Ectopic germline recombination activity of the widely-used Foxp3-YFP-Cre mouse: a case-report.

Ectopic germline recombination activity of the widely-used Foxp3-YFP-Cre mouse: a case-report. Immunology. 2019 Nov 11;: Authors: Wu D, Huang Q, Orban PC, Levings MK Abstract Regulatory T cell (Treg)-specific deletion of a gene of interest is a procedure widely used to study mechanisms controlling Treg development, homeostasis and function. Accordingly, several transgenic mouse lines have been generated that bear the Cre-recombinase under control of the Foxp3 promoter either as a random transgene insertion or knocked into the endogenous Foxp3 locus, with the Foxp3YFP-Cre strain of mice being one of the most widely used. In an attempt to generate Tregs which lacked expression of the insulin receptor (Insr), we crossed Foxp3YFP-Cre mice to Insrfl/fl mice. Using a conventional two-band PCR genotyping method we found that offspring genotypes did not correspond to the expected mendelian ratios. We thus developed a quantitative PCR-based genotyping method to investigate possible ectopic recombination outside of the Treg lineage. With this method we found that ~50% of the F1-generation mice showed evidence of ectopic recombination and that ~10% of the F2-generation mice had germline Cre recombination activity leading to a high frequency of offspring with global Insr deletion. Use of the quantitative PCR genotyping method enabled accurate selection of mice without ectopic recombination and only the desired Treg-specific Insr deletion. Our da...
Source: Immunology - Category: Allergy & Immunology Authors: Tags: Immunology Source Type: research