Highly-efficient, fluorescent, locus directed Cre and FlpO deleter mice on a pure C57BL/6N genetic background

In order to facilitate the use of the new mutant resources developed in the mouse, we have generated Cre and FlpO deleter mice on a pure inbred C57BL/6N background. The new transgenic constructs were designed to drive either the Cre or FlpO recombinase, fused to a specific fluorescent marker (respectively the eGFP or the eYFP) and were inserted by homologous recombination in the neutral Rosa26 locus. They allow a rapid, cost-effective and efficient identification of the carrier individuals through the co-expression of the fluorescent marker. The main advantages of these deleters are:

• Preservation of a pure genetic background when used to remove specific selection cassette or to induce complete loss-of-function allele (pure inbred C57BL/6N background)
• Insertion in the Rosa26 locus
• Simplicity of genotype identification (fluorescence evaluation)
• High and stable recombination efficiency (up to 100%)
• Expression of cre and FlpO in developing oocytes irrespectively of the transmission of the Cre and FlpO transgenes