title: Development of a BAC vector for integration-independent and tight regulation of transgenes in rodents via the Tet system.
abstract: The establishment of functional transgenic mouse lines is often limited by problems caused by integration site effects on the expression construct. Similarly, tetracycline (Tet) controlled transcription units most commonly used for conditional transgene expression in mice are strongly influenced by their genomic surrounding. Using bacterial artificial chromosome (BAC) technology in constitutive expression systems, it has been shown that integration site effects resulting in unwanted expression patterns can be largely eliminated. Here we describe a strategy to minimize unfavourable integration effects on conditional expression constructs based on a 75 kb genomic BAC fragment. This fragment was derived from a transgenic mouse line, termed LC-1, which carries the Tet-inducible genes luciferase and cre (Schönig et al. 2002). Animals of this mouse line have previously been shown to exhibit optimal expression properties in terms of tightness in the off state and the absolute level of induction, when mated to appropriate transactivator expressing mice. Here we report the cloning and identification of the transgenic LC-1 integration site which was subsequently inserted into a bacterial artificial chromosome. We demonstrate that this vector facilitates the efficient generation of transgenic mouse and rat lines, where the Tet-controlled expression unit is shielded from perturbations caused by the integration site.
authors.affiliation: Department of Molecular Biology, Central Institute of Metal Health and Heidelberg University, Medical Faculty Mannheim, J5, 68159, Mannheim, Germany. kai.schoenig@zi-mannheim.de
authors.forename: Kai
authors.initials: K
authors.lastname: Schönig
authors.forename: David
authors.initials: D
authors.lastname: Kentner
authors.forename: Manfred
authors.initials: M
authors.lastname: Gossen
authors.forename: Tina
authors.initials: T
authors.lastname: Baldinger
authors.forename: Jun
authors.initials: J
authors.lastname: Miao
authors.forename: Katrin
authors.initials: K
authors.lastname: Welzel
authors.forename: Andreas
authors.initials: A
authors.lastname: Vente
authors.forename: Dusan
authors.initials: D
authors.lastname: Bartsch
authors.forename: Hermann
authors.initials: H
authors.lastname: Bujard
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D019426:Integrases / Q000235:genetics / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D051381:Rats; D012377:Rodentia / Q000235:genetics* / Q000378:metabolism; D013752:Tetracycline / Q000494:pharmacology*; D019076:Transgenes / Q000235:genetics / Q000502:physiology*
chemical_list: D008156:Luciferases; C045073:Cre recombinase; D019426:Integrases; D013752:Tetracycline