally-controlled site-specific mutagenesis in the basal layer of the epidermis: comparison of the recombinase activity of the tamoxifen-inducible Cre-ER(T) and Cre-ER(T2) recombinases.
Conditional DNA excision between two LoxP sites can be achieved in the mouse using Cre-ER(T), a fusion protein between a mutated ligand binding domain of the human estrogen receptor (ER) and the Cre recombinase, the activity of which can be induced by 4-hydroxy-tamoxifen (OHT), but not natural ER ligands. We have recently characterized a new ligand-dependent recombinase, Cre-ER(T2), which was approximately 4-fold more efficiently induced by OHT than Cre-ER(T) in cultured cells. In order to compare the in vivo efficiency of these two ligand-inducible recombinases to generate temporally-controlled somatic mutations, we have engineered transgenic mice expressing a LoxP-flanked (floxed) transgene reporter and either Cre-ER(T) or Cre-ER(T2) under the control of the bovine keratin 5 promoter that is specifically active in the epidermis basal cell layer. No background recombinase activity could be detected, while recombination was induced in basal keratinocytes upon OHT administration. Interestingly, a dose-response study showed that Cre-ER(T2) was approximately 10-fold more sensitive to OHT induction than Cre-ER(T).
Indra
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Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Collège de France, BP 163, 67404 Illkirch Cedex, C. U. de Strasbourg, France.
Warot
X
X
Brocard
J
J
Bornert
J M
JM
Xiao
J H
JH
Chambon
P
P
Metzger
D
D
D000818:Animals; D004790:Enzyme Induction; D004817:Epidermis / Q000187:drug effects / Q000201:enzymology*; D020847:Estrogen Receptor Modulators / Q000494:pharmacology*; D017930:Genes, Reporter; D006801:Humans; D019426:Integrases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D016297:Mutagenesis, Site-Directed; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000378:metabolism; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000494:pharmacology; D014764:Viral Proteins
D020847:Estrogen Receptor Modulators; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D013629:Tamoxifen; C016601:afimoxifene; C045073:Cre recombinase; D019426:Integrases