Unspecific DNA recombination in AdipoqCre-ER(T2) – mediated knockout approaches in transgenic mice is sex-, age- and genotype-dependent

Due to the epidemic rise of obesity prevalence, adipose tissue (AT) research is of major interest. Our aim was to study specificity of the most-common Cre/loxP approach for inducible gene manipulation of AT in mice (AdipoqCre-ER(T2)). We used mice with tamoxifen-sensitive Cre recombinase controlled by the adiponectin promoter (AdipoqCre-ER(T2)), which were crossed to a tdTomato reporter mouse to visualize the site of recombination on a single-cell resolution. Albeit tamoxifen induced tdTomato expression in this model, also non-stimulated background recombination (‘Cre leakage’) was detected in AT of untreated Adipoq-CreER(T2)xTDTO mice in vivo. Quantification of Cre leakage revealed age, sex and genotype as factors impacting on non-induced Cre recombination.