Rr27^tm1Pes

Point mutations were introduced into the core sequence of all 4 CTCF binding sites resulting in five G-to-T, two C-to-A, one (G/A)-to-T, and one-(T/C)-to-G conversions at each site. A single loxP site was also present after excision of a floxed neomycin resistance gene cassette. EMSA analysis confirmed that these mutated CTCF binding sites are unable to bind CTCF. (J:91020)