title: Use of ERT2-iCre-ERT2 for conditional transgenesis.
abstract: We examined the use of ERT2-iCre-ERT2 (Cre2ERT2), a tamoxifen-regulated form of Cre that has been described to have a background activity lower than that of other tamoxifen-regulated Cre constructs, for establishing performant conditional deleter mouse lines. Cre2ERT2 was inserted by homologous recombination into the Rosa26 locus. These mice were mated with R26R Cre-reporter mice. No recombination could be observed in the progenies in the absence of tamoxifen treatment. Tamoxifen treatment at E13-14 led to a high level, albeit variable, recombination in most of the tissues examined: liver, heart, kidney, brain, lung etc. Treatment of adult animals also induced recombination in these tissues, although at a lower level. Northern blot and qPCR studies suggested that these differences are not linked to significant variations of the level of expression of Cre2ERT2. Thus, Cre2ERT2 appears to be a good alternative to existing modulatable Cre systems, displaying a lack of background activity and a high-level inducibility in vivo.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jullien
authors.forename: Isabelle
authors.initials: I
authors.lastname: Goddard
authors.forename: Samia
authors.initials: S
authors.lastname: Selmi-Ruby
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Fina
authors.forename: Harold
authors.initials: H
authors.lastname: Cremer
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Herman
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005260:Female; D018014:Gene Transfer Techniques; D006801:Humans; D019426:Integrases / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011506:Proteins / Q000235:genetics; D022661:RNA, Untranslated; D011995:Recombination, Genetic / Q000235:genetics
chemical_list: C110853:Gt(ROSA)26Sor non-coding RNA, mouse; D011506:Proteins; D022661:RNA, Untranslated; C045073:Cre recombinase; D019426:Integrases