Modification of gene activity in mouse embryos in utero by a tamoxifen-inducible form of Cre recombinase.
The ability to generate specific genetic modifications in mice provides a powerful approach to assess gene function. When genetic modifications have been generated in the germ line, however, the resulting phenotype often only reflects the first time a gene has an influence on - or is necessary for - a particular biological process. Therefore, systems allowing conditional genetic modification have been developed (for a review, see [1]); for example, inducible forms of the Cre recombinase from P1 phage have been generated that can catalyse intramolecular recombination between target recognition sequences (loxP sites) in response to ligand [2] [3] [4] [5]. Here, we assessed whether a tamoxifen-inducible form of Cre recombinase (Cre-ERTM) could be used to modify gene activity in the mouse embryo in utero. Using the enhancer of the Wnt1 gene to restrict the expression of Cre-ERTM to the embryonic neural tube, we found that a single injection of tamoxifen into pregnant mice induced Cre-mediated recombination within the embryonic central nervous system, thereby activating expression of a reporter gene. Induction was ligand dependent, rapid and efficient. The results demonstrate that tamoxifen-inducible recombination can be used to effectively modify gene function in the mouse embryo.
Danielian
P S
PS
Department of Molecular and Cellular Biology Harvard University 16 Divinity Avenue, Cambridge Massachusetts 02138 USA.
Muccino
D
D
Rowitch
D H
DH
Michael
S K
SK
McMahon
A P
AP
D000818:Animals; D002490:Central Nervous System / Q000187:drug effects / Q000196:embryology / Q000201:enzymology; D004622:Embryo, Mammalian / Q000187:drug effects* / Q000201:enzymology*; D004742:Enhancer Elements, Genetic; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D019426:Integrases / Q000096:biosynthesis* / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000235:genetics; D011995:Recombination, Genetic / Q000187:drug effects*; D013629:Tamoxifen / Q000494:pharmacology*; D014764:Viral Proteins; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
D011518:Proto-Oncogene Proteins; D014764:Viral Proteins; D051153:Wnt Proteins; D051155:Wnt1 Protein; C495246:Wnt1 protein, mouse; D029961:Zebrafish Proteins; D013629:Tamoxifen; C045073:Cre recombinase; D019426:Integrases; D001616:beta-Galactosidase