title: Screening strategy to generate cell specific recombination: a case report with the RIP-Cre mice.
abstract: Conditional gene knockout technology is a powerful tool to study the function of a gene in a specific tissue, organ or cell lineage. The most commonly used procedure applies the Cre-LoxP strategy, where the choice of the Cre driver promoter is critical to determine the efficiency and specificity of the system. However, a considered choice of an appropriate promoter does not always protect against the risk of unwanted recombination and the consequent deletion of the gene in other tissues than the desired one(s), due to phenomena of non-specific activation of the Cre transgene. Furthermore, the causes of these phenomena are not completely understood and this can potentially affect every strain of Cre-mice. In our study on the deletion of a same gene in two different tissues, we show that the incidence rate of non-specific recombination in unwanted tissues depends on the Cre driver strain, ranging from 100%, rendering it useless (aP2-Cre strain), to ~5%, which is still compatible with their use (RIP-Cre strain). The use of a simple PCR strategy conceived to detect this occurrence is indispensable when producing a tissue-specific knockout mouse. Therefore, when choosing the Cre-driver promoter, researchers not only have to be careful about its tissue-specificity and timing of activation, but should also include a systematical screening in order to exclude mice in which atypical recombination has occurred and to limit the unnecessary use of laboratory animals in uninterpretable experiments.
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Valeria
authors.initials: V
authors.lastname: Spinelli
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Martin
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Dorchies
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Vallez
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Dehondt
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Mohamed-Sami
authors.initials: MS
authors.lastname: Trabelsi
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Tailleux
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France.|INSERM UMR1011, 59000, Lille, France.|Univ Lille 2, 59000, Lille, France.|Institut Pasteur de Lille, 59000, Lille, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Caron
authors.affiliation: European Genomic Institute for Diabetes (EGID), FR 3508, 59000, Lille, France. Bart.Staels@pasteur-lille.fr.|INSERM UMR1011, 59000, Lille, France. Bart.Staels@pasteur-lille.fr.|Univ Lille 2, 59000, Lille, France. Bart.Staels@pasteur-lille.fr.|Institut Pasteur de Lille, 59000, Lille, France. Bart.Staels@pasteur-lille.fr.
authors.forename: Bart
authors.initials: B
authors.lastname: Staels
mesh_terms: D000483:Alleles; D000818:Animals; D005854:Germ Cells; D019426:Integrases / Q000235:genetics*; D007515:Islets of Langerhans / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic
chemical_list: C045073:Cre recombinase; D019426:Integrases
keywords: Genotyping; Germline recombination; Tissue-specific knockout